Bondo Fiberglass Mat Instructions
Boat and car owners use fiberglass mats for repairs to panels and hulls as they provide a strong, lightweight and weatherproof patch that can be painted to match the original finish. Bondo fiberglass mats do not require any special paint or for finishing. The same paint used on the rest of the car or boat can be used over the Bondo fiberglass mat so the repair will not be noticeable. Bondo fiberglass mat instructions are simple to follow; the only hard part is determining how much resin and hardener to mix when applying the cloth. Mix too much and it will harden before it can be used; mix too little and the mat can become deformed between applications.
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Things You'll Need
- Sandpaper (80 and 180-grit)
- Sander or sanding block
- Rag
- Bucket
- Warm water
- Liquid dish soap
- Sponge
- Lint free cloth
- Plastic sheeting
- Rubber gloves
- Scissors
- Bondo Fiberglass Resin
- Bondo Fiberglass Hardener
- Glass measuring cup
- Mixing stick
- Bondo Fiberglass Mat
- Paintbrush
- Plastic squeegee
Instructions
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1
Sand the paint, rust and other surface coatings, using 80-grit sandpaper, from the area that is to be repaired. Sand by hand, using a sanding block, or to do the job faster, use a power sander. Dust the surface with a rag when finished to remove the grit from the sanding.
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2
Place 2-drops of liquid dish soap in an empty bucket. Fill the bucket with warm water. Dunk a sponge in the soapy water and scrub the surface the fiberglass mat is going to be applied to clean. Dry the surface with a lint-free cloth.
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3
Lay plastic sheeting in the work area to protect the floor from the resins and hardeners and to provide a clean, non-porous to prepare the fiberglass mat. Make sure there is a large enough and flat enough area covered with the plastic sheeting to allow the mats to be laid flat on the ground.
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4
Lay the fiberglass mat over the area to be repaired, and use scissors to trim the mat so it is 2 or 3 inches larger than the area to be repaired. Make sure to wear rubber gloves while doing this as the fiberglass of the mat can cause irritation to bare skin.
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5
Mix the resin and hardener in a glass-measuring cup. Mix only what is needed to cover the fiberglass mat. The rule of thumb for how much resin/hardener to mat will be needed is: for every 30mL of resin, 12 drops of hardener from the Bondo Hardener bottle will be needed; and for every square foot of mat, 1 1/2-oz. of resin/hardener must be mixed. Remember, there are just about 30mL in 1-oz (29.56mL to 1-oz).
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6
Dip a paintbrush in the resin/hardener mix and paint a thin coat of the mix over the area to be covered by the fiberglass mat (2 to 3 inches beyond the area to be repaired).
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7
Lay the cut piece of fiberglass mat on the plastic sheeting and saturate the mat with resin/hardener, using the paintbrush to apply the mix.
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8
Pick the saturated mat up off the sheeting by two of its corners and lay the mat over the repair area. Smooth it into place by hand. Work from the center out to the edges, using a squeegee, to push any trapped air under from under the mat. Make sure to hold the mat in place while using the squeegee or the mat will shift.
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9
Coat the fiberglass mat again with resin/hardener, using the paintbrush. Wait for the fiberglass to cure (dry). Drying times will vary according to the temperature of the work area, but averages about two hours.
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10
Sand the cured fiberglass mat with 80-grit sandpaper. Sand the edges of the mat down to feather, using 180-grit paper, or blend, the edge of the mat into the rest of the panel being repaired. Running a hand over the surface of the panel, there should be no noticeable changes in the surface between the repair and the rest of the panel.
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11
Repeat the steps to add another layer of fiberglass mat to the repair if needed. The more layers applied, the stronger the repair.
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Tips & Warnings
Break down the surface being worked on into small areas and mix only enough resin and hardener for one small section at a time. Mixed resin hardens in about 12 minutes so the smaller the area and the smaller the amount mixed, the less chance there is of the resin hardening before the fiberglass mat is smoothed and fixed into place.
Do not pour the mixed resin back into the can and try to save it. It will cause the rest of the resin to harden in the can and be unusable.
References
Resources
- Photo Credit Zedcor Wholly Owned/PhotoObjects.net/Getty Images
