2-Sheet XPS Blanks

I’ve picked up enough Dow High-Load 40 and 60 to make 3 blanks.  I plan to glue one 2" sheet of High-Load 60 to one 3" sheet of High-Load 40 – 60 bottom and 40 top.  Also plan to try adding a 4’ long 1/4" EPS deck skin (2.25 pcf, actual) on at least one of the blanks.  I need to be able to hotwire the bond seams.

I need to glue the sheets together. Kokua mentioned using Clearco 444 to bond foam together once, been thinking about trying that.


Anybody got some good ideas on what glues or adhesives to use?


nr 77 maybe?

but shaping those "blanks" is awful


Thanks for the suggestion wouter.

Dow High Load XPS is my best option in rural west KY – cheapest way to experiment with some ideas I have.  Otherwise I’d have to pay around $200 for each shipped surfboard blank.

I plan to shape by hand (no electric planers) and will be building slowly over fairly long periods of time.  Hopefully hand shaping XPS won’t be too bad.  I’m not in any hurry.

Wouldn’t 77 eat the Polystyrene?

Don’t know anything about the 77.  But the 444 isn’t supposed to.

My biggest concern is working time, since I’ll have to spray or add glue to 2, 2’x8’ surfaces before putting them together.

Any other options?

Did some searching on N****R 77 (?).  Only 77 spray adhesive I could find was this:

3M Super 77 (could work I guess)


Did a little more digging and found this:

3M 78 (polystyrene foam insulation spray adhesive)


Looks like this might be better than the 77.  Anybody ever try this stuff?  How about you everysurfer?



Epoxy glue

Pu glue

Roo glue

3m eps spray glue


Always buy quality 3M products.


Super 77 will eat you Expanded Polystyrene Blanks. Use the 78.


Or better yet find. You live in Kentucky..well they have boat docks on lakes right?  Get som EPS foam from a dock place and hot wire something...Or I know you have an architeck type place dem dare homer? U know da one where de makem da stuff fo da fancy homes with out da wheels.

They can cut a slab of foam for you, in any weight foam EPS.

My 2 cents worth, (free advice is worth every penny);

Return the sheets for a refund, ask a blank reseller, like Greenlight, Foam EZ, or a Gulf source, to cut your choice in half, for shipping purposes, and then you glue it back together. 

Someone should ask them to build a hot wire jig system for customers in landlocked places,  If you want a stringer use a local source for the wood.  If EPS, Cut like tounge in groove, with longer T&G's.  In the case of PU with the stringer cut, no T&G necessary.  If foam EZ needs help with the system, they should PM me.

Also, Roo Glue is an air cure, it will take too long to dry.



I made my first three boards this way, only without the extra piece of EPS.  It’s an absolute pain in the yahoo.  I would only do it now as an absolute last resort.  That said, I used the super 77 cause I was an idiot teenager and didn’t know any better; didn’t have any particular issues.  I wasn’t hotwiring either, so I had to mow a looooot of foam.  Man, my dad was pissed beyond belief because every square millimeter of every item stored the garage was covered in a half inch of blue dust.

So, if you’re really desperate to shape something, go for it.  Just be aware of the next set of issues you’re going to run into, like storing and transporting your board without the glass ballooning off of the foam in the ugliest delamination you’ve ever seen (remember: vents don’t work on XPS).  Oh wait, where’d you say you were?  Kentucky?  It doesn’t get too warm in Kentucky now, does it?  Nah. . .

Hey, it’s all just for fun.

But, if you start internet searching for architechtural foam cutters, you’ll probly find you’re not too far from someone who can cut you a pretty little block of 1.5 or 2 lb eps for a very reasonable price.

Just saying, and please forgive me if you already know all this.

The hotwire is your friend.

I’ve been researchin and ponderin this for several years.

For now, I’m Gonna use what I’ve got in the barn.


