epoxy pros and cons

i know there are some devoted epoxy people here. What are the pro’s and cons of epoxy?

i heard from a friend about an XTR board that was epoxy and delaminated really quick because of the heat that the epoxy held in… Greg does XTR use rr epoxy? and what do the numbers on the epoxy mean also?

well, i’m not greg, but i’ll take a crack at it…

extruded foam is more prone to delam…if that’s a concern, use EPS. RR epoxy is safe for any kind of foam – EPS, XTR, PE, PU. the different numbers of epoxy resin refer to how flexy the resin is. 2000 offers roughly the same flex characteristics as poly resin. 2020 is more flexible, and 2040 is even more flexy than 2020. i like to lam with 2000, then hotcoat and gloss with 2020.

Oh boy, another rumor from the mill. Epoxy can’t possibly hold more heat than polyester. In surfboards their both just thin layers of fiberglass held together with hydrocarbons. I wonder who came up with that one.

Soulstice is exactly right. XPS has a lower melting point than EPS or urethane. If you don’t take care with that type of board you could have problems.

As for pros and cons, epoxy is:



Solvent free

Easier to work with

Low Vapor


Just as UV stable

More versitile in application

More versitile in use with co - materials

Has better elongation

Can be made with a variety of flex charateristics

Safer to work with

Doesn’t require clean up solvents

Sands just as well as polyester

and some more I can’t think of off the top of my head.

Fact is, surfboard polyesters are today even illegel to use in most areas of the country using standard building methods. This shouldn’t even be an issue but the status quo continues to make up ridiculas stories like this one in an attempt to run down superior product.

The issue should be, why does the government allow the polyester establishment to continue and why does the surfboard industry continue to push 50 year old technology when there is better available?

Lots of good info here:

Epoxy & EPS Construction Primer

well beyond what has been said already…

(1) less waistful because you can mix what you are likely to need and then if you run short just mix up some more.

(2) In similar fashion, easier to work with because #1 means you don’t have to work with in a pot time, mix what you can do in time, and then mix more

(3) epoxy wets out the glass better than polly (so I have been told, I have not used poly)

I’m sure there are other reasons.


Thanks for your post. What’s your answer to get an old-school looking gloss finish on epoxy?

ok. thanks for clearinguup alot of the rumors i have heard. i personally , except for my da cat replica want to only use epoxy from here on out does it work just as well with PU as EPS? cuz i don’t like to work with EPS.

The only cons I would note are:

~The slow cure times - Mainly comparing it to UV polyester and the inconvenience when doing repair work. When doing lam work, I see the slower as a plus.

~The expense - I’m not a pro and I still end up with a lot resin on the floor but I’m willing to pay more as you’re getting a better, safer product.

~The polish issue - I personally think epoxy shines well enough though.

Another pro to add would be:

~Less problems when used over top of art work.


ok. thanks for clearinguup alot of the rumors i have heard. i personally , except for my da cat replica want to only use epoxy from here on out does it work just as well with PU as EPS? cuz i don't like to work with EPS.

PU with epoxy is JUST fine.

It is more often used with styrene based foams because you cannot use polyester resin with it - polyester resin has styrene in it, and the styrene will dissolve the EPS/XPS foams.

That doesn’t mean epoxy is bad with PU foam. It is not.

A lot of delams come from very low weight foam, in which the vapor pressure changes with heat are too great. You cannot use a foam too light with any resin.

To me, the biggest reason to use epoxy is health. I dislike working with volatile organic compounds if I can help it, and modern surfboard epoxies have this truly minimized (especially RR epoxy). Polyester resin is a huge VOC fest no matter what.

is there / will there be a suncure epoxy that sets firm [?‘gels’?] within a few hours ?

I ask , because I have limited time to do board and fin stuff when at Grant’s , and it’s a bit of a worry if things are half finished when I leave …


Don’t do it…Just say no…Polyester Resin is the best…Always has been…Always will be…Take it from an old long time surfboard maker

I love using the stuff, because I take so much time doing my lams and freelaps getting them just right.

Easy to use, no strings, less sanding, easy to sand.

you wanna see it kick in 5-10 minutes…

take 2-1 epoxy and make it 1-1

I did it in error while glassing both the top and bottom of my 7’2" bamboo funboard . I was using t-88 5 minute epoxy glue doing my rails just before and got confused…

Talk about rushing and smoking resin. This was my first experience glassing with it got epoxy all over myself and with no orange goop I couldn’t get it off for a while even lava soap didn’t work. Even tried acetone which I know is a no no …

Lucky I was used to Poly going off in 5 minutes slop and squeegee like hell forget about the laps no time just get as much resin out of the weave on the flats before it catches fire… The cup started smoking and melted…

except for the rails, the rest of the lam surprisingly came out okay.

