Epoxy vs Poly for chambered wood board (no fiberglass)

Working on completing a 10 foot chambered wood board made of 16 conventional lumber hardware store 2x6’s. Board Dimentions are 10x24x3 3/4. Its has a noserioder shape with a fat beaver tail that I will install a 10.5 Bhain box and GreenLight Surf Supply vented leash plug (if you have any experience with these let me know very inserted in others opinion on strength gortex etc.) I have already applied 2 coats of Minwax Stain across the board and it looks pretty good not going to lie. I am questioning on wheather to seal the board with either poly or epoxy resin. Do you think poly resin is strong enough withought glass for a chaimbered wood board? The board has structural supports every foot which are 1 inch wide and the deck and bottom are 1/4" thick. Very interested on what you believe the board should be sealed with particularly if you believe poly is strong enough. I don’t want to go the hippy “oh just use bees wax or some mashed up banana tree stump works great” or something like a spray on/varnish sealer. I am looking for a smooth glossy professional finish that has some strength built in. Will post pictures once polished and let you all know how it rides.  

Poly is brittle, Epoxy has much more flex to it.  Poly will not move much when the wood expands and contracts…epoxy will a bit.

Poly will be clearer, and if you dont purchase the proper epoxy you can have all sorts of issues.  But if done right it can be perfect.

I would personally use epoxy, then spray it with a 2 pack auto finish like Max2K Glamour.  You can get it on Amazon…it’s not cheap but you can get 4 cans for 60-70 bucks.  it will probably take 2 cans.

Or you could glass it with 2oz cloth and poly and finish like a regular surfboard…that would turn out nice. If you are not much of a glasser, the 2 oz is super forgiving with getting bubbles etc.


All I make is EPS epoxy boards now, and they are as clear and shiny as any poly board…but it has taken me a few years to get there.


I don’t glass anything in PU, but I especially wouldn’t glass a wood board in PU, if for no other reason that the micro-cracking as it ages. 

Epoxy is significantly stronger, significantly more flexible and has significantly better adhesion.   I don’t even know how many repairs I’ve avoided over the years due to using epoxy instead of PU.   And if there’s one thing you don’t want to be doing with that wood board you’ve spent so much time/effort building it’s dealing with minor dings or seeping water.  I’d seal the board with a couple coats of epoxy prior to glassing, and fair those out.   

I bet polyEster resin would not even want to adhere very strongly to the stained pine.


If you stick your nose to the board and can still smell the minwax stain, might want to wait a bit longer before applying anything. If you did not immediately wipe up the excess stain, but let it dry all tacky, the resin is not going to bond to any wood in that tacky area.  Wiping with mineral spirits can lift the tacky areas, making the stina ll blotchy, but often it is easier to just apply more stain over the tacky areas and this time remove the excess before it dries. Lots of elbow grease and pressure to blend it nicely.


 Do some tests of your resin choice on samples of the same wood stained in the same manner, before committing to doing the whole board.


I’ve used only epoxy, with no cloth on some hulls, but used cloth on the rails, and it turned into a nightmare.  The cloth insures a nice even thickness, painting layers  with no cloth, insures frustration as the areas which repel epoxy continue to do so. These depressions need to be sanded carefully by hand and refilled and they often still repel the epoxy,

Read about preventing fisheyes with epoxy.  Dust and contaminents can become ones nemesis,  and stain can be considered a contaminent, that keeps on giving.


While you might not need any strength from fiberglass with your chambered pine tank what does it weigh… 45 lbs? , you will not be adding any significant weight, as a percentage of total weight, by using it, and will likely save a bunch of cursing, by having an even layer distributed around the shell. 

The weight added by a glass job can be mitigated the first session when that pinhole suckes up 14oz of water which you cannot hear sloshing around inside as it is likely an unsealed sponge.  When such a heavy board soaks up a few oz of water each surf, you will not notice it gaining weight.  it would have to be a bad leak to hear it sloshing around inside, and by the time you got it home it will have absorbed into the interior and no longer slosh.


