Traditional surfboards are fragile, and they’re made of toxic goo that ends up as landfill. A DIY kit from Greenlight Surfboard Supply is the ticket. For $395 it’s got all the materials and tools you need to make a tougher, greener epoxy board using expanded polystyrene (EPS) foam that’s recyclable. Greenlight’s new lamination technique, using stretchy bamboo fabric instead of fiberglass cloth, is easier and safer. And when this board finally fails, you can recycle or compost most of it. Nice. You can shape it in a weekend, but plan on a week or so to glass it.
I made a twin-fin “fish” with Greenlight’s 6'6" deluxe kit. They've got kits ranging from 6'0" shortboards to 9'8" longboards. Whatever style you make, it's a big help to keep a similar board on hand for reference.
Sand the board with 80-grit on your foam sanding pad and remove any dust. Everything look even and symmetrical? You're done shaping.
To seal the EPS foam, mix lightweight spackle (DAP Fast ’n Final or Custom Patch-N-Paint) with water to the consistency of thin mayonnaise, then spackle the board, scrape away excess, and let it dry. This type of spackle uses silica microcells as filler; pro shapers say it lets the epoxy resin penetrate and bond with the foam, but prevents the foam from soaking up too much.
Stretch bamboo cloth tight across the bottom, up over the rails, and down onto the deck tape. Much easier than fiberglass! Pull it tight and smooth, with no wrinkles on the rails. Minimize overlaps in the tail; you’ll have to sand them out later. At the tail and nose, where it’s tightest, tape excess fabric to the deck so it can’t pull away.
Put on 2 pairs of latex gloves, and mix up 9oz of epoxy resin. The formula is 2 parts resin, 1 part hardener, and 1ml of Additive F per ounce of hardener. Measure carefully: too little hardener and the resin won’t set; too much and it’ll get hot and set in the bucket, “exotherming” in a chain reaction. Stir well for 1 minute.
CAUTION: Wear disposable gloves and eye protection when working with epoxy resin; it can irritate skin and eyes, and can cause skin sensitivity with repeat exposure. Additive F is mostly xylene; keep it off your skin and don’t breathe it.
Using a paintbrush, saturate the fabric on the rails, working out any bubbles, and pull off the excess resin into your bucket.
Flip the board, and toss the first pair of gooey gloves. Saturate the entire bottom using the plastic spreader, working small areas from stringer to rails. Leave no dry spots. Mix more resin as needed.
Reinforce 2/3 of the deck with a lamination: put double-sided tape outside the lap line, stretch bamboo fabric onto it, and laminate with 9oz resin. This strengthens the deck where you'll jump and stand on it. You can see the finished deck patch here (in the red box).
Let the epoxy cure, then sand the laps flush to the foam, and remove any dust.
Download a template from Greenlight or make your own template by tracing fins that you like.
Cut fins from the bamboo panel with a coping saw. Foil them using a grinder, Dremel, or 60-grit block. Laminate in bamboo fabric, and sand with 80-grit. Be sure and stretch the fabric tight; mine was too loose and drank up too much resin.
Score carefully — don’t cut your bottom lamination. Sand laps flush. Congratulations — your board is “glassed” in bombproof epoxy, with double-strength rails and deck patch. Lightly sand with 60-grit on your foam pad, and remove dust.
It’s traditional to hide lap lines under painted “pinlines” about 3/16" wide. Use masking tape and acrylic paint, and pull up the tape while it’s wet. I did the rail laps on the bottom and deck, plus the deck patch lap.
Use clamps to hold the fins at your chosen toe-in and cant angle, as you glue them on with a little epoxy thickened with bamboo dust. Let it cure.
Strengthen the fin bases with “fillets” of resin: make a masking-tape dam around one side of each base, then tip the board on its side and pour a little resin along the bases, building them up about ¼". Let cure, then repeat on the other side.
When the epoxy is cured, sand your fillets nice and round using a pencil wrapped in 80-grit.
“Hot coat” is shaper-speak for the second coat of polyester resin, formulated to cure quicker, generating heat. Your epoxy hot coat won’t get hot, but serves the same purpose: to smooth the board and fill in the lamination texture.
Lightly sand with 120-grit and remove dust. Mix 12oz of resin with double Additive F (2ml per ounce of hardener). Paint the deck and rails, forcing resin into the fabric texture. Go over it again lightly to spread it evenly, letting the brush do the work. Scrape drips off the bottom, and let it cure.
Flip the board, sand down drips, and remove dust. Run masking tape around the rail just below the centerline, to save the deck from drips. Around the tail, add a resin dam of masking tape, sticking up; this will make a nice sharp edge.
Now paint the bottom and fins with 12oz of resin. Let it set 2 hours, then pull off the drip tape and let it cure.
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