Aluminum, cracks from work hardening it

[32chevy]

Wanted to share one of my first projects. I have read through half of the basic q's and A's threads,

I'm making a rear pulley cover for my delta drillpress. I chose 16ga 3003-h14 aluminum. I used wheeling machine, tuck fork , stump and heavy blocking hammer, and fsp.






The bottom piece seems trickier than the top. The bottom piece so far, has been tuck shrunk. I annealed once and feel I need to do it again. Two Stress cracks have formed which I will weld repair before I continue tucking shrinking to match FSP. The top piece formed without any cracks. Also need to trim extra material

any advice on how I can prevent cracking in the future?

[AllyBill]

Can't see where the cracks are in your job but if they are originating at the edges make sure you file the edges nice and smooth as you go to remove any stress raisers.


Will

[Kerry Pinkerton]

Ryan, in my experience tuck shrinking is very hard on aluminum. Wheeling/planishing will relieve the stresses but you will need to do it often if you are tuck shrinking. I'd suggest not doing the tucks in exactly the same place. Think about bending metal back and forth until it breaks.

[32chevy]

If I anneal the edge thurally shouldnt I be able to eliminate the compressive stress created on the edge from shrinking? the cracks are on the edge 1/4"-1/2" long

[Marty Comstock]

That may eliminate the internal stresses, but nt the micro fissures that are a result of working the metal. Like Kerry said, tuck shrinking is hard on aluminum, and even harder when its done repeatedly in the same spot.

Next time you can stretch your material more than tuck, and as mentioned before be careful to file the edge and keep it clean to prevent any visible stress concentrations. You may make it in more than two pieces, if you are that comfortable with welding and working out the resultant distortion. Just some different avenues to consider.

Your cover looks nice, there is a TON of shape in it!

Marty

[AllyBill]

You can always heat shrink the tucks. Aluminium heat shrinks very easily and doing it that way will anneal as you go.

Will

[32chevy]

Kerry, Marty; I had to tuck in the same spots eventually there so much shape to this piece. Maybe I should have cut the f.s.p. Up in different sections. It started to look like a mini 1940's rear fender.

Will I tried the heat shrinking, boy was that nice. I had to wear thick welder gloves.

I cut a thin 5" x .050 section of parent material for the filler, and fused those cracks. I then filled , hammered on dolly and then annealed the welds. I proceeded to tuck shrink. It worked for a series of tuck shrinks, but like you'll pointed out its hard on the material. I ran out of clearance with my tuck tool, going to have to use the Lancaster, I'm almost there. Thanks guys

[SWT Racing]

What filler rod did you use for the original weld?

[32chevy]

Andrew, I took my snips and cut a 6" long sliver of the edge off of some clean scrap 3003-h14. I cut the slivers width as close as I could to the material thickness. I didn't have any aluminum filler wire on hand. I'm not sure if 3003-h14 filler rod even exists/ is readily available.