Surfboard Resin Guide: Polyester vs Epoxy, and Which One to Buy
Shaping Supplies Guide
Which resin should you glass with?
Polyester or epoxy, laminating or sanding, UV cure or catalyst. Here is what each one is for, which combination your board actually needs, and what it costs.
Short answer. Your blank decides, not your preference. PU foam takes polyester. EPS foam takes epoxy. Polyester will dissolve EPS, so this one is not negotiable.
On a PU board, buy UV laminating resin and add surfacing agent to convert what you need into hot coat. On an EPS board, buy Resin Research 2000CE and you are done in one purchase.
A shortboard takes about a gallon of polyester or a 3-quart epoxy kit. Full quantities and costs are in the resin and cloth calculator.
The Only Decision That Is Not Yours
Polyester or epoxy? Your foam already answered.
| Polyester | Epoxy | |
|---|---|---|
| Use it on | PU (polyurethane) blanks | EPS blanks. Also fine on PU. |
| Never use it on | EPS — it dissolves the foam | Nothing. Epoxy is safe on both. |
| Feel | Traditional flex, damped underfoot | Stiffer, lighter, stronger |
| Cost, one shortboard | ~$55 gallon + hot coat | $78 for a 3 quart kit, all in |
| Working time | You control it with catalyst, or go UV | Set by cure speed: Slow, Fast or Kwik |
| Smell and cleanup | Strong styrene smell, acetone cleanup | Far less odor, but sensitizing over time |
If you are still choosing a blank rather than a resin, read the PU vs EPS guide first — that decision drives this one.
The Part Nobody Explains
Laminating, sanding and gloss are three different resins
This is where most first builds go wrong. A polyester glass job uses resin three times, and it is not the same resin each time. Buying one gallon of "surfboard resin" and expecting it to finish a board is the single most common mistake.
Laminating resin — wets out the cloth
Stays slightly tacky on purpose so the next layer chemically bonds to it. This is the bulk of what you buy. Silmar 249A from $16 a pint, or the UV version from $18.
Sanding resin — the hot coat you shape
Contains wax that rises to the surface so it cures hard and tack-free, which is what lets you sand it flat. Silmar 250A from $16, or the UV version from $18.
Gloss resin — optional, for a polished finish
A final flow coat you wet-sand and polish to a mirror shine. Reichhold gloss resin — the industry's "famous pink resin" — from $21 a pint. Skip this step entirely and sand to a matte finish instead; plenty of boards are finished that way and it saves you a coat.
The shortcut worth knowing. You do not have to buy sanding resin at all. Surfacing agent is $8 for 2 oz — stir it into your laminating resin and it becomes sanding resin. One less can on the shelf, one less thing to run out of, and it saves you around $24 on a single build.
Epoxy does not work this way. Epoxy kits come pre-matched with hardener and there is no separate hot-coat product — you laminate and hot coat out of the same kit. That simplicity is a real reason to choose it for a first build.
Shop Polyester ResinOur Recommendation
Go UV cure if you are glassing polyester
Standard polyester kicks when you add MEKP catalyst, and from that moment you are racing a clock you cannot pause. Too little and it stays soft. Too much and it gels in the bucket before you have wrapped the rails. On a hot afternoon that window gets brutally short.
UV resin removes the clock. It stays liquid indefinitely in the shade and cures in a couple of minutes once you carry the board into sunlight. You can take your time wetting out, chase down dry spots, get your laps neat — then kick it when you are actually ready.
For anyone glassing in a garage or a driveway rather than a production bay, that is worth far more than the roughly $7 a gallon it adds. It is what we would tell a friend to buy for their first board, and it is what we would buy for our second.
Standard catalyst still has its place: glassing indoors, working on an overcast day, or any time you genuinely cannot get the board into direct sun. Most shops run it because they are laminating all day under controlled conditions. You are probably not.
Already have standard resin? UV catalyst powder is $5 for 7 grams and converts standard polyester into UV cure. You do not have to rebuy resin to get the benefit.
