DIYbanter - View Single Post - Anybody here done this, soldering steel to aluminum?

Gray_Wolf

On 4/29/2016 9:54 PM, wrote:
All yooze soldering type folks,
I want to solder a steel tube into an aluminum one. I'm thinking that
if I tin the steel with the mostly tin lead free plumbing solder and
the aluminum with the mainly zinc aluminum solder I should then be
able to join them together with the lead free plumbing solder. I know,
because I have done it more than once, that I can get the lead/tin
solder and lead free plumbing solders to wet aluminum but it is not
nearly as easy as using the zinc based stuff. I know there are other
ways to do this but I am looking for a fairly simple, low tech, strong
and cheap, way to join the one tube into the other with a reliable
method using widely available materials that won't be affected by
solvents like gasoline, alcohol, acetone, benzene, and the other
typical components of pump gas. This is not just for me. I also want
to be able to show other folks how to do this, folks who have limited
resources and education.
Thanks,
Eric

Try Sal-Met flux. It worked well for me using Lead/Tin solder.