Contact   Imprint   Advertising   Guidelines

Closed cell foam blanks and rocker

Here you can exchange your experience and datas about your home build boards
merl
Frequent Poster
Posts: 401
Joined: Tue May 15, 2007 8:43 pm
Kiting since: 1999
Gear: Mixed, flysurfer peak, concept air pulsion, wave & firefly, various LEIs. Mostly HF these days.
Brand Affiliation: None
Location: Sweden
Has thanked: 56 times
Been thanked: 29 times

Re: Closed cell foam blanks and rocker

Postby merl » Fri Mar 13, 2020 2:39 pm

UK has some green stuff at 75Kg/M^3 which is cheap.

https://www.easycomposites.co.uk/#!/cor ... -core.html

But where should one buy in EU next year when we probably have to pay import duty for UK goods?

User avatar
Leelanau
Rare Poster
Posts: 13
Joined: Thu Jul 27, 2017 9:42 pm
Kiting since: 2016
Local Beach: Good Harbor, Frankfort
Gear: LF Thruster and Moses 101/637/420 foils on a variety of home-built boards.
Brand Affiliation: None
Has thanked: 6 times
Been thanked: 2 times

Re: Closed cell foam blanks and rocker

Postby Leelanau » Fri Mar 13, 2020 3:22 pm

I've built a few boards from 1/2" divinycell H80 and never had an issue with spring back. Two were built with 2 layers of 1/2" (12mm) for total thickness of 1". Just vacuum-bagged the 2 sheets together with thickened (& tinted) epoxy on the rocker table. I have a large vinyl bag and the foam and rocker form all go inside it. The blank is still quite flexible before carbon lamination, it but holds the shape very well. (I found that tinting the resin makes it easy to see the seam, which aids in sanding down the rails as I end up taking them down to about 1/2" thickness.) Other boards were just a single layer of foam with 1/8" (3mm) wood skins. So with multiple layer cores, it's no problem. But even with just a single layer, if you laminate just a single side while on the rocker table, it should hold it's shape very well. 4" (10cm) of rocker over maybe 12-15" of nose, isn't that much to ask of closed cell foam.
These users thanked the author Leelanau for the post:
RichR2 (Fri Mar 13, 2020 4:00 pm)
Rating: 8.33%

RichR2
Medium Poster
Posts: 96
Joined: Thu Aug 10, 2017 12:29 pm
Kiting since: 2000
Gear: Airush Ultra 10m, 8m
Airush Wave 6m
Solo 4,5m
Shinn K2 foil
125cm RR custom
Brand Affiliation: None
Has thanked: 5 times
Been thanked: 7 times

Re: Closed cell foam blanks and rocker

Postby RichR2 » Fri Mar 13, 2020 4:00 pm

Leelanau wrote:
Fri Mar 13, 2020 3:22 pm
I've built a few boards from 1/2" divinycell H80 and never had an issue with spring back. Two were built with 2 layers of 1/2" (12mm) for total thickness of 1". Just vacuum-bagged the 2 sheets together with thickened (& tinted) epoxy on the rocker table. I have a large vinyl bag and the foam and rocker form all go inside it. The blank is still quite flexible before carbon lamination, it but holds the shape very well. (I found that tinting the resin makes it easy to see the seam, which aids in sanding down the rails as I end up taking them down to about 1/2" thickness.) Other boards were just a single layer of foam with 1/8" (3mm) wood skins. So with multiple layer cores, it's no problem. But even with just a single layer, if you laminate just a single side while on the rocker table, it should hold it's shape very well. 4" (10cm) of rocker over maybe 12-15" of nose, isn't that much to ask of closed cell foam.
That's pretty much the approach I was going to take, so it's good to know that it will keep the rocker set from laminating the first side. I wasnt keen on the idea of just guessing how much extra rocker to add. Thanks for all the advice
These users thanked the author RichR2 for the post:
merl (Fri Mar 13, 2020 7:51 pm)
Rating: 8.33%

BWD
Very Frequent Poster
Posts: 3728
Joined: Thu Jun 05, 2003 3:37 am
Has thanked: 1 time
Been thanked: 53 times

Re: Closed cell foam blanks and rocker

Postby BWD » Sat Mar 14, 2020 1:32 am

shrinkage
Is a cold water phenomenon. :o
In hot water, Corecell A500 will swell a little, maybe 2-5%. Don’t know about others.

RichR2
Medium Poster
Posts: 96
Joined: Thu Aug 10, 2017 12:29 pm
Kiting since: 2000
Gear: Airush Ultra 10m, 8m
Airush Wave 6m
Solo 4,5m
Shinn K2 foil
125cm RR custom
Brand Affiliation: None
Has thanked: 5 times
Been thanked: 7 times

Re: Closed cell foam blanks and rocker

Postby RichR2 » Sat Mar 14, 2020 8:52 am


Go 3.35mins in
When I was researching heat bending PVC closed cell foam I came across this, that's the shrinkage I was referring to, not that caused by expansion (hot) and contraction (cold).


Return to “Gear Builders”

Who is online

Users browsing this forum: No registered users and 1 guest