View Full Version : fiber glass fender repair


03-06-2006, 08:39 AM
I haven't ever worked on any of the newer glass fenders and need some advice. This is a new 2006 Ford dually with the rear fiberglass quarter fenders. One was busted on the top side and bottom bracket area as well. It is a strange yellow color where the cracked area is, never seen glass look like that. Do I need to "hog" out the areas to be filled and repaired? Can I put glass cloth behind repair areas to strengthen them ?
thanks for your advice ---

Phil V
03-06-2006, 11:39 AM
I doubt if those dually fenders are fiberglass. They are probably SMC which means you can't use regular fiberglass resin (polyester resin) to repair those areas. Several companies like 3M, Norton etc etc make 2 part kits for doing SMC repairs. I found a product called Fibertech which comes in one of those "soft tubes" like polyester spot putty comes in that has worked great for me in previous projects. I believe its made by USC (could be wrong on that) but it is designed to be used on regular fiberglass AND SMC panels. It spreads like bondo and uses a bondo type hardener and it has I believe kevlar strands for added structural strength. Definately a good idea to use fiberglass matt on the back side for more strength.

03-06-2006, 05:04 PM
I've used that Fibertech and it's made by Evercoat. I don't think i'll ever use it again b/c it swells up in the heat. I repaired some SMC panel( which i was told it was) with it and then finished it off with some evercoat putty to perfection. It was ultra straight and later i come to realize that when it was in the sun, it would swell up majorly. I grinded it back and tried again just to make sure i wasn't doing anything wrong and it happened again. I guess i learned not to use the stuff again

03-07-2006, 06:09 AM
I just read a link to Fusor SMC panel repair. Looks pretty involved. Has anyone tried their system ?

Phil V
03-07-2006, 10:09 AM
I've used three tubes of the Fibertech stuff over the last several years and never had a problem with it. Big truck front ends, snow mobile hoods, truck box fiberglass panels, Corvettes etc. never a problem.

Chris L
03-09-2006, 07:49 AM
Im not sure if its the same plastic as bumpers,but having tried on about 4 different ones,using fusor,3m and recently upol plastic repair,i can NOT get a rip or hole stable enough to not crack back loose once painted.Even the 3m rep screwed up one day showing us the stuff.I just dont have confidence in repairs like that.I'd rather replace it.

03-18-2006, 08:59 AM
The best way to fix that fender is with fiberglass mat and resin. Since we suspect that it is SMC, I would suggest fiberglass Evercoat SMC Repair Resin. First grind the back side down about 1" on either side of the crack. Taper this area till you almost go through a the actual crack. Now lay up at least 3 layers of 1.5 oz. mat saturated with the SMC resin. Be sure to Roll this repair with a fiberglass roller between each layer. This is very important!! This forces out the air pockets and the excess resin. Excess resin makes the repair brittle. This completes the "structural" repair of the crack. Let this fully cure and you are ready for the "cosmetic" repair. Now, on the out side, do the same grinding that you did on the back side. This time you want to grind through the crack till you hit the patch you put on the back. To it, not through it. Fiberglass the same as on the back, making sure that you roll between layers. Again this is very important. If you don't get all the air bubbles out of this patch, you will be doing it over after it's been painted and out In the sun because it will blister. I would let this cure at least 8 hours, then grind down and finish with a good grade body filler. When done this way, the fender will not crack there again, ever.