What kind of 1/4" Copper tubing?

[hendecp]

Hey experts out there, I am wondering what the best copper is to use for winding a coil for my boka. I wound one around an 1" pipe, then back on itself. It isn't pretty, but it does flow. It tended flatten out a bit, but not pinched or kinked. Like I said, it works, but I have seen much better. I did read the thread on winding a coil and his came out much better than mine..... Ok, it was pretty damn perfect. What I got at the local hardware super store was 1/4" for refrigerator water line. Is there something better that is not as susceptible to flattening or kinking? I did my roll with out salt or any of BS that I have read all over. Mine condenses enough to make distilled water at 212. I just want to make the "perfect" coil for the best surface area and cooling of the vapor.

Thanks in advance!

[myles]

The tube you have should be OK, that grade of copper is usually softer and a bit thinner in wall section than the plumbing equivalent. You do have to be aware though that it can introduce a fair amount of back pressure into your pump - the longer the length of tube used the more pressure - and some pumps do not like it.

In 1/4" I try to wind really slowly to prevent heating and work hardening - empty - I never had much success filling 1/4" tube. I have not tried using water for some time but it should work well by all accounts. For larger coils I would use a bit bigger tube.

[hendecp]

Thanks Myles, I thought so, but wasn't sure if there was a better grade. Oh, BTW, I did fill it with water and pinched the ends shut. The theory is that water does not compress, so you copper should not kink or flatten. Mine did flatten a bit, but I assume I still had some air in the line.....

[Usge]

Mine looks pretty flat, but it flows plenty. Just hook the coil up to your water, put the output hose in a gallon jug. Turn the water flow on high and measure how much flow you get in one min. If you are like most people you'll probably get close to (or right at) a gal. If that's the case, you can rest easy...that's way more than enough knockdown power.

[hendecp]

Good advice! I will try that tonight and see what my output is.... Thanks!

[Usge]

I always tell people...when doing this test...it's a good time to check for "leaks". A leak in an overhead reflux condenser can wreak havoc on the operation of your column. And the best time to check is when it's under pressure....(such as the test above). You'll probably never have to flow that much water during a run. If it's a single/double wound coil, the chances of a leak are slim unless it's kinked to the point of splitting. But, if you've got a coldfinger setup, there's a solder joins that can appear to be ok, but leak badly under pressure.

I bet you your coil is gonna flow more than you think. I think, if I recall correctly, that if you can get at least 800ml to a liter per min..you are good. My guess is your coil gonna flow 2x to 3x that.