I've done VHT with no primer it works, but I always sandblast.
I've got one set of headers that are individual tubes so I put them in the oven for 45 minutes @ 450° talk about nice.
I don't have an oven that big, so I'll cure them on the car. I'll just have to make sure the engine has enough timing in it so as not to over heat the headers. I went ahead and decided to use a 7 year old quart (still unopened) of VHT flat black. There was about an inch of solids in the bottom but I stirred for about 20 minutes or so and got it all back mixed together. It actually went on good for coat number one. We'll see how it turns out. Worst case is, they'll be coming back off and done again. It's all I have and I cannot afford another can so.........
