Basically what i want to do is use Alumahyde II in semi gloss black on a fake can. The can is bare aluminum. What is the prep work involved. Can i use mineral spirits to degrease/clean the metal or is that not sufficient enough? Is there any other surface prep involved?

Thanks

I would abrasive blast the can with aluminum oxide 80-120 grit with a psi setting around 70-80.  I do not recommend glass beads because the surface will peen rather than leave a slight rough surface for the paint to adhere.  You can clean the can with some hot water and Dawn dish detergent.  Use a hair dryer/heat gun to dry the part off.  Spray a light tack coat and use a hair dryer to warm the tack coat.  After that, a slightly heavier second coat and make sure you have even coverage.  Once you're happy with the coverage, you can either let it dry for several days or place it in a warming over until the paint cures.  A low temp of 150-200 for two hours and I'd call it good.

Thanks. What are my options other than blasting since i dont have access to such equipment? What about a fine grit sandpaper?

What part of the country are you in?  Maybe someone local would blast it for you.

I would make friends with someone at a machine shop or take it to a radiator repair shop and ask how much they charge.  It would take about five minutes in their blaster.  Take it home and clean it with Dawn and hot water.  I don't recommend sandpaper because it will leave striation (directional marks).  Another idea would to place the can into a mild solution of cold water and some red devil lye.  The can will bubble slightly and the surface will etch.  Depending how much lye and how long you leave it in there, the surface will pit if left too long or how strong of a solution.  This would be my last option.  This is done as a step in anodizing.

There is a cerakote place not to far from me. I guess i could give them a call. What a pain in the ass

If you happen to be in Oklahoma, I would do it for you.

Blasting isn't required but cleaning the bare metal is. I just used AlumaHyde II on a lower and rail yesterday but they were anodized. The lower is old and the rail is new. I sprayed them down with a new can of brake cleaner. Make sure you wear non-talc surgical/mechanic type gloves and don't touch the parts with your bare hands after you clean. I did a ton of research on using AHII and here are a few tips I picked up. I'm assuming you've spray painted stuff before and it came out well.

1) Heat the can. I put it in a large ziploc and put it in a pot of the hottest tap water that came out of my sink. I left it for about 10 mins, dumped the water and filled it again with hot water from the tap for another 10 mins. I kept it in front of a space heater the whole time I was spraying the parts. The nozzle will clog if it sits for too long (more than 15-20 mins). I was able to clean it with mineral spirits but others suggest getting extra nozzles. Shake the can. When you think it's good, shake it for another 2-5 mins. Keep shaking throughout the spraying process.

2) Warm up the parts to about 90°F and try to keep them about that temp while spraying. I went about 15-20 mins between coats and used a hair dryer to keep them up to temp.

3) Distance matters. If you want a glossy finish, spray at around 6"-8" and heavier on the last 2 coats. I was spraying at around 12" and got a flat, almost gritty finish which is what I wanted. I started with a very light coat that barely covered the part. Same with the 2nd coat. I went a bit heavier on the 3rd coat (maybe 3 passes at about 10") and a light dusting on the last coat.

4) Let it cure for 10-14 days. This is all from what I've read as this is my first experience with AHII. Some were too impatient and those are the guys that usually say that AHII isn't that durable. The guys that let it cure for 2 weeks are the guys that say it's better than Duracoat. Some say freeze it. Some have stated that multiple heating/cooling cycles will help speed the curing process. Ultimately, most agreed that letting it cure for 2 weeks is the only sure way.

I'll probably grab my coated stuff later today and throw them in the oven for a couple of hrs and then let them sit for a couple of weeks just to make sure before I assemble them.

Excellent, ill have to try this

So I'm one of those impatient guys .

I left the rail alone but I built out the lower and was messing around with it and got a few chips. You definitely need to clear the holes (trigger, hammer, safety, takedown and pivot, etc) or the pins will be tight. The color is just a bit lighter than Magpul FDE depending on the lighting. It's not nearly as drastic in person. Here's 2 shots, one with flash and one w/o.

W/o flash:


With flash:

Simple aluminum prep for those who don't have easy access to automotive paint supplies. Eagle One ETCHING mag wheel cleaner. Will clean and etch the aluminum making it ready to accept paint.



Excess oil  you want to clean off first? Most auto parts stores will have a solvent based cleaner that leaves no residue. This pic even came from O'Reilly's Auto parts. You need this stuff around the shop anyway.

I'm impatient as well and have been using AH2 for several years.  For curing you can also place the part in the oven at around 220 degrees for a few hours.  After it cools it is ready to assemble.  Have done FALs, AKs, an UZI, a few pistols this way and the finish holds up very well.