Why not glass?

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Re: Why not glass?

Postby thecroweater » Tue Jun 27, 2017 5:44 pm

Kareltje wrote:
der wo wrote:
pounsfos wrote:Odin is a Pillar in this Hobby and his Istill business is becoming a big Success, I joined this site a year after he did, and have watched him do some crazy experiments and move stillin" "technology" to a whole new level, he hasn't logged on since april, hope he's doin well.

Perhaps this thread is the reason for his abstinence:
viewtopic.php?f=17&t=66074&p=7469054#p7469054

That really is bad news. Not only his departure, but even more the reasons.
Although I would not think much of hate-mail and false accusations, they are a pollution of normal conversation. As if you have to wade through mud before reaching solid ground.

Yep much like this post and above champ. You guys don't give Odin the credit he deserves, who knows why he hasn't posted for a bit its happened before. Perhaps he's busy . One thing I'm pretty sure of is the reason is not because his possibly bias view is different to another possibly bias view. Odin has strong views but he has never come across as childish or fragile, I don't think its fair to insinuate he is in this case :thumbdown:
Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. Benjamin Franklin
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Re: Why not glass?

Postby skow69 » Wed Jun 28, 2017 12:53 am

And, back on topic:

Several of us run borosilicate columns. Like with anything, you need to understand the properties and limitations. But don't underestimate the value of having visual contact with the process.
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Re: Why not glass?

Postby The Baker » Wed Jun 28, 2017 2:32 am

I miss Odin.

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Re: Why not glass?

Postby Kareltje » Wed Jun 28, 2017 3:24 am

thecroweater wrote:One thing I'm pretty sure of is the reason is not because his possibly bias view is different to another possibly bias view. Odin has strong views but he has never come across as childish or fragile, I don't think its fair to insinuate he is in this case :thumbdown:

I really do not insinuate that: he stands his ground firmly!
But speaking for myself: people who send hate mails or attribute false motives I try to avoid! It is not worth the trouble explaining to or interacting with them, I have better things to do.

On topic: the argument that newbies and novices should not be confronted with to difficult things is feeble, imo.
If that is a reason to ban other materials than ss, copper and teflontape, you make your standards fit the most ignorant and dumb person and hinder any development or discussion. We should not lower ourselves to the level of the weakest, we should help raise the weak to the level of the strong.
I would love to have some glass parts in my still, to see what is going on.
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Re: Why not glass?

Postby spencoid » Sun Jul 02, 2017 8:40 am

I just made a still largely out of glass. There were a few reasons for choosing glass. It is nice to see what is going on inside the column. Glass is a pretty decent insulator so there is less heat loss. Glass is pretty easy to cut and does not need to be soldered making it easier to change your mind about things. I have taken my still apart several times changing things around in an attempt (not successful yet) to make the perfect gin. I just need to loosen the all-thread rods to pull it all apart.
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Re: Why not glass?

Postby miket » Sun Jul 23, 2017 4:19 pm

I am glad this topic is not locked.

I am a glass blower with skills to weld glass,some very expensive torches. a computerized kiln for proper annealing and also work primarily with scientific glass , 33coe borosilicate.

My recommendation is HELL NO! A tiny scratch turns to a crack, turns into 2 pieces of glass and its game over. I cut glass by putting a tiny scratch on it, and using heat separate it neatly. it is all to easy to break glass even the good stuff like borosilicate.

The big boys who are beyond the hobby level can do what they want with glass columns but beyond the collection jars of finished product id leave glass out of the equation.

A borosilicate glass parrot might be an acceptably use of glass, probably something I could make in 20-30 minutes. Even make it with some serious artwork style and have people asking "What the hell is that?" LOL :D

Anyway Id stick to jars for storage of product and drinking from glass.. :)
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Re: Why not glass?

Postby spencoid » Sun Jul 23, 2017 5:09 pm

i replaced the gold fluro part with a white teflon piece. the still worked fine but for some reason i decided to replace the teflon with stainless steel. it took a day to machine and i must have made it fit too tight because after a very short while the top piece of glass broke into three pieces. i did not actually see the break and was wondering why i could not get over 70 proof alcohol.

i had used non Chinese annealed glass and never had problem until i made the stainless part. i have a hole drilled in the main column for a "gin back" and the drilling is not perfect. there are minor chips here and there but none of this has caused cracking. just the stainless part that was probably a too tight fit. i have put the teflon part back in and made a bunch of improvements. it might have actually been the condenser hitting the glass combined with the stainless steel part not allowing for movement when it heats up that caused the cracking.

so, yes, glass can be a problem but i still like it. it is really important to be sure that parts are free to move when heated.
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Re: Why not glass?

Postby still_stirrin » Tue Jul 25, 2017 7:47 am

spencoid wrote:...just the stainless part that was probably a too tight fit...it might have actually been the condenser hitting the glass combined with the stainless steel part not allowing for movement when it heats up that caused the cracking.

