Waterblock for TO-220

[SwooshingRob]

Mates,
I need some ideas for a waterblock to cool ten TO-220 (power transistors).
I was thinking I could use a 2mm(~1/16") copper flat and attach the TO-220s to one side and solder a 13mm (1/2") copper tube to the other side, like this:
http://www.moonlight.plus.com/to_block.GIF

My concern is that there might not be enough surface area between the tube and the flat.

(One problem I'm having is that I have very limited access to tools, so I don't really want to make a too advanced solution. )

One thought I had about increasing the contact area would be to use a hammer and flatten the tube a bit. But that would restrict the waterflow, wouldn't it? What if I use a Y connector and put this waterblock in parallel to the main flow?

All comments are highly appreciated.

Cheers,
Rob

[SwooshingRob]

Anybody out there?
What if I use a huge amount of JBWeld instead of soldering? How good is JBWeld in transporting heat?

Rob

[#Rotor]

http://3rotor.homelinux.com/images/R_and_D/TEC-driver/Page01/DCP05089_sml.JPG (http://3rotor.homelinux.com/images/R_and_D/TEC-driver/Page01/DCP05089.JPG.html)
http://3rotor.homelinux.com/images/R_and_D/TEC-driver/Page01/DCP05093_sml.JPG (http://3rotor.homelinux.com/images/R_and_D/TEC-driver/Page01/DCP05093.JPG.html)

Something like So maybe...... :D

[Voodoo Rufus]

What are you trying to cool? An audio amp?

How about a square tube attached to the copper plate where the transistors are?

[eobard]

Originally posted by Voodoo Rufus
What are you trying to cool?
Ditto? Inquiring minds want to know.

[Stedeman]

Your idea should work fine the way it is, if you wanted a little better performance just use silver solder.

[SwooshingRob]

Thanks for your answers! (and questions...)

It sounds like a good idea using a square tube. While I'm looking for that I will give my first design a try. I will follow Stedemans advice and use silver solder instead of JBWeld.

The block is going into a PSU. I need to be able to draw 20 Amps out of it, so the regulating transistors will generate a lot of heat.
That's why I like the idea of using a tube, because that would mean no joints within the PSU box which guarantees no water leaks. Water leaks and mains voltage together with 20 Amps current is not a tasty cocktail.
I'm actually not that worried, but it's never a bad idea to minimise the risks.

Rob