I thought I'd share how I made the fiberglass fenders on my 72 MGB. From what I can gather about the car, it has been a race car since new. I am returning it to a street car that will look like SCCA production car. The car originally came with metal flares that were simply stock steel fenders that were pie cut, pulled and held in place with a strip of steel brazed along the wheel lip. They were covered in body filler and painted. Years of neglect allowed rust to permeate the structure rendering them useless. I decided to build all new fenders out of fiberglass, and bond them to the car. The metal panels were removed except for a couple of inches all around. More steel was added to box the unibody and to seal off the trunk area.
To make the fenders, I started by glueing a plastic contractors bag to the fender of a parts car with spray glue. I spread on a layer of resin and let it cure. I added two layers of fiberglass mat and resin. One layer of woven and one layer of strand were installed. After two days of curing, I pulled the whole thing off of the car. The bag mostly wanted to stick to the fiberglass and not the parts car. A little wipe down with prep sol and you can't even tell that there was a plastic bag glued to the car. I proceeded to rivet and bond the new fender to the car.
Now for the flares. I made a support along the fender lip with some cardboard and duct tape.(kind of like a form for concrete) I filled the cavity with expandable foam and shaped it with a knife to the make the flare. Once the shape was close to what it needed to be, fiberglass mat and resin was applied over the foam flare. I used a grinder to remove back side of the fiberglass lip and the foam center to reveal the inside of the flare. Typical body work and paint followed. This summer I made all four fenders, a rear Sebring stlye lower pan and a decklid. Total cost was around $600.00 to $800.00, and it took about 75 hours of labor to get to a point where I can paint the car. It currently sits in primer while I decide what to do about the front valance and bonnet.
To make the fenders, I started by glueing a plastic contractors bag to the fender of a parts car with spray glue. I spread on a layer of resin and let it cure. I added two layers of fiberglass mat and resin. One layer of woven and one layer of strand were installed. After two days of curing, I pulled the whole thing off of the car. The bag mostly wanted to stick to the fiberglass and not the parts car. A little wipe down with prep sol and you can't even tell that there was a plastic bag glued to the car. I proceeded to rivet and bond the new fender to the car.
Now for the flares. I made a support along the fender lip with some cardboard and duct tape.(kind of like a form for concrete) I filled the cavity with expandable foam and shaped it with a knife to the make the flare. Once the shape was close to what it needed to be, fiberglass mat and resin was applied over the foam flare. I used a grinder to remove back side of the fiberglass lip and the foam center to reveal the inside of the flare. Typical body work and paint followed. This summer I made all four fenders, a rear Sebring stlye lower pan and a decklid. Total cost was around $600.00 to $800.00, and it took about 75 hours of labor to get to a point where I can paint the car. It currently sits in primer while I decide what to do about the front valance and bonnet.