I am restoring my 1984 Corvette, which is coming along great so far, but I noticed that under the passenger seat, where your feet go, the fiberglass is broken under the car to the point where light is shining through into the car from the outside. I noticed this when I removed the old carpet and saw the pavement! Also, the drivers side has this too but is minor compared to the passenger side, which is literally hanging down a few inches. I don't know how or when this happened. Perhaps a past owner put something very heavy there that broke through. Or maybe I bottomed out and hit a large rock or something. Regardless, I don't know how to fix this problem. I patched the hole from the inside under the new carpet with a little scrap metal, but I feel like the car needs to be elevated completely and the fiberglass redone or patched up.

Has anyone had this happen to them? Is this an expensive fix? I don't know anything about fiberglass.

Thank you.

 

2 options. 1) take it to body shop. 2) What I would do is clean up surface where you put metal down. Leave the metal there. After clean, sand the entire area with 36 grit sandpaper. Scuff it all good. Clean again. Auto body paint stores sell different resins and fiberglass products. An easy product for you to use would be Kitty hair. Its fiberglass like the consistency of bondo with the mesh ground up in it. Apply a couple of smooth coats. After dry you can sand with 36 grit to knock down high spots. Very strong product. Good Luck!

 

That is what I did to my 86.

 

My '89 had a hole in the driver side footwell front left corner too.
I didn't know anything about fiberglass.
IIRC there is a fiberglass kit repair kit that includes some small patches of glass fabric, the resin, and the catalyst.
It wasn't too bad at all to fix. Actually it was kinda fun.
I dig the fiberglass medium.

 

Had the same problem:

If you have the pieces try to glue them in place using cianoacrilate/ Crazy Glue or ZAP.

Clean using a degreaser. I use thinner.
If you have only the hole put some masking tape on the underside, then put some Zap and then baking soda, you will keep doing this untill you have repaired the hole.
Now put some more glue and let dry. Beware of the fumes.

After it is dry I use some fiberglass ( boatmat ) and epoxy resin or poliester resin.
Impregnate the part with epoxy and when it is tacky lay the fiberglass and impregnate with more resin.
The more layers you put the more resistance.
The fiberglass must be larger than the hole.

Epoxy is a little bit more expensive and it takes a little bit more to harden but the result is better.
If you like exotic materials you can use a combination of fiberglass with carbon fiber and kevlar.

The result will be a very hard part that will resist a lot of load.

Now, if you do not like to mess around with resin, DEVCON has a fiberglass patch impregnated with resin that will cure wwhen exposed to air.
I have seen Grainger carry this product, and also Travers.

Good luck.

 

Sounds like someone tried to jack the car in the wrong place. All previous posts were right on. Great place to practice on fiberglass repair.

 

I think the hole might be too big for a small repair. I could slide my hand in almost. I like the jack idea, someone might have done that. I just don't know when this happened. It's a serious rip. Does this change anything?

Unrelated, but are these cars known for rust anywhere that I should be looking for?

 

Does this change anything?

Not really - only that you may need to brace/support the footwell from under the car. The hole itself will need to fill as in some of the posts above (I used the "hair" glass mixed in the resin.) Even if you had to remove the sheet metal you have from inside to the outside and use it to hold the resin/glass in place. IIRC, on the front edge of the footwell under the car, there was a metal piece riveted to the floor board, kinda like a deflector/protector. When the hole is filled, use heavy mesh both inside and outside. Follow the directions on the can of resin, don't try to do everything at one time. Not a hard job, just time consuming to do it right. To put it on a scale, it's not nearly as hard as getting the #8 plug out the first time.

 

I have to repair a plastic part of my Bike this weekend.
I will take pictures of the process that is exactly the same as the one you should do.

I'll post them Monday or tuesday.

 

Whatever you do, do not take this to a shop to fix. They will charge you an arm and a leg. Patching a hole, even a big one, in fiberglass is easy and the materials are very cheap. Buy some fiberglass mat and resin (or just use bondo) and hardener, use this to bulid on top of a sheet of tin foil a "backing plate" and while it's still uncured and sticky, stick this supporting plate onto the (sanded) surface under the floorboard, covering up the hole. Let it dry, peel the foil off, and then fill in the rest of the now covered-up hole with more of whatever polymer you're using. Once dry, use a dremel tool to cut it down to shape and to cut off any stray mat fibers. Since it won't be a visible spot you won't need to bother painting it or making it look perfect, although you could still use genuine SMC resin instead of regular fiberglass or bondo if you want to be sure the repair will bond well.

