On Wed, 12 Jun 2019 20:51:48 +0100, Chris Green wrote:

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:-

https://www.ebay.co.uk/p/DURAFIX-EAS...d=302591197676

Does anyone here have any experience of using this (or other similar,
but cheaper) aluminium brazing rods?

Yes.

I have used a Lumiweld kit with pretty good results.

https://www.frost.co.uk/lumiweld-kits.html

I bought it specifically to weld a threaded collar I had turned up,
into a thermostat housing I had bored out on the lathe, allowing me to
fit an electric fan switch where one was never previously fitted.

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