I'm looking around online for ball valves to make keg draining easier. My search criteria so far has required stainless fittings and PTFE seats, but I have two questions.
1) Is RPTFE acceptable? I know it stands for reinforced but not sure with what (saw somewhere it was fiberglass reinforced )
2) I've found a few SS valves with PTFE seats BUT the "o-ring" is made of Buna (NBA, ABR, Nitrile). I know this material is unacceptable but wasn't sure about ball valve construction . The o-ring seats the valve stem but does it come into contact with the fluid or does it stay of the way?
Not fiberglass but glass fiber. So I would consider it safe.
Do you have links to the valves?
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure.- Rosa Luxemburg
der wo wrote:Not fiberglass but glass fiber. So I would consider it safe.
+1.
RPTFE -> "reinforced" poly-tetra-floro-ethylene...some would say, "reinforced Teflon", because "Teflon" is a DuPont trade name but widely synonymous with PTFE (generic).
gflower1 wrote:The Buna O-Ring still makes me a little leary so I'll stay away...
Wise decision...Buna-N is a rubber. It most certainly would leach crap into your distillate. It's used in oil patch service with high temperature environments. Just not what you need, or want.
ss
These guys https://www.amazon.com/033-O-Ring-Durom ... tfe+o+ring have ptfe o-rings in every size there is, and the prices aren't devastating. I got a 6-bottle bar caddie dispenser a while back. 2 of them leaked. I opened one up and found squishy silicone o-rings. $5.86 got me 10 ptfe o-rings to replace them. I figure I can buy whatever part I like and replace o-rings as necessary. You can go crazy looking for valves with all ptfe seals.
Distilling at 110f and 75 torr.
I'm not an absinthe snob, I'm The Absinthe Nazi. "NO ABSINTHE FOR YOU!"
I bought these o-rings on ebay to replace the sanitary gasket where my column attaches to my keg. The sanitary gaskets were just too thick and always gave me a hard time connecting. Could never get the clamp on straight either. These o-ring work like a dream and the price was very reasonable.
I thought silicone would be ok. When clamped, the seal is so tight I didn't think any vapors would be able to come in contact with them. Guess I will have to wrap in teflon but still easier than those sanitary gaskets.
I have some 6 inch sight glass segments that have Tri clamp fittings. They have silicone gaskets between the fittings and the glass. I haven't been able to find any PTFE gaskets so I've wrapped those silicone gaskets in Teflon tape. Some here on the Forum have cautioned about this process and I'm watching it very carefully. I have not found any degradation so far.
i bought EPDM tri clover seals from Brewer's Supply for the Tri Clover fittings on my still. BS seemed to suggest they are good for alcohol however they are talking about low strength and not hot. I looked up EPDM chemical compatibility and several sites say it is excellent with ethanol. also found several references suggesting that the grade of the EPDM matters.
I just re-built my still because i had some Rulon J parts in it and forum members suggested that this is a NO NO !!! so i replaced all the Rulon J parts with virgin white teflon (the absolute last of my 1" thick stuff unfortunately)
so i have EPDM seals on the tri clover fittings and also EPDM o-rings on the teflon parts i just made. i can probably remove the o-rings because the virgin tef is so soft it is probably not necessary at all. the way the thing is put together, the o-rings are hardly exposed to anything, just there for cushioning.
should i be concerned? should i try to determine the grade of EPDM used in the McMaster Carr o-rings? this is the spec they list ASTM D2000, SAE AS568, SAE J200
the white material i used is in fact pure virgin white PTFE. i know the look and feel of teflon. i don't think i used the term squishy. i have pyrex next to the teflon and compared to that it is soft. i like the idea of using the o-rings because they are softer and seal with less pressure on the pyrex. i can monitor for leaks or looseness of parts that would suggest that the EPDM o-rings are deteriorating. the teflon fits tightly to the glass and to the tri clover fittings so there is really minimal contact with the alcohol.
is it more of a concern for seal failure when the material deteriorates or is it a concern for contamination of the liquor?
i machine a fair amount of plastic (delrin, ABS, PVC, poly carbonate, acrylic) also aluminum and other metals. teflon is soft compared to the other stuff i deal with. teflon is also somewhat of a bitch to machine because of its elasticity.
spencoid wrote:i machine a fair amount of plastic (delrin, ABS, PVC, poly carbonate, acrylic) also aluminum and other metals. teflon is soft compared to the other stuff i deal with. teflon is also somewhat of a bitch to machine because of its elasticity.
