Has anybody tried brazing with mapp gas and the aluminum brazing rods. The brochures put out by the manufactures make some impressive claims about the strength of the welds. Seems like this would simplify the home builders welding requirements a great deal.

?? Are u talking about alumaweld??

I am guessing you're talking about something like this:


Coincidentally, I found out about this type of aluminium brazing rods yesterday, and it looks like the cheapest and easiest option available to weld non-ferrous metals at home. However, I'm looking at brazing some crank arms, so I'm also very interested in finding out how strong this type of braze really is.

I think you will be disappointed. I don't know if the manufacturer will give you actual data, but I'm guessing that it's lacking in the area of fatigue resistance

Here you go:
https://durafix.com/

This stuff is for filling in non stress areas.If you want to fill in some engraving or a brand name it's perfect.If you trying to repair a crank arm,not so good.

This stuff is from the refrigeration industry,for building/repairing aluminum high pressure lines.Been around along time.

I'm not a builder but I doubt that will work to be used in something else besides maybe adding bosses to an AL frame, as somebody said... stress areas issues, well the other issue is that once u weld with AL u have to put the frame back in a furnace to get it heat threaded again so the whole frame gets its resistance back.

If you use this to weld the frame could crack somewhere else but in the weld. Maybe somebody made a frame using this thing? Wish there was something similar for steel.

there is, it's called low fuming bronze

I'm pretty sure there are no shortcuts. Everything has its downside. But in the end, it's going to take some investment to build a frame.

I've helped patch a crack in some old British car fender with that stuff and it worked well. But like everybody has said, it's not strong enough for a frame..... not to mention the fact that heat treating will make the Durafix go soft.

Low Fuming bronze?? It melts at super low temps???

LFB is not low temperature. Anything that melts at a low temperature has some additive in it that is going to keep it from being strong enough to use.

Brazage Low Fuming Bronze

It's not so much that the rod is not strong enough,it probably is,but that your far into the temps in which MOST aluminums anneal,gets dead soft,as in,bends with your hands.Most aluminum will start to anneal at about 375*,some as high as 800*.With enough dwell time,you can anneal 6061 T-6 back to dead soft at about 400*.The higher the temps,the less dwell time needed.

there have been gas welded aluminum frames in the past, but I know nothing about the process. I assume it took some skill