First VM build

[hsv8]

G'day fellas,

Looking to build a 2" VM very soon. Got the keg, gas ring, and copper for PC condenser already (1/2" inner, 3/4" outer, about 800mm long; this ok?).

I've been doing a lot of reading on this forum and have a couple of questions:

1) Coming off the 2" column, does the pipe going through the ball valve to the PC have to be 1"? Could you get away with 1/2", or would it be too small?

2) How do you join a stainless ball valve with female BSP threads into a copper system without using brass?

3) Does the RC need to have a bigger diameter than the column? Or do people just go bigger here to help squeeze in the coils for the RC?

Cheers,

Hsv8.

[maddogpearse]

Keep reading buddy. The answers to all of your questions are right at your finger tips. Everyone here is more than willing to share their wisdom, but I doubt you'll find anyone to spoon feed you and tell you step by step how to build a still. First because no one can be bothered helping if you haven't genuinely tried to find the answer first. But more importantly, the more you read the better understanding you will have of distilling in general. I'm not meaning to be nasty, but I don’t think your ready to build just yet. :handgestures-thumbupleft:

[1 2many]

:text-+1: just take your time and read and then reread you have only been here a short time and I think it would benefit you more if you did the studying.

If you study the forum and it is for you the money you save from making the wrong decision. :handgestures-thumbupleft:

[hsv8]

I understand.

Been reading every day maddogpearse and 1 2many; found some answers:

1) The ball valve and take-off pipe are commonly only 1/2" in 2" column builds. In fact, more restriction in the take-off pipe can enhance the reflux effect. I would have thought that creating more resistance here would tend to push the steam out the top of the column, but I guess not... That solves that.

3) There are plenty of builds out there where the RC is a 1/4" coil inside a 2" pipe, so from what I can gather, there's no real 'need' to go bigger here.

Still stumped on question 2, but will keep reading.

Cheers.

[TheMechwarrior]

Q2) Solve your problem by eliminating it. Go all stainless for the offtake section.
I'd suggest a 2" to 1" stainless tee, then use a 1" gate valve.
Since the tee will have sanitary triclamp ferrule fittings you can easily join that to your copper column.

Q3) If you wind a nice double helix copper coil out of 1/4" you'll need 3m and it will make a nice 180mm condenser.
Of that 180mm you'll only need 100mm to knock down 2.4kW of power, the rest is back-up.

PS...I'm gathering parts at the moment to build a double helix coil for a much bigger project. Keep your eyes on the forum for updates ;-)

Cheers,

Mech.

[hsv8]

Thanks for the reply Mech.

I've gotta ask; why would you go 1" take-off? From what I've seen, a lot of blokes use 1/2". I read that the opening on the gate valve can be pretty small, so having a big pipe coming into it doesn't mean much... What do you think?

I'm also considering using 4x 250mm vertical 1/2" pipes linked in series for the RC condenser, as I've already got the copper to do that job, and it seems quite straightforward. Seen a few designs using this style, so hopefully that would knock down the steam too.

Will keep an eye out for your new project; good luck with it!

Cheers,

Hsv8

[TheMechwarrior]

1/2" will be fine, it will make your SS gate valve that much cheaper.
I went 1.5" and it was crazy big and unnecessarily expensive, works fine on a 6" VM...

Your condenser should work but you'll want to pack some scrubbers down those tubes to slow down the vapour entering the condenser. I'd just place 1 scrubber in the bottom and top of each tube, that makes them easy to remove.

Cheers,

Mech.

[hsv8]

Thanks again, Mech. I appreciate you taking the time to answer my questions, and confirm that my plans aren't too ridiculous!

With a 6"VM I can understand why you have a 1.5" valve. Horses for courses hey?

Regarding the RC; I may not have been clear in my description, my apologies for that. I'm planning to run water through the 4x vertical 1/2" pipes, so kind of like a reverse shotgun design, if that makes sense? With that being the case, do you suggest I pack around these pipes to help slow the steam down?