Yes. But we are talking about sealing materials not generally plastics. PTFE is hard in comparision with other sealing materials like silicone or EPDM.
Both silicone and EPDM may have a good resistance against ethanol. But both are not resistant against foreshots and at least silicone has general problems with steam.
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure.- Rosa Luxemburg
Maybe we should use words like "incompressable." That is my experience with PTFE. It may feel soft compared to acrylic or Lexan in a milling machine, but it will not conform to any surface inconsistency without extreme pressure. Durometer 65 is the only option I've seen. It's totally nonmalleable (hard as a rock) and makes lousy o-rings.
This is the first I have heard of EPTFE.
Simulpost.
Distilling at 110f and 75 torr.
I'm not an absinthe snob, I'm The Absinthe Nazi. "NO ABSINTHE FOR YOU!"
EPTFE (extruded PTFE) makes a great seal. But once compressed it won't expand again like rubber. It has the consistency of cooked noodles. In theory you have to replace it each time you disassemble the connection. In practice it may seal permanent under perfect conditions (when also solid ptfe would seal well).
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure.- Rosa Luxemburg
I have used EPTFE to seal sight glass on the end of 2 inch threaded trap adapter with great success.
I have found the PTFE seals for Tri-clamp to Tri-clamp joins work just fine and are quite inexpensive. This was not the case when I tried to seal the Borosilicate glass tube to the Tri-clamp ends. This is when I went to the standard silicone gasket provided with the Tri-clamp sight glass module wrapped in PTFE tape. Seems to be working.
the EPDM o-rings in my still are very protected from the alcohol. the pyrex tube fits into grooves in the teflon. the o-rings are more for cushioning as (as others have stated, as "soft" as teflon is, it does not compress readily) of the glass. if they failed completely the leaks would be minor. it would not be very difficult to wrap the o-rings with teflon tape and i will do that the next time i take the still apart.
my only silicone exposed to alcohol is the drain line for the product. it does not get any vapor and does not seem to be swelling or deteriorating. i can replace it with whatever is better if someone has a suggestion. i have a bunch of teflon tubing but it is very thin walled and likely to kink so it did not seem like a good choice.
i have EPDM seals on the tri clover stuff. these are the standard seals and it seems that they would take a long time to deteriorate. i also have teflon seals i bought but i could not get the clamps on as they do not compress well. i can shave them down and try again or maybe is it better to get teflon o-rings that fit the tri clover fitting grooves?
i really want to make this still reliable and also do not want to taint my gin so any suggestions are really appreciated.
spencoid,
my advice is to build a still with connections you can seal without anything except ptfe and perhaps flour paste. Do you really need a hose from the liebig to the bottle? Simply place the bottle under the liebig. BTW you get better cuts this way. And if you really don't get the glass parts sealed without epdm or silicone, don't use glass parts.
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure.- Rosa Luxemburg
i take the advise on this forum seriously so i spent hours replacing parts on my still yesterday. i made pure teflon orings for the major tri clover connections. now that i know it works i am going to make them for the minor connections too. i got rid of all the rulon J. i figured out a way to make soft orings for the glass to teflon connections. i probably don't need anything there besides the teflon because the glass is ground flat and the teflon is machined flat. i have some teflon tubing that is the same diameter as the o-rings i am using (about 1/8") and it is nicely compressible. in fact, this might work well for the smaller tri clover fittings that are not opened or closed often. i will probably just make a teflon cap to replace the stainless tri clover cap so i don't have any parts to lose when i fill the still. i think i have a chunk of teflon just big enough.
any opinions on the o-rings listed above from McMaster? easier to buy them than to make them.
what about this flour paste? since i have pretty tight fitting glass to teflon, might that make sense? what about just lubricating the glass to teflon connections with dow corning 111 vacuum grease? it is silicone based, high temperature and used in lab equipment in critical applications because it does not creep even under vacuum?
"Fluoroelastomere" can be different formulas. It's not stated what exactly it is. FKM or FPM would be not resistant by far. FFKM or FFPM would be enough according to resistant charts. Perhaps you find out what it is?
Because EPDM and silicone is relatively resistant, I would consider it safe to wrap them with PTFE-tape.
Flour paste can seal perfect (and safe), but only at places where it is baked hard before it has to seal. For example the lid of the boiler or the connection of boiler and column are easy to seal with flour paste. But the product condenser after the column is a bad place to seal with it (except you bake it with a torch for example before use).