Here's a thought...different rates of thermal expansion....between the glass and steel. In fact, any metal will be significantly different than the glass, hence the requirement for a "seal". And soft seals are the most tolerant to the two opposing materials, allowing relative movement as the parts expand under heating conditions.

In your case, the steel "gasket" expanded exerting force on the glass, which eventually fractured. Not a wise design at all. I think it has been suggested before to wrap the end of the glass cylinder with teflon tape and then assemble the column. Sometimes education only results from failure, but hopefully not injury.
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Re: Why not glass?

Postby spencoid » Tue Jul 25, 2017 8:22 am

the joints between steel and glass were all using teflon tape wrapped EPDM O-rings i tried for a loose fit between the glass and the steel and it is in fact very forgiving of expansion. however the condenser coil was pretty close to the glass and i thing what probably happened is that it expanded and together with confinement from various lines going through the condenser, cause the stress on the glass.

i have completely redesigned the condenser. i had lines going through it to the reflux condenser because i did not want to make more hoes in the glass. i also had a tube going through to allow the head temp sensor to pass through. both of these have been eliminated. i made a copper plate for the reflux condenser lines to pass through. used my last piece of 1/4" copper plate. i have pretty much determined that the best place for the head sensor is right below the condenser bottom so i do not need the other tube either. so now i have a lot of clear space for the condenser which i also completely redesigned. it is now a cylinder of copper made of concentric 1 and 2 inch tubes. used up the last of my 2" copper rod for this. will test it soon.

this project is great, i am using up all the strange materials i have been saving for many years. will save my asbestos and mercury for other projects, though :)
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Re: Why not glass?

Postby skow69 » Wed Jul 26, 2017 4:17 am

-How 'bout some current pics? I'm having a hard time trying to conceptualize what is going on there.

the joints between steel and glass were all using teflon tape wrapped EPDM O-rings
Keep in mind that EPDM will not compress. It will deflect, but not compress.

i have completely redesigned the condenser. i had lines going through it to the reflux condenser because i did not want to make more hoes in the glass.

How were you making holes? With a drill? Through borosilicate tube? That sounds like a process fraught with peril. Did you rearrange things to eliminate them all? My basic design philosophy calls for no holes in glass tubing, unless you can blow them.
Last edited by skow69 on Wed Jul 26, 2017 4:51 am, edited 1 time in total.
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Re: Why not glass?

Postby skow69 » Wed Jul 26, 2017 4:36 am

still_stirrin wrote:
spencoid wrote:...just the stainless part that was probably a too tight fit...it might have actually been the condenser hitting the glass combined with the stainless steel part not allowing for movement when it heats up that caused the cracking.

Here's a thought...different rates of thermal expansion....between the glass and steel. In fact, any metal will be significantly different than the glass, hence the requirement for a "seal". And soft seals are the most tolerant to the two opposing materials, allowing relative movement as the parts expand under heating conditions.

In your case, the steel "gasket" expanded exerting force on the glass, which eventually fractured. Not a wise design at all. I think it has been suggested before to wrap the end of the glass cylinder with teflon tape and then assemble the column. Sometimes education only results from failure, but hopefully not injury.
ss


SS, ever hear of a housekeeper joint? Check this out.



I'd like to try it sometime, but I have a feeling there might be a learning curve, like a guy better practice a few times before you bet your life on the seal.
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Re: Why not glass?

Postby miket » Wed Jul 26, 2017 8:29 am

skow69 wrote:
still_stirrin wrote:
spencoid wrote:...just the stainless part that was probably a too tight fit...it might have actually been the condenser hitting the glass combined with the stainless steel part not allowing for movement when it heats up that caused the cracking.

Here's a thought...different rates of thermal expansion....between the glass and steel. In fact, any metal will be significantly different than the glass, hence the requirement for a "seal". And soft seals are the most tolerant to the two opposing materials, allowing relative movement as the parts expand under heating conditions.

In your case, the steel "gasket" expanded exerting force on the glass, which eventually fractured. Not a wise design at all. I think it has been suggested before to wrap the end of the glass cylinder with teflon tape and then assemble the column. Sometimes education only results from failure, but hopefully not injury.
ss


SS, ever hear of a housekeeper joint? Check this out.



I'd like to try it sometime, but I have a feeling there might be a learning curve, like a guy better practice a few times before you bet your life on the seal.


Wow , id have never believed it could work. Looks like as the glass cools you end up with a nice shrink fit. The fuel rich flame is called an annealing flame and is one of the tricks glass blowers use to get away with things when they cant use a kiln, such as a large piece of lab equipment thats too large to place in a kiln.
That guy also knew how much to heat the copper so as they cool they play nice together and the coefficient of expansion balances out nicely.

Anyone who works glass knows the dreaded "TINK" sound, all it means is you get to do it again. :D
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Re: Why not glass?