I've written a lot of big posts about patching holes on the exterior of our cars; the same general principles apply for any fiberglass work. Following this is one such post, and by reading the following you might gain some pointers:

(begin quote)

Buy some Evercoat SMC Resin (online) and some fiberglass mat (autozone). Grind out any loose or shattered material on the damaged body panel, sand the damage to a gradual taper, and clean it and the surrounding area. Completely cover around and below the damage with tape/paper to protect your paint from resin drips. Cut the fiberglass mat into one-inch squares (hundreds for a large repair).

Make a foil bowl and use a plastic knife to mix small batches of resin and hardener in the correct ratio (the ratio is very sensitive and you may be left with a sticky uncured mess if you get it wrong; err on the side of too much hardener, and clean up any uncured stuff with claybar). Spread some of the mixture onto the repair surface, then press squares of fiberglass mat all over the repair, in layers, spreading some more mixture on top of each layer. Let the mats partially go outside the repair area but then only apply resin over the repair area. Continue layering this way, squeezing in as much mat as possible for strength, until the stack of mats is taller than the repair needs to be. Wait thirty minutes and the repair should be hard; if not, your repair area was too cold or you were too stingy with the hardener. Detailing clay (autozone) can clean uncured resin from the car's body.

Note: If there are punctures of any size all the way through the fiberglass, you will have also needed to sand out the back of the damaged panel around the repair, down to bare fiberglass. Then, do as above, except instead of building directly onto the damaged area, build your layers of mat/resin on top of a big piece of foil, making a thick flat fiberglass piece that is larger than the puncture. Before this piece dries, press it over the hole from behind and conform it to the right shape (touch the foil only or the piece will stick to you). Build the remainder of the repair off of this structural backing.

After the repair cures, peel off foil from any backings, properly protect your lungs, dremel away the chunks of excess fiberglass mat, and then carefully dremel down the repair to its final shape and sand it flat with 150 grit. Clean the surface and apply any body putty (autozone) to smooth it. Apply primer and paint after uncovering the surrounding area to allow spray to gradually transition to the old paint. Use two thin coats of primer, then three thin coats of paint, then two thin coats of clearcoat, waiting about 15 minutes for each coat to tack. If it looks good after the paint cures, polish and wax it to fully blend it; otherwise, grind or sand it back out and try this all again another day.

(end quote)

 

Thank you for the information. This sounds complicated to me, as I know nothing at all about fiberglass. If anyone could pictures that would be great!

 

I've got some pictures of me building a new door handle hole in my door using this method. I'll post them when I find them (probably tomorrow), but PM me if I forget.

Fiberglass can be a bit complicated since you have to distribute pieces of fiber mat as you spread out the resin/hardener mixture onto the surface. With bondo you just mix it with the hardener and spread it, but you don't get the additional reinforcement that fiber-reinforced polymers give you. Fiberglass resin and bondo can be found at autozone and the like; genuine SMC resin can be bought online, and it's specially formulated to deal with the "mold release" chemical in our body panels that tends to mess up repairs.

Honestly since your problem is such a simple one in such an inconspicuous area I would just try what's most convenient. What I would do, is buy a little tub of regular fiberglass resin (hardener comes with it) and some sheets of mat, and give it a try. In your case, I personally would be leery about using bondo since it does have to take some structural load from your feet stomping around, and it may crack after enough of that.

Mix the resin/hardener up in a tin foil bowl with a plastic knife, making small batches of mixture and with the first few batches, play around with different amounts of hardener to get a feel for how much you should be using to make it cure right (it should harden in a matter of a couple minutes), and then after a few practices give it a try.