Thanks to all...
Did a google search on "3M eps spray glue."  Found this press release about 3M 78, definitely looks to be the right stuff for XPS/EPS:
Read something somewhere that said 3M 77 cavitates polystyrene.
Shuut fahr RezzinHayd.  Them dern arkyteks taynt got no youss fer mah leedull Kow Town.  Dad bern dahrk maykers muss be importun fohm frum ferun stayts.  Taint da raht stuhf.
Good suggestions ResinHead.  Will have to see if I can't find some architects next time I go to the big city.  Will ask around at a few of the marinas on the nearby lakes too (Kentucky and Barkley).  I've google searched the entire state of KY several times and haven't come with EPS, made many calls too.  I live 60 miles from the closest city of 20,000.  Not much demand for surfboard foam in farm towns.  Had to drive 90 miles (180 round trip) to buy the Dow High Load from a construction company in Indiana -- $25 a sheet was just too good to resist.
Shuhks sikdawg.  Ahm gunna keep da fohm... it ull be awraht cuz Bubba gunna hep me shayp.  Heez reeul guud wid a chayn saw.
Ahh thank ah'll juss pawnder thiss fohm sitchyayshun a tad bit wid mah Jugg in Hand.  Nuthun better'n a leedle waht lahtnun to git mah brayn luubreekaytud.

Howdy Bg

I say it is awful, but if you have a hard block with a linnen backed 40 grit, glued to it with 77, it shapes ok.

Right now I am shaping  exactly what you are planning… but with a balsa springer inside 

Can you not buy a block of EPS? Are there buyers out for your boards? I understand the Americans always have a bigger surf market than people in Scheveningen… like myself.

Do you have a -good- rocker bed?

I googled KY- google says kentucky?? Are you going down the same road Wlakestah took?

What are you going to use it for?

If you do choose epoxy to glue the sheets… use minimal amounts, i mean minimal… shaping hardened epoxy is not easy.

Shaping is not easy period

Will you make pictures? I haven’t. Chip must be angry, so many boards, so little pictures.


edit: does 77 eat foam?? maybe i was mistaken in the number, just saying glue shapes easier than epoxy.

I made a few PU/PE boards many years ago when I was a teenager living near a coastline.

Just making the boards for me and my son – vacations until (if) I can get back to the coast.  I just like making surfboards. And I have a few designs I’ve wanted to build for 3 years now.  If the shapes look good in XPS, I may move to commercial blanks.

 I have no interest in selling at the moment.  If the designs look good, who knows.

I’ve read plenty here and elsewhere about using XPS.  Dow High load 40 and 60 have 40 psi and 60 psi minimum compressive strength, respectively, pretty stiff/solid stuff.  Only foam I can get easily and I like the idea it won’t soak up water.  I don’t leave any of my boards in the heat any more.  I plan to prep with low grit (60 or less) sandpaper before glassing.  I am also going to go stringerless.

I am avoiding epoxy to avoid sanding solid glue seams.  Plus I don’t think epoxy seams will hotwire well.

I’ve used several types of spray glue and found that they won’t hold up to shaping. I had to add bamboo barbeque skewers to hold the foam together. The seam where the top and bottom layers is also a trouble spot. It’s easy to rip small chunks out of that seam. It’s ok if you end up covering the blank with a lot of pigment or skin the board as in a compsand.

Have you thought about cutting rocker slices instead of making a thick flat sheet that you have to cut.

I make rocker slices and glue them with a foaming PU glue like Gorilla glue. After the slices are glued together, I shape out the roughblank. I have also glued in preshaped stringers then all I had to do was shape the foam down to meet the stringer. The last 2 I made, I cut holes with a hole cutter
the middle sections to try and cut the weight down some.

I have also cut out boards from solid blocks, but I found that so wasteful. I think you can probably get one board from a 8’ x 2’ x 2" sheet if you cut out the rocker slices with minimal waste. Why bother getting the cheaper foam if you end up with so much waste?

I’ve found that XPS is lighter than EPS and it shapes easily. You can get a nice, clean, ready to glass finish that you can’t get with construction grade EPS.


What density XPS foam were you using when you had problems?

What brands/types of spray adhesive did you use?

One of my first XPS blank ideas was to use multiple foam (rocker) stringers like you are using.  But I had decided with so many glue lines, the blank would be too heavy and a pain to shape.

Did you post that foam stringered blank a while back in one of the XPS threads?

This is why I bought enough sheets for 3 blanks…  to experiment.

try 1" xps on the bottom and 2" eps on the top

roo glu is the best cause you can hot wire through it

if you can get a block and a blank its easier. but i’ve done dozens of boards this way 

it isn’t the easiest of ways to do things

but its completely doable as you can see below…

































































I don’t know what the specifics were for the Blue foam. I got 2 4" thick blocks off Craigslist here that were quite hard but very light for the hardness. I also got some 3" thick blue dow that was not as dense. Lowes sells 2" thick stuff that my brother buys.

I used a variety of spray glues, 3M, Elmers and others that I can’t remember. I just bought a different brand from an art supply store. I use these to stick sand paper to my sanders, and sanding blocks more than anything.

