specweldtom
Well-Known Member
I haven't done any duracoating yet. When I do, I'll know how to prep for it. It obviously needs the anchor pattern to really adhere. The 70 grit Al Ox sounds like it's the way to go.
Thanks, Tom
Thanks, Tom
I use Aluminum Oxide for surface prep before duracoating. Works great, nice rough uniform finish, duracoat adheres well. I usually use glass media for stainless steel parts. It creates a nice semi-matte sheen. Very uniform. I have been lazy once or twice a did a quick blast job with glass beads then followed woth a duracoat finish. Does NOT adhere well at all. If your media gets dirty or stops cutting, replace it. It is a whole lot easier to replace it when it gets "worn out" than standing there hunched over for twice as long trying to do the same job.
One time I forgot to plug the muzzle end of a Stainless varmint barrel before glass bead blasting. Big mistake. Had to have the Muzzle cut down and recrowned. The "gunsmith" (what do you call an incompetent gunsmith?) that did the crown- I wanted an 11 degree target crown- cut the crown at, around 30 degrees with a 45-60 degree chamfer. None of it was concentric- not even close. Had him redo it, same thing. I had to buy a PTG 11 degree crown tool, came out perfect, but wasn't cheap. It now shoots again, actually better than before. Lesson learned- plug the muzzle and chamber, protect your threads.
Once you have used your aluminum oxide on regular steel it will be contaminated and blow steel bits into your stainless and cause it to rust. If I have a steel receiver and a stainless barrel I will do them with the same media but do the stainless first and the steel parts last. Then that media get pulled and saved for steel jobs. I run as little amount of media as possible in the cabinet. Usually 4-5 pounds will feed it nicely.
The proper surface for most coatings is very specific 100-120 grit aluminum oxide. Too rough and it will scratch the coating off of the peaks. To fine and it will chip easily. I use rubber bottle stoppers to protect muzzles and chambers. They bulge over the edge slightly and protect the crown nicely even when directing the media directly at it. I never have trouble with chipping near a crown.
Have you found the compressor you want? My only recommendation is to stay away from the high rpm (direct drive) oil-less compressors. Some have rated outputs of 10 cfm or more, but I've never seen one hold together in hard use. They also have maximum pressures of around 125 psig. Fine for air tools, but my cabinet blaster likes 135-150 psig, and that pressure doesn't hurt any of the siphon blast guns. Might be too high for pressure pots though.
Good luck. Tom