Fiberglass will break down over time for one of several reasons. The sun's heat and ultraviolet rays can eventually cause fiberglass to get brittle. If the gel coat surface is cracked or damaged due to impacts or vibrations, water seeps in through the cracks and damages the structure.
Cracks, holes, chips, and stains in showers and tubs made from fiberglass can be repaired with gelcoat. A common rule of thumb is if the hole is smaller than 1/2 inch, you should be able to make the repairs yourself; if it is a larger hole, then it may require the replacement of the surface or unit.
Fill the crack with a fair amount of fiberglass epoxy resin, using a plastic applicator. Make sure the crack is completely filled. Let the epoxy dry for a day. When the area is dry, smooth the surface with sandpaper.
Bondo® All-Purpose Fiberglass Resin is your go-to material for sealing cracks, repairing breaks or filling holes in fiberglass, wood, concrete or metal. Along with cloth tape or matting, this 100% waterproof resin can be used for hundreds of repair projects to include cars, trucks, pools, showers, boats and more.
If you do choose to work with or around it, you'd best avoid skin contact. Play it safe to avoid itching. First apply a generous coat of barrier cream or petroleum jelly on all skin surfaces to keep minute fiberglass particles out of pores. Then cover as much skin as you can.
High-quality fiberglass boats can last up to 50 years or even more. However, lower quality fiberglass may have cracks, blisters, or irregularities; these can begin to show after a few years of use.
Surprising for a substance that is so strong, fiberglass is very flexible compared to other pool materials. This means that while the soil around a pool may expand, contract, and move as it freezes and thaws, a fiberglass pool can handle the changing pressure without cracking.
Apply Primer: Seal the surface with 2-3 coats of Tuff Stuff, or other high build epoxy primer. For Tuff Stuff, apply the first coat of primer and allow the surface to dry to become tacky.
To repair fiberglass and gelcoat, you need a low-viscosity epoxy such as a traditional 5:1 system or a 2:1 epoxy system, silica thickener to thicken the epoxy, if needed, and fiberglass cloth for repair patches.
Life Seal Silicone/Polyurethane Caulking Sealant
One of the most popular caulking sealants used especially for fiberglass is the Life Seal Silicon/Polyurethane Caulking Sealant.
Epoxy resin is ideal for most fiberglass repairs that are not using gelcoat as the final layer. This is because epoxy cures well in thin layers. Polyester does not cure well in thin layers. Also, as said above, epoxy can adhere to a polyester base.
Epoxy is usually considered highly durable; hence, there are fewer chances that it will develop cracks or chips in the future. But there are certain factors that aid in the formation of cracks with time.
The key difference between epoxy and fiberglass resin is that epoxy resins are made mainly from the reaction between epichlorohydrin and bisphenol A, whereas fiberglass resin is made from the combination of alcohols and organic acids.
Hairline cracks are thin cosmetic cracks that are caused by temperature or humidity fluctuation. These fluctuations can result in plaster shrinkage or swelling, creating small fissures. Hairline cracks are simply an eyesore and can be easily fixed with a new coat of paint.
You can use epoxy concrete repair products while the cracks are still small, but once they get larger, you'll have to use a product like mortar.
Painting cracks - when covering small hairline cracks, caulk can create a paintable layer on the crack within a matter of hours. To seal - windows and other moisture prone areas can be sealed using caulk to prevent gaps for moisture to attack.
FRP Liquid Nails Work Great
We are doing a remodel in our kitchen and put up fiberglass reinforced panels. We used the Liquid Nails FRP on our panels and the adhesive has held amazing well! The adhesive protects the panels from chemical effects and was easy to apply.
If the polishing compound does not provide the results you want visually, rubbing compound can then be used. Select a rubbing compound formulated for fiberglass and use it exactly like polish. Polishing compound may be needed after the use of rubbing compound to smooth out the gelcoat.
Bondo Body Filler cures fast, shapes in minutes and is formulated to be a non-shrinking and permanently durable material. In addition to its uses on vehicle exteriors and other metal surfaces it is also a suitable repair option for wood, fiberglass and concrete.