This stuff ain’t as easy as everyone thinks…

sounds fun …you didn’t need “lava soap” to clean up …you were making your very OWN volcano !!

[ I would have loved to have been there videoing that , but you would probaly have killed me ]


when i first started with epoxy i almost always had a smoking bucket… i was mixing up large wasteful batches like i did with poly… i would get my lam all wet out and then set the bucket on the floor and work with the squeege and forget about the bucket. i would forget about it until i would see the smoke… the Epoxy Construction Primer really helped limit my waste with its mixing amounts guide…

a good thing to remember with any resin is “when i doubt throw it out”…

even with the scales and fancy cup from time to time find my self saying what the hell a i doing again? how much was i adding? it is not worth putting it onto the board if there is any question… the other day i was mixing a batch and it just seemed too gooy… i poured it out into a big cardboard box and it never hardned, must have hit the wrong button on the calc. or just spaced out…

hey oceanrider… could you back up your comment with some facts? or are you just trying to throw others off the sent? The only two pros i can think of for poly is that it shines better when used as gloss and the uv is great for dings (espically when combined with FGH Fass Kine epoxy putty)…

yo chipfish… the Fiberglass Hawaii clear that i have been using is sandable after about 4hrs on hot Hawaii days…

hey jjp…nah just a boat rocker…forum rules apply

Finally, a few good ideas:

  1. Don’t feed the trolls!

  2. Substantiate your claims.

  3. Think before you post.

  4. Use your common sense.

  5. Go surfing.

Suncure makes a UV harding epoxy. I don’t know if it works

Patching epoxy boards is no big deal. Can you walk to Walgreens and get a polyester patch kit? No, but you can for epoxy. Might not be the best it works.

Smoking buckets, HAHAHAHA!!! sounds like you need to start useing a wider based bucket instead of a tall skinny ones. Also for you guys that mix alot of resin. After mixing you can pour you resin in a old 12" telon fring pan. The heat despence properties of the pans construction and the wide base will great help keep you eppoxy cool. Something I learned when mixing up big batches [60oz.+} although I never has this problem and was useing slow cue in Fla’s Nov-Jan.

Also hear is you want to use a fast cure epoxy you can put your hardner on Ice and it will greatly increase your kick time

Maybe my limeted experience with epoxy, but adding twice the amount of hardner doesn’t make for a hotter batch of epoxy.

i have a 4 to 1 mix which alows a 45 min pot life so can work it nice and slow , and yeah use trays instead of tubs … gregs epoxy primer article is great … this stuff is hell easy to work with… alway mix corect proportions as a (hot mix doesnt work the same) and is weaker …one thing though, you can apply filler coats after 3 hrs from gel time on cloth lam to get a chemical bond rather than mechanical. I have used epoxy for many years in boat repair and it is obviously a superior to polyester resin. poly peels real easy off a lam, epoxy doesnt…you get used to using it and can work cleanly cause there is no rush. i did a lam last week in my house with no waste and only a couple of drops on the floor (newspaper ) (6oz + 4 oz used 500 grams on an unsealed blank ) and it doesnt stink either…I was wondering about the term XTR though… does that mean extruded polystyrene cause “lost” are using XTR i thought the term was XPS… any way why are big companies using xps if it delams … unfortunately it just ends up giving the resin a bad name for the uneducated consumer…

heres some more pros…

polyester will keep progress in design and inovation in construction at a standstill …

epoxy allows for the introduction of techniques and construction methods never dreamed of in polyester …

why do big companies use crap foam ???

because decisions on direction are made by the guys holding the wallet …

when your advertizing budget is that big , you can continue to burn each successive generation and still have another bunch of suckers out of school the next year to sucker in with your glitzy glammour pro surfer ,magazine add …

take the adds away , and the sales stop …

what does that say about a product ???

more pros on epoxy …

better performance because it transfers energy better …

board lasts longer due to a longer resistence to fatigue …

polyester sucks …

xtr/xps sucks …

oceanrider sucks …

do unto trolls , a trolls own trollness …

but put it in simple words , coz there not very smart…



epoxy and urethane work fine …

well some of the negative listed here have easy fixes, which will make you love epoxy even more…

I personally use a wetout table and either brush or roll epoxy on, easy way to get a really good wet out…not much wasted, if there is some left over I might be able to do some fins, if its not enough, its simple, just get more resin…it doesn’t kick like polyester so oyu have more time to work. The long cure time can suck, believe me I know I used to do lams in my basement in Long Island where the temp wasn’t even at 70, prob near 55…Easy, cheap fix…aluminum foil, card board box and a hair drier. Cures that used to take 10 hrs take 2…