Author Topic: Divinycell PVC Foam Block  (Read 1041 times)

SanoSlatchSup

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Divinycell PVC Foam Block
« on: May 15, 2019, 11:54:07 AM »
After Googling whatever I could think of to find where I can purchase a Divinycell foam block that folks are using to install track boxes in, and all I've been able to find are sheets of it, and nothing in the block form I'm looking for, and that I know is out there...somewhere.  :(

I know someone here knows where to order it from (or go pick it up in SoOC CA even better), and any help y'all can offer would be much appreciated. Thanks in advance.
Me: 6'1"/200...5'11" & 6'0" Chelu Foil Boards...9'6" Bob Pearson "Laird Noserider"...9'6" Costa Azul Wide Body...14' Lahui Kai "Manta"...8'0" WaveStorm for when proning urges still hit, and 7'3" Chuck Glynn foil board backup.

Dwight (DW)

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Re: Divinycell PVC Foam Block
« Reply #1 on: May 15, 2019, 12:22:39 PM »
Supply houses that also serve the boat building industry stock full sheets for pickup. Otherwise guys are using two part pour foam.

Sometimes you can get lucky and have sheets cut up for shipping.

It’s no problem buying full sheets in Florida. Big boat industry.

SanoSlatchSup

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Re: Divinycell PVC Foam Block
« Reply #2 on: May 15, 2019, 02:02:05 PM »
Thanks Dwight, for some reason from looking at Robert's "Strongbox", and Dave Daum's "KingTut" box I was under the impression that they were starting out with a much thicker piece of material/block than the 1" thick sheets that were the thickest I was finding.

Me: 6'1"/200...5'11" & 6'0" Chelu Foil Boards...9'6" Bob Pearson "Laird Noserider"...9'6" Costa Azul Wide Body...14' Lahui Kai "Manta"...8'0" WaveStorm for when proning urges still hit, and 7'3" Chuck Glynn foil board backup.

Dwight (DW)

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Re: Divinycell PVC Foam Block
« Reply #3 on: May 15, 2019, 03:04:47 PM »
2” is the thickest we have locally.

blackeye

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Re: Divinycell PVC Foam Block
« Reply #4 on: May 15, 2019, 08:31:36 PM »
The sheets I have show that they are glued from strips. Its no big deal to get a partial sheet, cut and glue your own block.

I'm with you though - there doesn't seem to be a an online source in NA that is economical. http://www.fiberglasssupply.com/ seems to be a USA retail supplier.

I've tried to get scraps from boat shops, but the stuff is expensive and as a result they use every little bit. It is used in construction so it would be interesting to find a construction site that is disposing of scrap. It may not be the same quality though. Probably is but "marine use" is slapped on it to raise its value.

Beasho

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Re: Divinycell PVC Foam Block
« Reply #5 on: May 16, 2019, 06:42:43 AM »
Guys.

We need help.  I have not been a fan of the dual track system.

Here is the latest from another foiler.  The whole high density casette, with 2 tracks only, just broke in half.

This has happened on 3 of these boards now.  The bottom all delaminates.  Peel back the skin and it looks like this.  Horror!  :o

DW - You must have seen this and addressed a fix?  I am leaning towards ONLY TUTTLE BOXES at this stage.
« Last Edit: May 16, 2019, 06:44:14 AM by Beasho »

surfsupla

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Re: Divinycell PVC Foam Block
« Reply #6 on: May 16, 2019, 06:57:25 AM »
What kind of board and blank was that?!

TallDude

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Re: Divinycell PVC Foam Block
« Reply #7 on: May 16, 2019, 09:02:52 AM »
The delam was the beginning of the end. The way I see it, looks like not much lap on the moldy end. That got stressed and lifted (delam'd). Water started getting in. Enough time passed to develop mold, then it just pealed. I'm thinking increase the width and length of the high density foam insert. Then increase the lap and use a couple of layers of heavier 9 oz CF patch. My guess???

Bean

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Re: Divinycell PVC Foam Block
« Reply #8 on: May 16, 2019, 11:46:26 AM »
If the nylon/plastic fin boxes were bonded to both the top-deck glass and to the bottom glass it would be a bit stronger.  Each fin box could be wrapped and extended with FG or CF in order to connect with both the top and bottom skin.

SanoSlatchSup

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Re: Divinycell PVC Foam Block
« Reply #9 on: May 16, 2019, 11:54:14 AM »
Here's where we're going now with my board as a repair (not my actual board, but a drawing from a downloaded pic so the box widith proportions are off)...

....outside of boxes GG to the stringers that will now be set in into Divinycell to an inch or so below the boxes.

Previously we had glued the boxes onto the two stringers that were installed after the blank was shaped, and thus they were only partial thickness stringers that were not tied into the deck (entire board) and not the entire length of the board. After the above repair, the next thing we'll do is create a new blank for a new board that will have full length, and full thickness stringers, and then Divinycell between them so the inside of the boxes are setting in something more than 1 lb. foam. Hopefully will add the additional strength we're looking for.

