An Amazing Way to Build a Trunk Lid

This is so cool, it must be some sort of World War II Aircraft Manufacturing technique for welding aluminum by smashing it together that was used for cars. This trunk lid was made by Carrozzeria Touring in the late 1940′s and as much as I curse the way they build cars, this is some of the most amazing craftsmanship I have seen. Since it isn’t adding any new material its keeps the panel very light and super strong and without the heat of welding, the panel doesn’t warp and distort. I’m guessing that the force of smashing the two aluminum pieces together in a focused area causes enough heat to melt and stick them tight.

Welding aluminum with a punch

Welding aluminum with a punch

Aluminum welding technique

Aluminum welding technique

I’d like to see other examples of this attachment procedure and find out what it’s called.

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  1. Ross said,

    December 30, 2011 @ 12:33 pm

    Isn’t that just spot welding? It looks like the welds on my old beetle.

  2. DougD said,

    January 3, 2012 @ 11:41 am

    It looks like a spot weld in the photos, just pinching it can’t generate enough heat to weld it. We’ve made clinching presses at work that use mechanical distortion to hold copper sheets together, but you wind up with a sizeable welt on the upper surface. Always fun to see how these cars are put together, I attended FCA meeting in Toronto a few years ago and got to inspect a 365 very closely.

  3. admin said,

    January 10, 2012 @ 9:18 am

    Yes, there should some electrical current to attach the parts but in stripping all the paint, there aren’t any markings of heat or signs of distortion. It’s odd, I’t like you to see the parts in the flesh!

  4. admin said,

    January 10, 2012 @ 9:33 am


    I don’t know, as I mentioned in another comment, there doesn’t seem to be any distortion from heat or difference in surface finish of the material. There has got to be some electrical heat to make it stick but I can’t find the evidence

  5. Marc Bondini said,

    July 10, 2012 @ 2:37 am

    I’ve repaired a couple of old Pininfirna bonnets which have the same construction. They are definately spot welds with a(sacraficial) plate of brass or copper placed over the 2 surfaces. The finish that I acheived was very close to original. carefully tuning of current & time is neccessary.
    Bye from australia!

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