I have a new idea
At home I have enough XPS for 2 boards (I’ve already made 2 with that and 1 in EPS sandwish)
My idea is to make a deck sandwich on XPS to prevent delamination caused by pressure denting (pressure denting creates an overpressure under the deck laminate and makes the board delaminating).
Will this work? Will I need a stringer?
Is 4oz top, 4oz bottom and 2oz under sandwich enough?
The XPS is 38kg/m³
Hans
*edited because text disappeared
Does nobody has a meaning about this?
plz, tell me what you think.
Hey Hans,
Will this work?
Not enough info so it depends. It will work ‘better’ than without a cored skin.
Will I need a stringer?
Not enough info so again it depends. Small medium surf, proly ok…bigger more powerful surf proly not ok.
4 & 4 top…4 bottom is weak…better double up.
good idea ,worth a try
except for the xps
not that ive used it,but ive heard plenty of bad things
This idea is meant to eliminate the bad things of XPS 
XPS has his bad things but it’s really a pleasure to shape it! It is strong and it does not absorb water. Now I wanna try to eliminate the top delamination with the deck sandwich and make a durable board of it.
i recomend u try 2 pound eps
it shapes well and wont suck water
i wouldnt recomend xps for sandwhich construction.
its not used in other industrys for good reasons
as the foam retains it pentane gas which release when the foam is heated or damaged
although i believe they use it in sailboards
although i thought it might have some potential for finbox reinforcement
i guess that the possibility of water intrusion is the price you pay for outstanding performance
and superlight wieghts
btw. in the unlikey event of a ding on a balsa/foam skined epoxy
a quick fix with 5 min epoxy and your surfing ten minutes later
no surf shop wankas or 50 bills for a two minute ding repair
i have small sandthough on and olderboard and i covered it with 5 min epoxy and a bit of cloth
so i could surf it that day
still sweet after 6 months
In sailboards they use EPS/sandwich
But I have XPS at home and I don’t want to throw it away. I want to use it in a relatively good way.
So I thaught, with a deck sandwich the delamination will be much less.
In the boards I’ll make afterwards I’ll surely use EPS! But I want to use that XPS in a “good” way.
I think I will give it a try, we will see.
In july I’ll start working on it