Is there a fix? Al panel distortion

[camdigger]

I am trying to make a bomber style seat out of 18 ga. 5051 Aluminum sheet. After bead rolling, forming flanges, and folding, I have trapped some distortion. The edge toward the camera is cut straight, but the wave is due to the trapped distortion.

The solution I did find prestressed the panel with an English wheel (which I do not have) before bead rolling.

I would try heat shrinking, but all I can find on that involves steel panels, not Al.

[milomilo]

Don't think you shrink aluminum. It can be stretched though. A big rubber hammer with the seat on blocks may work.

[Whitetrash]

I would be tempted to experiment with some dry ice to see if I could work it slowly with extreme cold versus heat. Maybe start out with a test piece and figure out how it behaves.

[Rob65]

There are shrinking tools that have jaws in them that grip and squeeze the metal.

The ones I’ve seen only have a shallow throat so may be limited in how well it would work in this application.

There are also hammers that have groves in the face that can be used for shrinking but they do mark the surface.

I’ve not heard of any thermal (hot or cold) that work with ali.

Rob


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[Samcord]

How about rolling a bead or two all the way across the end towards the camera to stiffen it?

[camdigger]

There is a lot more to do to this before it is done. The sides will be trimmed. Back trimmed. Edges may be tipped/flared out. All edges will be capped with a channel that will be riveted on.

Trimming may make the issue worse as reenforcement is lost. Tipping or flaring the edge will stiffen and possibly force the edges straight. The edge treatment is to soften the edge of the seat. Rivetting the edge banding on is purely decorative.

Time will tell. It's been an interesting exercise so far.

[threepiece]

My experience forming sheet steel is fairly extensive on smaller pieces. I don’t recall ever making anything as large and complex as your seat. I don’t have anything to help you other than what has already been said. You are delving into an area of metalworking that is somewhat mysterious and potentially frustrating or exciting.

Good luck and have fun.

[racer-john]

Casmdigger: In future, best you acquire an English Wheel and use it areas before bead rolling.
Are you aware of "tuck shrinking"? This could be used to shrink that distortion.

[camdigger]

I was trying to solve the problem after the fact. I was hoping (in vain) that the pattern and flanges bent up would control the distortion. I don't do enough of this work to justify purchase of an English wheel. If this comes up again, I may try to pretreat by planishing rather than wheeling.

I have watched enough YouTube that I know what tuck shrinking is, but have never tried it. I might be more inclined to try a slapper with heat a la Wray Schalin of the Proshaper channel. He seems to be very skilled in shaping Aluminum especially and feels free to share his skills rather than put out teasers like Lazze, Tinman Tech, et al. My favourite sheet metal guy is Trev from Trev's blog, but Trev does not seem to do any Aluminum work.

[milomilo]

Originally Posted by camdigger

I was trying to solve the problem after the fact. I was hoping (in vain) that the pattern and flanges bent up would control the distortion. I don't do enough of this work to justify purchase of an English wheel. If this comes up again, I may try to pretreat by planishing rather than wheeling.

I have watched enough YouTube that I know what tuck shrinking is, but have never tried it. I might be more inclined to try a slapper with heat a la Wray Schalin of the Proshaper channel. He seems to be very skilled in shaping Aluminum especially and feels free to share his skills rather than put out teasers like Lazze, Tinman Tech, et al. My favourite sheet metal guy is Trev from Trev's blog, but Trev does not seem to do any Aluminum work.

Seems like a shop made English Wheel is on the to do list???