Brazing aluminum

[Micropuller]

One thing I have been wanting to learn over the past couple of years is to braze aluminum.
A couple of weeks ago I decided to give it a try. I bought a propane/oxigen brazing set, the Gloor ME2000:


Then I had to find some proper soldering rod and flux. I asked around and got a tip from an elderly metalworker that there was a company which produces what is, in his opinion, the only proper rod and flux. He warned me that using it wouldn't be easy, as the rod melts at 580 degrees celsius, where as the meltingpoint of aluminium is about 650 degrees celsius.

So i went and ordered some and started experimenting. After using up most of the propane (1 litre) and oxigen (4 litres), I finally got the hang of it. Once you know what to look out for, it's really not that difficult.

In the picture you can see two testpieces. On the left is a piece of solid aluminum (50mm in diameter and 13mm thick) with piece of tubing (31x28mm) brazed to it. On the right there's two pieces of solid aluminum (ok, the top piece has a hole drilled through it), one 50x21mm and the other 35x18mm.


I really like how clean the finish is and I think i'm going to try and make an aluminum exhaust flange and header for my new puller and braze them together.

[BMSMA]

What is the name of the flux and rod, and where did you get it. The joints look great.

[Micropuller]

On the packaging of the rod it says "Vedal 460-2" it's 88% aluminum and 12% silicium (Al88Si12)
The flux is called "Alumiet 163" On the label it only says that it contains sodium-fluoride. According to this website it's really nice stuff.

[JohnRobHolmes]

That is a nice joint there. So how do you get the flux to melt before the aluminum you are joining? Sounds like an impossible task to me.

[Mad Scientist]

Very nicely done - good find on the materials.