If you’re getting into shaping your own surfboards or doing some ding repair, epoxy resin is the way to go.
It’s easy to work with, less toxic, and it’s even available in BIO-based formulas from a handful of different suppliers.
Resin Research makes some quality epoxy resin in a variety of kit sizes that are the perfect solution for minor ding repair or full on surfboard lamination and hot coat jobs.
Safe to use on both EPS and PU foam.
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Bio-Epoxy Resin Showdown: Resin Research Bio vs. Entropy Super Sap
When I started Wave Arcade, I knew that bio-based epoxy resin was going to be a key component to making my fins and boards.
Bio-based epoxy resins are derived from plants and result in an epoxy that’s safer to make, safer to use, and that carries a much lower carbon footprint than polyester resins or chemical epoxies.
I’ve had about equal experience using both Entropy Resin Super Sap One and Resin Research BIO epoxy resins.
This page serves to compare the two and provide some of my experiences working with them.
Both are 2:1 resin:hardener epoxy systems, and I’ve had success with both of them.
A quick table to compare the two epoxies is probably the easiest way to do this, here we go. This table will first show a side-by-side comparison of the two bio-resins based on information from their website and my own experience. Information assumes fast hardener is used.
| Entropy Resin Super Sap ONE | Resin Research BIO | |
| Bio Content (When mixed w/ Fast Hardener | 30% | 21% |
| Viscosity | Low (1000cP @77°F) | Medium (399-600cP @ 77°F) |
| Color | Slight Amber/Clear | Slight Blue/Clear |
| Tack Free Time | 4 hours | 3 hours |
| Recommended Full Cure | 7 days | 2-7 days |
| Pot Life | 25 mins | 25 mins |
| Price (1.5 gallon kit) | ~ $165 | ~ $140 |
Both bio-based resins are pretty comparable on most items listed above.
In my experience, they’ve both produced great results in terms of workability, finishing, and end-product appearance and strength.
Here are some of my anecdotal observations of the two epoxies, take these with a grain of salt:
- I experienced amine blush after cure and during sanding with Entropy Resin Super Sap more so than I have with Resin Research BIO – this could be due to my experience with epoxy improving over time or ambient temperature and humidity during curing.
- When working with hemp cloth, I preferred using Resin Research BIO.
- I seem to experience more fish-eyes/bubbles with Resin Research BIO than I did with Super Sap – again this could be due to my experience level or ambient temperature.
- I’ve been able to source Resin Research BIO for a little bit cheaper than Entropy Super Sap.
Honestly, after using both resins – I don’t have a strong preference either way. Both have their strengths and weaknesses, and both require about equal finish work for a good final product (just like any epoxy).
I’ve been satisfied with the results from both – both in terms of working with them and surfing the final products.
I’m calling the final result a draw – both companies offer great options for bio-content epoxy resins and I’ll probably continue to use resins from both Resin Research and Entropy Resins moving forward.
Resin Research Epoxy for Surfboard Shaping & Ding Repair
Resin Research epoxy is super easy to work with if you’re new to shaping or repairing your own boards.
It’s easy to mix (either by volume or by weight), cures well, and sands well.
You can also pick up something called Additive F from Resin Research that can be added to the mix to eliminate amine blushing and peeling, make saturating your fiberglass easier, and help eliminate fish eyes and blemished during the hot coat.
Key features:
- UV stabilizers.
- Blue tint in the bottle, but cures clear.
- 2:1 mix ratio by volume.
- Odorless.
- Safe to work with.
- VOC free with low toxicity.
- Medium viscosity.
- High gloss.
Fast hardeners have a pot life of about 18-25 minutes and set within 2-3 hours at 77°F.
Slow hardeners have a pot life of about 40-50 minutes and set within about 4-6 hours at 77°F.
The pot life indicates how long the epoxy and hardener will last while mixed in your mixing bucket.
The set time indicates when you’ll be ready to flip or sand the board.
If you’re making a shortboard, a 96oz kit should be enough epoxy.
If you’re making a longboard, a 1.5 gallon kit is a good choice.
Longer longboards or sups will likely need a 3 gallon kit.
If you just need some epoxy for ding repair, a small 48oz kit will do just fine.
Slow Hardener vs. Fast Hardener Epoxy?
Epoxy resins are available with a variety of different hardeners that typically range from extra fast or fast to slow or extra slow.
The speed of the hardener will determine how long you’ll have to work with the epoxy once it’s mixed and how long it will take before it sets up so you can continue working with it.
If you’re new to working with epoxy, here are some useful tips:
- A faster hardener will typically suffice for shorter boards and the hot coat stage or ding repairs.
- A slower hardener can help during the lamination phase if your work slow or you’re glassing a large surfboard.
- A slower hardener can be a good choice if your working in particularly hot temperatures (above 80°F).
- A “Quick Kick” epoxy will be useful once you gain some more experience, when you’re doing a hot coat, or if you’re working in colder temperatures.
Epoxy Resin vs. Polyester Resin for Glassing a Surfboards
If you’re a homebuilder, epoxy resin is a good choice over polyester resin. Here’s why:
- Epoxy is less toxic and safer to work with than polyester resin.
- Polyester resins tend to be a little more porous than epoxies and degrade quicker.
- Epoxies are stronger than polyester resin.
- Epoxy can be used on PU or EPS, while polyester resin will melt EPS foam.
Epoxy resin will typically be a little more expensive than polyester resins, but the benefits certainly justify the cost.