Question about filling holes in a fiberglass '74 style tail

[UrQuattro]

Hey all,

I found a guy not too far away from me that ha a couple fiberglass tails that are the old '74-'77 carrera style wings. It fits fairly well already, so im not worried too much about making it line up on my car with way too much effort, but the biggest issue with it is that there are a LOT of holes along the bottom of the tail from previous badging.

I'm not sure at this point what the badges said - whether it was carrera or Porsche, or what, but I had emailed a few pictures of it to a local body shop that installed my new targa seals (I finally have a targa that doesn't really leak - it drips very lightly only on the driver's side when raining hard, compared to before when it would flood if left out in a light rain.) they initially estimated about 400 bucks to do a re-spray on it, cutting me a bit of a deal, but then they called me back and said that it would take a few extra hours in labor filling the little holes.

So, I was wondering I anyone could give me some tips on how I could fill them in myself.

I used to know the process of sanding down the paint, what series of grits to use, and such, but it's been 11 years since I did it, and I only did it a couple times.

On top of that, I've never worked on fiberglass, so I have nothing to build on.

So, what should I do? Is this something that I should be able to do fairly simply? My guess is that if I rough up the holes and expose the fiberglass from under the paint, I figure that I could fill the small holes with either body filler or fiberglass resin, and then sand it flat with the surface... If primer were applied over holes filled like this, wouldn't I be able to proceed with the painting process without concern?

I mean, ultimately, I would be willing to use small plug from the underside to fill the holes, which might be an easier way to do it. I'm not looking for a concourse solution at this point, just the least expensive for now.

I'm just trying to make this happen with the least amount of money invested at this point, yet still have it look good, as I don't have much to spend on it.

Anyway, thanks in advance for any help.

Michael

[DanielDudley]

Lots of people are going to come on in a while and tell you how to grind these out and fill them. It isn't to hard, and there are several ways to do it. What I am going to tell you is get a good respirator and use it. The chemicals are strong, and ground fiberglass is not good to breathe.

At the minimum you are going to need a small angle grinder or a sanding disk to fit your drill. You will also want a fiberglass reinforced filler, like Bondoglass, and a regular filler to skim over the top of that. You will also want a rubber sanding block and sandpaper to fit it.

Basicly you will grind out the holes into divots that you will fill and contour. You will be working from 80 or 100 grit paper to at least 220 grit, and trying to feather the final product into a smooth paintable finish, sanding in a crosshatch pattern across the repairs.


I expect that there are a few Utube videos on this subject.

[UrQuattro]

I'm guessing that a dremel with any kind of grinding wheel on it will be sufficient, yes?

As far as getting the chems, I should be able to pick them up at my FLAPS, likekragen or pep boys, yah? If not, I'll have to see where the nearest auto paint supply house is around where I live in san Francisco.

I tgink I know whatyou are getting at. I'll be reshaping the cylindrical holes, "| |" to look something more like "\ /"? That makes sense as it would provide a support for the filler, preventing it from falling through over time due to NVH and heat and such.

I'll definitely find a decent respirator, I remember how noxious some of this stuff can be. My raceteam at the time was starting to play with carbon fiber, andwe were really careful about ventilation and everything.

Plus, before that I used to work in plumbing and heating, so I know what you mean about breathing in fiberglass particles. That stuff is NASTY.

It sounds, though, that this is something that shouldn't be too difficult for an amateur who is good with his hands, and has lot of mechanical hours under his belt.

It's fiberglass, so I'm not expecting it to look flawless, but I don't want the addition of this wing to be a cosmetic detriment to an otherwise pretty clean 81 targa. The car is a repaint. It was originally guards red, but is now kalahari beige metallic.

Im really looking forward to seeing how this ends up looking. It was a tough choice between the duck and the early carrera tail, but I just really dig the look of the first whale tail, w/ the buttresses attaching the tail section to the car, and at the same time, allowing the natural curve of the stock grill to remain intact. To me it's probably the most well integrated style with the shape of the car.

