914-SHO Metal bending question . . .

[3d914]

I'm attempting to fix a trunk lid that has been tweaked. When installed - opposite corners are slightly raised and don't lay flush to the body line. The raised corners are the right front & the left rear. The edge closest in the pic is the front edge.

I've verified the shape of the support ribs on the left side (yellow arrows) using a set of forms from my original lid - see second pic. The ribs on the right side don't match the forms - they're slightly flattened out toward the forward edge.

My plan was to build a wooden jig with several support pieces whose radius is slightly less than the form radius. I would heat the metal ribs and using straps, pull the right & forward-right edges to reshape the ribs & hopefully the sheet metal. Does this seem like a reasonable approach?

I appreciate experienced feedback.

 

[LOUDSHO92]

From doing sheet metal forming at my work I would not heat the metal. To heat steel to where it is malleable you would need to hit over 1800deg, so you will not do anything to the steel. You can take some welding passes using a tig torch and that can cause the metal to contract on the side you heat, so that can help. If there were any heat treatment you undo them though.

If you cold form it as you suggest you need to go past the form you want as you will have spring back. So go at least a .5" more and see what it gets you and then work form there. Check after each attempt.

 

[sperold]

It can be done, but I would look at a publication like Old Autos and get a bodyman who is at least retirement age in your area. Leave it to the end and take the whole thing there (the car ) and a guy with experience will be able to coax the piece to the shape you need, and surprisingly quickly too.

It is a lost art now and anyone apprenticing will not be schooled in any of these techniques. It had to be learned at a time when panels were not available so readily.

Probably a lot of people in Cuba could do it!

The guys who can use an English Wheel and make replacement panels for things like Franklins, Auburns, and Cords can straighten it with ease.

You could give it a try, but skip the heat, and be ready to quit when you get ahead.
I would use forms and weights (like sandbags) to bend the unit into the shape you want, and i would not try to take the twist out of the reinforcing webs.

 

[Off Road SHO]

You won't be able to straighten that easily with the strengthening ribs still attached to the tin. To do it right you will have to separate them. Having said that, I have watched old guys at my Metal Meets do some fantastic straightening jobs.

On this particular problem you need to immobilze the bent rib on both ends and press down at the existing tweak. It will be hard because you can't go far enough past the resting dimension to get the stretch you need because of the tin.

Tom

 

[3d914]

Thanks for the insight guys. The sheet-metal is cold-rolled, so any annealing during the process shouldn't be an issue. I think I'm going to try this in two stages; first with the ribs attached and see if I can get the range of movement needed. If that fails, then I'll remove the ribs and work the pieces separately. This makes checking very difficult because all pieces will have to be rewelded before I can do a fit check.

I'm looking at this as an exercise so if I mess up the piece, I'll just revert back to my original lid, repair it, and add the spoiler.

 

[Pintony]

Cut the rib with the thinnest cutting wheel you can find, Remove the rib and straighten, mig weld the rib back in place.
Use body panel adhesive under the rib.