Pocket board building

[BalsaMichel]

How do you get rocker with a 15 mm B core QX ?

press with hydraulic car lifters helps here a bit to get this into shape. The plan is to mill the core down to 7mm in the front tip section where the most rocker is, starting from the split in the center of the board. Maybe there will be some springback.

Regards
Micha

[TomW]

How do you get rocker with a 15 mm B core QX ?

press with hydraulic car lifters helps here a bit to get this into shape. The plan is to mill the core down to 7mm in the front tip section where the most rocker is, starting from the split in the center of the board. Maybe there will be some springback.

Regards
Micha

Keep me updated on how that works.

[kollac]

calling all vacuum bag surfboard building ninjas - layup process question:

Suppose you want to build a quick prototype of a XPS foam core board because that's the material you have laying around right this moment. If the layup suggestion is 3 x 6oz glass top and bottom (has a stringer) as it was a few pages back - how do you apply those layers? Try to do top AND bottom at once, all layers together and then bag the whole banana? Do top separately from bottom, 3 layers each at a time or some other combination of steps (1 layer on 1 side at a time etc.?). Thanks!

[grandeand]

the vacuum if it pulls a lot can also crush the xps or deform it ...
for mine I did ...
first I laminated with 160 glass first fairing and then covered ...
I passed the 80-100 abrasive paper to scratch well the surface ...
then I laminated 2 layers of carbon 20o grams each and externally 100 glass to close ...
first the hull then the blanket ...
the table did not fold or crush ...

[tmcfarla]

calling all vacuum bag surfboard building ninjas - layup process question:

Suppose you want to build a quick prototype of a XPS foam core board because that's the material you have laying around right this moment. If the layup suggestion is 3 x 6oz glass top and bottom (has a stringer) as it was a few pages back - how do you apply those layers? Try to do top AND bottom at once, all layers together and then bag the whole banana? Do top separately from bottom, 3 layers each at a time or some other combination of steps (1 layer on 1 side at a time etc.?). Thanks!

I am decidedly not a vacuum bagging ninja, but tried it a couple times...

If it is your first time, I would definitely recommend doing the top and bottom in separate steps. Your epoxy is going to start curing, while wet fabric is falling off after you flip the board to get the other side of deck, while your vacuum isn’t sealing, while... you get it. Also, rails in vacuum bag are really tricky, especially if doing two sides at once- the bag wants to crease right at the rail and pull the fabric into a knife edge around the board, instead of overlapping. Other people seem to do alright, but mine came out horribly.

I would do two steps: first all layers of top, then all layers of bottom. Allow epoxy to harden, but not fully cure between steps.

Honestly, for my next board I’ll probably trim carbon down to just before the rails, vacuum bag that, and then wrap rails with a layer of fiberglass by hand. Most of it was fun, but I really didn’t enjoy doing the rails...

[kollac]

I am decidedly not a vacuum bagging ninja, but tried it a couple times...

If it is your first time, I would definitely recommend doing the top and bottom in separate steps. Your epoxy is going to start curing, while wet fabric is falling off after you flip the board to get the other side of deck, while your vacuum isn’t sealing, while... you get it. Also, rails in vacuum bag are really tricky, especially if doing two sides at once- the bag wants to crease right at the rail and pull the fabric into a knife edge around the board, instead of overlapping. Other people seem to do alright, but mine came out horribly.

I would do two steps: first all layers of top, then all layers of bottom. Allow epoxy to harden, but not fully cure between steps.

Honestly, for my next board I’ll probably trim carbon down to just before the rails, vacuum bag that, and then wrap rails with a layer of fiberglass by hand. Most of it was fun, but I really didn’t enjoy doing the rails...

Good info - appreciate it. First time with vacuum, not the first time with glass and epoxy so I'm fairly comfortable with that piece. I'll be conservative with the first (few). Maybe I'll go wild west later

[downunder]

What is your target with a vac?

B/c you'll not squeeze enough Epoxy to make the laminate lighter. Sure, if using >200g carbon fabric it might help to make it flat. But only if less vac is used, not full, or you risk more then profit from the vac.

It's quite a risk with XPS, maybe try wrapping it first with some light glass, like 100-120g.

D.

[handy]

XPS is no problem for vac bagging, same as EPS with 30kg/m3 and over, I pull foams like that with -0.9 bar.
when using EPS with 20kg/m3 or less you have to go down with your vacuum to -0.6bar, otherwise your board will be thin as a pancake.
and yes for sure glass first the bottom and lap the rails and then deck and lap the rails again.
and if you are afraid that your resin will kick to fast, put it in fridge first

[kollac]

What is your target with a vac?

B/c you'll not squeeze enough Epoxy to make the laminate lighter. Sure, if using >200g carbon fabric it might help to make it flat. But only if less vac is used, not full, or you risk more then profit from the vac.

It's quite a risk with XPS, maybe try wrapping it first with some light glass, like 100-120g.

D.

honestly, just playing. I built a venturi based vacuum generator this winter. Other than resin and inserts everything else is leftovers (foam, glass, stringer). Since I'm home all day every day (but working, luckily/unfortunately), I'm itching to build something "extra".

[thewindego]

Have a look at this video. Without vacuum you can do really nice layup using this technique.