Aluminum wheel crack repair

[jakeru]

I've done a few more crack & divot weld repairs for the aluminum wheel repair outfit.

Here is my latest I just welded today. This AMG (mercedes) wheel measured a little over .40" thick.
Attachment 1643Attachment 1649

Before repair:
Attachment 1642Attachment 1641

I veed the crack like I usually do and also used an aluminum oxide impregnated plastic bristle cup brush to remove the paint down to bare aluminum in the area around the weld. It took a little time to work, but worked well. The bristles get into and clean irregular surfaces really well. Followed by a solvent clean.
Attachment 1644Attachment 1645

The key to penetrating all the way through on thick material like this is to bevel the joint. I like to go over the joint with my TIG torch at a low power level first, using the AC cleaning action to blast away any remaining contaminants and burn/evaporate any remaining oils/solvents that may be stuck in the crack or in the pores of the metal. Then when it is all looking good, I hit it with the real metal melting power.
You know what, I didn't feel like I needed any more power than the 200 amps my machine can muster. I had it set at about 25% cleaning (EP%), no pulse, and the machine has a fixed 60 Hz AC frequency.
Attachment 1646Attachment 1647

3/32" tapered & blunted lanthanated electrode worked well; I didn't need to step up to 1/8". I did prepare the blunted tip with a smooth shaped dome tip, with no sharp edges. I did dip it once near the end, which is not extremely uncommon and usually calls for changing the tungsten on an aesthetic weld. Since this weld will just get ground down, I just rolled with it. Here is what it looked like afterwards, starting to get a little bad but it was still making a fairly decent arc shape even like this:
Attachment 1648

Do you guys want to hear something funny? The aluminum wheel repair outfit that keeps sending me these wheel weld jobs has a top-of-the-line, Dynasty 350 TIG welding outfit in their shop, dripping with the most expensive accessories: matching Miller watercooler, top of the line weldcraft "crafter series" watercooled torch, etc. They said they spent $8k on it, but apparently no one there knows how to use it! Unless you count customers seeing it and being impressed with the "name" and how much it cost.

They seem to like having me do all their welding work. They told me the previous welder who did their aluminum wheel TIG welding, often would have to re-weld it, as many as four times on one wheel, because his welds would often crack during wheel straightening. They said the ones I welded have yet to crack once during straightening. That was pretty nice to hear!