There seem to be lots of people selling aluminium brazing rods nowadays with claims that it's easy and as strong as welding.
One of the major suppliers is Durafix:-
Yes.
I have used a Lumiweld kit with pretty good results.
This was over 30 years ago when we built the kit car.
I remember it lasting pretty well (20+ years), but I believe I've since re-done it using two-part 'Liquid metal' epoxy and think I'd use the epoxy again, if I had to do anything similar (where there was room for the epoxy to have a fillet / reasonably large contact area).
When I was practicing with the Lumiweld I think I brazed a couple of bits of ally scrap together and when destruction testing, the metal failed before the joint.
Cheers, T i m
I seem to recall from my metalwork at school warnings were that not all ally is pure ally, so one needs to be careful. Brian
Couldn't get the damn stuff to stick, just a little gob here and there. Also, Aluminum conducts heat very, very well, so it needed plenty of torch.
Ended up using a two-part epoxy, as temperature, load, surface area, etc. allowed it.
Thomas Prufer
You can get alusol ( not anusol! ) And that claims to allow you to solder to aluminium.
Also a company called superior flux that offers an aluminium cleaner and AFCW 99C and AFCW 96S solder wire that can also solder to certain aluminium grades.
Thanks Tim, that's really useful. I have a little crack at the edge of a transmission case and I've been wondering if something like this would be worth trying. The crack doesn't *really* need fixing, it's only in the lip/edge so I'm pretty sure it will hold together and be oil tight anyway. I'd just be happier with the crack fixed.
Alternative is to TIG-weld it, i.e. go to someplace where they do it and let them do it. Easy for those practiced in the art, and those that have the expensive equipment (needs AC, and I think Argon, and plenty of current). Possibly done for a bit on the side.
I'd worry that torch welding would cause the whole edge to sag. The rods I used didn't take kindly to crud and oxides, and I spent a lot of time and gas on scraping and scratching at the ally to no avail. Don't see how you could get the inside of the crack clean, to give the flux a chance.
Or maybe "Loctite Fixmaster Aluminum Putty" or one of its brothers?
Thomas Prufer
I have soldered aluminium with ordinary lead tin solder. The secret is Carr's aluminium flux, and an open window.
I'm interested in this too. I bought some a couple of years ago just to play with. Not as easy as the videos suggest, in my experience, and I am fairly experienced in soldering and silver soldering with a gas torch for steel, copper alloys, and jewellery.
For things like crack sealing I'd look at epoxy first.
I managed to MIG weld ally at home. Not too complex - just a bush for an ATS into the side of an ally tube. After a bit of fettling, looked ok, and has certainly held - been on the car for some 10 years.
I'd have thought soft solder weaker than a decent epoxy?
Yes but it is ductile, and resistant to chemicals and UV, and feathers better.
In my case it was to make electrical contacts to aluminium electrodes in LI poly cells
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