Postby spencoid » Wed Jul 26, 2017 9:01 am

still-new-pic-small.jpg
i have just one large hole drilled in the large glass tube to allow placement of the gin aromatics. i do want to eliminate this is a future design but it seems to not be a problem so far. i drilled the hole with a cheap Chinese diamond hole saw. a few chips but no cracks and i have run the still several times and have forced junk through the hole and hit the edges with tools at least a few times. when i bought the tubing it was suggested that i get the annealed type made in Romania, i think, not the Chinese not annealed stuff. it is supposed to be OK to saw grind etc since there are no stresses in the annealed glass. so far so good. the broken part was probably caused by expansion of touching parts and occurred on a straight section of glass that had only been cut off, not drilled.

i do not have the new condenser installed yet. i will take pictures after i install it. i am still thinking about how i am going to vent the vapors so they go through and around it. i am going to try to post a more recent picture that shows the copper plate that allows the reflux condenser tube to pass through the glass. i do want to eliminate the hole for the gin stuff but i have not figured out the best way to make an inline "gin back" yet. it needs to have a vapor tight access hole. not sure if i want to make this threaded or some sort og compression seal. the sliding stainless clamp thing i have no works very well against the glass. maybe i just need to do the same with large diameter copper or stainless steel tube. the top of the still is getting a little heavy with the new condenser so i do not want to add much more weight.

the video on the housekeeper joint is interesting but i don't want to try it on a 75 mm tube that is 3 feet long. i think it really should be annealed in a furnace after the joint is made and i do not have a furnace big enough. just covering with insulation and slow cooling does not seem like a reliable was to anneal the glass.

the new picture is not great but you can see the little copper plate that is between the top most piece of glass and the lower one. it is just 1/4" thick so a little hard to see. once i change the condenser i will take better pictures.
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Re: Why not glass?

Postby skow69 » Wed Jul 26, 2017 10:07 pm

miket wrote:Anyone who works glass knows the dreaded "TINK" sound,


Hahahahahahaha. Yeah, no shit. I have learned that the standard little "TINK" is god's way of telling me I got in too big a hurry with something. When that piece of Chinese 2" self destructed there was a"TINK" that knocked me off my chair.



Spen, that is pretty nice work, but I am still confused.

What kind of still is it? I haven't found a takeoff point.

That looks like a double wound coil at the top, but then there is a small coil of 1/4" below it. What is that for?

Is that your botanicals bag between the coils? So you have to undo the threaded rods to get to it? Have you considered putting the bots in the boiler?

That stainless steel most-of-a-cylinder with the wing nut clamps--what does it do? This may be a stupid question, but, is it inside or outside the glass?

I'm not being critical, just trying to understand. I love unique and novel designs. Both of mine are one-offs. Darwin taught us that you can't have evolution without some random mutations along the way.
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Re: Why not glass?

Postby spencoid » Thu Jul 27, 2017 10:43 am

i hope to find time to assemble the still with the new condenser. i will then take a bunch of decent pictures. here is a description as to how it works which should answer all your questions about what the parts are. it is a fractional reflux still with a condenser on top as opposed to off to the side. i built it this way so all the joints could be held in compression with a set of four stainless steel all thread rods. there are also stainless steel aircraft cables from the top plate to the boiler to hold to prevent flexing of the column with respect to the base. the top glass tube houses only the main condenser. below that is a teflon piece that connects the top and bottom tubes with a copper plate between the teflon and the lower tube. this was added recently and the purpose is to allow the 1/8" tubes to the reflux condenser to enter the column without drilling holes in the glass. this condenser, together with the copper plate are responsible for reflux.

the condensers are cooled by recirculating water that passes through a large copper coil which is cooled with a fan. some day i will find a big fan cooled heat exchanger at a junk yard or ??? and will substitute that. pretty much everything i build is made largely with stuff i have collected over many years.

to cooling water to the main condenser is constant (except during preheat mode when the pump and cooling fan are switched off. the reflux condenser has a needle valve to control the flow and also a solenoid valve controlled by the microcontroller. the display panel has 5 different pages to allow for setting various options which are maintained in non volatile memory so the machine boots at the same state as the last run. under user control are the following: duty cycle of the heater from 0 to 100% the heater is a 5000 watt 220 volt water heater immersion type. there is a sight "glass" tube to indicate the level in the boiler to prevent running with the heater exposed which would destroy it quickly. the reference temp which tells the controler to turn the heater off is in the bottom of the main condenser where it monitors the vapor just before entering the condenser. i think this is the right place to measure? the duty cycle of the reflux condenser is settable by the user but eventually when i find the right settings, this and other settings will be controlled by the controller for different processes such as boiling off the heads and then stopping.

currently there are just two modes, distilling and preheating. preheating is so i can walk away and not have to watch while it comes up to temperature. there are several safety features so it should be safe to leave it in preheat mode, at least. several safety feaatures when running too but when the top piece of glass broke there was nothing that shut it down automatically. i need to think of something to sense that type of failure. it may be possible to determine this sort of failure using the currently implemented sensors but i might need to add something else. the still will shut down (requiring a reboot) if the condenser cooling water exceeds a set threshold. it will also shut down if the cooling water stops flowing. this is measured with a turbine wheel and a hall effect sensor and magnet. the flow sensor is at the outlet of the condenser so the combination of temperature and flow sensing should be all that is needed to protect against and cooling failure.

