Custom fiberglass bumper

crash

New member
Hello,
First time post. I am new to the forum. Been around awhile. I am not a body man, but I have done bodywork on a few cars over the past 30 or 40 years. Some of them even turned out okay. What I am wanting to do is customize an aftermarket fiberglass bumper cover. If you look at the pictures, the maroon bumper cover has a molded spoiler. It's a Shinoda bumper. I would like to replicate the spoiler. I am not interested in the lower ground effects portion. The Shinoda bumper is not available and I don't really care for the lower portion. It's going on a C4 Corvette. The replacement cover is not flexible like the OE bumper. How would I go about doing this or getting it done?

Thank you
 

Attachments

chopolds

Member
This is not an easy task for a beginner, and it wouldn't be inexpensive to have it done ...IF you could find someone to do it! It is a very complex piece to duplicate. But, it can be done.
I did a Miata bumper for a fellow a few years back. He wanted to add these huge fog/driving lights to the front bumper, similar to a concept car Miata he had seen in pictures. I don't have pics of the car he wanted to duplicate, but I did take some of his car getting done.
I took his stock bumper off. marked where he wanted the light housings. Then I made the basic shape for the light housings out of chicken wire, and bondo. Made a mold, then made 2 from the mold. so they were exact copies. I placed the fiberglass housings in the holes I cut for them on the bumper, and secured with JB weld, or something. None of this really mattes much, as it is all temporary, just to make the final mold. It does not have to last, or be very strong. I filled the gaps, and made the transition to the bumper with bondo, primered and smoothed it out, as if it was to be painted.
I made a mold from it. You'd be better off reading up on how to do this on a fiberglass site. You need lots of materials (gelcoat, tooling resin, fiberglass, parting agent, wax and polish, wood to strengthen the mold, microfoam or similar, to make 'dams' to make the mold in several pieces, etc.)
Once the mold is made, and left to cure for a few days, to a week, you can make the part for the car. Fiberglass matt, cloth, and resin (finishing resin) are needed for this. I left it in the mold for 2 days for full cure, then pulled it out, fixed any imperfections, and paint.
As you can see, it's not for the faint hearted. Not cheap, either for supplies, nor for labor. I did it once, but would be hard pressed to do it again!
The only way this is economically feasible, is to do a very strong mold, and make a bunch of copies, to sell, so you offset the costs. Not easy to find people to buy something to modify a Vette, esp. s part made for your tastes.Miata_1.jpgMiata_2.jpgMiata_3.jpgMiata_4.jpgMiata_5.jpgMiata_6.jpg
 

crash

New member
That's a really nice job on that Miata.
So I will just be using the bumper I make for a mold and then have to make a whole new bumper? In that case, there is no sense in me spending $750 for a fiberglass bumper. I wonder if I could make my flexible bumper rigid and use that for the molding process instead of spending the money on a new bumper. Another thought I had while typing this is why couldn't I create the duplicate bumper (using my bumper or a junkyard piece). I could build it up with body putty or fiberglass. Get it looking the way I want and have it 3-D printed?
On another site I posted this question and it was suggested I make a form out of foam and glass it over that adhering it to the fiberglass bumper.
I watched some Youtube of boat guys making parts and making the molds is no small task. It's a monumental task for a beginner and they make it look like it's just another day at the office. I guess it is.

Thanks
 

chopolds

Member
Well, if you do buy a fiberglass bumper, it would be easier to just add the spoiler to it. You could build up the area with spray foam, wire mesh & clay, just about anything that will keep it's shape. Foams, you have to check to see if the resin will attack it. If it does, you could always put a coat or 2 of latex paint over it to protect it from the resin. Be sure to make your form about 1/4" smaller than it needs to be to give you room to build up the fiberglass over it. The glass will go on lumpy, so after curing, you will have to grind it down a bit and use a short strand filler to smooth it out. A littel body filler to fix small imperfections is OK, too. Use a good high build sealer, or something like Slik Sand, or Feather Fil as a primer, to seal up the fiberglass, and give you a good coat to sand to perfection.
 
Top