More questions on building/shaping with xps

General Discussion
1

I know there have been many posts concerning the use of “bluefoam” extruded polystyrene, but after doing a search and reading many posts, I’m still confussed with the results. I work for an independant lumber yard (not Lowes or Home Depot), and we’ve got stacks of this stuff in all different dimensions, 2’ x 8’, 4’ x 8’ (I think maybe even 4’ x 10’), in thicknesses from 1" up to 4". We’ve got “blue” and “pink”. I can get tons of this stuff really cheap. I’m not sure off hand of the brand of this stuff, or the chemicals in it. Is this the stuff that everyone says has problems with delam and yellowing? Wouldn’t using a UV epoxy stop the yellowing? I want to try this stuff in a composite sandwhich/vacuum bagged board. And if this xps was used only as a core and balsa or d-cell was lamed over it for the bottom and deck would I have a problem with gassing? I’ll try to find more info on this stuff (including weight and tensile strength) tomorrow at work. Again, sorry if I’m repeating past posts, but like I said, I did a search and still never found any definative answers. If anyone has experience with this stuff in a composite sandwhich board, I’d really apreciate any tips. Thanks.

J.D.

Ua ola no i ka pane a ke aloha.
"There is life in a kindly reply."
2

it works for home made personal craft

rides better than EPS in my opinion

protect it from crushing damage(with decent skins)

and keep it out of the sun

shapes better than PU

leave it rough and fluffy before glassing (60 grit)

again don’t make a business out of selling these

and you should be fine…

3

Oneula, thanks, I just found a past post “Roll Call on XPS”. That’s pretty much the concensus. Mr. Burger seems to hate the stuff and says sheer strength is terrible. Well, dang. Guess I’ll see if I can det some EPS from one of our suppliers (Just wondering about the XPS 'cause I can get damaged pieces; i.e. bunged-up corners and such, for only a few bucks a sheet). Any tips on types of EPS? It seems that 3/4# and 1# are the most common.

Thanks,

J.D.

Ua ola no i ka pane a ke aloha.
"There is life in a kindly reply."
4

Oneula’s post is pretty spot on.

I have made many boards from the Blue XPS - Dow chemical. The White is from Corning (XTR).

About two years ago I made a board with a combination of XPS and EPS in a sandwich style construction using a vacuum bag. The deck was EPS and the bottom was XPS. I gave the board to a Team Rider who just love the board. The EPS dented like crazy and the XPS was un touched. I will make another one only this time I will use the XPS for the deck and the EPS for the bottom. I did use impact cloth and the board weighed in at 4.1 pounds (72" x 18.38" x 2.175").

Sea Ray Boats uses it in their hulls. The White is used by XTR. They put docking holes for venting. My warehouse is still full of XPS Blue blanks and I still have Whole billets of (8’ x 24" x 5.5"). Once you cut out your blanks you bend them to fit your rocker while performing your glue up. The yeild is normally two blanks per billet unless your making a thick one for a big guy? After the Clark shut down I bought 2 full truck loads of the stuff and starting making blanks. It took off pretty well until all the cheap PU was available. Surfers in general will go with the lowest cost possible. However I still think that if you do it right XPS has a lot of qualities. Used as a core under a veneer will give you a board that would not only ride unreal but last a lot longer than PU - Polyester would. The XPS has memory. They feel alive for a long time. Whereas PU feels great the first couple of months then it’s time for a fresh one. This is good for us board builders because it keeps us shaping …

5
Quote:

Oneula, thanks, I just found a past post “Roll Call on XPS”. That’s pretty much the concensus. Mr. Burger seems to hate the stuff and says sheer strength is terrible. Well, dang. Guess I’ll see if I can det some EPS from one of our suppliers (Just wondering about the XPS 'cause I can get damaged pieces; i.e. bunged-up corners and such, for only a few bucks a sheet). Any tips on types of EPS? It seems that 3/4# and 1# are the most common.

Bert’s right blue dow will bend and bend to a point and then fail big time like carbonfiber

But blue dow will take a slight bend and snap back to its position much faster and more consistantly than EPS any day even better than PU.

Blue dow has timbre when you tap on it EPS has a dull thud.

If you can get Blue or Pink Dow XPS for free or really cheap

why not get some and play around with the stuff

it’s easier to work with with standard handshaping tools than EPS

although the blue balloons seem the be more magnetic to humans

If I could get super cheap($2/sheet) blue XPS I’m play with it all day long versus spending ten times the cost for a similar sheet of EPS. EPS isn’t going to get you ten times the value.

If you have to pay a much higher price for the EPS foam sheets

you might as well not waste your time fooling around with flat sheets and buy a molded EPS surfboard blank from Marko, American, US Blanks etc etc instead. It’ll get you to a better finished product alot faster.

6

Blue beads with xps?? The blue Dow extruded poly styrene blocks I’ve worked with don’t have beads, the texture is like a low density pu. I’m working thru the last block of the stuff now, probably won’t use it anymore.

