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70chevy 02-22-2004 09:01 AM

Fiberglass Clarification
I have gone through and read all the post i can find about fiberglass. I made some door panels and two accent pieces, one is a big half oval and the other is a long stripe with a raised chevy bowtie. So far i am very happy with the results except, on the actual panel it keeps curling up. What is my problem. How much fiberglass is enough? I have seen that many people say put several layers. I have 4 layers is this enough? When I layed it on the shop floor to trim it i walked on it and had no problems. But I am worried about putting the bondo on to smooth it out and then it curling back up on me. I have tried setting it in the sun and it worked but once it cooled down in the afternoon it was curled worse than before. So I set weights on it with no results. Then I tried the heaat gun. Worked great then it curled back up. So I tried using a heat gun with weights and still no results. What am I missing?

kristkustoms 02-22-2004 01:45 PM

What are your molds/bases made out of? If its like 1/8" Luann plywood, they will almost always curl up on you. When i build stuff out of fiberglass, I always have some sort of wood base. Then i stretch the fiberglass or mold material over it and apply the resin. When the material is stretched, it wants to curl the wood as you stated. What i do is screw my mold to a 2x4 so it will not curl or bend, then apply the resin. It will cure it to its flattened state (uncurled). Then unsrew the 2x4. Make sense?

70chevy 02-22-2004 01:53 PM

Well from the sounds of that i went about it all backwards. I covered my door in cardboard to fix all the little fluctuations and holes and then covered it all in seran wrap and pam. I layed the fiberglass fabric over it and soaked it. That worked fine. It took the exact shape and was as good as i was expecting. Then i put 2-3 more layers of Resin. And the next day it started curling after it was dry!!! My two little molds (bow tie, and oval) have had no problems at all!

kristkustoms 02-22-2004 02:27 PM

One layer of fiberglass will not be enough on that size of a panel.

Adding multiple layers of resin will do nothing except make your fiberglass piece more brittle. You need to add layers of resin soaked fiberglass mat to add strength, preferably when the whole project is still "wet." If you do one layer, let it cure, then another layer, the two layers will not be "bonded" together very well. Alot of resins have a wax type substance that rises to the surface when it cures. You need to sand/scuff the fiberglass each time you let it cure if you are going to add another layer. And like i said before, always do something to keep your mold (in your case, your factory panel covered in saran wrap is the mold) straight, like with a 2x4.

70chevy 02-22-2004 03:05 PM

So my well shaped door panel is not trash if i sand it down and add another layer of mat? I was looking at going to the Tshirt material after lots of research. Lots recommended this because of its ease of use and it didnt clump up and come out in pieces while it was wet. What about somthing small like my kick panels do they need several layers or is one sufficent? How many layers of cloth do i need for optimum perfomance for things like a rear cab cover head liner and door panels? I am trying to do all that roddoors make and have my own designs for my pleasure and spite of the overpriced fancy pants corporation!

Oh and on the kick panels i was going to add speaker holes. Does somthing like this need to be reinforced? I am not running subs or anything just alpine 5 1/4's

One last item, since i am using my actual cab for a mold i.e. the door and ceiling etc, is there a way i can get the ceiling covered with ceran and pam and get the cloth up there while i am covering it or is there a better alternative. I want all the curves to fit i am not wanting just a flat piece up there but for it to come down on the edges a little more! Same thing with the Rear cab cover I want to perserve as much space as possible by conforming to all the curves that are already there

302 Z28 02-22-2004 07:25 PM

You also could be using too much catalyst that is generating too much heat causing the warping. Back off on the catalyst and use the extra cure time to place more resin soaked mat on it.

Vince 02-22-2004 08:30 PM

Resin without cloth or mat is a no-no! A good fiberglass composite part has minimum resin to saturate the fabric and a high percentage of glass. General rule of thumb is 3 layers of mat for the type of things you are building. For body parts, use 2 layers of mat, a layer of woven cloth, two more layers of mat and a final layer of cloth. For all parts, squeeze out the excess resin for a stable part. Your curling parts are due to too much resin.

