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Can you solder aluminum to aluminum?

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Breadfan

Inactive Moderator
Joined
Jan 4, 2001
Location
Northern VA
Well, I think I read somewhere you can't, and it sure didn't work to well last night!

Anyway, I found an old Antec Jetcool heatsink. I'm trying to see if soldering the little heatsink ring to the aluminum core will net better results compared to using AS3 between the two.

So I ran the test with AS3 on a Duron800, and then I went to solder the two peices together.

I cleaned both peices, sanded them with 180grit to rough 'em up, put some flux on, fired up the butane torche, and the solder would just roll right through the heatsink fins and would not be drawn into the cracks between the heatsink and core...

How can I bond these two peices? Will soldering work or must something else be done?

I got this heatsink for free, and I'm not using it, so I'm not too afraid to break it.
 
Because of alluminums heat transferance abilities it woudl be damn near impossible to solder the two pieces together. You could try J.B. Weld, but I'm not to sure how well it conducts heat. Good luck with this.
 
Cool, thanks guys. I might try those benzomatic aluminum brazing rods since they're cheap. This isn't a champion heatsink, I'm just trying to get some idea of the difference between joining to pieces with AS3 and solderig/welding.

It will be interesting to see if the brazing material will actually "flow" into the cracks...
 
The problem with aluminum is that it is really hard to solder. I know if the torch heats it up too much(which does not take very long to do) it will just melt the aluminum.
 
no no no no no no no.

aluminum cannot be soldiered. not because of the torch becaus esoldier doesnt stick to alu. copper has better thermal properties than alu and silver has better thermal proterties than copper. and i soldier silver so no it doesnt melt.

i have these little rod things though. its like soldiering alu but its not soldier. u heat up the alu and rub it on as if you were brazing it. well you are. this is some type of alu compound that sticks to the alu, no need for flux or anything. it is used on cars and very strong i however have a limited supply and dont know what it is called.
 
[EG]~NaTz~ said:

i have these little rod things though. its like soldiering alu but its not soldier. u heat up the alu and rub it on as if you were brazing it. well you are. this is some type of alu compound that sticks to the alu, no need for flux or anything. it is used on cars and very strong i however have a limited supply and dont know what it is called.

i mentioned it in the post that's linked to in here. it was called allumaloy. all you need is a propane torch to heat the base and then scrape it on the hot surface.
 
And this will only really work for the EDGES of the aluminum, so if you're going for heat transfer experiment between 2 peices - not even worth it. AS3 epoxied aluminum would probably work better.
 
or you could use good-ol JBWeld.. just clean the surfaces real good and apply... works great and you can drill, tap, cut, etc. it!!..

cheers
Charlie
 
64Thunderbolt said:
or you could use good-ol JBWeld.. just clean the surfaces real good and apply... works great and you can drill, tap, cut, etc. it!!..

cheers
Charlie

Yeah that'd work, but on the jet cool the fins go around the core, usually just with thermal past. The reason to solder or weld would be to make it one solid unit, i.e. better heat transfer.

I doubt JB weld would match AS3 though...

***edit

Here's the jet cool taken apart. The "ring" of fins goes around the core. In this pic the core is upside down. An all copper version that is soldered might not be so bad...sounds like it's way too much trouble to join these peices though.

jetcool001.jpg


Here it is put together and on a Duron800.

jetcool002.jpg
 
Last edited:
AS3? is that a thermal adhesive? Im not formilar with it, but I know from experiance that JBWeld works very well, and if your just joining the ends of the ring together then mounting it on the base, then JBWeld will do the job. Besides, the fins will be doing all the work (cooling), not the joint..

more of my 2 cents..lol
cheers
Charlie
 
64Thunderbolt said:
Besides, the fins will be doing all the work (cooling), not the joint..

more of my 2 cents..lol
cheers
Charlie

Thats the whole point to soldering it...would solder be more effective of a joint than just using Artic Silver thermal paste between the two peices? (Starting to sound more like a question for the general cooling forum!)

Thats what I was trying to see though, to see if the performance of this heatsink could be improved from stock by soldering/welding the fins on...but like I said, too much trouble for an obsolete heatsink.
 
ah i think u should not use solder but use "AL" instead because its better then lead holds better too and yes its too much troble for u to do it u no its hard to weld al right?? with out the right equipment
 
I didnt read all of the posts but you can use a filler rod and an asetylen torch to weld aluminum. You could also find an aluminum wire feed welder. Used one of those in metals freshman year and it worked great. If you dont have any off that try an epoxy to hold them toghether.
 
benzomatic aluminum brazing rods should work fine. Just make sure you use a stainless steal brush on the surfaces you want to join to get the oxide off. It will transfer heat much better than any epoxy will.

[EG]~NaTz~

that really made no sense. Yes there is a solder that will stick to aluminum but it needs a larger percentage of Zinc and I think silver works also. The trick is finding the right flux. No normal flux will work, it has to be made for aluminum and hardware stores wont carry it. Also you really need to remove the oxide on the surface using a stainless steal brush or it wont go on.

I havent made my case yet sense Im still messing around with this phase-change unit and now I see the shuttle case and its looking quite tempting at the moment:D
 
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