the bottom glass tube has a hole drilled in it near the top. this is where the gin aromatics are placed in little tea bags. i am still experimenting with different ways to encourage the vapor to pass through the bags of aromatics. the large teflon piece has a cone shaped bottom to encourage condensate below the top condenser to run down the column without wetting the gin aromatics. the hole is covered with a sleeve of thin stainless steel. wing nuts hold it tightly in place to prevent leakage. this is the large piece of stainless that was asked about. i sort of think that the best place for the gin bots is in the vapor stream just before the main condenser but i am only guessing on this. i can not find much detailed information online about gin backs and how they work.

the distillate is taken off from the teflon piece that fits between the two glass sections. a stainless steel pipe carries the distillate down to the collection jar.

should be able to assemble the new condenser and take pics later tonight.
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Re: Why not glass?

Postby spencoid » Thu Jul 27, 2017 10:56 am

one other thing. the "tink" the people that supply the glass i bought said that the Chinese stuff is not annealed. this is fine if you are going to hot work it and then anneal it when finished. i have a small kiln that is not big enough for the large tube that has a hole in it. just cutting non annealed glass can introduce unbalanced stresses. so i bought the more expensive (still pretty cheap) Romanian stuff that is supposed to be fully annealed. it can be cut and drilled without introducing uneven stress because all the stress is supposedly relieved. i have even dropped pieces of this stuff without breaking. i would like to eventually build some sort of gin back that does not require a large hole to be drilled. i am very slowly learning how to weld so if i either get good enough or figure out a way to make a gin back that does not have vastly different thicknesses of metal parts i might be able to TIG weld it vapor tight. will probably not be anything i would be proud to show to others. i could also make the gin back out of copper which would be easier especially since i have been working with copper for many years. i have a full set of rotary sheet metal machines (beading, burring etc etc), a circle shear, corner notcher, bar folder and a nice set of pexto bench stakes. i actually know how to use these tools so if i can come up with a design made of sheet copper, i should be able to make it without having to become an expert TIG welder.

i also have a few pounds of 99.9% tin (from dental tin foil) that i could cast into useful shapes if needed. tin melts at a very low temperature and is very easy to cast. i also have a 3D printer that could be used to make a pattern for the casting. i have never done this but supposedly you can use plastic parts just like wax pieces in making investment molds. burning out the plastic will be the worst part.
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Re: Why not glass?

Postby skow69 » Thu Jul 27, 2017 11:45 am

So I'm guessing you have never met Bokakob.

Got a dr. appt. More later.
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Re: Why not glass?

Postby spencoid » Thu Jul 27, 2017 2:42 pm

have not met Bokabob. is he a gin guy? here are pictures of the new arrangement. one shows the hole in the large lower pyrex tube. this is where the gin stuff goes in. the stainless steel sleeve covers the hole when the still is on. you can see the copper plate through which the tubes to the reflux condenser pass. this was to avoid drilling the glass even more. you can see the refluz coil right below the gin hole. having it on the plate makes it easier to modify it. i keep making it smaller as i find that i have to turn the needle valve to almost closed to not get total reflux. might make it even smaller, especially since the copper plate condenses some too.

the other picture is of the new condenser which is a concentric thing. i hope i have the teflon tube feeding it made right so the vapor goes up and the condensate goes down outside the tube and not into it. i can make different feed tubes to change the ratio of vapor that goes inside the condenser and outside it. the cooling water goes in and out the top but there is a dip tube on the infeed so the cool water goes to the bottom. not sure if this is the right way but it is easy to switch. not sure why the pictures came out so crappy. they were not bad before i rescaled them.
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Re: Why not glass?

Postby skow69 » Fri Jul 28, 2017 12:32 am

OK. So I will assume there is a dam or weir in there to direct condensate to the product takeoff tube. Otherwise it would mostly just drop straight down. I will further assume that there is a needle valve or something similar on the collection tube so you can control the reflux ratio. That makes this a liquid management or LM type still. (Bokakob was a well known designer and promoter of LMs.)

I believe your "lower condenser" is superfluous. The "main condenser" has to be capable of knocking down all of the vapor the boiler can send it, right? Otherwise you'd have precious ethanol vapor escaping out the top. This condensate then falls to the weir where some is taken off as product. The rest overflows the weir and gets returned to the top of the packing as reflux. The relative quantities of product and reflux are controlled by adjusting the needle valve on the takeoff tube. So what is gained by having the lower condenser?
Last edited by skow69 on Fri Jul 28, 2017 2:01 am, edited 1 time in total.
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Re: Why not glass?

Postby skow69 » Fri Jul 28, 2017 1:12 am

Nice job drilling that hole in the tubing. You are probably right that it will never cause a problem, but nonetheless, if it was me, I would make a point of inspecting that area before every run. Actually, I would inspect the whole thing, but especially that. I check mine for star cracks all the time, figuring that's probably how most problems begin. There is a story about the founder of Rolls-Royce who refused to stamp serial numbers into the frame because, "That would be a sure way to start a crack." One thing is for sure. If that column ever does develop a crack, you can bet it will start at that hole.
[End rant, put away soapbox.]