Cut up some mat into shapes that are bigger than the hole you're trying to cover, and lay them down one layer at a time on a sheet of tin foil, using your plastic knife to spread mixture on top of each mat layer, until that layer is completely saturated. Once you've got about 5 or 6 layers, before it dries stick it over your hole (from the bottom, and foil side down) and see if it holds. If you've properly sanded the area around the hole to a smooth bare-fiberglass surface, once you've held it there for a minute or so it should stick firmly, and you should be able to peel the foil off. From there it's all a matter of filling in the area from the top with more mat and resin, and after it dries sanding/grinding it until it's the shape you want.

 

Hmmm... I've noticed a crack in the floorboard where the accelerator pedal attaches at. Mine is an 89.

 

Personally, I'd cut the damaged area out to a square or rectangle,feather the edges a little, take a piece of galvanized sheathing or sheet metal, support it from the bottom and pop rivet it from the top (aluminum pop rivets). Then I'd cut a sheet of fiber glass just a little bigger than the cutout, using the right resin I'd paint it in thick, lay my glass on top of it (may take a few sheets) and work out the air bubbles. You're never going to get a perfect repair job that someone like me would over look. And what ever you do...don't try doing the total repair from the bottom, unless you're prepared for a total mess. Then if you wanted you could drill out the pop rivets and fill them. Good luck.

 

This also works but it is more work than I would be willing to do just to patch a fiberglass hole. Making the initial support plate out of fiberglass saves a lot of time and parts.

 

Since some of the floorboard is literally hanging down a few inches, will I need to use something like a stick to hold it up to where it should be when I do this? If so, will the new fiberglass I put on be able to hold it in place when the prop is removed? Or should I just let it hang down and try to cover the hole? How long should the whole process take typically?

 

I've used Gorilla Hair which is super easy to work with. It's a fibrous resin which you can pretty much mold to your liking and sand if you wish. I had to do this on a buddies ZR-1 and the problem was solved immediately. I believe I purchased this as Advanced Auto, btw, if you go this route make sure to wear your rubber gloves. Easy---yes, messy---sort of.

 

That was true for me too. I knew nothing about it.
Like I said, I ended up enjoying doing the repair, I learned something new, and the satisfication that I did it with my own two hands is .

Maybe practice on something else first so ya get the hand of it.

You can totally do it!

 

You need to use a dremel tool to grind out all of the damaged area; anything that is hanging down definitely counts as damaged. Grind out until you get to material that's in the same place and same condition as the factory put it there, and then use only that material as the foundation for your repair. Don't be afraid to grind out a pretty big hole since you'll be sticking a big wide homemade support panel over top of it on which to build your repair. If the damage is horrible, as in everything in a 12-inch diameter is unsalvageable, I would consider some other method such as a stiff pre-made reinforcement piece.

Agreed - the resin is super messy, tends to smear everywhere while you work with it, and doesn't come off of anything for days - fingers especially. God forbid you get some on your paint and fail to claybar it off before it cures.

This is the reason I have suggested mixing in a tin foil bowl (thus keeping the mixture in a small, controlled area), only making very small batches at a time so you're not rushing to beat its cure time, practicing with a few batches so you don't end up having to clean up uncured resin, having all your pieces of mat pre-cut so you don't have to alternate between fooling with resin and using scissors, and being sure to only handle the resin with your plastic knife and NOT your hands (even gloved hands).

When you apply the resin mixture, be sure to do it in this order: spread it onto the surface with the knife, then lightly place a pre-cut piece of mat on top of it with your hands, and then use the knife to press it into the resin and to spread more on top of it to saturate the piece, and repeat. At no point should you be handling pieces of mat that already have resin on them with your hands. If you do not follow this, the mat will stick to your hand and pull apart as you try to remove it, making a huge mess.

 

I helped my son do this repair on both sides of his '87 last winter. Those metal plates need to be removed from the leading edge underneath. I used a air chisel to wack the rivets off one at a time. I'm guessing you don't have an air chisel so just use a wide thin chisel and a hammer to get the rivets off. You need to get those plates out of there to get it all cleaned up good. Fiberglassing went very well. You just need to do a bit at a time to build it up. We used the fiberglass repair kits from O'Rielly Auto Parts. Wear rubber gloves. Look how thin that portion of the floor was when it was new. Then put a few layers of fiberglass on and see how much stronger it will be. After you're done patching hold the metal plates back up in place and drill new holes and use pop rivets to re-attach.