How do you prep parts for Powder coat?

[thorsblood]

I got a bunch of parts I want to get powdercoated. I have a powder coater who will do the powdercoating very reasonably if I prep the parts. I have scotchbrited the parts. (Lower legs, cowbells, primary and associated covers, tranny cover etc.) I am wondering about masking off the parts? If the tape is not removed before the heat treatment, is'nt that a problem? If so how do you plug holes, and preserve gasket surfaces from the powdercoat?

[junior]

threaded holes just thread a bolt in. i usually size blind and through holes large enough to accommodate the fastener WITH coating or paint. as for masking- my guys does that. there is tape out there (kind of like the metal tape used in HVAC work) that can stay on during baking, but my guy just masks it offf with masking tape during the power process and pulls it before he cooks it. seems to work.

as for the finish- powdercoat is somewhat more forgiving than paint in reflective qualities, but if you have a big goober or gouge it won't fill that- sand those out. my guy sandblasts the part to white metal and de-greases it on his side.

also-

the lower legs have a clear coat on them- that should be removed. any chrome parts (cowbells, outer primary, trans cover) should be abraded enough (i.e. sandblasted) for the coating to bite. on straight chrome it would maybe peel.

hope that helps-

j

[Nitram_b4]

I used to be involved in powdercoating...Junior has it about right...if your powdercoater has a good setup he is doing a pre treatment with iron phosphate, if set at the right PH will help the powdercoat adhere to the substrate.
Getting the core temp of the substrate up to the right temp durring cure will also have an impact on adhesion
So as long as you give him good clean parts (sand blasted or glass beaded) and holes plugged, areas masked you don't want powdercoat on, you should be in business

[joshj]

junior is right, i worked in a powder coating plant for 18 years. the cheap way of blanking the holes is old screws. there is a tape for stoving ( 3m heat resistant tape) removing the normal tape just before it gets too hot may leave some of the glue. all parts should be bead blasted(ant air cured or 2 pack will react with the heat. any alloy being coated should be de gassed or use de gassing powder or you will get micro bubbles. hope this helps, if you have any more give me a shout(about time i put more back into you guys) cheers,josh

[thorsblood]

Thank you gentlemen, as always I knew I could count on good information from HCG. And, as usual it would seem there is more than one imagines to doing something correctly. I am thinking that by the time I buy special tapes, get things bead blasted and use my parts as a trial attempt of my ability to properly tape and plug parts, I might be further ahead taking the parts to a place that is set up to do all of the above. Its well done parts I want, not okay parts done cheap. Thanks guys, appreciate it.

[boulderbean]

I came across this site a couple of years ago, does not answer your questions but I found it interesting
http://www.jamesriser.com/Machinery/...g/Testing.html