Aussiedistiller, Home Distilling, Moonshine, Home Brew

I'm trying to get a handle on whats better, where, as to thickness of materials for a: stills and b: boilers

I realise that insulation makes a big difference to what i'm putting forward here
I also realise that construction methods have a bearing on material selection too

Still - I have it in my mind that thinner materials would be better for columns to get up to equib faster and produce a fraction more reflux - the thinner material is easier to heat and there isnt as much mass there to keep the heat, so an uninsulated column would have a greater "cycling" through the walls ie reflux.
Whereas a heavier wall would hold the temp more - this would make the column more "stable" ??
Pipe wall thickness can have a bit of a bearing on making bubble caps too (at least on paper) - I have worked out a smidgen more flow area (vs standard pipe thicknesses) on to a plate by using constructed thin wall caps and risers - 0.5mm region - how thin can a cap get?

Boiler - All i can find on boilers is that if its externally heated, a thick base is good, so for an elec heated boiler it dosent matter how thin you make it? (within engineering/stregnth constraints) provided of course that its insulated? I looked at an US eng standard calculator (zero pressure) for wall thickness for a 2-300l pot - 0.2mm plus corrosion allowance - errr.... ummm.... dosent sound like enough, but then i think of what a 200l drum is made of and well... ok - depends if its going to used as a football i suppose.

Is there any advantage to going thicker than say 0.5mm on a SS boiler? What about on a jacketed one?

I would think a thicker colum means more stable temp less fluctuations from wind etc although this can also be achieved with thinner column and insulation...boiler strength strong enough to hold weight of column. Heavy duty colum needs heavy duty boiler...

Your over complicating things here mate, I love your enthusiasm but your splitting hairs :laughing-rolling: All these bubblers on here work even though they differ in many ways. Whatever you decide will work as long as it follows the main principles.

On the thin wall column, I agree with bluc. If your getting passive reflux all the way up the colomn you will have problems with the fractions not separating properly because they aren't reaching the top.

Thinner material is a lot harder ta TIG weld ,very well and it may have to hold up plated colomn of over 20kg and use over the years,adding up how many tri clamps and legs need fitting,a lot of pipe and fittings are standard thickness too,I thought about building a perfect boiler but after trying beer kegs(about 1.6-1.8mm and thicker) never considered it again over 10years ago .cheers hilzabilly ;-)

If you're talking thermodynamics of metals you're overthinking it way too much.
Thickness is important in still design mainly for structural strength and ease of building purposes.
Once your still is up to temp it will maintain things quite well. If you want to use the walls as a heat sink (buffer against the cold) you'll need unrealistically thick walls (which probably wouldn't work very well anyway) whereas a small amount of insulation will accomplish the same task easily.

Oh. And engineers always aim for minimum as more than the required minimum costs more money and clients don't like that. Believe me I've worked with enough under engineered cock ups over the years. And some of their designs were pretty ordinary too. A 0.2mm pot isn't designed to hold a 20+ kg still on the top of of it. Us hobby guys we want to over engineer a bit if we can.

I agree with everything that has been said above.

If you are looking at saving metal for reduced heat up time then have shorter modules. Don't go shorter than 100 mm between plates on a 4" bubbler, there's a rule that says you need to have them spaced as far apart as the plates are wide. On larger stills I think this becomes irrelevant as industrial stills using valve/caps/sieves, the plates seem to be much closer than the width of the plate. It won't make a huge difference though as the column heats up pretty fast anyway. 1 gram of copper requires 0.386 joules of energy to raise it's temperature by 1 degree Celsius.

The biggest energy sink in the heat up process is water in the boiler. It requires 4.18 joules of energy for every gram to be raised by 1 degree Celsius. Ethanol requires 2.46 joules per gram to be raised 1 degree Celsius. So you'll find that heatup times on a 40 % low wines boiler charge will be shorter than on a 10 % wash.

In addition to the insulation mentioned above, if in winter and you are already heating your ferments, you can also save time by keeping your finished washes warm right up until filling the boiler. I think hillz also runs a worm through his finishes washes to heat them up when running consecutive stripping runs, further reducing heatup time.

Thanks for the replies everyone

So if you haven't noticed, I can get a bit OC , I'm happy to split a hundred hairs before I cut anything :roll:
Sorry, please bear with me :D

I asked because sometimes I actually have a choice when scrounging the scrappy's, and in what I have grabbed so far I have two thicknesses in a couple of sizes of copper, so I can assign different bits for different stuff, I will use thinner sizes where it won't matter or where it would be beneficial, perhaps the product condenser or defleg?

I agree with Warra about over engineering a bit on anything that needs a bit of structural strength or has some sort of safety factor about it (boilers, columns, legs etc), but when it comes to bubble caps and risers, material thickness can have a significant affect size wise, on the free area for flow.
Now whether this affects to performance of your still to any great length... who knows? I’m fairly certain there are more than a few bubblers out there that work just fine and were just made from whatever was available, with little to no consideration of such things.

I tried very hard to make sure that the area of the riser, holes in the riser, area between riser and cap and finally slot size were all well balanced on my bubbler. My bubble plates work very well, but I have no ‘unbalanced’ caps to compare it to so again... who knows?

No real answers for you, maybe just some food for thought.

Cheers

On a hobby scale nothing really matters all that much.
I tend to split hairs a few times when overthinking things.

Thicker boiler material will be able to take more weight.
Thicker column material will be stronger and be less effected by errant breezes but if you add insulation to both of the above thermal properties of the boiler/column become a moot point.

Worst cast senario is that you need to run a few ml/min slower...
Which might mean an extra 10mins run time, maybe.

Were this an industrial column taking MWatts of power to run then yes absolute performance is a must.