This is a repost of some stuff I posted a while back, along with some updated lessons learned.
I've done a fair amount of "backyard GunKoting" now, and I'll gladly pass on a few hard-fought lessons learned. Before I say anything, if you want a truly professional, eye-watering job done, go with Mac's Shooting Iron Restorations (
www.shootiniron.com). You won't be disappointed. That being said, and being a DIYer from way back, here's more than you wanted to know.
1. Get the right tools. I recommend buying GK by the pint. Brownells has it in an aerosol can now, but I have no experience with it. I got mine from RB Treasures (
www.rb-treasures.com) for $24 or so a pint in different colors. I bought an amazingly good, low cost Badger airbrush from Reuels (
www.reuels.com). I got the BD-250 for less than $30 IIRC. It runs off a can of propellent, and works great. You can get refill cans of propellent at Wally-mart. It takes 5 minutes to figure out how to use the airbrush. I was very concerned about this part, and it turned out to be a no-brainer.
2. As was already alluded to, preparation is everything. You need to clean and degrease the parts to be GK'd. If you can get someone to bead-blast it first, so much the better. I haven't been able to find anyone to do this yet, but I'm going to check into it before I do too much more. An ultrasonic cleaner would be MOST BUENO, but I don't have one. To degrease, first put on a pair of good vinyl or latex gloves, GET YOUR EYE PRO ON, then use brake cleaner or carb cleaner in a well ventilated area. This stuff sprays right back toward your eyes, and you get it into an eye, you're going to know it. Brake/Carb cleaner will melt plastic parts, and probably take the white out of your sights, but that can be added back in later (
www.brightsights.com). Brownells sells some degreaser, too, but you can do just as well with brake/carb cleaner. THIS IS IMPORTANT! If the part is not degreased properly, the GK will not adhere correctly. It's that simple. (Go ahead and ask me how I know!) I recommend degreasing a couple of times to get the gork that seeps out from the cracks. You can also try heating the part up after degreasing to help coax out the ooze. From this point on, handle the parts ONLY with gloves on, to avoid oil from your hands contaminating all your hard work.
3. If you want a truly durable coat, you might consider parkerizing the parts BEFORE GKing them. That seems to be what all the "big" outfits are doing these days. Helps the GunKote get a "bite." KG Products is making something now called K-Phos pretreatment for GunKote. It sounds like an easy-to-apply coating similar to park'ing.
4. Give some thought as to how you're going to hold the parts while you GK them. In your hand--probably not. If you lay (lie?) them flat, you will have to turn them onto the tacky surface to shoot the other side, and possibly screw up your finish. (Ask me how I know this, too.) I prefer to shoot onto wood, as it seem to absorb the GK well and not "stick" to the piece. I have a 2x4 with a couple of wooden dowels sticking straight up that works well as a holder for frames, slides, and mag bodies. I'm sure you can be more creative than I in this area. The AR-15 guys that shoot PermaSlik onto their mags use pieces of clothes hangar suspended from a rod to hold AR-15 mags.
5. Get a heat gun and heat the part up to about 100 deg or so. I use the scientific method of holding my latex gloved hand close to the piece and seeing if I can feel heat coming off of it, i.e. it's hotter than 98.6 deg. I think here hotter is better--within reason--as you want the GK to dry as soon as it hits. You can tell if it's too hot because the GK "beads up" as it hits the surface. I have a helper moving the heat gun around the part as I GK it to keep the entire part hot as I spray. You can also use an oven to heat the parts.
6. Make sure you're in a well ventialated area (I like outside) and here's the easy part: spray away. It is MUCH easier than I thought. The GK will dry as soon as it hits the metal, so "runs" and "sags" aren't a problem. Just keep nice, straight passes with the airbrush, starting and finishing "off" the part. Shoot the entire part, and I like to put it on a little heavy on the slide rails or other high wear areas. I shoot every part of the gun, including the grip screws and pins. You can even shoot the springs, if you're so inclined. The airbrush helps keep the "overspray" to a minimum, but there is some overspray.
7. The parts are immediately dry to the touch, but I always let the parts dry for at least an hour. Then I examine each one. If I see something I screwed up, I just grab the brake cleaner, PUT ON MY EYE PRO, and spray away. The GK comes off like water. It's actually kind of scary, but don't worry. After baking, it can only be blasted off. Finish degreasing, and start over with the heat-and-spray. I shot the frame of my Hi-Power in matte stainless (to go with the matte black slide for a home-made two-tone), and wasn't happy the first
two times, so I just hosed it down and re-did it.
8. While the parts are drying, pour the remainder of your GK back into the can. You will have a lot left. A little goes a long way. You can clean the airbrush up with either Acetone (hard), MEK (too friggin' dangerous for me), or, simply, brake/carb cleaner. Works great. Be sure to clean the entire airbrush thoroughly.
9. Bake time. Come up with some amazingly good story, and send the wife to the store to get something you just can't live without, preferably a store on the other side of town/county. It should take her about 2 hours. With her safely out of the way, preheat the oven to 350 deg. Turn on the hood fan. Open the windows. And the door. I use bent hangar pieces to suspend the frame/slide/big pieces from the oven racks and one of those $.79 tinfoil "roasting pans" from the store for the small parts. The can says 350 deg for an hour, but it also says if you bake it hotter/longer, it will come out HARDER, although the color will be a bit darker. Good trade for me. I roast 'em at about 375 deg for about an hour and a half, then just turn off the oven and let it cool with the parts inside. When everything has cooled down, I inspect all the "bits," wipe them down with a clean cloth, and--this part is optional--I hit them with BreakFree CLP as I reassemble them. I know GK is self-lubricating, but, according to Mac's, the GK will actually absorb a certain amount of lubricant. I CLP the parts, assemble the weapon, then wipe down any excess. If you have to "repaint" your sights, use the BrightSights stuff mentioned above. Some people leave the weapon for a week at this point, as the GK actually gets harder as it gets older.
And then, shoot! I'm a huge GK fan, and it is MUCH easier to apply than I had imagined. Just think it through, don't rush the preparation, WEAR YOUR EYE PRO, and have a good time.
More than you wanted to know, I know.
YMMV, of course.
Scott
