Aluminium Bronze

Just spent an hour making a complicated composite elbow using some 1/4" dia copper tube and a piece of Al bronze to form a nipple to a 1/4 BSP gland nut.

First one turned out a bit too short, so spent a bit more time and turned up a second nipple.

Went to silver solder the tube into the nipple and THEN I remembered that Al Bronze (If that is what I have) doesn't silver solder (or lead solder).

A few choose words selected !!!

Bob

It can be silver-soldered, but it does usually need some specific flux for the job. I recall mixing some aluminium flux with silver solder flux for a job at work a long time ago and it worked well. Luker in his current Fire Queen series in ME shows what looks like an excellent join in aluminium bronze.

Thanks Nigel

From model engineering pro boards:-

"As the content (of aluminium) increases so does the need to remove the aluminium oxide. A special flux is often recommended. This special flux has a higher content of chloride.

Make your own by adding 25% by weight of kitchen salt (sodium chloride) to your conventional flux! Use it in the same manner."

That is an easy one to try out tomorrow. I will let you know.

How about the ‘lumiweld’ rods/wire for the job? I use it quite often for all sorts of jobs. No flux just scratch the surfaces to get the filler to run.

Quick update - EF flux plus 25% of common salt worked a treat to wet the joint surfaces and allow the silver solder to flow properly.