Bubbles and bad finish on PCing ... cause/solution plz?!

[Guest]

Hi Guys, so I'm all enthusiastic about powdercoating again now that I am using the king coat and NOT the progun

I have really been having problems with not being able to make professional grade work. This is purely just a hobby for me (its fun restoring parts) and for friends ... but I an envious of you guys when I see all this professional grade work coming out. When I coat, I always get some small defect even though I prep super thoroughly, clean with acetone, and torch the surface.

Wheel #1: acetone, torch, coat (forgot to outgas)

http://i177.photobucket.com/albums/w236 ... ng/wtf.jpg

this was satin black, and it just bubbled all over the place, and didnt stick to the metal at all ... it easily scrapped off. i usually hotflock, but now with the king coat i didnt ... i did forget to prebake to outgass the part ... is that what the issue here is? or is it something else?


now for wheel #2 below, i prepped it for hours and hours and outgassed it, hotflocked it, but i get these little bubbles ... what is this? is this also outgassing? or water in my air?

i have 2 air filters from harbor freight inline with my airline... good enough? or should i just pony up for a 'real' nice quality air filter/dryer?

http://i177.photobucket.com/albums/w236 ... ng/rs4.jpg

this BBS wheel near the bolt hole on the upper left has a different kind of defect, its not bubbling, it's just discoloration and fish eye look ... i blasted/acetoned/torched this wheel before coating

http://i177.photobucket.com/albums/w236 ... ng/bbs.jpg

thank you guys for your help. this forum is truly a valuable resource. i hope i can get good enough at coating so i can pay it forward and help other n00bs

[DxC]

hi

hey harley, thanks for your help. you are a scholar and a gentleman sir ,

the black wheel was blasted down, but the primer was impossible to get off so i left it on there ... i guess that must have been the issue.

the 2nd wheel with bubbles was prepped for a long time, blasted completely down to metal, acetoned, and torched ...

now that i think about it, my oven does have some funny smells from baking all sorts of stuff ... i think i will clean it for good measure, and check my air.

the king suggested using an outgas forgiving primer - good idea? this means that any issues would show up in the primer, and i can just sand it down, then coat the primer with the black chrome and have a nice finish ... ?

[benwish]

Re: Bubbles and bad finish on PCing ... cause/solution plz?!

Careful ! Paint can only cover a certain degree of errors in the substrate. If your pretreatment/cleaning is not good, do not expect the powder to cover it 100%. Sanding down the defects after the primer is not a guarentee. If your oven is giving off the contamination or you powder is dirty, you did not solve the problem.
Do a complete system check, and eliminate step by step all possible causes.
-substrate clean?
-Air without oil?
-guns clean?
-powder OK

B

[mjwash]

Re: Bubbles and bad finish on PCing ... cause/solution plz?!

The first defect is definitely the acetone. I had the exact same problem twice. Each time it was a recoat and the acetone wipe got me. I've never had the problem since switching to PRE.

[Guest]

Re: hi

hey harley, thanks for your help. you are a scholar and a gentleman sir ,

the black wheel was blasted down, but the primer was impossible to get off so i left it on there ... i guess that must have been the issue.

the 2nd wheel with bubbles was prepped for a long time, blasted completely down to metal, acetoned, and torched ...

now that i think about it, my oven does have some funny smells from baking all sorts of stuff ... i think i will clean it for good measure, and check my air.

the king suggested using an outgas forgiving primer - good idea? this means that any issues would show up in the primer, and i can just sand it down, then coat the primer with the black chrome and have a nice finish ... ?

First the Substrate must be clean of all contaminants, then outgassed, primed with an out gass forgiving primer when coating a cast part then you can start the powder coating process

[baz]

Re: Bubbles and bad finish on PCing ... cause/solution plz?!

no matter how many times you out gas or how many coats of primer you put on , if you don t clean well and if you don t remove all previous coatings on the surface you are asking for trouble
i only outgas parts when the casting seems to be porous , but i always spend a few extra minutes to make sure parts are completly cleaned before coating