Question for anyone who has used JB Weld

So I have a small crack on my header, nothing that was throwing a CEL or leaking enough that I could smell any fumes, and I got some JB Weld to patch it with. Scrubbed it clean and put some on, let it dry for 17 hours. Starting the car up this morning the color turned from grey to a brownish (see pic below) and smelled something awful.

After driving around for a bit the smell went away, but I checked it again and a lot of the excess JB Weld flaked off. There was still some over the crack though. Drove a bit more, and now its turned white. Did I not let it dry enough or is that normal?

no not JB the stuff is like JB Weld it’s in a small jar. it looks like it has metal flake in it. If i go down to Auto Zone tonight ill get the name of it.

Thanks dude, I’ll try to ask again at an auto place myself. Will the remainder of it just flake off? Or am I in for more scrubbing.

JB weld is not what you want. If it is what I think roush is suggesting its called thermosteel. Its like thermo epoxy used for exhaust manifold repairs. Good to like 5000*F or something. Ive used it before. Its pretty good stuff.

I found some stuff called Versa Chem, made for manifolds. Says its rated up to 2000 F. I’m not going FI for a bit, so I think I’m ok.

i can weld it four yah if yah would like…