Bending tubing - Question

[JohnFish]

Hey guys. I am trying to make a coil for an evaporator and I need to bend the tubing so that the result will be a coil with of approximately 4 cm diameter. Although, its really hard to bend it so much. Any ideas?

[JohnFish]

Also, I have another question concerning the evaporator I am trying to make. I am thinking of making 3 coils of 3.5m using 1/4 tubing using Ts to connect the coils together. Hoping you can understand the rough diagram below how can I be sure that the refrigerant will be distributed evenly? Thanks in advance

[water_cooler 20]

You could buy a tube bender
here's a link http://www.rparts.com/Catalog/Tools_...nt/benders.asp

[JohnFish]

I already have a tube bender but it doesnt seem to help. I mean its great for making 90 or 180 degrees bends but not for making a coil. Any ideas?

[water_cooler 20]

the spring tube benders at the bottom of the page might work since u put them on and then u can bend by hand into a coil
or
u can spend lots of time and effort bending it ur self thats how i made my evap coil but my hand sure did hurt after that

here a pic its not really a tight coil but it was the best i could do by hand

[Epsilon]

When using a round object like a thicker tube, and filling the tube with sand before bending you could make very tight coils by hand.

It isn't to hard actually.

[JohnFish]

you mean find a cylinder and "wrap" the tubing around it, right? I did this for the larger coils and I will try it for this one when I find some sand. Thanks for all the replies. How about the evaporator question?

[water_cooler 20]

Dabit used the 3 coil design on his last water chiller u can go find out how he didn't at his website
http://www.icecoldcomputing.com/
goto recent projects and click Phase Change IV

[JohnFish]

Dabits web page is like a bible to me. I got lots of ideas from his page although I cant understand (or to be more precise he doesnt say anything) how he distributes the refrigerant evenly. Dabit in case you read this thread maybe you could help. Thanks

[kayl]

Originally posted by JohnFish
Hey guys. I am trying to make a coil for an evaporator and I need to bend the tubing so that the result will be a coil with of approximately 4 cm diameter. Although, its really hard to bend it so much. Any ideas?

4cm is quite small, it if kinks have to start again with a larger diameter.
the smallest l've done is around a propane bottle.
maybe find some metal pip and place it in a vice.
drill a hole straight through the lowest point in the pipe and insert the copper pipe being bended. now heat the pipe slowly with a torch and bend the pipe around the smaller metal pipe.
by having the hole in the steal pipe it will hold it tight while you wrap it around it.

[JohnFish]

Ok. Just did it. it worked great. Thanks guys for your help

[kayl]

any pics, i haven’t actually done it before just an idea
what diameter of coil could you get with out kinks.

[JohnFish]

Originally posted by kayl
any pics, i haven’t actually done it before just an idea
what diameter of coil could you get with out kinks.

This is exactly 4 cm outer diameter.

[kayl]

well done
i bet that hurt ya hands

[oc_nightmare]

woo nice it could work very well as a hx

[OCme]

looks off the shelf... nice coil of copper ya got there

[Epsilon]

Originally posted by kayl
well done
i bet that hurt ya hands

I did the same with 12mm tubing, but that worked out fine

My hands didn't hurt at all

[i_jester]

actually, if you feed the tubing in the right way at a slight angle, you can coil tubing forever and very tightly with a tubing bender. It just leaves the coils spread apart a little to clear the side of the bender. Then you simply push the coils together when you are finished.

You just have to have patience and take your time feeding the tubing through the bender. Also easier with the single tube bender instead of the multi-size ones.