Help with flaking DIY painted calipers

[Machostallion]

I'm trying to figure out why my DIY paint job flaked/peeled on the rear caliper after a couple of weeks. Pic is attached.

I followed the method used in this thread: Want painted calipers? Don't want to spend $600+ on them?

Before painting I cleaned the calipers using brake fluid, rinsed, and wiped down. I applied 3 coats of VHT high temp caliper paint about 15 minutes apart. Then 2 coats of the clear coat.

This is the same procedure I used on the front calipers about 4 months ago and they still look great. So I'm not sure what happened with the rear. (I've only done one of the rears up to this point - haven't had time to do the other one).

The one thing that was different was the outside temperature when I did it. It was about 70 degrees when I did the front and 50 degrees when I did the rear. I have since noticed the paint can says to use between 60 and 95 degrees. Not sure if this could cause this spotty flaking.

Next question is how to fix the problem. I'm guessing just repainting at this juncture won't be good long term. Likely need to remove the paint that's still on there first. But how?

I also attached pics before the flaking.

Thanks for any ideas.

 

[Tessaract]

I think you answered your first question yourself. Painting at below 10˚C (51˚F) is asking for trouble, because paint adhesion is comprimised. Many different paints advise that. If you want a quality job, my advice is to remove all the old paint (I know it's a pain, but even the paint that hasn't flaked yet is likely compromised), clean, and repaint at 70˚F.

 

[Machostallion]

I think you answered your first question yourself. Painting at below 10˚C (51˚F) is asking for trouble, because paint adhesion is comprimised. Many different paints advise that. If you want a quality job, my advice is to remove all the old paint (I know it's a pain, but even the paint that hasn't flaked yet is likely compromised), clean, and repaint at 70˚F.

Thanks. Any recommendations on how to go about removing the rest of the paint?

 

[Jymmybob]

Sandpaper and wire brush, rinse everything down with solvents and re-paint. If there's sections with good adhesion then you don't need to go out of your way to remove it but sections that are left will impact the leveling of the new coat(s). Did you use brake fluid or brake cleaner? I assume it's a typo but you want cleaner or straight acetone since it'll leave a clean dry surface. Scuffing the plating on the caliper is also a good idea.

 

[Machostallion]

Sandpaper and wire brush, rinse everything down with solvents and re-paint. If there's sections with good adhesion then you don't need to go out of your way to remove it but sections that are left will impact the leveling of the new coat(s). Did you use brake fluid or brake cleaner? I assume it's a typo but you want cleaner or straight acetone since it'll leave a clean dry surface. Scuffing the plating on the caliper is also a good idea.

Thanks for the suggestions. I did use brake fluid. I must have picked up that instead of cleaner. As soon as it gets warmer out I'll give it another go.

 

[TLLMRRJ]

Brake fluid is oil, so surprised it lasted a couple of weeks even.

You do realize what you did is the equivalent of someone baking a cake using salt in the place of sugar??

 

[bpobill]

How do you mix up brake fluid and cleaner? lol