Choosing An Epoxy
Four epoxies, and how to pick
All four are Resin Research, all come pre-matched with hardener, and all are sold in the same four sizes. The differences are clarity and whether the resin is petroleum or plant based.
| Resin | From | Pick it when |
|---|---|---|
| 2000CE Ultra Bright | $78 / 3 qt | The default. Most-used epoxy in US surfboard manufacturing. Buy this unless you have a reason not to. |
| 2000CE Clear | $78 / 3 qt | You are doing resin tints or color work and need the color to read true. |
| Bio-Science CE | $95 / 3 qt | ECOBOARD-certified plant-based build, with the bright finish. |
| Bio-Science Clear | $95 / 3 qt | Plant-based and you are tinting. Pairs naturally with flax cloth. |
Slow, Fast or Kwik?
Same price across all three, so pick by your bay temperature rather than budget. Slow for hot days and big boards where you need working time. Fast is the all-rounder for normal conditions. Kwik for cold days, or when you want to hot coat the same afternoon you laminate.
Getting this wrong is the most common epoxy complaint. Fast resin on a 95°F day will go off in the bucket; Slow resin in a cold garage can stay soft overnight.
Shop Epoxy ResinThe Small Bottles
Additives: which ones you actually need
| Product | From | What it is for | Do you need it? |
|---|---|---|---|
| MEKP catalyst | $2 | Kicks standard polyester resin | Yes, with non-UV polyester. Not used with epoxy. |
| Surfacing agent | $8 | Turns laminating resin into sanding resin | Yes — cheapest way to skip a whole SKU. |
| UV catalyst powder | $5 | Converts standard polyester to UV cure | Only if you bought standard resin and want UV. |
| Additive F | $5 | Stops fish-eyes and improves epoxy sanding | Epoxy builds. Fixes the most common epoxy finish problem. |
| Styrene monomer | $6 | Thins polyester for cheater coats | Optional. Useful, not essential. |
| Z-Seal | $14 | Seals open-cell EPS before glassing | EPS builds, especially before airbrush work. |
For filling low spots and fin box gaps before you glass, see Q-Cel and Cab-O-Sil.
Shop Fillers & AdditivesCommon Questions
What people ask before they buy resin
Can I use polyester resin on an EPS blank?
No. The styrene in polyester resin dissolves EPS foam and will eat into your blank. EPS must be glassed in epoxy. Epoxy works over both EPS and PU, so if you are unsure what your blank is, epoxy is the safe choice.
Do I need both laminating and sanding resin?
Not necessarily. Laminating resin stays tacky so the next layer bonds; sanding resin cures hard and tack-free for the hot coat. You can buy both, or buy laminating resin and add surfacing agent at $8 to convert what you need. Epoxy kits do not need a separate hot-coat resin at all.
Do I need gloss resin?
No. Gloss resin is a final flow coat you wet-sand and polish to a mirror shine. It is what gives a traditional board that showroom finish, but plenty of boards are sanded to a matte finish and left there. Add it if you want the polish, skip it if you do not.
Is UV resin better than adding catalyst?
For most backyard builders, yes. UV resin stays liquid in the shade and cures in minutes once the board goes into sunlight, so you get unlimited working time and kick it when you are ready. Standard catalyst gives you more control indoors or on overcast days, which is why production bays still use it.
How much resin does one surfboard take?
About a gallon of polyester or a 3 quart (96 oz) epoxy kit for a shortboard under 7 feet. A longboard takes roughly two gallons of polyester or a gallon and a half of epoxy. Buy over rather than under — running dry mid-laminate ruins the board. Full breakdown in the resin and cloth calculator.
Which epoxy cure speed should I buy?
Slow for hot weather and larger boards, Fast for normal conditions, Kwik for cold days or when you want to hot coat the same day. They are all the same price, so choose by your shop temperature rather than cost.
Is epoxy or polyester cheaper for one board?
Almost identical at these quantities, around $102 against $103 for a shortboard once you include the hot coat. Cost is not the deciding factor — your blank is.
What is Additive F for?
It prevents fish-eyes and surface defects in epoxy and makes the cured resin easier to sand. If your epoxy hot coats keep coming out with craters or cloudy patches, Additive F is usually the fix.
Ready to Glass
Resin, cloth and everything in between
The same materials that go through our own bay in Menifee, California, shipped nationwide. Not sure how much to order? Start with the calculator.