70chevy 02-22-2004 08:56 PM

so trash the door panel shell and make a new one or sand it down a little and add some more mat/tshirt? 02-22-2004 10:55 PM

Do it right and start over. The practice will do you good and salvaging the current part will take more time than just making a good one from scratch.

70chevy 02-23-2004 06:30 AM

Thanks guys. Is there a way to keep the little bumps and ripples out while i am making the panel, or is that part of the sanding/bondo expericence.

So what about the speaker kick panels?? Do they need to be reinforced or can speakers be monunted to the fiberglass?

What is the best way to make a headliner? I want it to form to all the curves so i was hoping there was a way to get the cloth to stick to the ceiling (as well as the ceran and pam) any ideas or similiar experiences? 02-23-2004 08:47 AM

I'm afraid that the way you are building the parts, you are stuck with lumpy surfaces that need to be ground and bondo'd. The only way to get that super slick surface is to build a female mold with a polished surface and use gel coat as the surface of your part. There is nothing to be ashamed of using mold-less method - been done that way for decades and the overall body itch you will have for several days after grinding the part smooth is a wonderful badge of courage. I have done it innumerable times in my illustrious rodding career! In fact, Ed Roth built all of his wonderful creations that way - laid fiberglass over a plaster mold then ground and bondo'd the rough outer surface for a show painted finish. I commend your goal to make a headliner but that is one fiberglass task I would NOT try! You stand the chance of entombing yourself in hardened dripping resin for eternity!

Here are couple of photos of a multi purpose kick panel I made for my '36 Pontiac. It holds a speaker, the brake release, A/C outlet, a trunk/gas door remote actuators (just embedded the plastic donor housing in the fiberglass) and is a cover for the GM emergency brake. Ready to sand bondo and upholster.

70chevy 02-23-2004 09:46 AM

So is that reinforced? I am just getting over my itch. I found a loofah with a nice hard scrub got a lot of it out. Not all but a lot.

What would you suggest for a headliner? I am clueless as what to do. What about filling in the original trim holes and just using the 3m super 77 to glue my vinyl straight to the metal? Is there another option out there? I would like to be able to do a design. Could i make a mold and put just a raised piece and screw it in on top of my glued vinyl-to-metal Headliner? 02-23-2004 10:20 AM

The kick panel is just 3 layers of mat & resin. The curvy shape is very rigid and holds it's shape very well.

Sounds like you are stuck on the concept of the cardboard headliner insert which is a relatively new development. I don't know what model car you have but any competent upholsterer can install a sewn cloth headliner in older cars that don't have the cardboard insert. IMHO, the old style sewn type is much better looking than the glue-in type; says 'quality' rather than 'cheap to build'.

70chevy 02-23-2004 10:34 AM

Can you explain a little more of what you mean? I just want a black base vinyl with an oval that spans from side to side that is gray, then a slightly raised bowtie possibly or not i can go either way.

My mother was a fashion designer and has all the industrial sewing machine and is very handy with stuff of this nature. She offered to play around and sew whatever i need!! Trying to have as close to an owner built/CHEAP truck as possible. I am about 8,000 so far and have about 1000 in parts paint and 20's still to go. So if you could explain exactly what you mean for the headliner. That is the only thing i dont think i can do. I am very hand and willing to learn, so everything else should be a breeze. The kick panels are flat with nothing on them except a vent. So i am not worried about that. Shoud be the easiest one to make/cover. The rear cab may be a little tricky but i am not worried.

My truck is a 1970 c10 fyi 02-23-2004 10:44 AM

I'm not familiar with your truck. What did it have originally - just a steel inner roof? If so, you could wax it and lay three fiberglass on it for a removable insert to upholster. Just be ready to wear a lot of resin at the end of the day!

Here is a site that specializes in the sewn type headliner.

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