Hi guys - I need some help with fiberglass repair. I have never worked on fiberglass before and I am in way over my head.

I am trying to refinish my Targa top. My top was already smoothed and painted when I bought the car, but the paint was flaking so I decided to refinish it.

I stripped the paint using fiberglass-safe stripper and got down to the gelcoat. That was pretty easy. Then I went over the top with a random orbit sander (100 grit) and got rid of the rest of the paint and got it cleaned up pretty well.

The problem is, the gelcoat has already been sanded through in many places, some of the damage must have been done by the PO and some by me making it worse. There is also a 1/8" divot in the top where the gelcoat is completely gone and it is into the fabric.

I want to prep the top for paint. I am having a professional body shop shoot the top, but I want to prep it as much as possible myself. I want to fill in the divot and low spots and also get the surface smooth. I think the PO used bondo.

Someone told me to use epoxy and a little bit of fiberglass cloth to fill in the divot. Does that sound ok? I have epoxy I bought from TAP plastics but I am not totally sure I know how to use it correctly.

I also think I have to "seal" the exposed fiberglass where the gelcoat has been sanded through. Is that correct? What can I use to seal it? I think if I just use bondo or have the shop prime it then the primer will leech into the fiberglass and cause pinholes.

Help please, I officially have no idea what I am doing.

Here are a couple pics:

Targa top showing exposed fiberglass.
Gelcoat = darker colored stuff.

Divot.

Tops are like 50 bucks....wouldn't be cheaper to find a replacement?

This may sound odd but I suggest you get yourself over to West Coast Marine. There is one in Mtn. View on the corner of Charleston and San Antonio. Those guys (and gals) over there know all about fiberglass repair. I think you're going to want to get a little piece of glass and some epoxy to fix that divot.

Mike, yes, I have thought about that. When you say tops are $50, does that mean NICE tops are $50 or tops that need refinishing anyway??

If someone has a nice top around here I would gladly buy it, I have side seals and latches and stuff already... Maybe I should give Brad a call. I am guessing HPH wants a lot more than $50.

Actually last time I checked tops were $599 according to AA.

I would just use body filler for the divot..

Or let the body shop shoot some primer surfacer and level that area..

If I use body filler will there be issues with the paint leeching into the fiberglass underneath? Someone on a Corvette forum was saying that exposed fiberglass is like a black hole for paint - it will just keep sucking it up. Thick body shop type primer might not have the same problems though??

I was going to just bondo over the dent, but then a friend told me that it will eventually crack. I have a small piece of fiberglass cloth and some epoxy I could use. I could just epoxy over the whole top but I think it's too thick, and aren't there products made for that?

You can use bondo over the f/g
For the bigger damage, you can get f/g reinforced bondo for some extra strenght
(it's a bit more crude than regular bondo, so you'd have to finish it up with reg. bondo)

Dunno what you guys out there are using, but overhere, painters have a product that's called "aluspritz"
It's basically a spayable bondo. It works great over f/g parts. It makes a thick orange peel kind of layer that sands smooth real nice and easy

cheers,

Jeroen

Didn't someone once say that HPH had like a room full of tops??
Cheers, Elliot

Jeff,
I've seen the " Inner Sanctuary " at HPH.
They have a whole rack of tops like 30 ft long.
Doors, hoods, trunks in every color...Oh my!

I'm not the fiberglass master, but I have done many repairs on my boat and skimboard and other schtuff.

I would approach it this way:

Remove all the seals and hardware.
Rough up the surface over the entire top.
Use acetone to get all the dust and residual yuck off the top.
Cut a piece of fiberglass cloth slightly bigger than the entire top.
Practice mixing some resin and hardener and using a piece of scrap cloth, get used to the process.
DO NOT mix the resin too " hot". With more hardener than recommended. It can " go off " and turn into jelly before you're even done mixing it.
Take the practice cloth and lay it out over a piece of cardboard. Pour the mixed resin onto the cloth and use an "S" motion back and forth over the cloth with a plastic body filler spreader until the cloth is clear.
When you do this over the top let the resin spill over the sides. ( protect your floor )

After the 'glass is hard you can trim off the excess and sand it out very smooth to 400-600 grit wet. Any surface imperfections or divots can be filled with straight resin and sanded out.

Try the practice session before you commit.

It's really quite easy as long as you are patient and the resin doesn't get away from you.

KT

I found you a targa top for $25 on the Samba. Can't beat that buddy...

http://www.thesamba.com/vw/classifieds/det...il.php?id=50017

Here's how I do it at the old airplane factory.

Needed:

*Disposable cups (8 oz. or whatever's handy)

*Dust Mask

*Tongue Depressors for stirring/mixing (or whatever's handy)

*(3) 3" paint brushes (get cheap one's, they'll get tossed after each coat)

*Parting film (which you probably don't have, I've used the clear plastic page protectors used for reports with success at home.)

*Rolling Pin (or any smooth, cylindrical object. Depending on the size of the repair, a deep-well socket works well, or a piece of broom handle for larger repairs)

*MEK solvent (but paint thinner should work just as well)

*Assorted sand paper

*Surgical gloves

Wear a dust mask while doing this:

1) In a disposable cup, take some sharp scissors and chop the FG into 1/8" long pieces to make your "flock". Chop up more than you think you'll need because it sucks to have to make another batch of flock if you come up short for your repair.