Cheers,

Hsv8

[TheMechwarrior]

Yes, packing around the tube bundle.

PS, my 6" VM will have no take off valve at all, instead I'll have a lever at the base of the still that control a wire and pulley mechanism back up to the condenser. So offtake is controlled by raising or lowering the condenser.

[hsv8]

Wow! Very clever Mech! Can't wait to see the pictures. Do you have a diagram?

Here's the plan for mine. Please let me know if I've missed anything. Note the 3/4" take off pipe (after all that!). I've since been told that a 1/2" BSP thread can be cut on a 3/4" pipe, and that a 1/2" ball valve does not actually take 1/2" pipe.

Cheers.

[maddogpearse]

I personally would ditch the ball valve and use a gate valve. I reckon you'll find a gatey easier to adjust consistently.

[scythe]

Well 1/2" ball valves do take 1/2" pipe just not 1/2"copper pipe.
Standard weight steel pipe has wall thickness of about 4mm-ish but the bore is close enough to 12.7mm.
Most piping is named after its bore size not its outer diameter like copper and a few others.

As for valve type choice, ball valves are good at being open or shut, gatevalves are good for somewhere inbetween at high flow rates but you will have to count the number of turns from full open or full shut to be consistant, needle valves are great at low volume/ high pressure precision but again you need to count turns.

I would go with a needle valve eventually but a ball or gate valve will do for now.

[TheMechwarrior]

Don't be a tight arse, lose the ball valve and buy a gate valve.
You will run the gate valve in three positions, open/shut/4 turns open for example. You won't need any other positions but you can't dial in the sweet spot with a ball valve.

Can you afford the height? I'd like to see your packed section closer to 1,428mm, that's 30x your ID.
At present your packed section is sitting at the bottom of the performance curve at 21x your ID.

Cheers,

Mech.

[hsv8]

Thank you for the input everyone.

I understand that a gate valve is easier to control, and believe me, I've called every plumbing store around me to try and find one made from copper or staino. However, they all seem to be made from brass. Any tips on where to find a copper or staino gate valve? I really have tried! The only reason I've gone for a ball valve in the plan is because I've just about given up on trying to find a copper or staino gate valve.

Thanks for clearing that up about the piping Scythe, that helps a lot, and makes perfect sense! Will look into needle valves as well.

Mech, I based the column height off some similar designs I have seen. I was not aware of the theory "Height = 30x column ID". But yes, if that's the case, and it will increase the efficiency, then I will definitely look into making it taller. Might start by checking my ceiling height, as you suggested.

Cheers,

Hsv8

[TheMechwarrior]

SS gate valve:
http://www.ebay.com.au/itm/1-2-Gate-Val ... XQrhdTT4Tj

[hsv8]

Thanks Mech, EBay of course! Surprisingly cheap actually. Do you reckon coming from China it'd be any good though?

Re column height; surely the "height = 30x column ID" theory doesn't apply when you have a larger diameter column? Is there a different formula for that?

Cheers,

Hsv8

[TheMechwarrior]

For a packed reflux column you want 20-30 column diameters for your height, the column diameter does not change that ratio.
Any less than that you need to reduce your power or increase your reflux ratio to compensate, this will be my case as I don't 4.5m+ of head space to play with.

[hsv8]

How interesting! Thanks for sharing Mech.

[Undertaker]

.......Will look into needle valves as well.......

Forget the needle valve. They are designed for controlling flow at higher pressures and flow rates. At the low vapour speeds and zero pressure of a still you will not get consistent results.

Cheers Phil

[hsv8]

Thanks for that Phil. Will stick with the ball or gate valve.

Just measured up. I can easily go 1500mm total height, but 1600 is starting to get a bit close to the ceiling. So I'll go 1200 high on the column, and 300 high on the RC. By my Maths, that's about 24 times the column width, which is much better than the 21 I started out with. Thanks for the tip, Mech!

Just found some stainless 1/2" compression fittings for $5 each online. Might be easier than mucking around with shallow threads on 3/4" copper as previously mentioned...

Cheers,

Hsv8