This door needs some help

Still peeling the onion. I spent some time assessing the left door, a piece I know was going to be a problem. I’ve fixed worse but they were steel.

The skin is badly stretched due to a collision, about the only thing to be done to it is to hammer it flat and make a few well-placed slits and stitch them up.

Or, install a new skin. Has anyone installed a new skin? Who makes the best?

Aluminum is a bit tricky to work with but from what I can see there, Mitchell, I’d first attempt to repair and straighten that door skin and resort to installing a new one if the attempt fails. I suggest taking the door off the car and drilling out the rivets securing the internal panels leaving only the skin, hinge panel and shut panel attached. Next step is to hammer out the stretch using a leather wrapped wooden mallet or slapper, getting it as smooth as possible, though it will present a heck of a bulge. Tig weld those small holes closed and grind them flush on both sides. What’s left is to shrink the aluminum skin down to flat using a large shrinking disc and 6000 rpm body grinder - higher rpm will badly spall the metal. As it is, you need to lubricate the metal well before applying the disc and for that I use liquid hand soap.

Shrinking aluminum isn’t as straightforward as shrinking steel because there’s no colour change. The liquid soap in fact turns black from the minute amount of metal removed during the shrinking process. What you will see as you go along is the aluminum expanding slightly, indicating that it’s heated up sufficiently to shrink - hit it quickly with a spray of soapy water, wipe clean, reapply the hand soap and repeat. It will take many applications to get to flat.

1 Like

Thanks Nick. I’ve got a shrinking disc, I’ve done a few steel but haven’t tried aluminum yet. At this point I’ve not got much to loose.

What thoughts have you got on annealing/work hardening? I remember a few decades ago I had a sheet of aluminum turn so brittle it cracked while working it.

A legitimate concern. There’s a YouTube video of a bodyman annealing, straightening and shrinking a mashed in aluminum fender of, iirc, an AC Cobra. It might be worth digging up for insights. The process looked fairly straightforward, using oxyacetylene. I don’t perceive the action of the disc contributing too much to work hardening but using a standard hammer/slapper and dolly on aluminum alloy will definitely embrittle it.

I should add I have shrunk down the aluminum skins of three XK doors, two new ones and one original, and had no problem with work hardening.

Thanks…20 21 22

Example of patience and skill.

1 Like

I always anneal aluminium before working it if the shape’s at all complex. You can anneal many times with no ill effects - I use a propane torch with a big nozzle to spread the temp. A squiggle with a permanent marker, and once that has burned off you try marking it with a matchstick. As soon as the matchstick leaves a black mark, you’re there. Personally I think an oxy torch would be way too hot.
I used the technique a fair bit when restoring my Cobra a few years ago - the metal’s much less likely to split if it’s been annealed.

Edit - just clicked the link - yes, that’s David whacking out a rear wing on a Kirkham. They are made of made of harder ali than an original. Great company, Kirkham - can’t praise them enough.