I'm fortunate, too, in that both of the wings that this guy has are completely fiberglass and are painted to look like they have the rubber lip. After reading about how they are NLA, it spooked me for a while. So, I'm psyched.

Hopefully Ill like the results. Being a targa, the only two tails that work for me are the duk and this one. But that's just m opinion.

Thanks for the quick help.

Michael

[drcoastline]

Quattro-

A dremel with a sanding disk should be just fine provided the holes are from badge studs 1/6" to 1/8" holes. The divits you are making are so the mat lays in the hole not on top of the old gelcoat. The reason for this is so your finished repair lays even or ever so slightly below the finished surface. This is so you can lay filler on top to create a finished surface level with the original surface.

Fiberglass 101

The most common reinforcement in our boards, fiberglass is relatively easily applied well. Due to the way it is manufactured, though, it is quite vulnerable to sloppy handling and storage: left unprotected in a moist environment, it will absorb water, which will interfere with resin absorption. Likewise, greasy hands will prevent resin absorption. Chunks of debris (sand, wood fibers etc) will cause bubbles.
Once it has been thoroughly wet, the sizing is rinsed out of fiberglass. No drying will restore this sizing, so that the material will be useless. Store your fiberglass in Tupperware containers, or Ziplock bags or such!

Fiberglass cannot bridge gaps gracefully. All deep gouges, pits and other surface imperfections need to be filled, and the whole sanded with 60grit paper or similar.

To help the structure it is intended to reinforce, fiberglass needs to remain firmly attached to it. It won't be, if applied over glossy paint, flaking resin, crumbly sheet foam, wax, or a film of water. The substrate needs to be firm, smooth, clean and dry.

Here goes: a little rail scrape came in. All the damaged fiberglass is removed, the site sanded with 60 grit, and all the sanding debris blown off. Two layers of 4oz fiberglass cloth were involved, so two layers is what I will put back

It is past 4pm, and the temperature has been dropping for the last 1/2hr.



Gather the tools (acid brush, scissors, squeegee), cut the fiberglass, with the second piece a bit bigger all around then the first, measure out the Epoxy, and mix exceedingly well ("100 strokes!" my teacher used to say)



brush on Epoxy resin
don't pile it on, rather, just apply a "full wet" coat




o, I forgot to tell you: put on gloves, or your hands end up looking like mine!

lay the first piece of glass into this coat of Epoxy. With a moist brush (damp, not loaded), dab at the fiberglass until it is clear. Brush on a bit more Epoxy. Again, don't pile it on. Simply brush on enough to make the surface shiny.



Lay the second piece of glass over the first, centered nicely. Without dipping the brush again, dab at the fiberglass. Think of this step as compacting the fiberglass, not of brushing on resin.



When the glass has turned clear, signaling proper resin penetration, swipe at it with a squeegee.
Squish hard enough to push the glass down and wipe off resin, but just not so hard as to dislocate the fiberglass.
This will remove air trapped beneath the fiberglass. When air is present, it will make a distinct "sffft" sound (honest). When all air has been removed, the lamination is quiet.



It is also perfectly transparent. It is not flooded with resin. Rather, a good lamination has the texture of the fiberglass standing proud.
A good lamination - one with good resin-to-fiberglass ratio - also does not care about orientation - right-side-up, upside down - it does not matter. As a matter of fact, in my boatbuilding days, we routinely used to laminate up to 34oz of fiberglass overhead in one pass (but I am sure glad I don't have to do that anymore!)




After these stepa and the resin has cured you can sand flush and lay on some filler/ glazing putty to smooth and create a finished surface to paint.

Good luck.

Dr

PS- I am not the author of fiberglass 101. but it is a great tutorial for what you are doing. You can cut your patch pieces about the size of a dime if you are only filling stud holes.

[nineball]

for small holes like you describe i would just prep the area as mentioned above and use duraglass to fill them in. after sanding you can use a little rage gold body filler as a finishing coat and sand to paint.

i strongly suggest you stay away from any bondo-brand products. i have never had good results with them.