Like your Z, this site is always underconstruction. :-)

​Fiberglass fitting, surface prep, undercoating, and final paint.

"Some assembly required"

Whether intended for racing or street use, our fiberglass parts are not designed to be identical to original equipment parts in appearance, function, or installation/ mounting.

For all practical purposes it is impossible to make parts that are in some cases radically different from the original equipment, yet "bolt on" directly in place of original equipment.

Most of our panels utilize SOME of the factory mounting provisions. However, you may have to utilize and/or fabricate brackets, create standoffs, or devise other mounting methods to either replace or supplement the factory mounting provisions.

If you are not experienced in fabrication and/or you have any questions about whether you are up to the task, PLEASE discuss this with us in detail BEFORE you order.

There's no such thing as "paint ready." Unless you have specified some other finish, almost all my parts are made using a gray "sanding primer" gelcoat, which is typically glossy after de-molding.

But even the most perfect-looking panels (metal or composite) have to be prepped prior to painting. In fact, if you tried to paint over a glossy-out-of-the-mold part, the paint would not stick. It has to have at least some microscopic roughness to mechanically lock-on to the surface.

And in most cases, your fiberglass panels may need to be trimmed to fit, or if they are bonded on, they'll need to have the edges feathered and blended.

Many of my products are designed for racing and/or are made with “vintage” tooling (i.e., it has been around a while). One of my big objectives in operating my business is to save you money. One of the ways I do that is to nurse my tooling as long as possible. This allows me to tightly control the tooling cost that has to be amortized into every order I ship.

The downside is that some of my products are not glossy right out of the box. However, all the steps required to finish and paint the parts are exactly the same as if they WERE shiny, so please do not be concerned that I have sent you substandard parts. I feel it is far more important to ship robust parts that will stand up to sanding, painting, and real use, at a fair price.

In particular, some of the YZ molds and IMSA molds are among the oldest that I have. Thus, the surface finish isn't very good. However, I can assure you that the materials and layup schedule is consistent with all the other parts I build. Thus, even the less shiny panels are just as strong and durable as even the shiniest panels I build.

Another appearance issue is mold lines. On many of the parts I make, the shape of the part includes areas of “negative draft.” Like an ice cube tray, if the part at the bottom is bigger than the part at the top, the fiberglass won’t come out of the mold. The only practical way to solve this is to make the mold in several pieces which can be separated and removed individually as the fiberglass is pulled from the mold. There will be some resultant mold line discontinuities in the gel-coat finish that may make your part(s) appear as if they are several pieces bonded together. I assure you this is not the case! Look at the inside of your parts to see that they are indeed one continuous piece of fiberglass.

On the IMSA molds, I recently built new quarter panel molds, so those parts are very nice. The fenders are good. The nose is, frankly, a little rough. But I've priced it accordingly.

When it comes time to finish the parts, a critical (and often rushed) step is to mount them on the car and get the to fit properly. Especially on our old cars which may have unknown collision damage history, fiberglass can require some fussing to get the panels level and gaps adjusted.

Many builders are concerned about "waviness" in fiberglass panels, and rightly so. There has been a lot of really poor quality fiberglass sold over the years, and some of it requires a half-inch of body filler or more to make it level. Thankfully, our techs are pretty good at their jobs, and let the parts cure well before de-molding.

But it's always a good idea to guidecoat your parts. If you need to do fill-work, lightly sand all surfaces to be filled. If you sand through the gelcoat, it's a good idea to at least use some rattle-can primer to seal the raw fiberglass before you proceed. And be mindful that while gelcoat is fairly impervious to water, raw, cured fiberglass can actually hold moisture. So if you are wet-sanding, make sure you blow the surface before you primer it, and maybe let it sit in the sun for a little bit afterward.

Use a good quality body filler. Typical automotive parts store body filler will tend to shrink as it ages, and this will eventually show sanding marks or worse. Visit your closest auto body supply store and get their recommendations for a good filler (and paint system while you are at it). The difference between a $20 can of bond-x and a $50 can of DuPont Rage, etc., is negligible when you are looking at your car a year from now trying to figure out how to get rid of those sanding marks!

Once you are satisfied that you have everything fitting right, it can be helpful to treat the underside (the "rough side") of the fiberglass. You can do this step before or after your body work step, but just be mindful of over-spray and mask accordingly. You can use paint, undercoating, or a bed liner product. All will help seal the fiberglass against "outgassing."

Our resins tend to cure out better than cheaper products, but any resin is somewhat of a living product. If you cut or sand even an old piece of fiberglass, it smells like...fiberglass. This smell is due to volatile (i.e., they tend to evaporate) compounds in the resin that will outgas over time and cause resin shrinkage. Quality resins contains surfacers that migrate to the surface as the resin cures, to fight this process.

But especially in the wheel wells where rocks and dirt might be thrown up from the road and abrade the inner surface, some sort of surface finish will help prevent problems. The thicker products like undercoating and bed liner will also help prevent the larger debris from causing "star cracks" in the painted surface. Plus, if you use black products, it helps to hide any dirt that may accumulate in the wheel wells.

On panels where you might see the inside on a regular basis...mostly the hood...you may also want to undercoat, or even sand and fill the surface to be smooth before undercoating.

Back to the outer surface: Once any fill-work is done, I recommend a high-building primer, block sanding, and another guidecoat step prior to paint. Do not use an "etching primer." Those are chemically designed to microscopically erode the surface of METAL panels in order to promote paint adhesion.

After final sanding, use a wax and grease remover just like you'd do when painting metal panels. Fiberglass panels are technically "fiber-reinforced plastic," or FRP. The resin systems are plastic, and plastic tends to take on a static charge. So make sure you also use a tack cloth, again, just like you'd use before painting a metal panel.

From that point, painting fiberglass parts is just like painting metal parts. I won't get into all the do's and don'ts of automotive painting, as you probably know more about it than I do. But if you have any questions, feel free to ask and I'll answer if I can!


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