Do you have the oven that it was cured in? If you do then I would use the regular cure JB Weld. Scuff that area up with 80 grit and mix the JB and wait maybe 15 min. Then spread it over the area and let it cure over night or you can fast cure it in at 150 for 0ne hour and then once it cools down you...
It would really help if you could etch the metal with like 220 grit sand paper or use a Scotch Bright pad so the powder will have something to bite onto.
Have fun I guess is about all I can say.
The nice thing about gas is it does not take away powder from other equipment in your shop so you can do anything you like while the oven is running + they heat up faster. As for as inspections goes then if the person/company that makes them puts the UL stickers and is certified then you should not ...
If I mess up the second coat what is the best way to start again? Blow off? And what about removing the charge? Read about putting in oven and running under water... What is best practice for a second coat that you need to blow off and remove charge? Valve covers can be tricky at times because of t...
The concrete will slow the heat up time but once it gets warm it will stay warmer longer than your oven will. Just make sure you put down a good piece of sheet metal to protect the concrete and it will also take care of any concrete dust that may happen from the heat.