I've been playing with Buicks since I was in high school a "few" years ago. One thing I learned quickly was that a lot of common hot rod parts weren't readily available for Buicks. So if you want something, sometimes you have to build it yourself! As for fiberglass body parts, the only thing that was available for a '70-'72 Gran Sport in the early 80's was a hood. So here's some pictures and info on some of the parts I've built over the years. While some of them might not have popped out of the mold ready to be bolted onto the car without a little massaging, they did serve their purpose. It's been a on going lesson as different parts have been created! Each part has been a little better than the last.
I have made a couple of rear bumpers for Mike Tomasewski's '68 Buick Sportwagon over the years. The first one out of the "mold" was extremely light, weighing less than 4 pounds. Basically, I had no idea when to stop laying on layers of fiberglass mat. In hind sight, I stopped a little short here. Unfortunately it did not hold up to the constant wheels up launches the wagon was accustomed to performing. The second bumper I fabricated was made a little bit sturdier with an additional layer of mat. It's a learning curve!
Mike had a company build a custom one off fiberglass tailgate some years ago. This was not an inexpensive proposition. Building the mold is the costliest portion of making a new piece in fiberglass. A good steel tailgate is prepared. Gel coat or surfacing primer is then sprayed on the steel tailgate. Next, several layers of fiberglass mat are placed over the tailgate. Then to add rigidity to the mold, it is reinforced. The builder of this mold used balsa core. Very strong, yet very light. When everything has dried, the mold can be separated from the steel tailgate. You would have thought this mold was going to be used for production runs instead of something they were going to use to produce a single tailgate.
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The outside portion of the tailgate mold.
The inside portion of the tailgate mold.
The inside of the mold. Black gel coat was used on this mold.
A customer of Mike's TA Performance, Bill Lagna, was looking for a fiberglass tailgate for his '68 Sportwagon. Mike thought I might be interested in trying to make a tailgate. I had made single piece parts previously such as bumpers, a hood and a trunk lid. So the chance to try a two piece part peaked my interest. I had been thinking about making some doors for my GS and getting my hands on this tailgate mold would give me some insight as to how a professional makes a two piece mold.
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The mold is first waxed with several coats of a 2 part mold release wax. The mold is then sprayed with several thin coats of PVA (Polyvinyl Alcohol) This is a thin, water soluble release film.
The next step is to spray on several layers of surface coat. This will be the coating on the outside of the piece when it's pulled out of the mold. In this case I used surfacing primer. The primer is used because the piece will be sanded before paint. In a case where there would be no further prep to the outer surface, such as a boat, gel coat would be used.
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1 1/2 oz. fiberglass mat is cut and laid into the mold.
The fiberglass mat is wetted out with resin using a brush and a roller.
You have to try and work all air bubbles out of the mat and resin. Four layers of mat were used on each piece.
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All four layers of mat are in place.
You extend the mat out an inch or so and then trim it back.
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The outer fiberglass skin was trimmed prior to removing it from the mold. If the mold was properly waxed the fiberglass piece pops right out of the mold.
On the inner section, hinges and cables are attached to the fiberglass. Once the fiberglass lay up was complete, pieces of 1/4" aluminum were glassed to the inside of the inner section. The attachment point holes can be drilled and then tapped providing a solid anchor point.
Once both sections are completed, the flange areas of both pieces are dressed with 36 grit sandpaper. A small strip of mat is laid on one flange.
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The strips of mat were wetted out with resin. The two pieces are joined and then clamped together and left to cure for a day.
The two pieces are now one.
The next thing to do is trim the excess mat.
So here's the completed tailgate. The original tailgate weighed over 65 pounds. This fiberglass piece only weighs 23 pounds.
UPDATE 12/06
Bill finally got the car back together with the bumper and tailgate I made! The car broke into the 9's with a 9.98 ET!
While Bill was inquiring with TA about the tailgate, he also asked about a rear bumper? Mike offered him the damaged original fiberglass bumper I made for him. I said, "I could probably repair the old bumper even though it was in three pieces at this point."
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The wheelie bars were the main cause of the damage.
The bumper was broke in two large sections and had a third smaller piece.
The slicks would throw small bits of rubber and stones into the bumper during Mike's burn outs. Because of the thin nature of the original bumper, they caused these star cracks. I added additional mat in this area to reduce the chance of it happening again.
The pieces were put back into the original "mold". To prevent the new mat and resin from sticking to the mold a piece of wax paper was used instead of the laborious task of wax and PVA. Kind of a quick easy solution for small jobs.
Here's the bumper with a couple of layers of new mat and resin in place.
After being pulled from the mold again, the only thing left was to do some cosmetic work on the outside.
The finished product! This one weighed a little more than the original creation, but still weighed in at only 10 pounds. The original steel bumper weighs 25 pounds.
As I mentioned earlier, the typical process for creating a fiberglass component is to first have the steel version of the part you want to create, then you straighten it as best as you can. The finished glass part will only be as good as the repaired steel piece. The mold typically requires a lot more time and material to create. Then if you're only going to make one or two copies of the mold, you can see where it could get expensive. The mold can easily cost 4 to 5 times the cost of just a normal fiberglass part.
But, there is an alternative possibility that may never be used by the real manufacturers, but can save you some money. You take the original steel piece, flip it over, clean and prep it like it was the outside. There are a few minor issues you'll have to live with when using this method.
This was a bumper I made for Mike Tomazewski's Sportwagon
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All of the small holes should be filled in
The back side of the bumper was cleaned up, pitting was wire wheeled and then filled with bondo and sanded smooth. After primer and sanding I then used an inexpensive acrylic enamel paint to coat the inside of the bumper.
One down side of using the bumper as the mold is when you go to remove the fiberglass piece from the steel "mold" the lips that fold over into the mold, will hinder the removal. You can bend these lips back to ease removal, but typically, you'll chip up the fiberglass piece some on removal. Nothing that can't be repaired after it is free. The only other minor downside is the fiberglass piece will be smaller by the thickness of the original steel. You'll never notice it though.
The finished product.
The bumper installed on the wagon.
Here's a few of the other projects I've made over the years.
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This was actually my first fiberglass project. I made a fiberglass front bumper for my GS.
At the time, there was not a fiberglass hood available for a 1970 Dodge Charger. So I decided to try and make one for a friend. Given it was my first large project, it came out OK. One mistake I made was not bracing the backside of the original hood, which I used for the mold once the bracing was cut out. After I had the first layer of mat in place, the mold flexed when I moved it. This made a portion of the new hood pop out of the mold so it wasn't flat in the mold any more, hence the bricks to try and keep the thing flat. Kind of a half ass fix, but I was in the middle of the project and didn't want to start over. You can also see the bracing before it was glassed in to the hood.
Here's the new fiberglass hood on the left and the steel hood/mold on the right.
This is the finished project after I straightened out the waves caused by the flex.
Alas, all of my work was for naught. The hood sat on the Charger for 10 years in the scorching Arizona sun. Combine the brutal summer heat with my novice lack of the appropriate amount of reinforcement material, plus not having the hood mounted on the car, the edges curled up, regulating it to junk. Just as well, the car won't be at the track any time soon. Sorry Tony!
I did make a trunk lid for the Charger. Because it was smaller and was actually pinned to the body all these years, it still looks OK, just slightly faded! I couldn't find a picture of it though!
Well, that's the projects. I am by no means a professional fiberglass fabricator, but if anyone has any suggestions, I'm always trying to learn more!
One good source of information is Fibreglast Development Corp. http://www.fibreglast.com They have a lot of info for the Do It Yourself guy.
