Aluminium brazing.

[Stevex]

Anyone used this method with butane or mapp gas torch?
Was it easy and what did you think of the results?

[rodekyll]

I bought a pound of that rod a few years back.  Looked easy and effective in the videos, but I couldn't do anything meaningful with it.  They said any idiot could make it work.  I guess I don't qualify.   

[John A]

I couldn't get that to work for me either. What did work was some aluminum flux and some aluminum rod and lots of practice before doing the piece I wanted to weld. The flux gives the indication of temperature ,just before the whole glob hits the floor. It can be done but I don't think it works very well

[oldbike54]

 Watched a demonstration years ago , the guy was brazing beer cans together , so I bought a tube of the rods . Burned up the entire tube and only succeeded in burning up the rods 

  Dusty

[Markcarovilli]

I did manage to fix a pin hole leak in an aluminum baking pan.  Shuda just bought a new pan....

Mark

[Triple Jim]

I've used it successfully many times in past decades.  One problem is that once you use it, if it breaks and you want to weld it, you have to get all the brazing rod out first.  I've since gotten suitable welding equipment and don't use the brazing rod any more.

To answer your specific questions:

1.  No, it wasn't easy.  It  took some practice to get decent results, and usually quite a bit of shaping with a Dremel tool or other method to make look decent.

2.  The results were very good once I did the stuff in "1." above.  Strength and adhesion were decent.  It can be polished, but dulls over time, so after a while the braze material is dull grey, and the aluminum is still shiny.

[StuCorpe]

I have used it several times, worked most of the time on thin pieces, never got it to work on thicker pieces.

[Sasquatch Jim]

 Fifty years ago I was taught by an old blacksmith to use an oxyacetylene torch to weld aluminum using indicator flux and filler rod.
 With practice I became very good at it.  Then I discovered Allstate 11, an aluminum filler rod with flux on it.  I found that it worked best if I still used the indicater flux  This was actual welding and not brazing.  The trick was that the filler rod was of an alloy that melted at a temperature about 100 degrees less than aluminum so if you did not understand the visual clues of the indicator flux, it would all melt into a puddle.  The torch was lit and adjusted to a slightly carburising flame rather than the neutral flame used for steel welding.  A neutral flame was too hot and would scorch the aluminum before it reached melting temp. thus making it impossible for the metals to flow together.  The work had to be cleaned with a stainless steel brush that had never been used on other metals.  Microscopic contamination on the surface could prevent a weld from taking place.  Unfortunately, in the last twenty years I have not been able to find any Allstate 11 rod and even indicator flux has become difficult to find.  All the pros now use tig welders and the skills of oxyacetylene welding  are being lost.  For aluminum such skills are a rarity made more so by the lack of proper materials.
 I one tried the use of a propane torch as described above.  It didn't work, oxyacetylene or tig is the only way.

[cruzziguzzi]

I used to buy some odd-ball flux-less rods at a gunshow up Reno. Use it of aluminum framed guns for repairs and had good success in using it to build up items like AR15 receivers.

Cleanliness was VERY important in success and I recall it having a tendency to extend cracks after cooling if I did not terminate the crack with a relief cut/hole first.

Sacrificial shavings from the item being welded helped in steering clear of overheating the base item and a fine tip worked wonders.

Todd.

[56Pan]

I never had much luck with those aluminum brazing rods.  Got a tig welder years ago and it was a good investment.  Cleanliness of the weld bead area is very important though.

[Groover]

There is a way to arc weld aluminum. I don't know how, but have seen it and have had it done. They were Vespa engine crankcases that we would weld/build up certain areas so the transfer ports could be enlarged to mate properly with larger top ends and other for other mods. If was my friend's dad (he passed away years ago) that would do it for us. He used aluminum rated sticks for the welder and would tinker with the amps on it. I don't know how to braze aluminum however, that would be great.

[Pancake]

I used something called HTS 2000 and it worked a treat. I've repaired a rocker cover, a footrest hanger and a brake lever with it.

[Triple Jim]

I used something called HTS 2000 and it worked a treat. I've repaired a rocker cover, a footrest hanger and a brake lever with it.

That's pretty much the same as the others, just a different name, I think.  The idea is you get the aluminum near its melting point and put melt some rod on it.  Then by either scratching the aluminum through the new melted metal with the rod itself, or with a stainless steel brush, you get rid of the oxide on the aluminum's surface, and the new metal sticks well.  I think most or all of these rods are mostly zinc.