Conductive Copper Paint/Spray for aluminum that is solderable

Dear All :

My name is Shreyas and I have an interesting problem. I have a piece of aluminium that needs to be soft-soldered onto a copper strip (of the same dimensions as the aluminium piece) on my printed circuit board. When I gave this piece for manufacturing I chose aluminium because it was easy to machine compared to copper or brass, however now I find it impossible to soft-solder the aluminium onto the copper piece. The reason is aluminium needs to reach a very high temperature before it can be soldered.

I was thinking of electroplating copper on the aluminium piece or spraying it with some sort of conductive spray/paint and then soldering it. Do you think this approach would work? If not, could you suggest some alternative means by which I could get out of this problem ? I am working on a research problem and this is a small part of my research work which has stopped me from looking at the big picture. I would be highly obliged if I could find a suitable way out of my predicament.

Thanks and Regards.

Hi, Shreyas. Fortunately you are far from the first person who thought aluminum would be a good material of construction for electronics applications. It is rather routine to electroplate aluminum parts like this for soldering. The usual process is zincate, copper plate, tin plate -- and you should be able to locate a plating shop who can do this for you. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey