I use nothing but 3M Panel Bond on cut to size patches. No heat, no warp, and done in an hour. Just rough up with 36 grit around holes and the same on the patch. Smear enough on to squish out around the edges and the patch is waterproof. All airliners and super sonic fighters are panel bonded so an AD pickup shouldn't have a problem.
49 with 61 holes in firewall panel bonded:
[img]https://i.postimg.cc/5YXQ7PCR/dan-s-49-011.jpg[/img]Center of dash had been butchered with several modern radios so panel bonded in:
[img]https://i.postimg.cc/TpVL45Kf/dan-s-49-002.jpg[/img]Model A soft top replaced with bonded in metal filler panel---1 hour labor time; welding used to take a week
[img]https://i.postimg.cc/svr17fw8/IMG-4335.jpg[/img]
