Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Doors & windows in Fiberglass body

Doors & windows in Fiberglass body

Doors & windows in Fiberglass body

Hi Everybody

I'm pretty new in the field of composites . I intent to construct a race car body out of fiberglass. I've a problem imagining how Doors can be made since I think that when a cutout is made in the body it'll cause large deformation that the door will not fit in . also i think that the door itself will be very elastic if it is cut directly from the body. to make it short , could anybody give me a short explanation of making Doors in fiberglass body . and if there is any resources explaining the process in details i'll be grateful .

RE: Doors & windows in Fiberglass body

In most racing classes where you would be butchering a body by yourself, nobody cares if the door is flimsy, or exists.
You could pre-reinforce the cut lines by laminating some tape on the inside. It will take quite a lot of tape, and weight, to make a difference in how the post-cut door feels.

If you want it to look like you knew what you were doing, you would mold the door separately from the body, and give both some depth around their interface, like flanges deep enough to host weatherstripping, hinges, and latches.

It will take a lot of time and junkyard visits, but you might want to study exactly how the doors interface with the body in current and past fiberglass bodied production cars, and also focus a little on where the cracks appear.

Mike Halloran
Pembroke Pines, FL, USA

RE: Doors & windows in Fiberglass body

Thanks for your reply Mike.

RE: Doors & windows in Fiberglass body

I have a fiber glass streetrod and I've installed a number of funny car bodies on the frames.

The two are very radically different. The race car is just a shell about 1/8 to 1/4 inch thick at the most. There are no doors in funny cars. They do have a roof hatch. These are framed with foam an inch or so thick then glassed over to make a rigid structure. The hatch itself is the same but much thinner as it is not meant to sat upon. I usually put a couple of carbon fiber strips in the roof frame on the foam so it is strong enough for a person to stand on.

The street rod is built more like a conventional car. The body has the Doors and trunk outlined with a substantial wood framework. The hinges are mounted in this. The doors are two pieces laminated together similar to real steel cars. Since mine is a replica it's very close to the original. There is no wood in the doors. The outer skin is about 1/4 inch thick and the inner is 1/8 to 1/4 thick. There are steel backing plates for the hinges. Even with power windows the doors only weigh about fifty pounds if that. The car weighs 2850 with a supercharged small block Chev...about 500 hp.

Molding a body like this is a huge task. The molds are very complex to say the least.

The funnycar bodies are much simpler. They usually come mounted on saw horses on a skid. They aren't really stiff enough to hold their own weight until we get them mounted on the chassis and install the interior aluminum work. It's called " the tin" in the race car world. You must refer to it this way or you will be considered a " newby ". The funny car has a tubing frame work both front and rear made for easy removal of the body. You must refer to this as front or rear " tree" . It's not a tubing frame work in race car conversation. You have to talk the talk..haha

Even building a relatively simple body like this is a monster task. In the old days of the early funny cars the builders would go rent a car and " splash" a female mold off of it. Then it was stiffened and became the plug. Then the first body was molded. From this the modifications were made and another mold from this was made. It was heavily reinforced, cut in various sections for easy break away from the body. These were made easily bolted back together for the final body mold.

That's it very simply.

RE: Doors & windows in Fiberglass body

Your explanation help me to understand the race car .

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


White Paper: Rapid Manufacturing with FDM
The automotive industry is increasingly turning to additive manufacturing, and fused deposition modeling (FDM) specifically, as a reliable alternative to traditional metal-cutting methods, like milling, turning and boring. Download Now
White Paper: Revolution in Design
Open up new possibilities for your business by changing the way you think about product development. Compared to traditional methods, 3D printing offers advantages that allow you to make more innovative products and get them to market faster. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close