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What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 7:56 pm
by WoodpeckerWelder
Just wondering what a good metal would be to use for keeping aluminum from getting too hot while TIG welding and warping. I fused a couple of 4x12 pieces of 1/8th inch brass together with that intent and am wondering if that would work.

Re: What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 8:27 pm
by Farmwelding
Copper and aluminum are the two most common. Big chunk of aluminum though.

Re: What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 8:50 pm
by WoodpeckerWelder
Can you describe "big"? Like plate or heavy wall tube? How thick? What I am limited by is what I can find in the offcut pile.

Re: What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 8:54 pm
by Farmwelding
The thickest you have is best I would say no more than like 3/4"-1" for weight. If you've got some 1/4"-1/2" that will help some.

Re: What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 8:57 pm
by LtBadd
Might be helpful if we could see what it is your welding, I'm guessing thin aluminum??

As Farm said AL and copper are very good heatsinks, without seeing your part I'd say AL flatbar would be the least expensive, how thick depends on how much amps you need to make the weld, and maybe a little try and see...

Re: What's the best metal for a heat sink?

Posted: Sat Feb 25, 2017 9:13 pm
by WoodpeckerWelder
I'm not welding anything specific, just practicing flat welds between two AL plates (1/8th, 3/16th, 1/4) & fillet welds on the same. Also been told to practice on stainless 1/16th inch sheets cut into squares and corner welded, tees, etc.
As I have a scrap pile to pull from, I could get 1/8th inch AL all day long. Would stacking them and fusing the edges have the same effect? The brass seemed to fuse well, but it's it effective? We don't do copper except on rare occasions, so that option is out.

Re: What's the best metal for a heat sink?

Posted: Sun Feb 26, 2017 6:56 am
by cj737
Look up MetalSupermarkets, have them cut you a 24"x24" piece of 3/8" AL. Use it as a bottom plate to suck the heat out. It should be really affordable and very durable. Thicker is always better.

Can you fuse multiple sheets of 1/8 together? Yes, but they will not "stick" in the middle and will warp and buckle differently from each other and that will be like welding on marbles. Not recommended.

The thing to bear in mind, the AL heat sink will do just that, suck all the heat into "it". So be prepared,, it will get HOT to your arms and hands. No more short sleeve welding with an AL block. I have a 3/8" welding table of AL and while it has some great uses, I often forget I'm using it versus my steel table and have the blisters to prove it. :oops:

Re: What's the best metal for a heat sink?

Posted: Sun Feb 26, 2017 11:33 am
by WoodpeckerWelder
Thanks for the advice guys. Will check out the AL plate. And wear sleeves! :mrgreen:

Re: What's the best metal for a heat sink?

Posted: Sun Feb 26, 2017 2:15 pm
by Oscar
Brass, while still twice as fast as steel at wicking heat energy out, it is still just over 25% of what copper is capable of. So copper is ~4x faster than brass.

Silver is the best metal with regards to thermal conductivity; it will wick it out even faster than copper and dissipate it just as fast, BUT if asked to wick out too much heat, it will saturate twice as fast as copper as well (difference between thermal conductivity and specific heat capacity). Overall, I'm pretty confident copper still reigns as king. Unless you have pure silver plated copper-core heat sinks. :)

Re: What's the best metal for a heat sink?

Posted: Sun Feb 26, 2017 4:38 pm
by Poland308
If your going to go that far you might as well solder a tube system to the bottom of your table and run a pump cooler.

Re: What's the best metal for a heat sink?

Posted: Sun Feb 26, 2017 7:10 pm
by WoodpeckerWelder
Poland308 wrote:If your going to go that far you might as well solder a tube system to the bottom of your table and run a pump cooler.
Or dissect a cheap yard - sale window a/c and slide the evaporator coil into an aluminum box.... ;)

Re: What's the best metal for a heat sink?

Posted: Wed Mar 01, 2017 12:33 pm
by pgk
If money isn't a issue go with a copper heat sink if it is go with Aluminum, as stated copper will pull more heat out it will also pull more out of pocket. LOL

Re: What's the best metal for a heat sink?

Posted: Wed Mar 01, 2017 7:28 pm
by Poland308
WoodpeckerWelder wrote:
Poland308 wrote:If your going to go that far you might as well solder a tube system to the bottom of your table and run a pump cooler.
Or dissect a cheap yard - sale window a/c and slide the evaporator coil into an aluminum box.... ;)
Ditto over done! Yep. Good enough! Yep. Cheap and dirty! Yep.