How to Build a Motorcycle Seat
Building a unique custom motorcycle, whether it's a cafe racer, chopper or bobber, hinges on the creation of a seat that fits the bike's appearance. Although there are many methods used by bike builders to fashion their seats, creating a seat with fiberglass is often the easiest and most inexpensive route taken by determined DIYers. Be prepared for some work, though, since you will need to sand down the seat before it can be finished.
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Things You'll Need
- Blue painter's tape
- Silver duct tape
- Automotive wax
- Plastic drop cloth
- Fleece
- Clothes pins
- Fiberglass resin and matting
- Disposable container
- Scissors
- Paint brushes
- Rotary cutting tool
- Sandpaper (coarse, medium and fine grit)
- Primer
- Body filler
- Spray paint (black, base color and clear)
Instructions
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Remove the stock seat from the motorcycle. Depending on the exact model of your motorcycle, you will need to either unbolt the seat from the frame or unlock the seat via a hidden latch.
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2
Prepare the motorcycle by covering the frame, gas tank and rear fender with a layer of high-quality blue painter's tape. Extend the tape layers well past the limit of your intended design to allow for resin run-off or spatter. Cover the taped-off area of your motorcycle with a second layer of silver duct tape. Unlike painter's tape, which will protect your motorcycle, duct tape will be used to lay fiberglass and resin directly onto the motorcycle. Finally, apply a thick coating of automotive wax to the taped-off section to help remove the final product from the motorcycle.
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3
Cover the rest of your motorcycle with a plastic drop cloth to protect it from resin spills or drops. Secure the drop cloth to the motorcycle with painter's tape to prevent damaging the motorcycle's painted surfaces.
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4
Lay a sheet of fleece over the seat portion of your frame and pull it down against the frame, tank and fender until it is stretched tightly. Secure it to the frame with clothes pins or clips. The fleece will add a strong base for your fiberglass to bond with, strengthening the final product.
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Mix the resin in a large, disposable container according to the manufacturer's directions. Use scissors to pre-cut the fiberglass matting into strips to fit your design.
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Apply a coat of resin to the fleece using a paintbrush and lay the fiberglass strips onto the resin. Once you have laid the first layer of fiberglass, apply another coat of resin with the paintbrush, dabbing the fiberglass with the brush's tip to prevent the strips from moving. Continue laying the fiberglass and coating along with the resin until you reach the desired thickness. Refer to the manufacturer's recommended cure times and allow the fiberglass to cure completely.
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7
Pull the rough seat off of the motorcycle once the fiberglass has cured and trim off the excess with a rotary cutting tool or grinder. Sand the seat with a coarse-grit sandpaper to remove any large ridges or jagged areas on the surface of the seat. Once the seat has been sanded to a fairly uniform condition, switch to a medium-grit sandpaper to smooth the seat's surface.
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8
Apply a light "glide" coat of black spray paint to the seat and allow it to dry for 10 minutes. Spray a uniform coat of primer over the black paint and allow it to dry. Sand the seat again, using a fine-grit sandpaper, to smooth the surface of the seat. High and low spots in the fiberglass will be revealed as you sand the seat, leaving the primer in a low spot untouched and high spots being sanded down to the fiberglass. Sand away any high spots and fill low spots with body filler.
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9
Test-fit the seat on the motorcycle. Trim away any unwanted/excess portions from the seat until it meets your expectations. Sand down any trimmed areas.
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Spray a layer of primer over the seat and allow it to dry before spraying the base color coat. Apply two to three coats of the base color, allowing each coat to dry for 10 minutes. Finish by spraying two to three coats of clear top coat to protect the base color coat and to add a shiny luster to the seat.
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Attach the seat's mounting hardware and have the seat upholstered before installing it.
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Tips & Warnings
Work in a well-ventilated environment to avoid dangerous fumes from the fiberglass resin.
References
- "The Professional Motorcycle Repair Program;" Professional Career Development Institute; 1995
