Can I use ertruded polystyrene foam as the core for a Composite board. The foam does not seem to be as flexible..... Any other issue..... have any of tried it.
keep well
Grant
Depending on density it might be too stiff. I’ve used 2# xps on rails of compsand and that works well. But generally use 0.75# eps for most of the core.
A while back one of the compsand experts said that because of the poor shear strength, XPS wasn't good for compsands. However I recently did a ding repair on a Santa Cruz that sure looked like XPS under a wood veneer and a shitload of paint. love riding my XPS boards but have not tried a compsand with it.
The guy who started Compsand surfboards and who’s patents we’ve all be ripping off uses XPS foam because it does not absorb water. I’ve used it before and still use a combination of XPS and EPS. The exterior skin of the compsand board is where the strength is, not the core. This is where it all started, we all owe Gary Young a lot of respect for figuring out how to do this.
get a small 6-8" long piece of eps hold it in one hand and flick your finger on the end with your other hand
now do the same with some blue dow XPS
hold the piece of EPS under a running facet and watch how the water runs off the surface
now do the same with the piece of XPS
this should answer allot of your questions.
XPS has a very lively memory but like stressed carbon fiber it fails catastrophically when it does
the 1/8" or 1/16" wood shell of a compsand helps keep that in check but its not needed if you want to keep the weight down as XPS is denser(this heavier) than EPS
plus it shapes “like butah” as my brother says.
reminds me of mowing thru a creamcycle
seems like you can beat the new molded eps blanks or the hotwired block cut ones for ease of use.
also a PU blank and UV reason is the easiest
Swifto, Ive only made a dozen or so boards with XPS and someone hear told me to sand the surface with 120 grit to ensure a good mechanical bond with the resin. I use 2 oz under and over the veneer and bag it. This one is hollow with internal supports and veneer between thin XPS layers.
Small grain for easy shaping, Mega stiff but snaps like a cannons gone off !
OK XPS is not ideal but will certainly work is what it looks from the responses above. One of the qualities is that it is not as flexable as EPS. so do I cut the rocker or can I bend it. or a combo of both.
Cheers
Grant
Ooh Cynthia, tell me more !!??
"....holy foam ban , batman ! ..."
if they ban their foam love .... will the next thing for New York Surfers be a ban on their rubberlove ??
"...tune in next week , same bat time , same bat channel ! "