So you have got your botanicals located where they get infused into the rising vapor and also soaked by the reflux, right? That is a little unusual, I think, but that is part of the fun of making gin, There are so many variations of the process to explore. Are you chasing a particular flavor profile with that? I would think that would make a pretty strong, bold kind of gin. Have you tried using the LM just to make a clean neutral base spirit, and then using a potstill for the actual gin production?
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Re: Why not glass?

Postby skow69 » Fri Jul 28, 2017 1:52 am

spen wrote:i can not find much detailed information online about gin backs and how they work.


Are you familiar with the Carter Head?

Thumpers are used in every way imaginable for gin. I like to put the macerate and botanicals in the thumper and water in the pot. Makes for a sort of a steam distillation.

Lots of people just macerate in the boiler and let her rip. Others don't macerate at all. On the fringe there are those who distill all of their components separately and then blend up their gin bottle by bottle. They say they get better control of the product I think. Kinda sounds like Frankengin to me. But what do I know? Maybe Frankengin is delicious.

There's a bunch more ideas here.

Seems to me there is almost no wrong way to make gin. And if you don't like any of the techniques you read about, you can just make up your own. Who's to say yours isn't the best?
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Re: Why not glass?

Postby spencoid » Fri Jul 28, 2017 9:27 am

i googled Carter head and it looks like that is what i need and almost what i am doing although my still is a little less than 700 gallons, imperial or otherwise.

most of what i read suggested that vapor infusion is the best way to add gin flavors. the thumper would have the botanicals sit in liquid but it would be more like re-distilling not steeping so maybe that would be good. i could make an inline thumper that sit in between the main tube and the condenser but it seems like more work than the Carter head. still have the problem of accessing for filling and unloading. i have been thinking about how to do this without buying expensive stainless tube that i would have to weld and possibly destroy.

i have spent a lot of time fiddling with the design of the current "gin back" to prevent the botanicals from being saturated by distillate falling back down. i am going to do a test run today to see if it does this. it sort of worked pretty well with the previous design using the coiled tube condenser but the new design should be better for the following reasons. 1 there are no lines running between the condenser and the reflux coil since i now have a separate plate for those tubes and it is below the main condenser completely. also i had a sensor cable running through the main condenser so i could experiment with placement. since i am pretty sure that the heater should be controlled with reference to the temperature of the vapor just as it enters the condenser, i can eliminate this extr tube running through the condenser. the sensor lead is a fairly thin teflon tube so it does not condense much vapor itself, just adds a little to the reflux. the big teflon thing between the bottom tube and the condenser was carefully shaped to allow vapor to pass up through the center and any condensate to pass along the outside. it is funnel shaped where you can't see it (inside bottom) the tube that feeds it (first time trying this) is smaller in diameter than the center tube of the condenser and has a conical top. this should pass vapor into the condenser center which will then flow down and spill over the feed tube and not reflux. the holes in the feed tube are beveled so as to send condensate outside the tube instead of through the holes and back to the column. the new condenser is screwed to the top plate so it stays centered and the gap between the feed tube and condenser should be maintained. if it tends to creep i will make a tube with little bumps on it to keep it centered. this is not an easy thing to do with teflon so i would probably have to try another material, probably copper.

in my last design the gin botanicals did not get soaked as they had before and i think i got a stronger gin flavor. with the new design i hope they do not get wet at all and are constantly bathed with vapor. i am currently using empty tea bags to contain the bots but think it might be better if i make a basket of stainless mesh. if the next test shows that the bots will in fact not get wet (i did test the feed tube theory by running water over it and it does what i wanted but things could change once the vapor is flowing through it, but hopefully for the better) will be more encouraged to work on a better basket.

i do want to make a really good separate gin insert but don't want to spend a lot of time and money making something that is theoretically doomed from the start. that is why i am doing a lot of fiddling and asking before i do make one.

one of the main reasons for making the glass column design is that i can add and subtract components without soldering and or using expensive tri clover joints which also dissipate a lot of heat.

so if anyone has any ideas about how to make a gin back that would be better than my latest attempt, i am all ears. but who knows the new design might be good enough at least for a while. i have a bunch of materials to work with and can buy anything online if i am sure it is what i need. i live far from town and what is available is limited. very often i solve a problem with stuff i have on hand before the expensive stuff i ordered arrives :)

i have the following tools and materials available with which to make new parts. unfortunately i am a pretty bad TIG welder but this has improved considerably since i bought a better (not from Harbor Freight) autodarkening helmet with built in magnification. being able to see what i am welding really helps but i need a lot of practice before i can do difficult welds such as between thin and thick material. this might be my chance to become a better welder. i have a bunch of teflon sheet 1/4" and thinner but have exhausted my supply of 1" stuff and also of 3 plus inch rod but can buy that online for an almost reasonable price of about $100 a foot. i have tons of sheet copper but very little plate left. tubes of all sizes up to 2" but unfortunately no 3" stainless steel from shim stock to 12 gauge. lots of 1" teflon rod and smaller diameters as well. a few pounds of pure tin i have the following tools: decent jet lathe, very nice "mini bridgeport" manual mill, CNC mill, CNC router, 3D printer, TIG welder MIG welder, gas welding torches, small ceramic kiln (about one half cubic foot) centrifugal casting machine that i never used (might be good for casting tin) all sorts of sheet metal tools including slip roller/brake (light gauge metal only) rotary forming machines, bar folder, full set of bench stakes, shears of all kinds.

