Welding Tips and Tricks

I have a a stud hole in the Aluminum Tailhousing of my T56 transmission that I need to fill and drill/tap. I cant helicoil/timesert due to some issues with tolerances, I wanted to refill it and drill/tap it out to spec. I'm just unsure of what rods/melt an ingot? to use. I was unable to find more specific metallurgy of the T56 case other than it's aluminum.

Any help would be appreciated, thanks.

I've done this on a vintage motorcycle case a time or two. I "suspect" they're cast from 3000 series aluminum. I've used 5356 and 4043 without seeing much difference in the results.

What I have found to be very important was to drill out the original threaded hole to help clean the base material. Clean it extensively before welding. Preheat, wipe with Acetone, and weld in very short durations. I do this to reduce to the total amount of heat applied to the part to help avoid pulling impurities out of the base part. When I haven't done this, I have discovered porosity deeper in the fill when I go back to tap the hole. And let it cool for a long while before drilling our new hole.

I have been lucky that these repairs seem to have held up by good technique or sheer dumb luck.

This is the type of repair that is well suited to braze type rods like HTS2000 - you don't need to melt the base metal so contamination is less of a problem - some people will insist on welding & turn they're nose up at this but why make life harder than necessary - I've used it plenty of times & had great results - not sure what thread you will be putting back but a coarse one will always hold better in soft material.

Before I purchased a Tig welder I repaired several threads with the above mentioned HTS 2000 - the stuff tends to have a bad reputation amongst 'real welders' but for applications like this it works.

Makes a neat repair and side-steps that situation where you might start welding on a rare mystery metal part, only to find that mismatched metals and years of contamination are making a real mess of what started out as a simple thread repair.


Kym