Fiberglass patch kit

[J-440]

Evening all. I have just finished installing my glass fenders (already painted) and some of the gaps are a little too wide. The body shop that painted my car did so...but painted the fenders separately. Yeah, backasswards I know. It's a long story. Anyway, I was wondering if there was a patch/gap fill kit that I could do myself. Instead of taking the car back up to a different shop and paying the big bucks. It's 2014, don't tell me no one's come up with an idea like this. Thanks again.

[astroracer]

Evening all. I have just finished installing my glass fenders (already painted) and some of the gaps are a little too wide. The body shop that painted my car did so...but painted the fenders separately. Yeah, backasswards I know. It's a long story. Anyway, I was wondering if there was a patch/gap fill kit that I could do myself. Instead of taking the car back up to a different shop and paying the big bucks. It's 2014, don't tell me no one's come up with an idea like this. Thanks again.

Nope, not new at all, been doing stuff like this for 35 years...
Working with 'glass you will want to grind the fender, both inside and out, about three inches back from the edge you want to lengthen. This will let you wrap the matte around the fender and blend it into the existing surface. I did this on a couple of cars back in the early eighties. Trunk and hood gaps on a 55 and fender gaps like you have on a '69 Camaro.
I actually soaked cotton cord in resin and applied it to the edges first. After it cured I remounted the pieces and adjusted the gaps with a grinder, leaving room for three layers of matte.
I then wrapped the edges with the matte. Started with a two inch wide piece (one inch on each side), then 4", then 6", wrapping equally inside and out. After it all cooked I sanded and body worked it up to the primer stage. I had eyes on the '55 about 10 years ago. There was no evidence of the work I had done...
Mark

[charchri4]

Maybe I'm not following this quite right. The car was just painted so you want to patch it and paint it again?

Marks suggestion of how to extend the fender is good but there is a couple variables there. Have you ever worked with fiberglass before?

[broken1234]

Mark's method is good, but there are better products out there. Google U S Composites or West Systems or Fiberglast... they will have woven products that will be stronger and thinner than matt... and if you haven't worked with glass, find somebody who has... it's not hard to learn, but your 2nd job will be better than your first...

[J-440]

Charch...the whole car is already painted but the fenders were painted not mounted or fitted to the car. The body shop I had used was going under so they half-assed the work. However the paint and bodywork on the rest of the car look great. Just those gaps are pretty nasty.
Broken and Astro...thanks for the advice. This will be my first attempt at glass work. Think I'll experiment on something else before I tackle the fenders. Ya'll have a good one.

[J-440]

Hey Astro, have you tried Percy's hyperfiber composite kits? It's a type of material you can cut with scissors, form it to any shape, then hit it with a UV or sunlight and it instantly hardens. I'm wondering if you can sand it, blend it then paint it though. I imagine you can. Thanks again.

[charchri4]

Depends on the budget because you can fiberglass it for a fraction of the cost of percys. A gallon of fiberglass at NAPA is 50 bucks and a couple of yards of matt is $6 and both are probably more than you would need. I just hate the idea of having to repaint it all though. And why are the gaps so messed up anyway? I can't imagine a gap being so messed up to need to add on to the finder to fix it. That just doesn't compute to me.

Working with fiberglass is not hard. The most important things is getting a good bond with your fender. Matt bonds a little better than weave but weave is easier to work with. I don't really see strength as being an issue for what you are doing. I would suggest about an 8 oz cloth and if you want to go all out put a piece of the lightest matt you can get under it. I think that is 1/2 oz or so. I don't think you would need more than one layer to get the job done. That will end up being thicker than your sheet metal.

I guess the way I am picturing this you would just put the glass on the back side of the fender and let it extend out about a 1/4 or what ever is needed to fill the gap. Tape a piece of foil covered cardboard or thin plywood on the top of the fender to act as a mold. That will get your glass the same shape and level as the fender. Scrape up the back side bonding surface really good with 25 grit on a DA. Clean it with acetone - not wax and grease remover and you are ready to go. Some will say paint it with epoxy primer and you can but I think it's a waste of a step. Fiberglass sticks just as well as primer does. Maybe even better.

When I mix glass I use a cheap ebay postage scale to measure it. You can measure by cups or whatever but I like the scale because I can use the same cup to mix in all day and it doesn't matter how much crap builds up on it. Don't mix more than about 8 oz at a time because it will build up too much heat. It is temperature sensitive so if it's hot out use less catalyst and mix smaller batches. I usually start with 8 drops per oz at 80 degrees. That is scale oz not fluid oz. Use 9 or 10 drops at 70 degrees and 5 or 6 drops at 90. Don't mix over 95 because it gets to volatile and hard to control. Under 60 you will probably have to hit it with a heater to get it to set even at 12+ drops per oz.

It doesn't take long to get a feel for it and I would not do any test batches. But then I'm the kind of guy that just goes for it. The first time I ever pulled the trigger on a welder was on my roll bar...