7

Sorry I should’ve said blue dust

in any case it seem more sensitive to static electricity

being that it’s supposed have teflon in it you’d think it’d all just fall on the floor like nice non-congregating teflon particles should…

Anyone other than Surfding and I notice that they seem to ride better than EPS…

or am I hallucinating again…

8

I just found out today that we are discontinuing the blue “styrofaom” brand stuff and bringing in Insulfoam EPS to replace it, it’s foil backed though. Is anyone familiar with this brand or material, I called Insulfoam and I can get the “non-foiled” stuff. If this is an acceptable material (better than the blue), I can get as many or as few sheets as I want shipped to my store with the next truck of our foil-backed stuff. I don’t know if the insulfoam brand is comparable to Marko foam or the others, and of coarse it will come in sheets rather than blocks, but as I plan to build a composite on a rocker this shouldn’t matter right? The sample of EPS we were sent from Insulfoam was 3 1/2" thick, so I guess I could hotwire off the foil backing. Also, Insulfoam claims that their EPS sucks less water than other XPS. That is why we are switching. Suppossedly our builders were complaining about the water resistance of XPS! Could this be true? Or is it only due to the foil-backing? Hmmm…

Anyway, it looks like I can get the blue stuff REALLY cheap now since we’ll be pushing the new Insulfoam. So I’ll probably pick up a few sheets just to mess with it. If anyone has any info on the Insulfoam brand EPS, if it is a suitable material, etc. please let us know. I could get that cheap too. This will be the first composite board I’ve built, the others were from blanks. But this time I’d like to do the whole thing myself from scratch, if for no other reason than to satisfy my ego. Thanks in advance for any tips or advice.

J.D.

Ua ola no i ka pane a ke aloha.
There is life in a kindly reply.
9

Insulfoam is the same stuff the big block companies sell to folks who cut their own blanks like American.

It comes in multiple densities but the stuff most likely to go for home insulation is .75-1.0 pound stuff.

You can make boards from it but it’s lower quality than the stuff sold to blank makers which is why its cheaper.

$15-$35 is the usual price range for 1"-2" thick panels at Lowes or HomeDepot

2" blue dow usually runs $45-$55 a panel and it’s supposidly being discontinued and hard to get

Blue Dow is a better insulator for both temp and sound than EPS so it’s unusual that it doesn’t have a market wall and roof insulation.

Build a hotwire table ripper wire stretched tight 1/2" above the table and slice out 1/2" thick sheets of insulfoam EPS from 1" panels.Make a blue down blank, preshape it with your hot wire about a half inch smaller than needed and then cover the deck in the 1/2" EPS before finish shaping. Seal and glass heavy like you would a standard 1lb EPS core. do the same will a 100% EPS blank and then check the ride out.

Report back here when done.

Various bent flat sheet Blue Dow & Insulfoam EPS Experiments to show you it is possible

Personal Use Only not for sale



10

I have to 2nd Oneula’s opinion that the blue xps is my favorite type of board to ride. has a much livlier feel than pu or eps. I’m not a huge fan of working with it as it tears and dents easily. I posted one of mine not long ago. had it for a year now and no yellowing (sytem 3 SB112 epoxy) and just had my first small delam (lent it to a friend who left it on the beach all day in 30C weather). I buy the dock floats about 10 " thick and can get 3 boards out of one.

Wouter has made some really nice boards out of it if you search for some of his posts.

cheers

11

Man, those are beautiful. You give me hope that I can build something good with the materials I have easy access to. I only hope that someday I can build something close to those. Thanks for the inspiration and thanks for the tips. It’s the coolest thing that you guys here at Swaylocks are so patient with us novices and are so willing to share your hard earned experience with us. Much Respect.

J.D.

`A`ohe lokomaika`i i nele i ke pâna`i.
"No kind deed has ever lacked its reward."
12

I was talking to a local guy about this stuff…I’m about to pick some billets up from surfding and want to use

XPS in a dual density blank setup.

The dude says that the stuff is a nightmare when it comes to delam.

I’ve seen this alluded to elsewhere, but I’m curious if anyone has any specifics around XPS’ propensity to delam

and ways to get around it…is that tip to rough it up with 60g the trick?

13

Just ask SurfDing about it

why does he have the billets in the first place?

They make good boards

but they will delam if not taken care of

if you are making a high density railed perimeter stringered composite

go back and read Bert’s 2004 post then ask yourself

just what the hell is the core for in those things.

60 grit or lower is perfect

but if you’re securely binding your deck and bottom skins to your perimeter stringer and or HD rails

then who the hell cares if the core delams or not

cause its still serving its purpose providing structural support

This is way different thinking

than if you were just glassing the outside of the blue and using it like that

but roughed up the blue even works well that way too

before you shape it

take your finger and flick tap it in the center against the blue blank and listen

then go do the same with an EPS blank

and the same with a PU blank

the intonations and resonance

should tell you everything you need to know why blue makes sense as a composite core.

then takes some pieces and soak them in water

that’ll show you another reason

if you figure out the glassing puzzle

you can’t go wrong

just my take

I’m not a professional

so I wouldn’t plan on making a retail business out of blue boards

14

Your right on!

I have some left and I think I will just keep them.

Swaylockians seem to be afraid of XPS?

They do ride unreal so I will make myself a few.

60 grit and your good to go!