if i know i have a design that will work i can have excellent welding done by a professional but not until the winter. there are good welders here but distance and scheduling makes it difficult. basically a two week turnaround to get something done and it might not be right and have to be re-done. when in winter quarters there is a local welder who will weld while you wait if it is a small job. he welded the nuts to the keg i am using for a boiler and did a terrific job.
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Re: Why not glass?

Postby spencoid » Fri Jul 28, 2017 9:45 am

i had missed the posting from skow69 before writing my last long letter.

in my last still i first used a needle valve to proportion the reflux. i tried all sorts of ideas based on what i found online but i never could get it to be reliable. the low pressure on the liquid and surface tension or whatever, in the needle valve seemed to make it very difficult to control. so i added the reflux condenser below the main one and control the cooling water to it to adjust the reflux ratio. it is much easier to accurately regulate higher pressure water than very low pressure distillate. i have a needle valve on the reflux condenser and also a solenoid valve that pulses on and off under microcontroller control. once i set the needle valve correctly i can vary the reflux accurately over a wide range with the solenoid valve. living in a remote rural location in California, i do not have the luxury of cheap water to waste. when i have water i have tones of it but in the summer i have to watch every gallon. that is why i have an air cooled radiator system for the still. because of this, the cooling water temp varies some. that might be bad and maybe i need to increase the radiator size. anyway, among other things, the computer controlled reflux rate can be adjusted in response to all sorts of measurements and differently for different processes. ideally once i figure out the right values for temperature etc, i can have the controller adjust the reflux ratio appropriately instead of having to constantly watch and make adjustments. i can make a variety of different "processes" which can be run automatically. now i have just three. one is to run the still with the saved parameters and no ability to change them, another that allows changing parameters while running and one that just preheats the boiler and maintains a set temperature. it defaults to 70% of the distillation temperature but measured at the pot so it can maintain a temperature lower than the set distillation temp.
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Re: Why not glass?

Postby skow69 » Sat Jul 29, 2017 1:00 am

spen wrote:i have spent a lot of time fiddling with the design of the current "gin back" to prevent the botanicals from being saturated by distillate falling back down. i am going to do a test run today to see if it does this. it sort of worked pretty well with the previous design using the coiled tube condenser but the new design should be better for the following reasons. 1 there are no lines running between the condenser and the reflux coil since i now have a separate plate for those tubes and it is below the main condenser completely. also i had a sensor cable running through the main condenser so i could experiment with placement. since i am pretty sure that the heater should be controlled with reference to the temperature of the vapor just as it enters the condenser, i can eliminate this extr tube running through the condenser. the sensor lead is a fairly thin teflon tube so it does not condense much vapor itself, just adds a little to the reflux. the big teflon thing between the bottom tube and the condenser was carefully shaped to allow vapor to pass up through the center and any condensate to pass along the outside. it is funnel shaped where you can't see it (inside bottom) the tube that feeds it (first time trying this) is smaller in diameter than the center tube of the condenser and has a conical top. this should pass vapor into the condenser center which will then flow down and spill over the feed tube and not reflux. the holes in the feed tube are beveled so as to send condensate outside the tube instead of through the holes and back to the column. the new condenser is screwed to the top plate so it stays centered and the gap between the feed tube and condenser should be maintained. if it tends to creep i will make a tube with little bumps on it to keep it centered. this is not an easy thing to do with teflon so i would probably have to try another material, probably copper.


Sorry, man, but I need visual aids. Could you draw a picture/schematic diagram?
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Re: Why not glass?

Postby spencoid » Sat Jul 29, 2017 7:38 am

if you go back a couple of posts in this thread there is one with two pictures of the top of my still. i did test the new configuration and it worked pretty well but i modified it again. reduced the size of the reflux condenser and also changed the feed tube to the main condenser. the goal is to allow vapor to go through the aromatics and not have condensate wet them. will see later today if the new feed pipe works better.

it looks like i get a lot of condensation from the funnel shaped bottom of the large teflon piece that is above the main column. it must be because the condensate cools this part and turns it into another condenser. i think i need to find a way to prevent this so the reflux condenser is more controllable.
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Re: Why not glass?

Postby skow69 » Sun Jul 30, 2017 2:32 pm

spencoid wrote: i added the reflux condenser below the main one and control the cooling water to it to adjust the reflux ratio.


