I just wanted to share the following info from a new chapter in my personal book of "Hey, That Don't Work" http://www.chevelles.com/forum/smile.gif

For Background, I'm working on a budget restification. The metal on the roof is swiss cheese from the damage caused by the former vinyl top. Replacing the roof is not an option for me right now.

My "solution" was to prep and POR 15 the roof, then rough up and cover with fiberglass.

Never one to get the answers BEFORE proceeding, I put the fiberglass over the cured and roughed-up POR. http://www.chevelles.com/forum/redface.gif

Too late, I e-mailed POR on this in response to comments from others here. They sent me this response:

"The problem that you are encountering is one that many people as
you know run into with their restorations. As we don't recommend the
POR-15 products to paint your entire vehicle it is strongly and widely used
to repair areas on the body including fenders, roofs, and other areas on
the body. The correct application is to sandwich the fiberglass in between
two coats of POR-15 paint. Then over that section you can use our epoxy
putty or bondo to give you a cosmetic finish."

I'm here to tell you that they are absolutely right. You should NOT attempt to use fiberglass with standard fiberglass resin on a POR15 coated surface.
The fiberglass resin will NOT adhere properly to the POR15 coated
surface and the cured fiberglass WILL peel-off in sheets.

On a positive note, I do now have some rather curious looking fiberglass "molds" of my roof - great conversation pieces! http://www.chevelles.com/forum/biggrin.gif

Hope this helps somebody out there.

so what are you going to do? are you saying to just use the fiberglass mat between layors of pro-15 without using any of the fiberglass poly.... resin at all? on a different note, this is telling me por-15 is an excellent mold release for fiberglass! http://www.chevelles.com/forum/smile.gif
please tell us what you did do and how it turned out.

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I couldn't repair my brakes, so I made my horn louder.
Just let me apolagize for my spelling right now!
www.EINSTYN.com (http://www.EINSTYN.com) TC Gold#1460, VCEA#2, SCPC#44
68-72 Wagon resto & mod info, parts & sales.

I'm redoing the fiberglass layer, omitting the resin and painting the POR 15 on the fiberglass mat, which of course, is laid on top of the POR coated roof. I've got most of the first layer on and it appears to have adhered very well and is also very hard.

Fortunately, the other fiberglass peeled off cleanly from the POR coated roof. Cleanup and rescuffing of the roof was pretty easy.

The downside is that it takes alot of POR to saturate the fiber mat. The POR will not melt the mat like regular resin, it just gets all in it and dries hard. One positive I'm seeing in this is that the mat with the POR loks rough and "toothy" so the filler that will go over it should stick really well.