2) In a separate cup, thoroughly mix a small batch of resin. Pour some of the resin in the cup containing your FG flock and stir it up. Repeat this adding and stirring until your flock mixture is completely saturated with resin, but not too wet (think cat fur-ball), and definitely not runny. Too wet of a mixture, or resin alone in a repair will eventually crack. If you do accidentally pour too much resin in the flock mixture, no biggy, add more chopped FG.

3) Clean the repair area with MEK (or paint thinner) and a clean cloth.

4) After the cleaned area is thoroughly dry, take some of the resin left over from step #2, and lightly wet the area to be repaired, extending about 1" beyond the area to be filled with flock.

5) Apply enough of your flock mixture to fill the repair area slightly high.

6) Lay your parting film (plastic sheet, at least 4" in each direction bigger than the repair area) over the flock mixture, and starting from the center of the repair, roll it out leaving it a little high. If you roll it out too much, you'll have to start over again. Too high, and it's just more to sand later. Leave the film on, and walk away.

At this point we would apply heat lamps to speed the curing process, but that's because we use epoxy resin (EA956) that takes 5 days at room temp. to completely cure.

7) After the resin is completely cured as per the directions that came with the resin you're using, block sand the repair as well as the rest of the roof to the desired contour. Wipe the entire roof clean with solvent and a clean cloth.

8) Mix a large (1/2 - 3/4 cup) batch of resin, and thin with solvent until you get a brushable, self-leveling consistency. Brush on a light coat of the thinned resin mixture, and watch for bristles coming off the brush. Let this coat cure until tacky, repeat the resin coating/cure to tack procedure until you've got 3 coats total (using a new brush and resin mixture each time to prevent contamination). Don't allow any of the coats cure completely, or you'll have to lightly sand the roof prior to laying on another coat of resin.

9) Got the last coat on, looks good, walk away and allow the resin cure completely.

10) Now you've got your resin/gel coat. Lightly block sand (220 grit) the entire roof, being careful not to go through the resin down to the FG. High build prime, sand and paint.


Not real hard, it just takes some patients.

Kevin

Kevin,

Sounds like you have done this before! What kind of resin would you use? I have a 2 part epoxy, resin+hardener. I forget the cure time, maybe 15 minutes? It's from TAP plastics. Can epoxy be thinned with solvent, or do I have to use a polyester based resin? I like the idea of brushing it on over the whole top to get a smooth surface.

Thanks for all of the replies.

Trekkor - I don't think I want to lay any more FG on top if possible. It will only make the top thicker (won't fit into clips in trunk) and heavier. I think it would also be hard to fit new FG to the fancy lip on both sides of the top. If I totally screw up the top I will do that as a last resort and have a nice new surface to work with.

If you're using an epoxy resin use only MEK for thinning (forget about the paint thinner thing I said, it's good for cleaning, but my adversely effect the cure). And then just enough to make it thin enough to apply by brush. There's a mil. spec. for the exact ratio, but I can't recall it off hand (I always "eyeballed" it and never had a problem, use an eye dropper if you have one, cause it doesn't take much at all). You're looking for a shellac like consistency. Do a test on some scrap material to ensure a full cure. Also keep in mind that thinning the resin will increase its cure time, so don't panic if it takes longer than the flock repair mixture to completely harden, or tack in the case of the brush coats. We use Hysol EA956 epoxy resin for composite repairs at work (Boeing), but I don't recall seeing it anywhere outside of there.

If you determine with your test piece that the MEK isn't allowing a full cure (which can be tested by light sanding, if resin "balls up" rather than scuffing when sanded there's too much MEK in the mix, or the TAP resin isn't compatible with MEK). Then there's always plan 'B'.

Plan 'B': Your 15 min. cure (or is that the pot life?) is a little quick for covering such a large area as a Targa top. You definitely don't want it to gel before you can get the entire coat down, so you may consider purchasing a small kit (pint) of epoxy with a pot life of 1 hour or better for this method. Essentially, instead of using MEK to thin the epoxy enough for brushing, you'll use heat.

Mix your epoxy as per directions (adding hardener for a fast cure, or more resin to slow the cure is a big NO-NO), pour the contents of the cup onto the roof, and using a hair dryer, or heat gun on low, heat the resin while you spread it with your brush. Heating the resin thins it nicely, but also decreases the amount of time you have to work with it. Hence, 1 hr or better epoxy for this method.


Kevin

Ok, I will do some experiments with my epoxy later on. Is there any risk of the top coat cracking after it is applied?

Well, I'm not a painter, but I've never seen a Harrier or Hornet with cracks in the paint job, and they flex all over the place.

Remember, the object of coating the top with resin is to encapsulate the FG fibers. These should be very thin coats, not a "bar top" finish. If prepped and primed correctly, I can't think of a reason the paint would crack.

Jeff, is your painter going to paint it with some kind of textured paint that mimics the original finish? My top is pretty good but I've often thought that a "like new" top would really do a lot for the car.