Want more info on this for sure! Funny you should mention POR15 -I bought the starter kit just to find out that the surface needs to be rusted to Adhere properly.
Let me first say I don't know how long the paint will last but I'm confident it has a better chance of surviving rather than just painting without the Prep and Rust Prevent applications.
As far as the surface needing to be rusty to adhere, I don't think so. After I cleaned and used the caliper/metal prep the surface flash rusted immediately.
Here's what I used. A box of gloves( the paint is hard to get off your hands). Two assortment packages of Taklon brushes from walmart. Cheap Bristle shop brushes from harbor freight and a tooth brush.
1. Caliper Cleaner: Brushed it on and scrubbed. I used a spray bottle with water to carefully rinse around the boots and piston.
2. Caliper/Metal Prep: I didn't want this stuff on the piston, boot or retaining ring. It will begin to eat away the piston and retaining ring surface. So this is when I masked everything. I used a small bottle as a template to match the dia. of the top of the piston and boot. I used 3 overlapping pieces of tape on a cutting board and an xacto to cut that top circle using the bottle as a guide. I then cut a bunch of approx. 2"x1/4" strips to cover the sides of the boot and retaining ring up OVER the top circle. PITA. I then brushed the Prep on up to the masked boots and kept it wet for 10 minutes. Then I carefully rinsed again with the spray bottle.
3. Rust Preventive Paint: I started on the inside around the boots with a small brush and worked my way out until I had painted about half of the outside as well. I then flipped the caliper over and put it on small wood blocks on each end of the caliper. I wanted to keep from messing up the painted area. Then I finished the remaining half of the caliper.
4. Caliper Paint: The Rust Preventive paint needs to be slightly tacky when you put the Caliper Paint on for best adhesion. I flipped the tacky caliper over again so I could start on the inside around the boots with the small brushes. I used long screw drivers through the two caliper mounting holes to help turn it over. I worked my way out as in step 3. Turned it over again and finished the remaining half of the outside. I ended up just putting one coat on the inside and two on the outside. The paint can be brushed out more than I expected and leveled out good. I used the Black caliper paint.
So was all this worth it? I don't know. I do know I don't want rusty orange calipers. I'm also hoping that by painting up to the boots it will help keep the rust from reaching the piston and cylinder wall. It seems like that's one of the main reasons the pistons seize.
Then finally if I'm not mistaken the Starter Kit doesn't have the Caliper Paint included. You'll probably need that. Something about the Rust Prevent Paint needing to be top coated because of UV issues when in direct sun light. You can get it on ebay $18. Good luck.
