Powder coating into recesses Help!

[woodjames]

Hello everyone, first post, been reading up and trying to figure this out but I can't.

My question is how do I get even powder coverage in deep 2" deep by 1/2" wide recesses? I'm trying to do a motorcylce cylinder head, between fins is where the problem lies. I'm using the $95 powder coating gun that caswell sells.

So far, I've tried different angles, holding the gun close, applying it onto a hot part with and without ground. Eventually I get it in between the fins by applying it onto a hot part, but it builds sooo quickly onto the flat areas that it shows sags, not quite runs. I've seens heads that have been done in candy colors, and it just boggles me how they get it so evenly.

I'm using the super wet black, which off the top of my head is recommended at between 1.3 and 3 mils, which I get well above trying to jam the powder in there.

Let's say that the voltage is too high, I've heard/read lowering the voltage can help with this, but the voltage on the gun isn't adjustable. Can a potentionmeter be installed inline to adjust the voltage, anyone ever try this?

Thanks in advance, hope this isn't too much of a run on thought, just want to make everything clear. I can get pictures it necessary.

-Jimmy

[BottleFed70]

Don't install anything inline unless you want a nasty shock. Most electronic components are not ment to handle that kind of voltage. If you do find something that can handle the voltage, it'll probably cost as much as the gun.

Here's something to try.... turn off the transformer completely and see what you can do. The powder won't stick as well, but should be a lot easier to get into the tight areas. If it's not sticking at all, try turning on the transformer (and stepping on the foot pedal) to build up a small residual charge, then turn it off and give it a try. You may need to do this multiple times as you bleed off the small residual charge.

[woodjames]

Thanks for the response, I never thought about trying to turn off the unit. I'll give it a try.

[baz]

you will have a hard time getting the powder in those recessed areas with that type of gun , bottlefed has given you a trick that might work . if you intend on doing lots of cyl and heads with fins you might consider upgrading your gun
to one with adjustable voltage , and if you really want to go pro
voltage ,amps , air and powder supply ,all adjustable + a fluidizing hopper will make it easier but will also make your wallet lighter $$$$

[woodjames]

For the time being, I've only got a few heads to do, but if it comes up again I'll have to check out upgrading the gun. I tried it again last night with greater success, I didn't cure it, just shot it on and the blew it off (I still have to strip the last attempt). It seemed like the best way was what bottlefed said, but also to shoot it without the tip on, I came across that one on the forum the other day.

What if I made up a reducer for the end of the gun, so the pattern would be smaller yet, has anyone ever tried that? say out of PVC or something.

Strangley enough...
I took a closer look at the head, and it has two, we'll call them tunnels, that go clear from on side to the other. Somehow the powder had no problem sticking in there. Kind of like shooting throught a 1" pipe, say 5" long. I'm going to try to butt up a piece of cardboard or something perpendicular to the ribs and try shooting between the ribs like they are pipes, maybe this will help. I'll post if it works or not.

[woodjames]

Baz! If I could get my head looking a 1/4 as good as the ones on the your site I'd be happy. Incredible work!!!

-Jimmy

[precise]

I have done several cylinder heads,, what i have done was heat up the part then take off the plastic tip, and spary in the tight areas first them reinstall the tip and finish , I have real good luck doing it this way Keep the grounding clip on also

[baz]

Originally Posted by woodjames

Baz! If I could get my head looking a 1/4 as good as the ones on the your site I'd be happy. Incredible work!!!

-Jimmy

thanks , using a pro gun sure helps but i have seen pics of amazing jobs here that were done with a hobby gun .
i think by trying different tricks and a bit of practice you will get thevresults that you want

[woodjames]

Got it done the right way last night. I tried everything suggested, and it turned out really good. I did have a little problem, maybe someone can explain. I got one coat with let's say 80% covered, the deepest parts still a little chalky. Then I cured, recoated at around 400 degrees, no problem getting it to stick in the recesses then. But, for some reason, some of the areas between the fins, not that deep... .5" or so, they got a little texture to them (not glassy smooth), like they wouldn't flow out well. Is this due to the 16kv gun not having quite enough juice for 2 coats? They won't be visible, so it's not that important, just want to improve for next time.

If I can figure out how to put a picture here, I'll post the pictures of the completed job if anyone's interested. THANKS AGAIN FOR EVERYONE"S HELP!!!

[baz]

Originally Posted by woodjames

Got it done the right way last night. I tried everything suggested, and it turned out really good. I did have a little problem, maybe someone can explain. I got one coat with let's say 80% covered, the deepest parts still a little chalky. Then I cured, recoated at around 400 degrees, no problem getting it to stick in the recesses then. But, for some reason, some of the areas between the fins, not that deep... .5" or so, they got a little texture to them (not glassy smooth), like they wouldn't flow out well. Is this due to the 16kv gun not having quite enough juice for 2 coats? They won't be visible, so it's not that important, just want to improve for next time.

If I can figure out how to put a picture here, I'll post the pictures of the completed job if anyone's interested. THANKS AGAIN FOR EVERYONE"S HELP!!!

yes pictures would help . i never do heads hot because it builds up too much in some areas, but with a hobby gun that might be the way to go