Fiberglass Question

[rspears]

I was adding glass to the mounting flange on my hood top today and followed all the steps - grind away the gel coat and about 1/2 of the thickness of the existing flange; cut strips of mat to fit the new area, plus more to span the new and old area; wax the metal form piece; etc. When it came time to mix the resin I added hardner from memory, using the 12 drops per small batch instruction. Problem is the 12 drops is per ounce of resin, and I was doing the six tablespoon measure which needed 1/4 ounce. I figure I was off by at least 1/3, and perhaps 1/2 on hardner. After four hours it is mostly hard with a few tacky spots, but seems to be hardened. Do I need to be concerned with strength? Do I need to do anything special, like let it bake in the sun for a few hours?

[HOTRODPAINT]

Most resins are called "air inhibited", and will cure, leaving the surface uncured for a while, so you can add more layers. Just because it's feels tacky, that may not mean anything.

I always just add a thin coat of bodyfiller to finish the curing, then you have a head start on smoothing it out.

Another option would be to put a heat lamp on it, or a light bulb with reflector, for an hour or two. Don't put it so close that it gets hot... just "very warm" to the touch. This will help to cure it.

[Itoldyouso]

Also make sure your hardener is fresh. If old it will lose it's ability to catalyze the resin. I had some stale hardener one time and the mixture never did cure, had to get it all up and start over.

Don

[rspears]

Thanks, guys. On the hardner, luckily it was a brand new tube, just broke the seal on a new can of resin & a new tube of hardner. It seems to be setting up, just pretty slow. I will check it in the morning and see how it has done overnight. Sounds like if it hardens strength is not an issue so I may be OK on this round.

[Itoldyouso]

No, you will be fine. I had some on my 27 floor that wasn't curing so I brushed a hot mix of resin over the top of it and it cured fine. That was 20 years ago and it still is holding like it should. Fiberglas is a pretty forgiving medium.

Don

[rspears]

.....so I brushed a hot mix of resin over the top of it and it cured fine.

Don

I had thought about doing just that, mixing an ounce with a heavy dose of hardner, and laying a thin layer on top to hasten the set. Hotrodpaint also mentioned a skim coat of bondo, which is the same concept.