3" or 4" column?

[DAD300]

There is a design issue with 3" or 4" that is often overlooked. The size of the boiler is a significant factor hear.

If your boiler is too small, say a 4" over a 15gal SS keg, you can get into a situation where all the potential alcohol in the boiler is now in the column, waiting for something to push it out to collection.

I had this problem with first 4" on a beer keg. A 10% charge is only going to produce 1.6ish gallons of 95% alcohol and an SPP filled 4" x 36" column will hold far more than that. So, the column becomes a second boiler and requires a lot of power to push it to collection. Meanwhile you may be boiling water in the keg. Column width can be over sized.

[cayars]

I've tried to bring this up a few times in the forums and have given up on it as people just say they run 4" on a keg and have no problems.
Meanwhile in other topics you'll see them mention they have to strip first to get the ABV up.

[Yummyrum]

I’ve only once run wash in a reflux still and the results weren’t that spectacular . Since then , its always been my practice to run stripped wash in them . I just transfered the method over to 4” .
I don’t see a problem using a 50 liter boiler on 4” as far as how it runs with strip in it , my only gripe is that the bottom / shape isn’t sufficient to be gas heated efficiently. would be fine on electric but the power required is at the limits of what a typical Domestic dwelling will have available .

[Dannbo]

Thanks for your input everyone. I am moving forward on the 3" x 48" packed column design with a 16" reflux head. l am limited to 92" total height including keg. I am looking to put short legs on the keg as well to accommodate a drain on the bottom. After reading Yummy"s post I think, for myself, that a 4" would be impractical. I drew out my final design and created a parts list of things I have not acquired yet. I have also drawn up a pot head to use. Thanks again.

[The Baker]

Yummy, this would be a bit radical but probably, actually, simple.
And might depend on what you have in your scrap or can scrounge or get cheap.

Just suppose you cut the bottom off completely.
Either square or maybe just where it curves in a bit (which might give you a more solid base for a stand.)
And replace it with heavy copper.

Copper will be much more efficient to heat than stainless. And the heating surface will, I think, be greater.

A non-mechanical person, obviously, kicking it around...

Geoff

[Yummyrum]

Not such a bad Idea Geoff

I happen to have an old 80 liter keg that had the top cut off and I’ve been using it as a Big O’l Pot . Flip it upside down with a copper bum in it ....I’m almost picturing something like Saltbush did .

How I’d attach a Copper Bum to the SS keg is the prickly bit but I’m sure it can be done .

[The Baker]

That is what is done to copper based saucepans and pots.

If you put legs on it, welded (whatever) to the sides of the keg; you could fix (weld?) supports-for-the-copper-base onto the insides of the 'legs'....?

Geoff

[LunaDogFever707]

If ya got a dc stick welder, just hook up a tig torch, get some argon and regulator, run it dc negative with some silicon bronze brazing rod. For me, it's easier than silver soldering with a torch. The puddle freezes a good bit faster, is more forgiving on gaps, and also stronger.

[NZChris]

A problem with a copper bottom welded to an SS boiler is the different coefficients of expansion of the two metals. That doesn't mean not to do it, just to do it well and allow for any problems caused by metal fatigue over time.

The copper bottom of my main boiler is clamped to the SS body and has a PTFE seal, so I've never had problems with fatigue or leaks.