2 inch shotgun build

[piperdave]

Is there any requirement for vapor path size reduction before it hits the shotgun condenser? Will this work (see below)?

shotgun build concept.

edit: spelling

[Danespirit]

No, you're not required to reduce the tubing before the shotgun condenser.
As you've drawn it...it will work. That is if it can handle the power input...
What's the heat source and the power input?

Edit: I don't see why you want that pipe before the 90 elbow.
Why not connect a tri clamp ferrule to the tee and one to the elbow and be done with it?

[piperdave]

Right now 2000W in an eight gallon boiler but since I've got everything modular I can see moving to a keg in the future and getting 5500W.

Edit: just saw your edit question. For product collection... I want a little distance from the riser and boiler.

[still_stirrin]

piperdave,

The shotgun looks good. I like the design to stay 2" all the way to the shotgun...it keeps the vapor velocity as slow as possible. Goodness.

But, I don't think you can fit 7 x 1/2" ID pipes into a 2" ID shell. It will be very, very tight, if even possible. But, I know 5 tubes would fit. However, 7 tubes will help the condensation "power" with the additional surface area contacting the vapor.

Adding baffles in the water jacket to agitate the water through the shell will help efficiency significantly. Well worth the effort.
ss

[Lyonsie]

Im building one quite similar. I wouldn't pay too much attention to my thread though. Feck knows what ya would end up building.
Seriously though mine is 2 inch pipe too with 7 inner pipes. 7 x 10 millimeter inner pipes fits perfectly. You definitely wont get 7 half inch pipes into it. Maybe try 5?

[piperdave]

Yeah 7 was the starting point. I haven't cut anything yet so if it's 5 pipes, it's 5. Waiting on parts but glad the plan is okay. Now to execute...


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[Danespirit]

Right now 2000W in an eight gallon boiler but since I've got everything modular I can see moving to a keg in the future and getting 5500W.

Edit: just saw your edit question. For product collection... I want a little distance from the riser and boiler.

It will handle the 2 KW, but as you have thoughts about a keg and 5 KW in the future, you may as well go a little larger than the 14" ( 355 mm) you have on the drawing by now.

If that piece of pipe is there just to give it some distance, you may as well forget about it.
The reason I write so is...with a tri-clamp on the tee, your shotgun condenser can turn quite a lot up and down already.
That will move the collection point by several CM.
Furthermore...the additional pipe section will move the center of gravity and cause some stress to the solder joint.
The pipe will act like a lever, with your condenser and the weight of the water hanging on there.
If you still want the pipe there, there is also the option for some kind of support arrangement, though.

[badbird]

From experience, 18" of 2" with 4 tubes knocks down 5kw with ease

[skow69]

I have to quantify everything. It's an obsession.

7 x 3/8" (10 mm) tubes only gets you 5% more surface area than 5 x 1/2". I'd go with the 1/2.

I know, I know. Nobody asked, nobody cares. Numbers' lives matter.

[Lyonsie]

If i had have known that skow i would have too. Well done with the sums

[still_stirrin]

piperdave, I agree with skow.

Five 1/2" ID pipes are much easier to work with than squeezing 7 x 3/8" tubes in. The 3/8" will fit easy enough, but working with the soft copper is more difficult because it is hard to get perfectly straight like the rigid (tyoe M) 1/2" copper is. When you assemble the tube bank with the baffles, you'll appreciate the straight rigid pipes over the soft copper tubing (experience here).

Although you have slightly more surface area with 7 x 3/8" tubes for the same condenser length, the shotgun can easily be lengthened to increase the surface area when using the 1/2" pipes. And I would consider increasing the length to 20" or 22" to "future proof" your shotgun for when you do increase boiler power to 5.5kW.

I use the calculator on the parent site to calculate a Liebig length and calculate the vapor surface contact area. Then divide that by the number of tubes you'll put into the shotgun. And for good margin, I derate that area by adding 10% more area to it for calculating the length of the shotgun. It'll give you a little headroom when you're running it hard.
ss

[piperdave]

I have enough 2 inch to make it 21 inches. Go big or go home. I went modular so I could upgrade so I might as well do it right now.

Never thought about the stress that a shotgun full of water would apply. May have to rethink that extension from the tee. Thanks for all the input fellas.


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[rad14701]

Three 3/4" tubes will also fit in a 2" shotgun which yields ~32% more surface area than five 1/2" tubes... They'd be a bit snug but should work... Just depends on whether the added surface area is needed...

[shadylane]

Just a thought
Before you clamp it to the boiler
You might want to bolt the 8 gallon pot down
Edited: On a side note
Your proposed rig would be real easy to convert to CCVM column.

[skow69]

My calculator says 3 x 3/4" has 10% less surface area than 5 x 1/2".

[still_stirrin]

Conduction surface area is the area of the vapor tubes in contact with the cooling water jacket.

-> Area = (No) # tubes x (L) length of tubes x pi x (d) ID of vapor tube
where,
3/8" ID: 1.178 sq.in/in x 7 tubes x 1 in. length = 8.247 sq.in/in
1/2" ID: 1.571 sq.in/in x 5 tubes x 1 in. length = 7.854 sq.in/in <-- winner
3/4" ID: 2.356 sq.in/in x 3 tubes x 1 in. length = 7.069 sq.in/in

So, the increase in conduction surface area for 7 x 3/8" ID tubes is roughly 5.0% over the 5 x 1/2" ID tubes.
And the increase in conduction surface area for 5 x 1/2" ID tubes is roughly 11.1% over the 3 x 3/4" ID tubes.

Therefore, for the 2" ID shotgun shell, the 5 x 1/2" ID vapor tubes appears to be the best advantage due to manufacturing ease and relative efficiency.

