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First Double Coil Condenser
Posted: Sun Jul 17, 2011 4:39 pm
by yankeeclear
I finally got around to - well more like got up the nerve to - attempt a double wound copper condenser. Special thanks to HookLine for posting the tutorial
Double Coil Tutorial.
I used about 14' of 1/4" soft copper tubing which yielded a double coil of 12" length with two leads that are ~10" long. After two false starts kinking on the first turns, I was off to the races. It was surprising how smooth it went once establishing a rhythm, although I definitely have left plenty of room for improvement!
Thanks to HookLine and others for posting there coil experiences otherwise I would have never gotten through it!
Re: First Double Coil Condenser
Posted: Sun Jul 17, 2011 4:48 pm
by Samohon
Your third attempt seems to have turned out great...
Seems to me that 3 is the magic number for a successful coil...
6" - 8" would have given you plenty length on the coil, apart from that, well done...
Re: First Double Coil Condenser
Posted: Mon Jul 18, 2011 9:56 am
by yankeeclear
Samohon, thanks for the feedback. Is there any penalty to a longer coil other than quicker rise in temp to the cooling water with more exposure?
I'm not sure I stumbled across this in my reading, but I did search for it last night and came up empty: Is there a preference to cooling the inside or outside coil first?
Continued thanks!
Re: First Double Coil Condenser
Posted: Tue Jul 19, 2011 2:08 am
by HookLine
yankeeclear wrote:Is there any penalty to a longer coil other than quicker rise in temp to the cooling water with more exposure?
Longer coolant pathway increases flow resistance (back pressure), and hence reduces maximum coolant flow rate, which in turn reduces maximum cooling capacity even though the condenser is bigger. That length should be okay, if you got decent coolant supply pressure. If you can get at least a litre a minute of coolant through it you should be okay, depending of course on how much heat you are using.
I'm not sure I stumbled across this in my reading, but I did search for it last night and came up empty: Is there a preference to cooling the inside or outside coil first?
I use coolant in to the outer coil, and out of the inner coil. Reason is the outer coil is much larger and does most of the cooling. Either way, you should put a bit of mesh in the top of the coils, especially the inner one, to help force the vapour onto the cooling surfaces.
Continued thanks!
Another satisfied customer. 
Re: First Double Coil Condenser
Posted: Wed Jul 20, 2011 3:56 pm
by maritime
before you place the reducer on top, drill holes on each side of the 3/4
run your coil tails through the holes. solder them in place.
this will give you a clear 3/4 hole. from this hole, if you go into the tails too far or forget to add the heads and tails from the last batch, you can put a funnel on top and pour right into a boka. just have to reflux again.
Re: First Double Coil Condenser
Posted: Thu Jul 21, 2011 5:53 pm
by yankeeclear
Thanks guys for the feedback and tips. I am turning out a VM but slowly as I am just havin a blast with the pot head! I lean heavily on the whiskey but will eventually like to be able to run off neutral spirits as well.
Re: First Double Coil Condenser
Posted: Fri May 03, 2013 9:00 am
by drinktofabfabtodrink
Just wondering about the packing in the condensing coil - recently finished a 3" Bok and was running it yesterday with a mash for the first time. not using packing up the column because i was going for some flavor. everything went well until my hearts with the alcohol at ~40%. then vapor kept wanting to escape out the top. cooling water exiting was still very cold, which made me think there is just not enough surface area. using double helix calcs (Thanks for the spreadsheet) there is little less then 15' of 1/4" copper tube. when i turned down my heat enough that no vapor would escape, it was going SOOOO SLOW!!!! been reading about bending a new one, try and double the surface area. do you think packing in the condensing coil will help enough that i wont have to bend a new coil?
i could easily double the surface area by bending a new one, but i'm on a budget....
Length is 10 inches
outter coil: dia = 2.75, coil spacing = average of .4 or .5, 14 coils, .25" tubing
Inner coil: dia = 1.5", coil spacing about .4 too, 15 coils
(total length = 178 inches = 14.8 ft
Re: First Double Coil Condenser
Posted: Fri May 03, 2013 9:27 am
by MegaJohn
My coil is ~10" double wound. I did notice the flow rate is less than optimal, but it does a good job knocking down the vapors. While doing my vinegar/water cleaning run for a 2" Boka, I noticed vapor from the top of my column. I added a small piece of copper mesh inside the very top of the inner coil and have seen no vapors since.
I suspect my reduced flow rate is due to the length of the coil... but it works well for me, so I don't plan to change it at this time. If I rebuild the coil, I'll likely go with a 1/2" cold finger down the middle... in a 2" column I may not have enough room for a double coil.
drinktofabfabtodrink - With the 3" column, you have lot of space to fill with the coil. I'd consider one of the following...
1. Try packing your existing coil with copper mesh... it may do the trick for you.
2. Consider a double wound coil with a cold finger. Also, if you have the room, build a longer coil... with a cold finger. The cold finger will give you better flow through the two coils.
3. Consider a longer double wound coil with 3/8" tube. The flow rate would be better with 3/8" (a cold finger will give even better flow rate) with a 3" column, you have the room for it. If you do not add a cold finger and needed more surface area, you could pack the coil with copper mesh.
Happy & Safe Stilling!
John.
Re: First Double Coil Condenser
Posted: Fri May 03, 2013 10:01 am
by drinktofabfabtodrink
drinktofabfabtodrink - With the 3" column, you have lot of space to fill with the coil. I'd consider one of the following...
1. Try packing your existing coil with copper mesh... it may do the trick for you.
2. Consider a double wound coil with a cold finger. Also, if you have the room, build a longer coil... with a cold finger. The cold finger will give you better flow through the two coils.
3. Consider a longer double wound coil with 3/8" tube. The flow rate would be better with 3/8" (a cold finger will give even better flow rate) with a 3" column, you have the room for it. If you do not add a cold finger and needed more surface area, you could pack the coil with copper mesh.
i think i will try a small batch with the copper mesh. i would hate to spend time/money over fixing the problem. if that doesnt work, i want to try and bend a double wound coil with more coils, increase surface area. and if i mess that up im already set for a coldfinger!
Re: First Double Coil Condenser
Posted: Fri May 03, 2013 10:35 am
by bowhunt76
Wrapped mine inside and out with copper mesh.
Re: First Double Coil Condenser
Posted: Fri May 03, 2013 2:14 pm
by drinktofabfabtodrink
Copper mesh did 'er. collected down into the low twenties. Thanks for the ideas!
happy stilling
Re: First Double Coil Condenser
Posted: Sun May 05, 2013 5:38 pm
by copperwaldo
I also have a 3 inch column I use a double wound cold finger have no trouble knocking down vapor on ny cleaning run with vi.vinegar I knocked down vapor. Check out copperwaldoes still in my 1sts look at my double wound I use it with no packing and barely any water flow it works like a champ. Thinking I could run it on a closed system with a swamp cooler pump and not have problems.