View Full Version : fiberglass fenders

09-22-2006, 11:03 AM
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.

09-22-2006, 03:23 PM
Thanks for sharing.
We'd love to see pictures.

09-22-2006, 03:44 PM
neat, I have always used solid foam and shaped it and then pretty much the same process.

tony barnhill
09-22-2006, 06:16 PM
Sounds pretty neat...do you think you really saved enough, though, to merit the 75 hours of labor?

09-22-2006, 07:02 PM
The 75 hours represents everything, including the metal work and the paint prep. The actual making of the fenders only added up to about one third of the total time. I did it because I wanted to, not to save any money. I am enjoying bringing this car back from the dead. How many people can say they own a 72 MGB that was never even registered before. It was used as a showroom stock race car during the 70's and converted to a modified autocrosser around 1978.

tony barnhill
09-22-2006, 07:13 PM
Then, will you register it as a "new" car?

09-23-2006, 05:25 AM
That is where the parts car comes into play. The log book went missing before I acquired the car. I removed what was left of the original bolt in cage in favor of a simple weld in hoop. This should allow a folding top or the hard top to be installed. Since the history of this car is gone, it's not worth restoring as a race car. I plan on putting this car, a parts car, and a bunch of other spare parts into a bag, shaking real hard, and seeing what falls out the bottom. wink wink. That day is still pretty far off. This resto has been and will continue to be a tremendous amount of work. I have a garage full of projects, and I bounce around from car to car. At this point, I am tired of sanding fiberglass. I will spend most of the winter finishing a resto I started on a 28,000 mile TR8 convertible, which sat from 1986 until I bought it 2 years ago.