Blank.. XPS or EPS?

EFOIL.builders Builds
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I’m about to start making a blank for my 2nd build (jetboard).

Now a lot of people suggest to use XPS instead of EPS as XPS is harder and the cells are closed.
But. a lot of people are also suggesting to use EPS as XPS seems to delaminate really easy.

Also. The plan is to build the blank like so (with vacuum bag) :

However some days ago a person here ( @Restless ) showed me another way of doing this. (Carbon fiber and no vacuum bag):

I do not have any experience with CF, however I think that CF is the same as glass.

What do you guys think?
XPS?? EPS??? Vacuum bagging or not??? Glass or CF??

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I’m going to be building one soon with higher density eps, but I’ve heard people using either for boards.

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XPS is crap to shape and relatively heavy. You can laminate straight over 28kgM2 EPS and it will be strong enough, exept for the standing area which will need a pvc sandwich to prevent heel dents.
Forget vacuum, not worth it. I use a 200gsm CF twill under a 200-300gsm plain weave s glass. Look for one that drapes well. Not all of them do. I also sandwich a 200gsm CF under 3mm pvc core in the standing area.

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Sounds like a good plan!
EPS it will be!

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Pink panther XPS can be shaped, but as @michion says, it’s difficult and easy to mess up. I use it to build plugs for parts - it’s readily available and cheap at hardware stores in the US.

Regarding vacuum bagging, it is definitely useful for more complex shapes / parts and for building long lasting plugs / molds. Wet layup with a vacuum assist, infusion, & vacuum bagging in the oven with prepreg are a core part of my building process. It does add complications and costs…

Composite Envisions has a great selection of vacuum bag materials. A decent, cheap pump is readily available from Amazon. @virus YouTube channel is a go-to for knowledge on that process.

In the US, it’s hard to find the EPS. FGCI is pretty good and has this EPS blank.

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look into greenlight surf supply eps foam blanks

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I do not think that they will have a blank that I will be needing for my jetboard!

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You can order any size for eps , they have a guide on how to request any thickness , rocker etc. if you contact them you can prob buy just a solid block of foam

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Thank you for the info.
As I’m in Europe, I do not think shipping will be cheap.
Also. I am going to give this DIY’ing a blank myself a go. If it’s a big fail I will try again and again. :slight_smile:

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Local concrete supply store had some higher density stuff. Just brought this home today… Hopefully get the cnc cutting it next week.

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Also @Wade told me about buying foam from sign shops. Apparently they typically stock thick pieces of EPS.

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Does anyone have a recommendation for 1.5 or 2 pcf EPS construction foam? I can get a full sheet of 5" thick material in either density. Is it worthwhile using the 1.5 pcf and save some 1.5 pounds of weight, or is the extra strength worth it? I am planning to use a 6-8 pcf insert 1" thick for the foil mount, and 2 layer patches on the bottom, 3 layers in battery box 6 pound cf twill. Top and bottom 6 pound cf 2x2 twill and 6 pound glass.