POR-15 and Raptor Liner

I recently coated my roof with POR-15 and finished it with POR015 Top Coat to protect it from UV damage. I must not have followed the directions or just misunderstood because it is starting to peel off.

I am now settled on coating the roof with black UPOL Raptor liner. Has anyone had any luck with using Raptor liner over POR15? Their website says they are "pretty sure" it can but wondering if anyone had any real world experience? If so can I just sand the current coat with 120, clean degrease and then coat?

This is a 2008 work truck that Im not too concerned with how spectacular it looks. My main concern and reason of using POR15 was to stop the large amount of rust on the roof.

Any guidance is appreciated.

 

That depends on a few things. If you can pull a flake of the peeling coating, look at the surface that failed. Likely, the reason your paint was failing in the first place, is the reason the new coating is releasing now. It may well be holding on to the clearcoat to which you applied it, but that clearcoat is continuing to release from the original basecoat.
If you simply sand and coat the POR you have on there, the failure mechanism you're currently experiencing will continue and it will still peel.
For best results, I'd recommend removing everything down to bare metal.
Yes, that will be messy and will be a lot of work, but the majority of success of any coating is in the prep work.

 

Take all that POR15 off and sand the paint under it with a heavy grit, then apply your raptor lining.

The rest of your POR15 is likely to peel. Any spot where you applied over paint just isn’t going to stay adhered in the long run. My only recommended application for POR15 is as a last ditch effort to buy a little extra life out of a rusted frame. It’s a finnicky product at times and does not like intact coatings. It either likes etched bare metal or heavy rust only.

 

Good point @JdevTac I need to get some before pictures here because it was definitely last ditch and not my first choice. Other than the rust the truck is in immaculate condition mechanically. Thanks for the reply

 

@winkel That's what my fear was :/
I figured I would have to remove everything down to bare metal. Ill go look further but at first glance it looks like it may be like you said: the clearcoat peeling where as the actual POR coating appears to be OK. Still would need to sand past that POR you think?

 

Yes, I think so. The paint underneath will just keep peeling.