Manning

So, thinking I was being very clever, I base coated the strut housings for the set I was using for the ARHK with POR15 just to help keep them from getting too crusty. Then, following their explicit instructions I used their self etching primer before I top coated with Schoolbus Yellow. Everything looked great and I was happy as a clam until I went to install everything today. Anyplace that had a little too much paint buildup scraped off when I slid the struts onto the steering knuckle, which I expected. But it scraped off like it wasn't even remotely adhered to the POR15 below it. I mean it caused it too peel off in sheets in some places. I knew POR15 was a bitch to paint over, but this is ridiculous. As advertised though, the POR15 is unscathed, just the topcoat and primer peeled off. Fortunately it is all under the car, so it will rarely be seen.

Anybody else use this stuff before? Same or different experience?

tifosiman

I've used it before, and it is a biatch. Had the same experience as you on the inside of some fenderwells (on a different car than my 944). Honestly, I wouldn't use it for anything that wasn't going to get carpet or trim panels placed over it (ie, doesn't need paint, like floor pans or sills). It's very finnicky.

xsboost90

you have to sand it real good to get anything to stick. I sanded it and used a paint adhesive product before primering and had no problems.

Manning

I've used it a bunch in the past on things that aen't visible, like you said Tifo, but this was the first time I actually tried to paint over it that it mattered at all. Not that it really matters all that much since not too many people will ever see it. I tried knocking the gloss down a bit with sandpaper, even though the instructions on their self etching primer claims you don't need to. They claim it is the only thing that will stick to POR15. You live you learn.

I do have to say though that POR15 itself is incredible. Very, very tough stuff.

tomrc

Man I rebuilt a rusty old Scirocco with that stuff, never had a problem. Did you get all the loose stuff off first? Also it adheres best to rust not bare metal.

Manning

Oh, believe me, the POR 15 itself is adhered to the metal underneath like a tick on a hounddog. It's the paint I sprayed over top that didn't stick very well to the POR15. Like I said, I've used POR15 a lot in the past, I just have never really topcoated it before.

xsboost90

yeah i never tried their primer stuff, huh, i guess i wont either!

Manning

No, I wouldn't bother. The only other time I did anything close to topcoating was on the bumper brackets. When I did that I sprayed them with regular off the shelf Plastikote primer while the POR15 was still tacky, like it says to do on the POR15 label, and it worked OK.

Actually, looking at the primer directions, it does say to lightly sand first if the POR15 is fully cured. Even though I did do that it still didn't work properly. So I guess best bet is prime while POR15 is still tacky.

tomrc

Oh, I used the por15 primer over the por15, yea, regular paints don't work well. If it's not going to be seen, don't worry about the top coat. If you want to paint it though use the proper por15 primer.

Manning

A day later and it is really bugging me that the paint is chipped. Remove and repaint or not?

Mike1982

Well, if makes you feel better Mike, look at my car now... How sad....

Manning

Hmm, yeah I guess you have a point. I guess also considering all of the stone chips and door dings on my car, what the struts look like doesn't really matter, huh?

You need to change your avatar to a picture of your door until they finish fixing it. ouch.