So that would make it analogous to an RLM. I would suggest that, for this to work, your reflux condenser must be capable of achieving 100% reflux.


spencoid wrote:it looks like i get a lot of condensation from the funnel shaped bottom of the large teflon piece that is above the main column. it must be because the condensate cools this part and turns it into another condenser. i think i need to find a way to prevent this so the reflux condenser is more controllable.


What makes you think that this liquid results from vapor condensing on the teflon piece rather than vapor condensing on the main condenser and dripping down through or past the teflon piece?

If I understand correctly, the reflux condenser is intended to prevent vapor from rising to the level of the botanicals. It appears from the top photo that it is far too small to accomplish this at any reasonable amount of heat input, and you are making it smaller? Is it possible to get 100% reflux from it? Also how would stopping the teflon piece from condensing make it more controllable? What is your collection rate? How do you control the heat input?
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Re: Why not glass?

Postby skow69 » Sun Jul 30, 2017 2:45 pm

Not trying to be a smartass, just hoping to avoid unnecessary confusion.

spencoid wrote: it looks like i get a lot of condensation from the funnel shaped bottom of the large teflon piece that is above the main column. it must be because the condensate cools this part and turns it into another condenser.


Actually, that is impossible. The laws of thermodynamics simply will not allow it. You can't fight the math. I don't have the numbers on top of my head, but I will walk you through it if you like. :)
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Re: Why not glass?

Postby spencoid » Sun Jul 30, 2017 3:13 pm

What makes you think that this liquid results from vapor condensing on the teflon piece rather than vapor condensing on the main condenser and dripping down through or past the teflon piece?

the feed tube has a cone shaped top that overextends the holes in the side that allow vapor to pass through. there is a small hole in the top, inside the main condenser for the temp sensor wire to pass. a very small amount of condensate might run down this wire through the hole but the vast majority of the condensate dripping off the main condenser goes out through the collection tube. very little, if any drips through the feed tube at least as far as i can see while watching it very carefully. i tested this before putting the thing together and it seemed to work. with the vapor passing through the side holes of the feed tube, i think there would be even less chance of condensate sneaking through these holes.

Actually, that is impossible. The laws of thermodynamics simply will not allow it. You can't fight the math. I don't have the numbers on top of my head, but I will walk you through it if you like.

If I understand correctly, the reflux condenser is intended to prevent vapor from rising to the level of the botanicals. It appears from the top photo that it is far too small to accomplish this at any reasonable amount of heat input, and you are making it smaller? Is it possible to get 100% reflux from it? Also how would stopping the teflon piece from condensing make it more controllable? What is your collection rate? How do you control the heat input?

the reflux condenser is only to control the reflux rate. there is no intention to prevent vapor from getting to the bots. in fact it is vapor i want to pass through them. if it is preventing vapor from passing through the bots, i need to make yet another modification so this does not happen. maybe sticking the bots up higher, right below the funnel will do it especially if i can stop all that condensate from forming on the funnel.

the condensate from the main condenser falls on the teflon piece and since it has already been cooled by the main condenser, it is pretty cool. it is my thought that this acts like another condenser to condense vapor lower down. i plan to make a little tilted shelf and bevel the exit hole in the teflon piece so the distillate runs out instead of sitting on the teflon absorbing heat. i think that the bottom of the main condenser also might be of thick enough copper that i can bevel it and maybe add a little trough that will collect it that way instead of having to make a tight fitting shelf on the vapor tube. i can get 100% reflux at about 1500 watts or so. i did just make the reflux condenser smaller and that might not be possible now especially if i do get the distillate from sitting on the teflon piece. collection rate when making strong alcohol, over 140 proof is not real fast, have not measured it but can next run. takes over an hour for a quart depending on the heating rate and the reflux rate and the amount of alcohol left in the mash. heating rate is controlled by slowly pulse width modulating the heater. the microcontroller controls a solid state relay. the pulse width is adjusted in 1/10 second intervals. this resolution was chosen to meet the requirement of not exceeding the line frequency and also not switching the SSR too much which is supposed to cause overheating. it is a 100 amp SSR on a heat sink and the heater is just 5000 watts
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Re: Why not glass?

Postby skow69 » Wed Aug 02, 2017 1:06 am

spen wrote:the reflux condenser is only to control the reflux rate. there is no intention to prevent vapor from getting to the bots. in fact it is vapor i want to pass through them. if it is preventing vapor from passing through the bots, i need to make yet another modification so this does not happen. maybe sticking the bots up higher, right below the funnel will do it especially if i can stop all that condensate from forming on the funnel.


I understand what you are trying to do. But how does the reflux condenser control the reflux "rate?" It does it by stopping the rising vapor from reaching the botanicals, and returning it to the packing as reflux, right?. ( I am assuming that the bots reside directly above the reflux condenser, but I have no confirmation of that.) I suspect that any vapor which makes it past the RC will indeed pass through the bots, so I don't think you need any more modifications on that score. My point was that the lower coil (which looks like 1/4" tubing, but I think you said it was 1/8") appears to be too small to function as a reflux condenser, although all I have to judge it by is a partial view in your photo posted july 2.. An RC that is not capable of knocking down all of the vapor the pot produces is (normally) considered to be insufficient.



