Best gas for brazing/welding aluminum

[Pat]

Just wondering if there is any gas best suited for brazing or welding aluminum. I searched the web but did not really come across anything that specifically promotes one gas over the other.

I started wondering about this after reading an article about using Oxy/Ace for the gas welding of steel. If I recall correctly it stated that petroleum based gases are too much of an oxidizer, and result in very crappy welds. I was wondering if the same would hold true using petroleum based gasses for welding or brazing aluminum. If so it may explain why my aluminum brazing results in somewhat ugly and slightly porous joints using map gas..........thanks.

[LKeithR]

All I've ever used for regular brazing or gas welding of aluminum is oxy-acetylene. Easy to control the oxidization by how you set the flame.

I wouldn't say that either method is obsolete in today's world but in almost every case we encounter there are other, mostly better, processes that can be used. Back many years ago we used to use oxy-acetylene when building small, lightweight fuel tanks for race cars or hot rods. It was a functional process but once we got our first tig welder we never used it again.

My wife's uncle, who really got me started in the welding game, worked in the I.E.L. chainsaw plant in Vancouver for a couple years immediately after WWII. To keep weight down they used as much aluminum as possible and all the gearcases, tanks and frames were made of aluminum and gas welded.

Brazing is also something we don't do much of anymore. There are a lot of really good tig rods out there now that can do a fantastic job of cast iron repair...

[LW Hiway]

The only times I've used mapp gas for anything was in a welding shop setting as a cost saver over Acety, although we kept Acety on hand in smaller qty's for Al welding.

Never found Mapp to be an alternate to Acety.

But, there is a learning curve doing Al due to Al's lower melting pt under steels.

Clean clean clean still applies.

[Harvuskong]

Yes, clean, clean and clean the metal surfaces before you start to braze the aluminum.

The demos of aluminum brazing that I seen at the farm shows involved the use of small propane torches attached to the small non-refillable handheld propane cylinders.

And it appeared to work too.

Of course, they were using the special aluminum brazing rods that they were selling too.

Have seen any demos in the past 10 plus years however. The farm shows got smaller and smaller because of the drought and bad years in the ag sector.