anyone tried using 1/2" to make a coil?

[spencer321]

still in design process for a 4" boka going to need quite a large condenser, if the 2.5 x diameter for center ring rule holds true, i can do a double helix with 1/2" around a 1.5" center diameter, but i'd like to hear some real world experience with wrapping a coil this large

[Usge]

spencer...was waiting to see if anyone else jumped in. I haven't made a double helix using 1/2". But, I can tell you from experience using 1/4" OD that you have to work "very" slowly and that it "will" flatten a good bit and still be fine (so long as it's not kinked). And I would also add that using the 2.5x x center rule...that inner coil is going to flatten more than outter, and that the transition coming back over the top is where you have to be very careful. Heat/reanneal it as many times as you need and work really slow, steady.

Check it at the end by hooking it up to water source and measuring how much flow you get in one min. Min was nearly flat..and flowed a gal a min without much trouble....which was way more than enough. I hardly ever had to run much past a trickle out of it to knock down everything. I also used copper mesh around outside and stuffed in the gap inside to help with the fit. Hope that helps.

[myles]

Not sure about your reasoning here. OK a 4" column will need a bigger reflux condenser but in my opinion increasing the tube size is the wrong thing to do. The only reason for increasing the tube size is to allow a greater coolant flow rate and to reduce the back pressure for the pump.

OK you could wind a double coil in 1/2" but it would be easier and provide more surface area to wind 3 or even 4 parallel coils in smaller tube. Your best option is to think about the tube length required, and pick a diameter to suit your pump capacity.

[HookLine]

Tight winding larger size tube is difficult. Work hardens real fast.

Even 3/8" can get pretty stubborn.

Better of doing 2-3 larger separate single coils feeding into a centre cold finger for the return path.

[just-a-sip]

Tight winding larger size tube is difficult. Work hardens real fast.

Even 3/8" can get pretty stubborn.

Better of doing 2-3 larger separate single coils feeding into a centre cold finger for the return path.

+1 as i am a hydraulics specialist by trade, let me tell you that with the diameter
and wall thickness of 1/2 tubing, even if you anneal it your going to struggle. I would look into a smaller coil with cold finger model. Maybe even some fins or packing around condenser to allow for more surface area. Shoot with 4 in you can even do a shotgun type condenser with lanes just like in a flute.

[myles]

Another alternative coil configuration for the larger condensers is the "pancake" coil

These are fairly easy to wind and you just stack them up and join them all in parallel.

[mash rookie]

Everybody is giving you some good advice. 1/2” is difficult to wind tight and will allow greater vapor space being less efficient.

Thin wall 3/8 can be used. Some use water to fill and cap before winding. I like to use fine silica sand. Because it work hardens fast you really only have one shot. Wind slow and determined. When I screw up and over work it I can re-anneal a small area with a large torch. You can not do that with water unless you drain and re fill.

I would follow Hooklines advice. Wind three - four 3/8” coils and join them into a center cold finger for return. To test flow run backwards with water into the center tube. Carefully crimp the ones that flow faster until all flow is equal. Its easier than it sounds.

Myles I like your idea too. If you used two 3/8” elbows you might be able to flat wind in, elbow, flat wind out, elbow and etc,etc. Like stacking stove elements. I might have to try that one. I am looking for a simpler dephlag build.

[myles]

Myles I like your idea too..... I might have to try that one. I am looking for a simpler dephlag build.

Now hang on a minute MR, don't let the KISS principle take too strong a hold. There is also a lot to be said for over-engineering - just because it is possible to do so.

[myles]

The german approach to this dephlegmator issue is to just use a large diameter cold finger. That is probably as simple as it is possible to get.