Engineering toolbox/Thermodynamics wrote:The Zeroth law of Temperature states that
"Heat flows from one source to an other only if there is a temperature difference between the two.
Two systems are in thermal equilibrium if they are at same temperature."


So the teflon piece will probably condense a little at first (a phenomenon also known as passive reflux), but as soon as the system gets up to operating temperature, it will reach equilibrium with the vapor it is in contact with. The reason condensers don't achieve equilibrium is because they act as a heat sink and continuously wick the heat away in the cooling water. Your teflon piece can't do this, so its temperature rises to equilibrium with the vapor.

All of the vapor in your system will be at the temperature of boiling, or within a degree or two in special circumstances. The latent heat of vaporization for ethanol is 846 kJ/kg (2257 kJ/kg for water.) This is the energy that it gives up to make the phase change back to liquid. The specific heat capacity if ethanol is 2.7 kJ/kg. (4.4 kJ/kg for water.) This is the amount of energy required raise the temperature 1oC.

Now suppose that the condensate from your main coil lands on your teflon thing at 2oC below boiling. Suppose also that it can absorb the maximum amount of energy from the teflon before exiting the system. Then if you collect 1 liter (0.79kg) of product, the condensate could possibly suck a maximum of 4.3kJ of heat out of the teflon. [0.79kg * 2oC * 2.7kJ/kg].

We expect the rising vapor to donate whatever energy is necessary to maintain equilibrium, so it kicks down 4.3 kJ to replace what the condensate stole, and. having given up that amount of heat, some of the vapor will now change phase to liquid. Referring to the heat of vaporization, we find that 4.3 kJ will result in the condensation of 5 grams (6.3 ml or 1.25 tsp) of the rising vapor. Your description sounded like you were getting a lot more than that dripping off the teflon. In conclusion, I think you need to keep looking for the source of that condensate.

Look, spen, you are obviously a sharp and creative guy, and I encourage you to keep experimenting. That is the only way we make progress. But I think you have fallen into that trap where we bend our observations until they support (sort of) some preconceived notion that we don't want to give up. It's easy to get wrapped up in some theory that you really like, to the point of disbelieving or completely ignoring evidence to the contrary. It's happened to all of us, including the smartest people on earth prior to Copernicus. They loved being the center of the universe so much that would invent epicycles within epicycles within epicycles to explain the wandering planets, rather than accept the much simpler sun-centric explanation. Of course we now understand that the only way to find a meaningful explanation for natural processes is to look at the data with an open mind and go where it leads you.

You just can't fight the math, man.

Cheers.
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Re: Why not glass?

Postby spencoid » Wed Aug 02, 2017 9:56 am

i made a new piece to intercept the distillate and run it out the condenser area more directly. i will try to test it tomorrow or the next day. my mash is almost ready.

it is entirely possible that i am "seeing" what matches my theory but i really try to avoid this. my theory is based on observation and experimentation. i have been trying to change single parameters one at a time to see if a change is effected.

i think you missed part of my explanation. thee big teflon piece certainly would reach equilibrium and only work as a condenser if it was dissipating heat somewhere. my point is that it is. the distillate from the top condenser is cooled to something close to the cooling water temperature. it then falls on the top of the big teflon piece and slowly dribbles out the collection tube. this is where i think that cooling is occurring. so the teflon piece is continually cooled and does act as another condenser between the reflux condenser and the main condenser. it is difficult to really know because i did not take temperatures of the distillate before i changed the big teflon piece but i am pretty sure it was cooler when i had just a flat plate of rulon J. the distillate does seem warmer now as evidenced by the smell and the fact that it seems i need to cool it longer in order to check density. for a brief period i had a huge stainless steel piece between the glass column pieces and the reflux was extreme, i could barely get anything but reflux. i think this huge thermal mass was radiating heat out the side to the air and was also being cooled by the distillate. when i wrapped this stainless steel piece with insulating foam, i think the reflux decreased but i did not measure anything to determine this, just observation.

the new piece is a shelf that collects all the distillate and hopefully will run it out without cooling the teflon piece. if this works i will probably have to increase the size of the reflux condenser back to what it was before :) at least the modular design of this thing lets me do that without much effort. unfortunately the picture is not great but i think it is good enough to see the new piece.

about the possibility that the flow i am seeing is actually from the top condenser running down the vapor feed tube through the teflon piece ... that was my first thought and i made several attempts to prevent this. the feed tube has a cone shaped top and a "drip edge" cut into the bottom so it should shed anything dripping on it around the tube and not allow it to run back through. i tested this tube outside of the still with water running over it and it seemed to do the job. my latest untested modification has an even bigger cone top that extends out farther and has a very deeply cut groove in it to make a drip edge. i also made the feed tube out of copper so it can have a thinner wall and larger ID. also used the very last of my 1/2" teflon plate to make the cone top larger than it was in the last version. i hope that this works even better and that i will be able to see this working. that is one of the benefits of the glass design.
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