hi!
I´m about to build my third foilboard in xps and due to the higher density it adds more weight to the final board than EPS. To reduce weight I was plaining with the idea of making a few chaneels of hollow interiar to get down to about the same weight as EPS or lower.
might be a stuped idea or it might not. I use xps because it is easier to get in right size where I live. no or no go? what is your opinion?
Hello Dun,
Welcome to the forum. You’d have to do the math (volume of foam removed x density of foam = reduction in weight) and see if it is worth it and decide if there will be a compromise in strength of the core, if it will need to vented, etc. I take it you have to add some even heavier HD foam to support the mast box/connection?
I made some ‘racing’ parts for a sailboat where I drilled out this and that and carbon fiber-ed this and that to remove weight and in the end I only saved maybe 2 oz (60g) and they were more of a pain to finish, but I do get to say they are made from ‘drillium’…
What is your XPS foam density?
yes I hear you! since the board is pretty thick. about 13cm at thickest parts there is a lot to be removed so on a good day i could maybe get down 1/3 of the total xps weight with is 30g/liter in density. epes i think is about 20g/L
will use a pvsfoam around the foilinserts and probablu not hollow board at that point. maybe do two channels in both side of the board
and thanks for the welcome!
20 g/L is not a foam density I would use for Surfcraft builds.
XPS needs some surface prep before glassing. Higher density insets for box installations would be helpful. What is the volume of your board design?
If your board was 60 liters volume the difference between one made with 20 g/l vs 30 g/l foam is 600 g.
i get it to be 650 g for a 65 liter board if i do my calculation right. 65 liter xps blank would be 1950g and 1/3 of it is 650g. not much but everything counts like Dave Gahan sings:)
I chambered a stringerless 8’ XPS board I made years ago. It is the only board I have ever broke in half. The break was where a chamber was. The board lasted several years, but it broke paddling out and I don’t recall getting hammered by the lip. One thing I did wrong was I didn’t stagger the holes, I did holes straight across several sections. It may have lasted longer if I staggered the holes. I really liked that board, but it was a good learning experience.
thansk for the input! I do not get what you mean with stagger the holes? my foilboard will probably be thincker than your longboard, but still you make a point. might not be worth the risk of breaking it.
I cut rockers slices then glue them up the smae way they make balsa boards. I made chambers like they do when they make Balsa boards, but I just drilled out holes across several pieces instead of staggering where the empty spaces would be. I think it is possible to cut out some of the foam. My impression is that foil boards don’t get the same pounding because they float on the wings.
yes you might be right and I will not do any jumping with it. only surf waves. I might give it a go anyway;)
