Just got my new LS1 Calipers back from the powder coaters and I am unhappy with the finish on the calipers.

The carriers seem fine and the finish is smooth and even.

The calipers though have large very rough patches. The rough patches look like there is grit in the powder or maybe small bubbles that have burst. I had hoped to put stickers on the calipers, but the sides are too rough for this.

The calipers are new, were disassembled, masked and then sand blasted.

I spoke with the powder coating shop and they said oxidation in the aluminium calipers caused this, and that it didn't happen in the carriers because they are steel.

Any suggestions what went wrong and how it can be fixed?

Would be it be possible to sand the rough patches?

 

?

 

Wait, they were okay in giving those to you? Take them back to the coater and say you want a smooth finish like every other PC'd caliper ever. If the calipers are new the oxidation excuse should be nullified.

 

I think the powder coating guy was slack. My son picked up the callipers for me. I wouldn't have accepted them.

The powder coating guy blamed the aluminium callipers, but after reading up on this I think the bead blasting material left small particles embedded in the aluminium which came out when they were baked.

I phoned him today and after a heated discussion he has agreed to blast and redo the callipers.

I suspect the problem could have been avoided if the callipers had been cleaned properly before coating.

I've thought about sanding the callipers down for a smooth finish, but suspect the baked powder coating may be too hard for a hand rub with wet and dry paper.

 

Never had coating done, but as far as I was aware the people doing the coating are supposed to scrupulously clean the work item, then etch and dip in some form of surface protectant immediately prior to coating, to avoid problems like this. If the surface prep isn't done, the final finish can't be garaunteed. Sounds like he slacked out on you.

Edit: Just enlarged those thumbnails and had a good look. That guy can't seriously be giving you that as a finished job. Take them back and shove them up his a$$!

 

I wouldn't have taken those. Its almost like the surface was either covered with sand from blasting or the surface was to hot and the plastic bubbled up (like boiling water)Its kinda hard to see in the pic...
Easyoff oven cleaner takes the plastic coating off. (I hear)
So does certain brands of spray carb and choke cleaner.

 

Thanks for the tip about removing the powder coating.

I'm thinking of stripping the powder coating and just using VHT Calliper paint instead.

 

That is out gassing... Your coater doesn't have experience in coating aluminum calipers obviously. Oils and soaps are trapped in the aluminum's pores over the years and must be out-gassed prior to coating, this means baking the calipers to release these gasses before coating, its an extra step that he may or may not know about. I would take them back and have them stripped then out gassed then re-coated BUT you may be better off just starting with another set to be honest...it`s on him though he should have never shipped that.

 

"Gasket remover" from the parts store will eat powder coating right off.


And yes, he failed in the surface prep. They're fixable though.

 

Do you guys find the powder coated callipers handle the heat ok?

I'm starting to think I might just sane down the side of the callipers enough to attach the "Camaro" decals and put them on the car.

Should have been simple, but has turned into a PITA.

 

wow that looks like a PITA

 

I powder coat and those calipers need to stripped and redone. That is a disgrace and should have never been given to you like that. It looks like the first coat didn't cover and a second coat was applied to thin and made it do that. Probably because of a cheap gun.

 

The powder coating business I used was a big operation, so I'd be surprised if they used a cheap gun.

More likely the operator was inexperienced and screwed it up.

When I phoned to discuss it the business owner moaned big time, but eventually agreed to redo the job.

He did a lot of suspension parts for me, which turned out fine, pity about this stuff up.

 

Its good to hear he took care it. From experience I have had happen before and it was from too little powder and a cheap gun so it didn't stick right.

 

Those calipers wernt washed and outgased after media blasting.
Its aluminum so they could have glass embedded in them and if not outgassed then washed thats what happens. Get yourself some Napa brand carb cleaner and soak them down. The powder will come off.

POwder will hold upto caliper heat and baking no problem.

 

The strange thing is that the callipers were new, but I still got charged for sand blasting ???

My theory is that he didn't bake and then clean the callipers before powder coating, and that then impurities sweated out when they were baked.

Wish I'd just used VHT calliper paint and saved the cash and grief.

 

No need for theory. I powder coat. some people like to blast everything to know its clean, etc.... They didnt outgas the aluminum pieces proper.

ask if they were prebaked/out gassed and see what they say.

 

Thanks for the tip, I'll ask them that.