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Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 1:19 pm
by dragon613
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After a 6 year hiatus from making alcohol I'm trying to assemble another still, and this time I don't have a keg sitting around (I did a couple months ago, but someone :problem: took it back to the liquor store for me), this is a convenience driven project so I'm going to pull it together from what I have around the house in my junk piles, if I'm put into a corner I'll break down and spend a dollar on a fitting or stopper or something but beyond that, it's opportunistic, I went by the scrapyard today but didn't find any kegs, but I do have something that I think should work as a less than ideal still pot, but I haven't seen anyone else using these for stills so I want to post the idea here so the community can review,

I've had this oxygen bottle sitting in my storage locker for months, bought it at aforementioned scrapyard for $10 for the metered flow regulator on it, it's aluminum, very thick, about 3ft tall, and has that handy dandy handle on it,

First, the obvious problems that make it less than ideal, it is HEAVY, like 60lbs empty heavy, and it is so thick that it doesn't have that much volume, 5 gallons fills it to the brim, and the opening on it isn't very large, just under 1 inch, that might make dumping it tedious, but I had the idea that if I need to empty it faster, use compressed gas to blow the spent wash out

But these are really issues of labor intensity and shouldn't negatively affect performance, I don't think,

Also, this was a medical oxy tank so all the materials should be better than food grade, im thinking about using the valve as a head to attach pot to condenser, it goes down to a 3/8" nipple, and I have a roll of 3/8" copper, I figured I could just join them with a stub of vinyl tubing and a couple hose clamps,

Seems as simple as I can get, and everything threads together tight with gaskets, I expect this may be my first still to never have a vapor leak,

Another thing, I've been scratching around for a heat source but my propane burners are dead till I replace my regulators (need to get on that before turkey fryin season) I'd like to use an electric hotplate like I used to but can't find em, so I was considering heating it over wood fire, I've been burning scraps from the deck I just put in to fend off the skeeters, I don't want to scorch anything in this tank given my limited access for cleaning, but it is so thick walled, the top around the valve is almost 3 inch thick, the walls have to be a good inch plus, I'd think that it would spread the heat so well that it would prevent scorching the same way thick copper does, should I be concerned about this thick walled vessel being to hard to heat? I don't think so given aluminum's low specific heat capacity, I'd think that if it's thickness contributes to the wash warming slowly that it would be beneficial to it's performance, I've had keg still heat too fast and smear the heads and hearts

Regardless this clearly isn't an ideal solution but I dont see why I couldnt use it to produce a little shine till a keg comes my way, I have a couple barrels of homemade wine (cherry and guava) sitting around back so if nobody brings up any hidden dangers to this material choice I could be cooking shine later tonight
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Re: Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 2:05 pm
by Demy
Hi, from what I know it is not recommended to use aluminum as a boiler because of the hot alcohol vapors and high ABV (therefore a very hot solvent). This is also what I have read on this forum. There are people who use aluminum but it may not be the ideal material as a distillation boiler, even if it is for food use. Maybe overconfident or maybe not but I'd be on the safe side. Apart from that it's a nice tank, it will have its place for sure! A greeting

Re: Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 3:08 pm
by dragon613
Hello, Ive heard that about alum, but I think it's been debunked, the only issue with aluminum I've found is that under intense heating, (directly on propane burner for example) it pits, which for thin alum pots like the stockpot next to the tank in photo, leads to pinholes, but this tank is so thick I don't think any amount of pitting that could be expected from direct heating could compromise it's air tightness in the pressure range a still should expect,

I'm more concerned that someone who's worked with these cylinders will drop the bomb that they're coated on the inside with a layer of plastic (doesn't look like it but it's hard to inspect through a 1" hole) or that the nickel plated fitting on the valve will leach something toxic in ethanol vapor, I think it's unlikely they're will be an issue of this nature but since I couldn't find a thread on using these alu bottles (same as co2 or nitrogen or nitrous, or scuba tanks) so it bore asking

Re: Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 3:10 pm
by still_stirrin
Nope.

Aluminum won’t work. It isn’t even advisable to use aluminum cookware, including an aluminum campstove coffee pot, for food any more. The aluminum is attacked in a heated environment in an acidic solution and will release chemicals which can be toxic.

So, back to square one. I suggest going to the housewares store and buying a 16 to 20 quart (liter?) stainless steel stock pot and get a roll of 1/2” soft copper from the big box store. Get a bulkhead adapter for the tubing from the big box store too. Then, scrounge a 5 gallon bucket to use as a flake stand.

You can heat the stock pot boiler with a propane burner, wood, or even a modified hotplate.

But first, you really do need to read more...we don’t want you to do anything dangerous.
ss

Re: Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 3:43 pm
by cob
dragon613 wrote:
Sun Sep 27, 2020 3:08 pm
Hello, Ive heard that about alum, but I think it's been debunked,
you think incorrectly, more research is required.

thinking you can reneck a still together from the scrap pile can work if

you actually know what the materials at hand are compatible with.

believing what you want to believe without proper research is dangerous.

Re: Aluminum oxy bottle as boiler?

Posted: Sun Sep 27, 2020 4:27 pm
by dragon613
Erg, just lost a long reply I tapped out. Hate that,

Not retyping it all, but long story short I'm familiar with metallurgical chemistry, and of all the compounds that could be produced by aluminum in an aqeuos environment at STP most are inert, many are used for intentional ingestion, and even if some mysterious yet to be discovered (because non has been discovered) toxic compound existed it would have a boiling point in the hundreds of degrees centigrade, so it may off gass in a foundry but isn't going to distill over

This places the accusations made against alum somewhere between an urban legend and mass hysteria

Stainless steel contains nickel and chromium, heavy metal with notoriously poisonous compounds, some of which are produced at temps as low as 150c (nickel carbonyl, one of the deadliest industrial heavy metal poisons there is)

So we can throw Barb's at each other non ferrous metals copper isn't innocent either, those green corrosion salts, were at one point responsible for a liquor related poisoning epidemic in Europe,

Re: Aluminum oxy bottle as boiler?

Posted: Mon Sep 28, 2020 3:53 pm
by Tater
While its not a written rule not to use aluminum, It has been shown time and time agin that washes acidity plays hell on that type boiler. Pits and leaks were end results So we wont support any talk about use of them. Use what you want but keep it off this site .tks