How to Repair Cracked Fiberglass Chair Shells

Alex Smith

Fiberglass shell chairs were first seen in the 1970s, and as of 2011, still are manufactured. Fiberglass is a strong, inexpensive material out of which to make generic chairs. Eventually, fiberglass can crack, making the chair unusable. There is no need to throw the chair away. Cracked fiberglass can be repaired, restoring the damaged chair to working order. All of the materials are available at any hardware store.

Cracked fiberglass chairs are not difficult to repair.

Step 1

Sand the back of the chair shell with 100-grit sandpaper to roughen the surface.

Step 2

Wash the front and back of the chair shell with acetone and a rag.

Step 3

Apply masking tape over the crack on the front of the chair.

Step 4

Tear four pieces of fiberglass mat into pieces to cover the crack. The first piece should be one inch larger than the crack on all sides. The other three should each be slightly larger than the previous one.

Step 5

Put on rubber gloves.

Step 6

Mix a small batch of fiberglass resin with catalyst in a bucket, following the mixing ratio on the resin container.

Step 7

Brush resin onto the sanded portion of the chair's back.

Step 8

Place the smallest piece of fiberglass over the crack.

Step 9

Tap more resin into the fiberglass until it turns clear, indicating that it is saturated. Work out any trapped air bubbles with the bristles of the brush.

Step 10

Place the next larger piece of fiberglass over the first and saturate it with more resin. Add the third and fourth pieces of fiberglass in the same way.

Step 11

Allow the resin to harden for several hours.

Step 12

Remove the tape from the front of the chair.

Step 13

Mix a small batch of gelcoat and catalyst. The gelcoat color should match the chair.

Step 14

Scrape gelcoat across the crack with a putty knife, completely filling the crack.

Step 15

Allow the gelcoat to harden.

Step 16

Sand the repaired crack with 120-grit sandpaper to remove any marks left by the putty knife. Sand it again with 200-grit, 300-grit and so on until the repair is polished and blends into the surrounding surface.

Step 17

Apply a clear coat product to the chair if desired.

Step 18

Sand the back of the chair smooth if desired.