Help: Paint/Painting Knee Armor

I need a little help.

I have a pair of FP rubber knees that I am trying to paint. I am now on my third attempt.

First attempt: Testor Acrylic paint - had some cracking on the sides of the knees so I decided to redo.

I read that PACTRA paint was a bit more elastic and would hold up well and not crack which led to the second attempt.

Second attempt: Testors pactra paint. Absolute mess. Not only did it crack on the sides but also everywhere else and peeled off easily in strips.

Does anybody have a recommendation/technique they used and had success with? I really don't want to shell out more cash for paints/thinners etc but will if there is something better out there.

I am thinking of going back to the first attempt and Acyrlic paints and do very light layers with sanding between to see if that would reduce any of the cracking.

A bit fustrated at this point as I have other pieces to be working on and the knees have taken way more time than and resources than I had anticipated.

Thanks

for my s1p rubber knees i started with rustoleum automotive primer, then just used regular spray paints, i.e. rustoleum, krylon, color place, etc. i haven't had any problems with the paint yet.

I've had the same problems.

Yvette

Any suggested colors for the spray paints? (for the yellow)

Someone used to make a bumper primer that was supposed to help paint stick to rubber and flexible plastic car bumpers are made of, that might help.

Cool, thanks... I'm in the middle of using some rattlecans right now. Just applied the yellow last night, so far so good. (Haven't checked it yet today). I plan on doing a light airbrush mist of UP Yellow too try and tone it down a little today.

Success with using the rattle cans. I then misted them over with UP Yellow (airbrush) and seems to have worked well.