To begin laying up a fender, I mix about a half a cup of gelcoat with the recommended amount of hardener. Once this is thoroughly mixed, I use a disposable chip brush to paint the gelcoat into the mold. I try to get a heavy layer of consistent thickness. This gelcoat needs to cure to a tackiness before I apply the fiberglass mat and resin. Usually this takes about 45 minutes.
While I am waiting for the gelcoat to cure a bit, I begin to prepare for the next steps of this process by tearing 1 ½ ounce mat into small pieces that will be easy to lay into my mold. Since this is a fender, it has compound curves – one that goes side to side and one that goes front to back. In my experience, smaller pieces of mat are easier to work with in a mold like this. Just FYI, my pieces of mat are approximately 4” X 4”.
Now that the gelcoat has cured to a tack, I mix an 8 ounce cup of resin and catalyst (as directed by the manufacturer) and begin to work my way around the inside of the mold with resin and mat. I soak a chip brush with resin and use it to blot the resin onto the mat over my freshly applied gelcoat. Since the gelcoat is still tacky to the touch, it holds the mat in place while I soak it with resin. I work my way from one end of the fender to the other and then back again (two layers of mat and resin) being careful to make sure that the mat has no air trapped underneath and that the mat overhangs the mold by an inch or so.
Once this mat and resin cure to a gel-like state (this takes about ½ hour of 45 minutes) you can safely trim the overhanging extra mat with a razor knife. If the resin pulls or is too sticky to cut, check back in another 15 minutes and try it again. This is the best way to clean up your parts of excess fiberglass.
After trimming, I allow the part to sit in the mold for a day or so to let it fully cure. Once fully cured, I pop the part from the mold using a couple of plastic putty spreaders. I simply use my fingers to pick at the part until I get slight separation from the mold then I push the plastic spreader between the part and the mold and work my way around until the part pops out. Since I used adequate release wax and two coats of PVA, this part easily separated from the mold. One fender down, one to go!
My New Beach Cruiser With Fiberglass Fenders Installed