[ShineonCrazyDiamond]

In Rad's defense, he just skipped over the geometry questions on the IQ test. Those things are all about approximation, anyways.

I hated geometry.

[rad14701]

In Rad's defense, he just skipped over the geometry questions on the IQ test. Those things are all about approximation, anyways.

I hated geometry.

No, I accidentally calculated volume instead of surface area...

[still_stirrin]

Not accusing anybody for math errors...I'm just as guilty.

My thought was to help piperdave with his decision for his shotgun build. Only that.

I have built shotguns with 3/8" ID tubing and it is very difficult to get and keep the tubing straight for building the tube bank. Looking at the surface area calculations, I will use 1/2" ID rigid copper in the future builds. All I mean to relate is my experience backed up with analysis of the advantage/disadvantage of either.
ss

[ShineonCrazyDiamond]

Regardless, I built a 24" shotgun with (4) 1/2" tubes, and use a 5500 uldw element, 15 gallons. Even on full blast stripping, I can't use more than a trickle. 5 is still more than enough.

[still_stirrin]

Also to add, the vapor flow area [# of tubes x pi x (ID/2) x (ID/2)] is:

3/8" ID: 0.773 sq.in.
1/2" ID: 0.982 sq.in. <-- winner
3/4" ID: 1.325 sq.in.

So, the 1/2" ID vapor tube design results in a slower vapor speed than the 3/8" ID tubes, allowing for a longer contact time, also key to efficiency.

Again, my suggestion is to use 1/2" ID rigid (type M) copper for the shotgun in a 2" ID shell.
ss

[still_stirrin]

Regardless, I built a 24" shotgun with (4) 1/2" tubes, and use a 5500 uldw element, 15 gallons. Even on full blast stripping, I can't use more than a trickle. 5 is still more than enough.

I bet.

And 4 x 1/2" ID tubes would fit into a 1-1/2" ID shell too, reducing the water jacket volume & weight. <-- winner
ss

[ShineonCrazyDiamond]

I used (4) 1/2-end-plate baffles along the pipes, and also flattened (3/8, I think? ) pipes and twisted into a spiral to put in each pipe to both slow water and value, respectively.

It's a beast.

[piperdave]

With all due consideration and all research and my most esteemed colleagues due diligence and thoughtful deliberations I think 1/2 inch tubes, 5 in number and in a 21 inch 2 inch tube, will sufficiently suppress any noxious vapour I may try to pass by it's watchful gaze.


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[piperdave]

Build pic's to follow...where are my parts Amazon?


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[still_stirrin]

And one more recommendation for your build, piperdave.

Add a tri-clover attachment for the shotgun to 90* elbow joint..to allow removal of the shotgun separately. Doing that will allow you to put flattened strips of copper into each of the 5 vapor tubes to act as vanes and increase the vapor contact surface area inside the vapor tubes.

If the vanes have a slight twist to them, that will help even more. When you cut them, leave a slight tab at the top so the vanes will slide down into the vapor tubes, yet the tab at the top will hold them in place (keep them from falling down into the tubes).

The TC clamp will give you the flexibilty to remove the vanes to rinse them off occasionally if you want/need to. The vanes will significantly increase the heat capacity of the shotgun and would be an easy-to-add feature. Since you are going to use the 1/2" ID vapor tubes, this enhancement is easy and cost effective...just gotta buy another 2" tri-clover clamp and a pair of ferrules.
ss

[ShineonCrazyDiamond]

And one more recommendation for your build, piperdave.

Add a tri-clover attachment for the shotgun to 90* elbow joint..to allow removal of the shotgun separately. Doing that will allow you to put flattened strips of copper into each of the 5 vapor tubes to act as vanes and increase the vapor contact surface area inside the vapor tubes.

If the vanes have a slight twist to them, that will help even more. When you cut them, leave a slight tab at the top so the vanes will slide down into the vapor tubes, yet the tab at the top will hold them in place (keep them from falling down into the tubes).

The TC clamp will give you the flexibilty to remove the vanes to rinse them off occasionally if you want/need to. The vanes will significantly increase the heat capacity of the shotgun and would be an easy-to-add feature. Since you are going to use the 1/2" ID vapor tubes, this enhancement is easy and cost effective...just gotta buy another 2" tri-clover clamp and a pair of ferrules.
ss

+1.

This is what I was referring to when I spoke of the flattened 3/8" pipe twisted. SS has a better explanation.

[piperdave]

Here's an update. Slow going but getting there. 2" pipe 16 " long with 5 1/2" tubes. More work but getting there.

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[craftsman]

Piper, I tried to make a dephlamator, using 5 1/2 tubes into a 2-inch pipe. The problem I run into was soldering the tubes to the copper caps/ends I made. The tubes were too close to distribute the heat and allow a good water tight seal. I played with it for an awful long time and had no luck. Since I make all my stills and accessories, I have no problem with soldering good joints using all the tricks I learned using wet rag strips around each pipe after I soldered them. I am thinking about getting a fellow I know that is a good tig/mig welder to give it a go.

I know how slow this goes. I'd like to hear how you make out and if it works maybe I could figure out what you did to make it work for me. I am considering another type of cooling, but I still hope that a dephlamator is in my future. Your probably working with a foot or more pipe. I am trying to make 8-inches work. I have a CM still That I am fooling with for this project.

[piperdave]

Craftsman...yep, the end caps are the sticking point in my build. I'm going with silver solder and acetylene and regular lead free for the other joints. I will update this thread as I (hopefully) make progress. There are some excellent shotgun build threads here that I have taken inspiration from. Here's some more pic's. still working on the end caps.[img]https://uploads.tapatalk-cdn.com/201701 ... f25b94.jpg[/img][img]https://uploads.tapatalk-cdn.com/201701 ... c4697b.jpg[/img]


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