And if it's for the steel mate, Caswell has some great products you can get posted to your door.
I have used these products a bit for jobs for others, and myself for some fun stuff.
I am about to do a few rifles using this product, it self-mixes and is very good.
I also use this companies steel and stainless steel blackening products when doing jobs or mods.
I have always blasted the steel surfaces first, then I don't have any issues with chipping. Again, this product does not use a primer.
https://www.caswellplating.com.au/store ... rosol-kitsYou can get a simple cheap sandblasting kit, and the blast media for stainless or carbon steels (different) from Supercheap or E-bay.