Stainless fabbers, need some advice on building a boiler.

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FuelMaker
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Stainless fabbers, need some advice on building a boiler.

Post by FuelMaker »

Due to basement ceiling height constraints (6.5') my boiler has to be short and wide (like a hockey puck) and there's nothing out there that I can find that can be adapted so I'm going to have to make it myself. All I have to weld with is a flux core 120V wire feed welder which does not have a gas feed.

I'm thinking I'll just make a squat cylinder out of stainless sheet metal w/ the two ends overlapping a half inch, tack weld the outside overlap and silver solder from the inside part of the overlap, then cut out a bottom that's a half inch wider, tack it again, then solder it from the inside.

For the top I'll use a thicker gauge of of SS (prevent sagging), cut out a circle, solder on a 12 inch triclamp manway, tack it in place, flip it upside down and then solder it from the inside.

The technique I'm intending to use for the top/bottom soldering is to flux the join, put a "ring" of solder in place and then heat it from the outside until the solder flows. I think the solder will spread in a radius at the 90 degree join and creep up the sides and out the vertical a bit and give me a airtight & strong join. After the soldering I'll grind down the top&bottoms leftover outside flange so its all flush and clean. Then I'll add spuds for drainage and the 4" triclamp ferrule that the column will attach to.

I've never fabbed anything this big before in stainless and I'd like to get some experienced opinions before I start.

Thanks!
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Re: Stainless fabbers, need some advice on building a boiler

Post by Pooch »

http://homedistiller.org/forum/viewtopi ... 50&t=64472
What about a short keg like the one posted in link?
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Re: Stainless fabbers, need some advice on building a boiler

Post by Badmotivator »

Sounds cool. Tacking the parts together sounds like a nice way to ensure the thing stays together.

I have sometimes wished that I tinned every mating surface before I did the soldering to help insure complete seals. There were times when my flux burned, prevented wetting, and the result was pinholes or inconsistent fillets. I think you might have better control of the process and more confidence in the seal if you wet each surface by itself first, then put them together and add enough solder and heat to fill up the fillet. Hope that helps. Good luck.
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Re: Stainless fabbers, need some advice on building a boiler

Post by The Baker »

Don't lose sight of the fact that the boiler need not be upright, it can lie on its side.
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Re: Stainless fabbers, need some advice on building a boiler

Post by DFitz »

FuelMaker wrote:Due to basement ceiling height constraints (6.5') my boiler has to be short and wide (like a hockey puck) and there's nothing out there that I can find that can be adapted so I'm going to have to make it myself. All I have to weld with is a flux core 120V wire feed welder which does not have a gas feed.
Why not just shell out some clams for a solenoid kit? Most wire welders are easily adapted. Add C02 or oxygen tank (depending on gas choice) from harbor freight. If your going to build a boiler I'd bet you going to shell out quite a bit for oxeygen and acetylene to solder, not to mention the cash you'll spend on solder. What heat source do you have available? What size are your tanks? Tools for sheet metal work (creating proper joints) the last thing you'll want is a joint failure with a full boiler. Gas refills can add up quickly.
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Re: Stainless fabbers, need some advice on building a boiler

Post by corene1 »

Just want to know what are the dimensions of the boiler you want to make and what gauge of stainless are you planning on using. This will help on getting proper advice. If you use a slight cone for your top instead of a flat lid it will increase the rigidity quite a bit so you won't have to use as heavy of material which will make soldering easier. What tools do you have to work with. I would assume that since you are mentioning silver brazing the joints that you have an Oxy Acetylene set up. You will have a difficult time with a brenz o matic type torch getting the stainless hot enough for silver to flow. Basically silver braze is very high temp (1125 degrees to flow) .
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Re: Stainless fabbers, need some advice on building a boiler

Post by FuelMaker »

Heh, didnt know this thread had gone active.. The short keg is interesting but too small. I'll be making it out of 304 stainless and the dimensions are 12 inches high by 28 inches wide - which give me somewhere around 28 gallons. Because of the headspace I'll need I figure I'll be able to run 20 gallons at a time or so.

I'm also thinking seriously about making it a rectangle instead so it doesnt stick out quite so far. And I could go to a standard metal fabbing shop and ask them to make me a RV potable water tank of such-and-such dimensions and they wouldnt think twice about it.