NOTE: The partial thickness stringers were way stronger than I had expected, and had it not been for a full speed smack into the bottom two weeks after I got the board (where I was positive I would see the boxes torn out when I flipped the board over, only to find that they "looked" like nothing had happened to them at all :o)....I'm pretty sure that I'd not be making the repair I am now several months later when I found one of the boxes to be loose, and a small part of the bottom starting to delam.  :-\
« Last Edit: May 16, 2019, 11:58:46 AM by SanoSlatchSup »
Me: 6'1"/200...5'11" & 6'0" Chelu Foil Boards...9'6" Bob Pearson "Laird Noserider"...9'6" Costa Azul Wide Body...14' Lahui Kai "Manta"...8'0" WaveStorm for when proning urges still hit, and 7'3" Chuck Glynn foil board backup.

kiwi

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Re: Divinycell PVC Foam Block
« Reply #10 on: May 16, 2019, 01:19:52 PM »
Heres the plan for my next board, sure it takes away the ease of mast position change but tuttle cant move either, there could be large adjustment if u put another set 25-50mm behind or in front etc..

container

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Re: Divinycell PVC Foam Block
« Reply #11 on: May 16, 2019, 08:14:03 PM »
kiwi my shorty has a mount set up like that, 6mm i.d glass tube glassed to each end of a piece of 9mm ply and carbonated into the board. bulletproof and cheap

Beasho

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Re: Divinycell PVC Foam Block
« Reply #12 on: May 17, 2019, 06:23:06 AM »
If the nylon/plastic fin boxes were bonded to both the top-deck glass and to the bottom glass it would be a bit stronger.  Each fin box could be wrapped and extended with FG or CF in order to connect with both the top and bottom skin.

I am really SOUR on the dual tracks.   The theory was the plate would dissipate the load.  But I have seen and learned of many failures with dual tracks. 

The point was also made by this failure that the high density foam failed.  It cracked leaving a wobbling matrix in beer cooler foam.  SO whether or not the high density extends to the upper deck the twisting and crunching on 2 boxes 1 1/2" just isn't going to hold up.

The Tuttle solves this by serving as a carbon pillar extending between the 2 decks.  When my tuttles have failed they too have split the divinycel.  In all but ONE failure the divinycel has cracked.   Mmmmmmm are we on to something? 

The through bolt system looks like it could evolve into something functional.

Here is another example.  This board lasted 2 sessions.  With hindsight we can say "Really!"
« Last Edit: May 17, 2019, 06:28:01 AM by Beasho »

PonoBill

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Re: Divinycell PVC Foam Block
« Reply #13 on: May 17, 2019, 07:28:31 AM »
The divinycell can't do the job by itself. Any attachment system can fail and should fail when the forces get high enough, but how the rest of the board is built is equally important. Windsurfers used to blow out their mast tracks frequently as the sport progressed from sailing around slowly on 12-foot boards in protected water to working on forward flips at Ho'okipa. As Talldude said, this failure didn't start in the divy, it started in the deck reinforcement. It was broken for a substantial amount of time and finally, the divy failed.

Look at how short that reinforcement was on the leading edge of the patch, and it's exactly where it failed. The carbon patch was WAY too short. The major stress on that side of the installation is pulling up on the edge, and the very short patch made a stress riser--not only wouldn't it resist the force, but it multiplied the shearing force. No surprise there. Don't do that.

You're tossing the baby out with the bathwater. The last time I recall a mast track failing on a windsurfer was about 1990, and if one failed you wouldn't blame the design, you'd blame the manufacturer. Double skin sandwich construction and other more advanced systems meant the board would break in half before the track pulled out. The problem is not intrinsic to double tracks, which could and should actually have strength advantages over tuttle boxes, but in how they are being built.
« Last Edit: May 17, 2019, 07:41:53 AM by PonoBill »
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Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

TallDude

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Re: Divinycell PVC Foam Block
« Reply #14 on: May 17, 2019, 09:01:02 AM »
You might consider glassing the entire tail area (foil mount area) to the rails and fore and aft 6 inches with maybe 2 or 3 layers of 9 oz CF. Then install one of these retrofit type of base plates that increases the strength at the mast base and distributes the load across a larger surface area on the base of the board.
 
https://www.liquidsurfandsail.com/foil-mount-standard/?utm_source=google&utm_medium=cpc&adpos=1o1&scid=scplp4482&sc_intid=4482&gclid=Cj0KCQjwt_nmBRD0ARIsAJYs6o30foNPfplWGRRBq6dhNv6wh0AcC1F7PFG8T7ksYFs8-ijq6S18zuYaAgi9EALw_wcB


In addition, you could run some fiberglass tubes top to bottom. Drill holes through the foil-mount near the corners and run through-bolts. The top deck where the bolts come through would need to be reinforced as well. Maybe a poly-carbonate plate (as was mentioned) under the stomp pad.

Or just run the bolts through your foot strap, kind of like a foil leash in case it starts to break away ;D     



« Last Edit: May 17, 2019, 09:13:01 AM by TallDude »