Brazing aluminium? Anyone tried this?

[The_Doctor]

I usually do use fine surfacing and drilled and tapped fittings to join aluminium but I think this stuff might be a goer, it could be like soldering. That's an ideal method for small stuff too, IF it works.

Anyway, I went for it, £18 for ten rods is about half the price of the best deal on eBay, and it's direct from the UK branch of the maker's operation and includes postage.

I did search for forums discussing it, and it either has people curious but a bit doubtful, or a smaller number who have tried similar things and found them ok but with some caveats. This new stuff has clearly defined improvements of specific problems with the older stuff (better resistance to thermal stresses, better penetration of oxide layer and dirt).

I think this stuff is useful; for a start, not having to use fluxes, welders (expensive if you're not doing a lot of work) or gasses or elaborate pre-treatments makes it an ideal for (careful) use in a domestic setting. Aluminium has never really been safe to work in a domestic setting before except for hand working, and maybe a small range of fixed power tools. (I say 'fixed' meaning that alumium while soft has a tendency to catch on moving tools and is elastic and moderately brittle, very dangerous if not anchored firmly). Even soldering uses acid fluxes and results in poor bonds and slaggy ones at that, and some truly NASTY fumes, so this new stuff is either a dead loss, or a minor miracle, and it has to be worth £18 to find out which. If it were a dead loss I'd probably already know by now, I read as much as a couple of hours work could find me.

[carmangary]

Cool. Sounds like it will be fun to try regardless of the outcome. Let us know how it works out.

[The_Doctor]

Will do. One nice idea occured to me later than it should: I read that it can bond other nonferrous metals. What will be truly awesome is the heatsink potential if it can bond copper and aluminium. At 17 and 23 10-6/K at 20 °C respectively, their coefficients of expansion are similar enough for small copper plates to be bonded to large aluminium heatsinks. Each might be found in alloy form to even closer. This might be very useful in constructing lasers using soldering and basing them directly on aluminum baseplates. It could dramatically improve heat conduction and stability of alignment.