pre painting recievers

[lanceriley]

Is it necessary to bead blast recievers before painting a bake on finish? I tried 400 grit sandpaper. it seems to make the part ... smooth?

[kcshooter]

All I have experience with is GunKote. Prep is the absolute most important step when it comes to durability. You will want to have it aluminum oxide blasted at the right grit in order to do it right. You will also need to completely degrease it afterwards.

Brownells tech section has videos that take you step by step thru it. You can also call them and they will be more than happy to help.

I can tell you right now that using 400 grit sandpaper will be far from sufficient. You don't want it smooth, you want it somewhat rough in order to give the coating something to adhere to.

[Dave Berryhill]

Yes, kcshooter is correct. Surface prep is everything. You need a textured surface for the spray coating to adhere to or it will chip off easily. Blasting with glass beads doesn't work either. You need to blast with a sharp media such as aluminum oxide. Another option is to parkerize it first as an undercoat.

[lanceriley]

how about silica as a media? the local aluminum shop has only silica.. something.. don't remember.

[kcshooter]

I have limited experience here, so don't take this as gospel truth.

As I understand it, silica is sand, which is most likely far too fine to do the job right. There are a couple alternative medias to aluminum oxide because aluminum oxide is expensive and not the most commonly used material in most shops.

However, I think the most important thing here is using a media material that is
A: The right grit, and
B: Hard and sharp enough to roughen up the surface.

Call Brownells, ask what grit the aluminum oxide blasting is supposed to be and then call several shops in the area to see if they have that exact match or a media that is close enough to it that the results will be the same.

I had a heck of a time finding a local shop that would do it right, and was only successful when I called a blasting media distributor in Lawrence, KS and ask who would have something that would work for me. It cost be $50 because that was a minimum charge, they were used to MUCH larger projects. If I had it to do over again, I would have gone with parkerization as a base, and Brownells also has a home parkerization kit from AGI that has everything in it you need to do it right, plus an instructional DVD. I haven't used that kit yet, however.

[lanceriley]

I am familiar with parkerization as a base. but unfortunately im in another part of the world. I do buy from brownells but I can't order anything chemical. (hazmat fee too much)