And if I have a tank I can hydroform a shallow cone to the bottom without too much problem.
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Re: Stainless fabbers, need some advice on building a boiler

Post by aircarbonarc »

I will tell you this right now. Stainless is a pain in the ass, it warps with heat and ripples and bends so be careful when hot working it. Also gasless mig welding can be a pain in the ass to get a clean weld, I'd suggest going thicker and trying to get it Tig welded. Maybe a keg might be better to use before you over use and stress your brain. Keep it simple.
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Re: Stainless fabbers, need some advice on building a boiler

Post by corene1 »

Something to think about as far as dimensions, Having your boiler so short may make it prone to puking . Your column will be very close to your wash even at 3/4 full. After re reading your original post . You say you have 6 1/2 feet to the ceiling That is a bunch of room. Are you thinking of making a really tall column? My plated column and boiler is only about 6 feet tall when fully assembled. Most of the time I only run 2 plate sections so it is about 12 inches shorter than the photo. A pot still can be much shorter. The pot still was not quite finished here but it is only 36 inches tall from top to bottom and both hold over 20 gallons. The stainless boiler is 23 gallons and the copper one is close to 30. Just something to think about.
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Re: Stainless fabbers, need some advice on building a boiler

Post by cob »

corene1 for the op, in your opinion is it more cost effective parts and labor wise

to build a boiler with 6 sides or a cylinder

I know that that is a loaded question, depending on if the

builder can bend 90's
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Re: Stainless fabbers, need some advice on building a boiler

Post by FuelMaker »

Bending 90s is easy - just clamp two rectangular steel bars to your piece and bend it using a steel plate to bend against. I've done it lots to make sheet metal project box housings that are pop riveted together.
Soldering gas-tight seams is hard...

Edit:
Yes, I'm (slowly) making a 4 inch column and I'm trying to keep the packed section to as close to a 12 to 1 height-to-width ratio as I can
Last edited by FuelMaker on Wed Feb 01, 2017 10:04 pm, edited 1 time in total.
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Re: Stainless fabbers, need some advice on building a boiler

Post by corene1 »

cob wrote:corene1 for the op, in your opinion is it more cost effective parts and labor wise

to build a boiler with 6 sides or a cylinder

I know that that is a loaded question, depending on if the

builder can bend 90's


A lot of that answer depends on what the builder can do their self and what equipment they have at their disposal. Do they have any friends that work in a metal shop , do they have a steel supply that sells remnant sheet and tube. Either shape is about the same work with the proper tools and equipment. I don't think soldering is the way to go building either one out of stainless though. Some type of welder would be beneficial, MIG or TIG but proper filler material and shielding gas come into play here also. There are a few gases that will work just some better than others. I always use argon for TIG and Tri Mix for MIG on stainless material. It makes less spatter and lets you run less amperage while keeping a good weld bead

The neat thing about a square vessel is that it holds more liquid while taking up the same amount of floor space. A 12 by 12 by 15 vessel will hold much more than a 12 inch diameter cylinder 15 inches tall. As far as forming the edges it depends on the gauge of the material being used. 16 gauge stainless is pretty tough to bend by hand. You can use the method that is described above but the bend won't be a nice sharp bend but it will work fine. If you have to cut and weld each piece you are looking at a lot of work and the material will definitely warp a bit with that much weld. I am fortunate to have a friend that has a metal forming shop complete with all equipment you can imagine, so getting my cylinder rolled is pretty simple. If you have a shop in town you could always go by and see if they have anything that a customer didn't pick up or that was formed wrong, or if they would roll your sheet into a cylinder, always offer cash money , it makes it cheaper.
I have thought of making a square still with a pyramid type top though. It would look different, that is for sure. Use some thin wall square tubing for the column and a square outer tube for the liebeg . You could even cut flanges and make a plated column with square sight glasses, definitely a unique set up . Not much of an answer but food for thought.
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Re: Stainless fabbers, need some advice on building a boiler

Post by cob »

food for thought was all I was after thanks.
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Re: Stainless fabbers, need some advice on building a boiler

Post by Oldvine Zin »

corene1 wrote:[
I have thought of making a square still with a pyramid type top though. It would look different, that is for sure. Use some thin wall square tubing for the column and a square outer tube for the liebeg . You could even cut flanges and make a plated column with square sight glasses, definitely a unique set up . Not much of an answer but food for thought.
I like that Idea!

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