I'm using weld els and mild steel 1/2 flanges, when I get done, I would like to paint it so it doesn't rust. I'm more worried about the steel flanges, like the inside of them, what should I do because it's going to be very hot in there? Is regular high temp paint for like BBQ grills? (if so, spray can or paint on with brush?)

 

WTF? heat kills rust... dont worry about it

 

I would not paint on the inside. For the outside you can use some spray can exhaust paint. It's not going to last for ever, but will look nice for quite some time.

 

use POR (paint over rust ) high temp paint it works great .....
not that it matters every one is right its jsut surface rust anyways

but here is the link for the site
I used it to restore my friends datsun 260Z

http://www.por15.com/product.asp?productid=268

 

I used 1500 degree engine paint, it lasted about 5 hard drives, now is back to semi rusted

 

other then ceramic coatings, not much is going to stand up to the heat.