Oxy-fuel aluminum brazing

[Joel_BC]

Okay, I'm posting about this because of this YouTube vid where a guy brazes an aluminum tube to a copper tube, using a propane torch, an aluminum brazing rod and some kind of white flux. Process looked simple, but I don't actually know about the flux. Here's the vid:

YouTube

I bought some general powdered brazing flux the other day (I needed it for working with brass and bronze rod) and asked the counter guy at our small-town industrial-supply shop if the flux could be used for propane brazing (or soldering) using aluminum brazing rod - he just read the blurb on the jar and said 'works for ferrous and non-ferrous metals', so he figured it would work. However, I figure the guy was 'just a clerk'. Was the clerk right, though?

Alright, on the YouTube page, the guy who made and uploaded the video has been asked a question about the flux he's using. And he replies, and calls the flux "040". Whatever that is! Maybe you know?

Ever used a simple propane torch to braze with aluminum rod? Thanks for all answers.

[Bearfootfarm]

Maybe this will help:

http://www.google.com/search?q=flux+...ed=0CDUQrQQwAg

I don't think propane alone will get the metal hot enough

[Joel_BC]

Originally Posted by Bearfootfarm

I don't think propane alone will get the metal hot enough

Besides a propane/air torch, I've also got O/A equipment. I guess I could select an appropriate tip with the acetylene, and then use only the outer flame to heat the parts.

[ace admirer]

its a type of "solder" northern tool used to sell it,,,,among others i,ve seen it used in storm window manufacturing.

many years ago ox-acc was used for al welding, most systems used a liquid flux that was injected into the gas stream up stream from the flame.

[Ray]

some aluminum will melt at 660F the tip of a cigarette gets to 800 deg.the best way to weld aluminum is have a sharp eye and watch for the aluminum to start the change to dull gray when it will fall, then get out. you must have good eyes and practice.
when you are welding an aluminum pot metal low temp is fine, practice on soda cans until you get it, then move thicker and thicker, then to pot metal, but i don't advise using the low temp rods on the high temp pot metal. best wishes, tig is easier, ray

[Joel_BC]

Originally Posted by Bearfootfarm

Maybe this will help:

http://www.google.com/search?q=flux+...ed=0CDUQrQQwAg

I don't think propane alone will get the metal hot enough

Originally Posted by Ray

some aluminum will melt at 660F the tip of a cigarette gets to 800 deg.the best way to weld aluminum is have a sharp eye and watch for the aluminum to start the change to dull gray when it will fall, then get out. you must have good eyes and practice.
when you are welding an aluminum pot metal low temp is fine, practice on soda cans until you get it, then move thicker and thicker, then to pot metal, but i don't advise using the low temp rods on the high temp pot metal. best wishes, tig is easier, ray

Thanks for all the tips on this, Ray.

And you add "tig is easier" - ah, yes... but I don't own a tig rig, nor do I have access to one. I've got air/propane and O/A. But about the tig, I'd have infrequent use for it, so it would definitely not be worth the investment.