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure.- Rosa Luxemburg
i just made teflon orings (with the last of my sufficiently large diameter teflon rod (it is gone and my surplus place never gets this anymore) for the one remaining tri clover joint. so all that is left is three orings that are EPDM and against the large glass tube. i can easily wrap these in teflon tape but am going to try some other things too. somewhere i have some braided teflon valve stem packing. it is very soft and pliable. the only problem is finding it.
i was not suggesting the dow 111 as a packing material. i just thought that the lube it provides and ever so slight gap filling might be enough. as i said before, the joints are probably tight enough with no gasket at all, just glass against teflon, but i want something in there that is a little elastic.
i also replaced the silicone hose from the liebig to the bottle with a stainless steel tube. it fits in in such a way that i can see the dripping into the bottle to get an idea about the rate of flow without having to use clear tube.
i could not find my teflon valve stem packing material. i found some asbestos but decided to pass on that so, i decided to try the wrapping approach. i thought it was going to be a bitch. three of the fingers on my left hand are somewhat damaged so i hate doing this sort of thing that requires the coordinated use of both hands. it was much easier than i anticipated. i first tried regular 1/2" regular plumber's tape and it came out OK but not great. i found a roll of 1" wide 2.5 mi thick stuff and that was much easier to use and the rings look very good. i advanced about .2" per turn, holding the tape in my left hand and using my right hand to roll the o-ring. so i have something like 3 layers over all parts of the ring. i feel confident that this will keep the alcohol from the EPDM even as it moves around from expansion and contraction over time. i really like having the cushioning of the EPDM so there is no strain on the glass. trying to crank down the tension enough to seal the glass to the teflon seemed risky although the pyrex is heavy walled and very tough. it is also the better annealed stuff unlike the Chinese product so there should be no stresses even after sawing and drilling it.
i have some mash that will be ready in a week and am looking forward to distilling it in a still that has all approved materials. all that is in the still now is stainless steel, pyrex glass, copper tubing and teflon gaskets and orings. and stainless steel pot scrubbers.
my still is ow only made with glass copper stainless steel and teflon. all orings are wrapped with teflon tape. i would like to make some more parts and have pretty much run out of teflon. this stuff is very expensive and most of the parts i need involve a lot of waste. too bad i can't 3D print teflon
i was looking at the properties of UHMW (ultra high molecular weight polyethylene) and it looks like it might be a lower cost substitute for teflon??? it is compatible with ethanol at up to 95% concentration and one source even suggests it might be good at higher temps but unfortunately they did not say whether the testing temperature is Fahrenheit of Celsius so maybe not.
any sources for information as to the suitability of UHMW in an alcohol still? UHMW is approved for use in the food industry and is also used in body replacement parts such as artificial hips and other joints.
spencoid wrote:i was looking at the properties of UHMW (ultra high molecular weight polyethylene) and it looks like it might be a lower cost substitute for teflon???
any sources for information as to the suitability of UHMW in an alcohol still?
there is no HD approved substitute for PTFE. NONE. and you have presented a good
share of the NOT approved (on HD) examples. PTFE only.
spencoid wrote:i could not find my teflon valve stem packing material.
my local Lowes has PTFE valve packing. labeled as such.
I AM A NOOB!!
Plus this is NOT my idea but I saw it suggested.
Somebody needing gaskets advocated cutting out the correct size then wrapping it in PTFE tape.
I was at Home Depot last night and thought, what the heck, as long as I'm here, I'll spend 96 cents in case I need it for something!
I'd be interested in thoughts on that for hard to find sizes.
Also, Noob Question: I have a 5 gal copper pot with cap. Is there anything new and exciting to take the place of flour/water paste to seal the cap?
Just askin
)
. The o-ring seats the valve stem but does it come into contact with the fluid or does it stay of the way?
so, i decided to try the wrapping approach. i thought it was going to be a bitch. three of the fingers on my left hand are somewhat damaged so i hate doing this sort of thing that requires the coordinated use of both hands. it was much easier than i anticipated. i first tried regular 1/2" regular plumber's tape and it came out OK but not great. i found a roll of 1" wide 2.5 mi thick stuff and that was much easier to use and the rings look very good. i advanced about .2" per turn, holding the tape in my left hand and using my right hand to roll the o-ring. so i have something like 3 layers over all parts of the ring. i feel confident that this will keep the alcohol from the EPDM even as it moves around from expansion and contraction over time. i really like having the cushioning of the EPDM so there is no strain on the glass. trying to crank down the tension enough to seal the glass to the teflon seemed risky although the pyrex is heavy walled and very tough. it is also the better annealed stuff unlike the Chinese product so there should be no stresses even after sawing and drilling it. 
