How to repair the car surface with glass fiber？

Glass fiber has a wide range of applications in various fields, especially in the automotive field. Long glass fiber reinforced polypropylene material can reduce weight and cost at the same time, and can replace the short glass fiber reinforced nylon or metal materials currently used in large quantities. The application of glass fiber in the automotive field helps cars achieve lightweight. For the wear and tear on the surface of the car shell, the following methods can be used to repair it, for reference only.

Before repairing, first confirm the repair of glass fiber materials and related parts (such as energy/force absorbing parts). If the function cannot be guaranteed after repair, these parts must not be repaired.

Repair method of damage to automobile glass fiber parts

Repair cracked skin/holes

Sand the perimeter of the crack/hole to 45°. Use P150 sandpaper to grind out a 100mm wide area around the broken hole (the area enclosed by the dotted line) and clean the area with a silicone cleaner.

Cut out three pieces of fiberglass mat to cover the break.

Paste glass fiber mat.

Mixed polyester resin (according to the manufacturer's instructions).

Apply a layer of polyester resin to the cracks/holes.

The smallest fiberglass mat 1 is completely immersed in the polyester resin, and then placed on the crack/hole 4.

After pasting, use a pointed tool to remove air bubbles in the polyester resin.

After the material is cured, sand the surface with P120 sandpaper.

Clean repair parts with silicone cleaner.

The second and third glass fiber mats are operated in the same order.

Repair surface damage

Cut the damaged surface into a V shape.

Use P150 sandpaper to grind out a 50mm wide area around the damaged surface.

Clean the repaired area with silicone cleaner.

Mix glass fiber reinforced polyester resin according to the manufacturer's instructions and apply it to the repaired part.

After curing, sand the repaired area and clean it with silicone scavenger.

How to use glass fiber to repair plastic parts after damage？

Material and tool preparation

Main materials needed: unsaturated polyester resin (196# or 191#), peroxide cycloalkanoate (initiator H), cobalt naphthenate (accelerator E), medium-alkali glass fiber checkered cloth, dry no Impurities of talcum powder (425 mesh and above). 1.2 Main tools: a pair of scissors, an angle grinder, a number of cutting wheels, two plastic basins of about 1L, 2-3 flat paint brushes, and a putty knife.

Preparation work before repairing parts

If there are small cracks, first use an angle grinder to clamp the grinding wheel to open the crack on the front to a 90° bevel. The bevel must be opened to the end, and then use emery cloth (80#) to polish the periphery of the bevel and the back Remove old paint film and other dirt.

For the parts with cracks and holes, you should first use an angle grinder to cut off all the damaged parts. It is not necessary to bevel the edges, but you need to sand the periphery with emery cloth. The polishing range on the back should be based on the actual damage range and paste fiber It depends on the size of the cloth.

Repair of damage

Cut the fiberglass cloth according to the size of the damage. The first piece is generally 20-30mm larger than the periphery of the restoration site, and each subsequent piece is 20-25mm larger than the periphery of the previous piece. Two layers of glass fiber cloth can be used to repair 1-2mm thick parts; 4 layers can be used for 2-4mm thick parts; 6 or 8 layers can be used for parts with high strength requirements.

According to the actual needs, take appropriate amount of resin (usually 2.3 times the weight of the fiber cloth), add the initiator-cycloperoxide peroxide and accelerator-cobalt naphthenate in the ratio of 100:4:4, and stir immediately Evenly.

Dip the adjusted resin with a flat brush and apply a layer of resin on the back of the area to be repaired, and then paste the fiber cloth on the area to be repaired from small to large. The fiber cloth must be impregnated with resin, without bubbles, interlayers, etc. After curing, use an angle grinder to remove the burrs.

Then mix a small amount of resin according to the second method, add talc and cut short glass fiber to make a resin putty with fibers, and use a putty knife to fill in the V-shaped grooves and holes on the front. When squeegeeing, it is better not to be able to get the polishing range. After curing, it can be smoothed with an angle grinder, and then sanded and smoothed with water sandpaper. If it fails to meet the requirements once, it can be patched again, and the putty to be patched is consistent with the whole part, preferably a paste made with a lower 0.5-lmm.

If there is an insert in the damaged place, paste the insert directly in the middle of the glass fiber. When some parts only need strength, but the appearance requirements are low (or no requirements), glass fiber cloth can be pasted on both sides at the same time to meet the standard of use.

After completing the above operations, you can follow the general repair treatment-scraping putty, sanding, spraying paint, etc. on the FRP patch. Repairing plastic parts with the above method is low cost, fast, and its strength is not inferior to the original. As long as there is a glass fiber reinforced plastic factory, repair work can be carried out, and it can even be repaired by yourself.