If you use spray glue there won’t be ugly glue lines because its so thin. Even with the foaming glue it will be fairly thin because you need to clamp it together really tight.

In the photos my brother posted above we used Epoxy with a woven bamboo springer between the sheets. I’m not sure what he used to wrap the blue dow on the rails. Some of the blanks have a 1/8" wood rail strip between the white foam and the blue rails. He mentioned Roo glue. That looks like white Elmers glue, but it’s different. I did that too, I used the same white glue kids use in school. That will come apart when you start shaping.

When we do full sheets, we use another surfboard as a rocker table then bend the foam to match that rocker. Once the rocker is set, we add the wood rails to hold the rocker in place. The blank is the same thickness from nose to tail, so there’s still a lot of work to get the profile you want. We also have a rocker table with my favorite rocker and you can place a board with the top or bottom against it so once we have the bottom lam vacuumed on we can profile the deck then place the bottom on the rocker table and vacuum bag the top lam on.

You can do it any way you want, but from my experience, I’ve found making the rocker slices then tuning up the blank works best for me. If you are good with the hot wire, and don’t mind the waste, hot wiring out the blank should be less work. I always get wavy cuts, so I end up having to fix that, and I don’t end up with what I wanted when I started. I cut out 2 8’ boards from full sheets with just my planer, sanding blocks and cheese graters too, so I’ve tried every possible way. 

Just wanted to pass on some of what I’ve learned. 

Exactly what I’m looking for.  I want to know about all the options others have tried before I decide how I’m going to make the first XPS blank.  Thanks!

For reference, so we are all working from the same page.  Here is the information I have picked up about XPS foams over the past few years:


psi = pounds per square inch (compressive strength)

pcf = pounds per cubic foot (density)

Dow “Blue Foam” (XPS):

STYROFOAM™ High Load 100 – 100 psi min. compressive strength (density, 3.0 pcf)

STYROFOAM™ High Load 60 = 60 psi min. compressive strength (density, 2.2 pcf)

STYROFOAM™ High Load 40 – 40 psi min. compressive strength (density, 1.8 pcf)

STYROFOAM™ Brand Square Edge Insulation – 25 psi (density, 1.6 pcf)


STYROFOAM™ Brand Square Edge Insulation (U.S. Only)

STYROFOAM™ Brand Residential Sheathing (RS) – 15 psi (1.3 pcf)


Dow Blue Foam Densities (Dow Building & Construction Answer Center)



Owens-Corning “Pink Foam” (XPS also):

Foamular 1000 – 100 psi, 3.0 pcf density


Foamular 600 – 60 psi, 2.2 pcf density


Foamular 400 – 40 psi, 1.8 pcf density


Foamular 250 – 25 psi, 1.55 pcf density


Foamular 150 – 15 psi,  1.3 pcf



XPS & EPS Foams

Dow Blue Foam (“Styrofoam”) and Owens-Corning Pink Foam (Foamular) are extruded polystyrene (XPS).  XPS is a closed-cell polystyrene foam that is not porous (made light by injecting a blowing agent during polystyrene extrusion, that causes small bubbles to form in the polystyrene as it comes out of the extrusion die) and therefore does not absorb water.  Resin does not adhere well because the foam is not porous (less surface area for bonding because there are no connecting passages, open spaces, between cells) and some gas is released from the cells when they are ruptured.  Some surfboard builders claim good success glassing XPS after the shaped core (final) is scored/roughed with 20-50 grit sandpaper (IMO the lower grit would be better).

EPS foam is expanded polystyrene.  EPS is made by heat fusing polystyrene beads. There are air spaces between beads, which means it will soak up water, but epoxy resin bonds well to it in the 2.0-2.5 pcf densities.  It can be found in 1.0-3.0 pcf densities.  The 2.0-2.5 pcf densities are commonly used for surfboard cores.

Read the following link for a good discussion about EPS and a brief discussion of XPS foams:



BG, you’ve gotten some good advice here telling you to pass on the XTS. But I understand that you want to experiment. So here is my tip. Use epoxy for the glue and use one of those little 2 inch rollers to apply it in a very thin coat. The hot wire will cut it just fine. Be sure and rough up the mating surfaces of the foam before you glue with with epoxy. It will not bond well to the smooth or hot wired surface. Like oneula said, other glues don’t hold well enough to hold the shape.

You better post some pics. Ok?