Building surfboards 101: Note about brushes when doing your hotcoat

Ok so I'm in Subic right now working on a classic Lis fish for a friend Mio. There are many types of fishes when talking surfboards. The earliest came about during the early 70's in the form of short stubby boards with twin keel fins. Steve Lis was the first to combine the swallow or split tail (no its not called the "fish tail" but more on tail design later) with the short, fat twin fin to give you what you know today as the classic twin fin fish.

Its an EPS Epoxy stingerless fish. I'm through the shaping part of the building process and I've laminated both sides already. Now its time to hotcoat the board so I head to the local hardware store to get a three-inch brush. The hotcoat is step three in the process of making surfboards, the step after you've already put your fiberglass skin on the foam core and it's bumpy where the fiberglass overlaps and you can see the weave in the hardened fiberglass cloth. To get these bumps out and to get a smooth surface, you need to put a layer of resin over the fiberglass skin essentially filling in all the little weave grooves- This is the hotcoat.

Anyway, back to the brush. I have my own suppliers in manila, in fact I like to get the brushes available at Polymere products because they have soft bristles to give you a good even hotcoat and the handle is bare wood so if you're working with solvent based resin, there is no paint that will melt and get all over your beautiful work. I didn't have the option of getting in Manila so I went to the local hardware and bought the only available 3 inch brush. By the way, 4 inch brushes are better for hotcoat. The brush I bought had a thick yellow painted handle with a red tip and nasty thick plastic bristles. The oposite of ideal for hotcoating. I mixed up a batch of my own recipe of hotcoat epoxy and let it sit for ten min so that it heats up. It hardens quicker that way and wont flow out onto the floor as much.

During the hot coat you pour out all your resin along the middle of the board and use your brush to do figure eights working the resin into the grooves of the weave wetting the whole board. Then you brush the resin diagonal to evenly spread the resin to both sides of the board working your way from one end to the other and then back the other way. I like to do it 4 times total, two each way. then you do a final, light run (meaning you just let the brush sit on its own weight) from nose to tail and back as many times as it takes to long-stroke the whole board. let the resin sit and it will flatten itself out and if you do it right, you have a great hotcoat with little sanding to do on the next step. Do it wrong and you add hours onto the process as well as lots of weight. With this shit brush that I bought, the bristles started falling out all over the board and the resin thickened which is a pain because then I had to go back with a blade and pick them all off. The bristles were so thick that it took more work than usual to get a good flat coat but I did it eventually and the hotcoat looks good.

Bottom line I guess is to make sure you use a good brush for your hotcoat.