MTFCA Forum

I have a set of '26 roadster sill plates that are semi decent except for a couple cracks. Is zinc repairable?

It will not weld. It won't take solder. You may be is to back it with some shim brass and use epoxy/JB weld to hold the shim in place. Others may have better ideas.

Allan from down under.

While I have never used this product I have know about it for years.
https://www.muggyweld.com/product/super-alloy-1/

It works on Zinc and Pot metal alloys.
But I would use a backer plate to keep cracks away in the future.
No matter what it is, the chrome platers use a filler product to repair the pinholes, cracks, and defects in pot metal before plating.

I confirm what Allan said. I tried welding zinc and it did not go so well.
What zinc does well at is forming to a mold, even more so than aluminum. I suppose you could research any safety concerns about re-pouring zinc into a mold that is made from the piece itself.

varmint wrote: ↑

Mon May 19, 2025 7:54 am

I confirm what Allan said. I tried welding zinc and it did not go so well.
What zinc does well at is forming to a mold, even more so than aluminum. I suppose you could research any safety concerns about re-pouring zinc into a mold that is made from the piece itself.

The sill plate is a stamping, not a casting.

varmint wrote: ↑

Mon May 19, 2025 7:54 am

I confirm what Allan said. I tried welding zinc and it did not go so well.
What zinc does well at is forming to a mold, even more so than aluminum. I suppose you could research any safety concerns about re-pouring zinc into a mold that is made from the piece itself.

Vernon, Did you try TIG welding zinc? I have TIG welded it a few times. Tricky but doable. Set my Tig machine to AC like welding aluminum and using a non-ferrous filler rod is key. Preheating slightly seems to allow it to take the weld. A very fine line between a nice weld and total disaster. lol

I use Muggyweld to repair Winfield cracks. Great stuff. Low temp, like soldering. As for you sill plates, it just depends on the repair.

Allan has the simplest repair idea that works. I have a 24 Coupe that has the zinc/aluminum sill plates and using the method that Allan spoke about is the best way for cracks in this application. It will last as long you own and drive your car and beyond.