EPS thoughts

I have been working with 1lb EPS (Home Depot). The foam is soft so for my first board I used a lot of glass which made it heavy and expensive. For the second board I used veneer with glass under and over. Lighter but the veneer

was a little pricey. Both boards have to be vented.

I was thinking that I could could get around the vent problem and the softness if I shaped the blank and then ripped it down into 4" lengths on the band saw and then glued it back together with epoxy. The glue lines would act like stringers and would give more support to the glass. The blank would also be divided into smaller sections that would not contain enough air to expand and cause delams.

Will it work or am I dreaming ?

you still will need to vent as it will gas, and this will not address the softness of the deck and bottom requiring more glass. If you get your glass/resin ratio good you should be able to do 3x6oz deck and 2x6oz and have good weight.

If you want to get it down, then balsa; its cheaper than you think.


i’ve made about 8 boards with the 1 lb. eps. i know what you mean about not wanting to vent. but i would rather vent that cut it up into strips. haven’t vented any yet. but they haven’t been around long enough to know better and plus i’m in a cool climate. A vent is only a buck or two and you would save all the extra weight and work of cutting and gluing. and then shaping through the glue ribs. yikes… no, i definitely wouldn’t do the glue thing. just vent it. there’s other ways of reinforcing the 1 lb eps. ie. perimeter stringer or lamming glass or wood strips between the foam layers. or just puttin in a center stringer. i’m gonna do a perimeter stringer on my next board. its suppose to have some interesting results. i try to get around the foam softness in other ways… there’s balsa , carbon fiber, 6 oz s glass… at some point you really have to decide if you’re after saving money or getting a better board.

Your Special order desk will order denser eps from insulfoam for you, it takes about 2 weeks to get no minimums. I assume your using the insulfoam. that should solve all your issues right there

hey EC, would that be the special order desk at home depot or the like ?

I got a hold of the local insulfoam rep and the best i could get direct was a $ 400 block of the stuff(2lb eps)

I called InsulFoam last year and they would not sell to me at the size I wanted (10’x2’x1’) but they directed me to Bay foam in Fremont, Ca. They are just an hours drive for me so called and picked up the block, $90. Made 3 boards of it. 10’er, 2x6oz. carbon top, 1x6oz. carbon bottom, carbon perimiter stringers, 18lbs. depressions where I knee paddle is all thats there after 6mo.

and a 10’er, 5oz. carbon, 1/16"balsa, 4oz S Glass, top and bottom with carbon perimeter stringers = 20lbs. It’s 3 3/4" thick! Next one will be 2 1/2" thick and should be only 18lbs or less.


yeah of the insulfoam i got i got it only in an 8 foot length, i special ordered it from home depot it was cheap like 45 bucks i think and each sheet nets 2 boards since they are 4 foot wide

Hey Marke,

I thought in the past about taking some heavy density XPS - like some DOW 60lbs. stuff - and chambering it like you would a balsa board.

There would be little shaping involved other than the rails as a cad program should be able to give you the side profile of every 2" section as seen from the side, which you could then cut out and chamber, before joining it with its neighbor. The last pieces on either side could be replaced with wood.

At work recently I cut a 2" slice out of some some 4" foam and drilled some 2.5" holes through it. I was able to stand on it just as well as a solid piece.


Sounds interesting but you would have to vent it some how.

My EPS veneer board has a perimeter stringer and bending ply. rails. I have noticed that in the middle of the board I can push the deck in a little with my thumb. Out at the edge near the stringer I cannot. I think that no matter how thick the veneer or how much glass I use the foam will compress in the middle without support ftom a center stringer. This leads me to believe that if I have multipule stringers I can get away with using less glass. If I use epoxy and glass stringers I could make a light board. The only problem that I see is venting since the board would be divided up into several sections.

marke, are you vacuum bagging ? I wonder if that would make a difference ? I put a carbon fiber strip down the middle of a recent 1lb eps board and it is hard. no depression. on the other hand i put a carbon fiber strip in a board that i didn’t vac bag and it is soft. and i put 3 layers of 6 oz s glass over the deck.

You could vent it into one of the hollowed chambers, but I’m wondering if it was glued up in a vacuum if the chambers themselves would be able to handle the expansion of trapped air.

If you use the heavy duty foam - 40, 60. or 100 lbs / sq in comp strength - support shouldn’t be a problem but if you wanted, a matching chambered piece of thin balsa or ply between each section?

hey waaahoo… i did some boards a year ago with xps and they didn’t last very long. bad delam problems. one of them was out of the sun almost all the time (my son didn’t like it) and still delammed. my personal board was xps. i took good care of it and it still fell apart. I heard that if you leave the blank rough the glass will stick better. A guy who surfs in the Gulf where it gets real hot, told me he leaves his blanks real rough and uses white pigment on 'em and he can leave them in the sun all day and not get any delam. Mine were all very smooth, so maybe he’s right. But I’m not making anymore with XPS.

I vacuum bagged the veneer but not the glass. Lost my nerve. Didn’t want to ruin it. I think if I did a carbon fiber stringer the board would be bullet proof since it has the wood rails as well.

Wish I didn’t have to vent EPS. I have to remember to carry vents with me in case I loose one and I have to keep a quarter in the leash pocket so that I can tighten it up. I think it is only a matter of time before I loose the quarter in the sand I cannot remove the vent.

Yeah Roger on the delam. I think that’s the general consensus around here.

Just kicking around ideas for a quick and dirty no skills necessary surfboard. Cut out to pattern, chamber, and glue together.

I agree with EC on the 2 lb. Its just that I haven’t been able to locate a small amount. But I’m gonna check with home depot and see if they will order me enough for just a few boards. I just shaped a 6-2 eps 1 lb and i put 2) 2" strips of ply in it and fully shaped it weighs 2.5 lbs. I weighed the strips first and they added a little over a pound. So then with 2 lb eps would weigh 3 lbs on this board. I don’t know how much lighter that is than pu foam. I wonder if I would have to use a stringer with 2 lb ?

You shouldnt have a hard time in nor-cal because im pretty sure my 2 pound came from chico,s insulfoam plant

two words

Linden Recycler

My very first exposure to EPS epoxy till it delammed one of the best dam boards I ever owned…

Also go see Rohan’s blue xps experiment

You just need to support the board like LeeDD said when shaping it that’s all…

You can try using your local EPS dealer.


this just in… 4x8x12" 2lb density eps $ 129 delivered to my local HD in 10 days.

Thanks EC for the suggestion.