polystyrene

hansel · January 8, 2008, 9:49pm

i have a mass amount of polystyrene, and was wondering if i can use it for a blank? i was going to put a bamboo stringer, and was going to make it around 6’2" x 24" x 4". the only thing i was worrying about was that i don’t know if the density of the foam would effect the performance and the strength of the board. let me know!

Colin-

Rikds · January 8, 2008, 9:54pm

Strength should be all in the skins. Thickness will affect stiffness. Density affects how high it floats. Go ahead, use it. See the posts, go stringerless, high density foam or wooden rails.

JUST USE EPOXY!!

hans · January 8, 2008, 10:05pm

density has more influence!

density gives resistance to pressure denting. And with stonger (denser) foam the laminate will resist better to pressure.

Try to find out what density your foam is. Weigh and calculate it. If it’s less than 25kg/m² then you have to make a compsand.

And like said, use epoxy!

hansel · January 9, 2008, 2:08am

ive contacted mike Becker, of natures shaped out here on long island, and he said that it shuld be alright, but i shuld check if it produces gas? ive herd of this happening but how would i test it, im making a sample piece but how will i know if it dose actually produce gas? ive always used epoxy resin (resin research) and, what do you mean by compsand? and how would i calculate the density of the foam? thanks alot for the help!

Colin-

tridrles · January 9, 2008, 3:03am

EPS (polystyrene) should have beads in it that you can see and (I don’t think) won’t gas.

XPS is blue or pink and is smooth consistant texture like Pu. it gasses.

Compsand - Composite Sandwich - foam inside (usually light weight… I use 1 pound density) then a layer of glass, balsa (or other wood/high density foam/cardboard) then top it off with another layer of glass.

________ glass 

________ Balsa 

________ glass 

________ 

    Foam 

________ glass 

________ balsa 

________ glass

I just gave a class/demo on how I make my Balsa CompSand boards. I have a video available in the SwayStore:

http://www.swaylocks.com/cgi/surfshop/page.cgi?g=Detailed/2428.html&d=1

Density of the foam? Cut a piece 2"x6"x6" and weigh it, I’ll do the same on my 1 and 2 pound and we’ll compare.

Les

surfteach · January 9, 2008, 4:31am

EPS is measured in pounds per cubic foot here

in the US. An easy way to calculate weight is to

cut a cube that is one inch on each side, weigh it

which will usually be in grams, multiply by 144 (the

number of cubic inches in a cubic foot) and

translate into pounds. 1 gram = 0.0022 lbs.

Just remember that EPS blank weights are calculated

from the pre-expanded material (non-molded) and

so a 2 lb. molded blank/block may be as light as 1.5 lbs!

I wouldn’t worry too much unless the foam you

are using is around 1 pound density. You can always

and more layers of cloth (within reason) if the foam is

a little light.

Extruded foam that is made from polystyrene can also

be white (XPS) and does gas. I just saw an XPS Merrick

Black Beauty that was made of XPS and had small holes

drilled in the board to help with outgassing. It also had

a temperature sticker on the board so you would know the

exposure range and not leave it in the sun/hot car, etc.

Rikds · January 9, 2008, 8:28am

Hi, like the idea of a compsand video. Have read all the posts and made some preliminary experiments but all info is useful…Is the DVD playable in Europe or is it USA only?

Cheers

Rik

tridrles · January 9, 2008, 9:00pm

I’ve checked the program that I used to edit the video and can’t find anything on changing the format.

PAL is for Europe and NTSC is for US and a few others. I’m a home do-it-yourselfer… if anyone out there knows how I can change the format in coping my video I would (and Rikds) like to know how to do it.

If it helps…I used a panasonic camcorder (H18) and the software was Nero and Adobe Premier Elements 3.0

Les

hansel · January 9, 2008, 9:13pm

hey,

ive been looking around, and its actually not the foam used, and i refuse to pay 290$ for a 6’2" blank, so i found this site. is this the type of foam needed? it looks like it but what do i know =) heres a link for the dealer, let me know. colin-

http://www.r-control.com/eps.asp

Keen · January 9, 2008, 10:05pm

The website you posted is eps. It is the “right” foam. I think your best bet to find out the density is to call up the supplier, or whoever you bought it from. Did you drive up to RI to buy that stuff? I ask because I am looking for a source of eps in the NYC area.

hansel · January 9, 2008, 10:23pm

keen,

no i e-mailed them, i shuld get a reply tomorrow, ill check out the density and price, i feel your pain, the only place to really get blanks is from California, and for some reason shipping is like 200 bucks, but to nj its like 100.

Colin-

sharkcountry · January 9, 2008, 10:54pm

Hi Les, I don’t use Premier Elements, but see if you can export a movie of the whole timeline as a PAL movie. There may be options in the settings that allow you to chose the type of movie and all the parameters. I’ve done it with Premier Pro.

I don’t know about recording it to disk though. You’ll need to make the file small enough to fit on a DVD-R disk or create a PAL DVD. I haven’t done a PAL DVD yet.

I hope you’re all doing OK and have a great 2008!!