6 replies to this topic

[Ethel]

Look what I brung for show 'n tell



Mmmph I hear you say, that just a random alloy pipe.

Indeed it is, but it's a random pipe for the heater take off on my cylinder head that I made with my own fair hand....

AND it started out as two separate bits of aluminium that I joined together using a domestic electric hob and
this stuff:


It really is as amazing as they make out and could prove invaluable as the alloy components on your Mini start to show their age.

My botching as moved on to a whole new level

[Jupitus]

That demo's pretty darned impressive!!!

[dklawson]

Similar products have been available for quite some time. They are frequently lumped together as a family under the name of "aluminum rub-on solder" since they use no flux.

These were first demonstrated to me when I was about 16 (a mere 31 years ago) when a very skilled acquaintance of mine used an oxy-acetylene torch and the rub-on solder to close pin holes in a disposable pie pan (roughly 0.010" thick) just to show he could do it. I bought some of the rub-on solder shortly thereafter but have only used it a few times.

An ex-boss of mine had a leak in his car's aluminum air conditioning condenser. All the Freon had leaked out and he was upset that he was going to have to replace the condenser and recharge the system just to sell the car. I gave him a stick of the rub-on solder and instruction on how to apply it since he knew the leak was at one of the hose connection compression fittings. He didn't believe it would work but gave it a try. He kept applying heat and rubbing the stuff on thinking it was a waste of time... and then he hit the critical temperature and the solder flowed around the gap, closing the crack and leaving a nice bead behind. A little Freon and he has good-to-go.

The rub-on solders are worth their weight in gold when they can save you money like that.

[samwell]

wow, i want some.

[Ethel]

It is peculiar stuff to work with. As Ed said you can scratch around for ages with nothing happening then it hits the temperature and it all becomes a bit hectic.

From my limited experiments so far I've learnt that you need all the heat you can get but not too much temperature - the hotplate is certainly a good idea even if you use a blow torch as well. I was thinking of trying one of those electric paint strippers too. you get best results if you get it right first time but you can spread it about with something steel like a screwdriver tip - tends to make it sit in ridges like a tig weld. It doesn't flow into joints thanks to that crazy surface tension - I've bridged a few bolt holes I never intended too! Use a good chamfer on seams, as you would for a built up weld. For that pipe I "welded" the underside first and used a steel plate as a chill while I did the top - if you want nice radiused joins you need gravity on your side.

The joins clean up nicely with a file (better than weld) the solder is harder and shinier than the aluminium.

Actually weld is probably a better term than solder as it really does fuse into the aluminium - as I found out when I reheated a joint to reposition it and it ran off leaving big craters behind

[che]

interesting piercing - the mind boggles as to the body part though!

keep up the good work

[Ethel]

lol - I reread the entire thread - thought it must've been something I mistyped that never occurred to me!

Guess I'm just getting old