When you do apply whatever resin you choose,  get the board warm, and the resin warm, and work in falling temperatures  and with low humidity, if possible.



Do any of the above as described by resinhead.  Yes the stain could be an adhesion problem if an oil stain.  Also oil stain will pull under certain finish products.  A finishers term for a chemical reaction.  Do a sample test before applying Poly.  Epoxy should be fine.  You could also do a couple or three coats of floor sealer.  Very durable and easy to apply.  Comes in Satin and High Gloss or “Wet” look.  I have combined the two in the past to make a Semi Gloss.  The more I think about it, the more I am sure the floor sealer would be a great, easy, wipe on finish, that is flexible and durable.  It is an Acrylic and can be burnished with an Orbital sander and a 3M pad in maroon or grey.  Two to three coats will definitely seal it.  And the Satin would give it a natural rubbed look.  I use Behr floor and tile sealer.  Have used it on exterior front doors and it lasts for years.  

I have a plywood boat that is partially glassed and fully epoxied. The glassed parts look almost new, the plain epoxied parts look like crap after 3 years outside in the weather.

Wood expands and contracts, epoxy cracks and starts to allow water in, an the mositure starts a chain reaction of epoxy delamination and water damage.

Huck’s latest thread describes the cracking of poly resin w/o glass on a wood veneered board.

My only non-glassed board leaks like a sieve.

I cannot reccomend glass-free constructions.



Wood boat builder’s i know used pu tie coat on wood before cover with fiber and polyester resin then gelcoated. They all moved to epoxy years ago because it m’s far durable for all reasons exposed before. 

Now they used water based epoxy to threaten wood, go deep, increase threngh and durability by far so some only cover with fiber for harden skin against abrasion where needed.

The board has structural supports every foot which are 1 inch wide and the deck and bottom are 1/4” thick"- 

Uhmmm, 2x6 framing lumber is typically spruce or some sort of pine and quarter inch thick spruce ( or pine) isn’t terribly strong. You can punch a hole in it with your fist. Let alone the heel stomps you’ll get turning a very heavy ten footer. If you’re staggering your chambers as you should be in order to let it release air pressure with one plug, life is gonna get very interesting. 

I strongly ( pun intended) suggest glassing it. Just resin sealing the thing, be it poly or epoxy, isn’t going to do a helluva lot beyond making interesting cracks where the wood gives in under it. Just before it starts to flake off. You might as well use varnish or polyurethane floor finish. Which will look good, at least. 

Sorry about that, hope it’s of use


I haven’t built a chambered board, but I’ve built 8-10 hollow wooden boards. My first board I painted many layers of resin on and in less than a year it leaked at the glue joints. Not saying that fiberglass cloth is the answer, but it does significantly lower your chances of leaks even as the wood moves. Out of the 8 boards I’ve finished only one other leaked, and it leaked at a finbox that didn’t get sealed properly. As someone already mentioned fiberglass cloth gives a nice even resin layer which helps ensure everything is fully sealed and if done well can save time sanding wave resin. I generally use 4 oz just for the extra insurance. Cloth will also help keep the resin on the board as it cures in the event that not all of your glue joints are tight. I don’t mean to imply that you are not a skilled wood worker, but hardware store 2x6s aren’t known for their manufacturing quality. They be crooked and knotty.

You probably have a couple hundred dollars in wood and supplies, plus however many countless hours cutting, glueing, chambering, glueing, and sanding. Do you really want to skimp on a finish that would insure its watertight integrity? Quite literally a sink or swim decision. My quite unprofessional opinion is glass with resin and some sort of cloth.

As far as type of resin. I personally prefer polyester, but that is me. Use whatever you are more comfortable with or have more experience with. Both have pros and cons that are well documented. The stain will affect adhesion of both resins. It will affect polyester more than epoxy. I would also suggest a cheater coat before you glass because soft woods, especially the exposed endgrain around the rails, will suck up resin. A cheater coat will seal the grain in the board and prevent/limit the amount of resin that gets wicked into the grain.

Somehow my second and third paragraphs got swapped so it reads a little funk.