How Do You Repair Cracks In Plastic With Fiberglass

Dealing with fiberglass repair is no fun, but unfortunately it is a necessary office of owning a fiberglass-bodied machine, especially a archetype like a C2 Corvette. The C2 was built from 1963 through 1967 and is considered by many to exist the ultimate in Corvettes. The problem is that the very nature of fiberglass is that it never stops shrinking. Combine this with years of hard road employ, and there are bound to be stress fractures.

While working on a 1966 Corvette coupe, nosotros found a few spiderweb cracks while we were stripping abroad the paint under the hood. We could spend a lot of time and money replacing the panels or nosotros could try a fiberglass repair. We had been looking for a reason to attempt out the JB Weld Plastic Bonder we found at our local NAPA store, so the choice was made.

The Corvette bodies were not created in a single mold, rather congenital from multiple pieces bonded together using the first type of structural body adhesive, information technology was cutting edge technology at the time. Modernistic cars are almost completely glued together for the most part, using modernistic structural body adhesive epoxies. JB Weld Plastic Bonder is essentially the same stuff, merely in an easy to apply syringe dispenser. Structural trunk adhesives are then strong that the material they are bonded to often fails before the epoxy does. Plastic Bonder is a 2-part epoxy that bonds to just most anything, but it is specifically designed for plastic and fiberglass. Y'all can even employ it to bond metallic to plastic or fiberglass, which is actually handy when you need to add some support.

To get the process going, we need a few tools. While y'all could certainly simply glue whatever parts together and brand information technology work, nosotros want a fiberglass repair that not only functions , only looks skillful every bit well.

Fiberglass Repair Tools

Mixing board
Drill
1/8" drill bit
Spreader (metal or plastic)
Sandpaper
Dice-grinder with a carbide burr (optional)

Repair Time

1 hour work time
24 hour wait time, plus refinishing

Repair Difficulty

On a scale from 1-10, x beingness the hardest, three

The carbide burr and die-grinder are optional, just for the kind of repair we are doing, it volition help usa get a meliorate consequence. If you lot don't take one, you can always become like results with a triangle file or even a piece of coarse sandpaper (36-80-grit). More on that later.

i. The procedure begins by locating the cracks and then finding where they beginning and stop.

two. Each scissure gets drilled at the stop points. This is to ensure that the scissure stops growing. The size of the drill chip will be adamant past the size of the crack. Broad splits will need a larger bit.

3. Adjacent, the cracks were grooved with the die-grinder. The epoxy needs a place to bond to the material, and the more than epoxy y'all can fit into the crack, the better. We are not cutting very deep, about one-half the thickness of the base material.

4. The next step would ordinarily be to sand the surface area down for a practiced adhesion surface, merely the Corvette panels have already been sanded, that is how nosotros found the cracks in the commencement place. At this betoken, the area was wiped downwardly with some 3M paint prep and it was gear up for the epoxy.

5. Using a mixing lath, a chip of epoxy was pushed out and then mixed upwards with a spreader. We are using a metal spreader because they clean easily and are more sturdy than plastic. That helps when you are pushing the material into a fissure. Merely mix what yous can use in a few minutes, the epoxy has a piece of work time of almost five minutes.

half dozen. The epoxy was spread over the cracks and pushed into the crevices. You want to leave extra on top of the repaired surface area to be sanded off later; otherwise you volition have to practise more finish work.

seven. The epoxy takes fifteen-20 minutes to harden, simply we permit our repairs sit down overnight to fully cure earlier sanding. We did have a batch that never fully hardened, instead it stayed rubbery. This was the commencement mix out of the tube; we suspect it was improperly mixed.

8. Side by side, the entire area was sanded with 120-grit sandpaper until it was level with the original surface. The epoxy sands very easily, resulting in a smooth end that did not require whatever additional stop work. At this point, the repairs are done.

ix. The finished repair looks pretty practiced, but it needs to be painted.

10. To finish off the underhood of the Corvette, nosotros needed to pigment information technology. The fiberglass repair will show through regular pigment, and then the area was sprayed with a primer sealer. This covers all repairs and provides a uniform surface for the paint.

11. And then we sprayed some unmarried-stage semi-gloss paint that we ordered through our local NAPA Auto Parts Store.

The results of the JB Weld Plastic Bonder fiberglass repair were excellent. Not only was the procedure quick and easy, only the panels expect like they did from factory. The bond is strong; nosotros would use this stuff on just nigh any plastic or fiberglass component that needed to be repaired. In other words, you lot tin get professional results when you take the time to do it right.

Bank check out all the chemic productsavailable on NAPA Online or trust 1 of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on fiberglass repair, chat with a knowledgeable proficient at your local NAPA AUTO PARTS store.

Jefferson Bryant View All

A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the automobile audio industry as a store manager, somewhen working his manner into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His piece of work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin', Mopar Muscle, and many more. Jefferson has too written 4 books and produced endless videos. Jefferson operates Red Clay Rodz, his personal garage studio, where all of his mag articles and tech videos are produced.