D-cell and vac bagging longboard Q's

General Discussion
1

Coupla questions:

Would like to try vacuum bagging in the near future, but have a few q’s for those who’ve done work with D-cell or D-cell in a longboard configuration. Eventually would like to go the balsa route, but for now I’m going with a more simplistic approach and using PVC foam and 1# EPS for the structure.

  1. How did you lay out the D-cell on a board that’s longer than the nominal sheet length of 8 ft.? Did you cut “planks” of D-cell and stagger them or just use a single butt joint, or otherwise? What about rails… what did you do there?

I’m leaning toward staggered planks for the deck/bottom, and thinner strips layered and staggered for the rails at this point, but any input will be helpful.

  1. With regard to the outer glassing of the board, do you seal the D-cell or laminate to unsealed D-cell? Having done a few tests with scrap pieces from another project, the foam just wants to suck a ton of resin. In using it as the outer skin layer of my sandwich board project, I’m somewhat concerned with weight, and also possible dry spots if I don’t seal it off prior to lamination.

I’ve been thru Bert’s thread a good number times, but didn’t see these points addressed.

Thanks in advance for any help!

Tom

2

Hi Tom. I did one. d-cell over 1#. I don’t like the way it surfs, but the good news is that I do know what’s wrong with it :slight_smile:

I hope I’ll hit most of your questions…

I put on 1/8" sheets for the deck & bottom sandwiches, and 2 pc. 1/2" d-cell (1" total) for the rails. I used butt joints, the bottom one towards the back end & the top one towards the front. No strength or creasing issues at all; no micro cracks in the glass…nothing to worry about there. The rail pieces each had a front & back joint, and I made sure none of those were within a foot of the top & bottom sheet joints.

I bagged on the bottom skin first, on a square but thicknessed & rockered blank. Then templated (2" smaller than intended finish size) and used the offcuts as clamps to add on the rail pieces while gluing with gorilla glue. The 1/2" bends well enough for most of the board, but nose & tail blocks helped fill in the curves. Then I glassed the bottom & wrapped the rails. After that, I bagged on the deck skin & then glassed over the whole thing.

I sealed the rails with epoxy/microballoon, but not enough. I did not seal the sheets & I should have. I ended up with a board that I have previously described as “All the stiffness of a Serftech and all the weight of a poly”. Not so good.

So I would recommend - go waaaaay thinner than you think. I usually surf 3 1/4" or so at 10’. This one ended up 3 3/8" because I thought I’d need a knee patch…wasn’t accurately accounting for adding the skins & glass…was scared of the 1#…I should have listend to Bert. This board would be better at 2 3/4" and probably 2 5/8" would work if you’re lighter than me (I’m 210 +/-).

Seal the bejezus out of the d-cell. I’d recommend epoxy & cabosil & make it THICK. D-cell does suck resin like its water draining into sand.

Use gorilla glue or similar where you can. It soaks in a lot less, is cheaper than epoxy, and bonds d-cell to d-cell and to EPS GREAT. Put a thin layer of glue on one side & spray the other side with water. Clamp together -it foams enough to push joints apart if they’re not held together well. It also shapes a lot easier than a line of cured epoxy. Surforms & planers don’t even notice it’s there.

Use lightweight glass. I used all 6 oz with a volan deck patch on the deck & both layers on the bottom are 4 oz. Totally unecessary.

But my real recommendation…use balsa. You can pay retail for 4" x 36" sheets at Michael’s (Midwest Balsa products) and still it’ll cost less then the d-cell. Its a better core material & makes a better product. If you can’t find soft 1/4" balsa for building up your rails, use 1/2" d-cell there, but remember a lot of the flex/return comes from the wood rails which become a perimeter stringer. Even a cork/ply combination like Jensen’s would work, although it appears to be labor-intensive. Your tools will thank you too, d-cell dulls tools like mad.

Good luck.

Marginal:

Good:

Better:

And the best is yet to come…

3

Hi Benny-

Thanks much for the info, I was hoping you’d chime in on this one!

Spent the weekend in the archives. My mind is doing backflips with all the info from Bert, yourself, Mr. J and others. Gotta filter some more info before I get rolling on my project!!!

I found a Michaels near me, so I’ll go have a look at balsa real soon. Hopefully they have enough in the correct size. I’ll probably go with 1/8" inch thick planks.

I think the reason I was leaning toward D-cell/PVC foam for the skins was because it’s an engineered product with very little manufacturing variance. I’m really looking for a simple way to get started (no joints, just a single sheet of core matl. for the deck and bottom) as opposed to obtaining the high-performance board which is (in my mind) a more complex animal.

I have zero vac experience yet… =)

…but I’m getting started. Have the hotwire bow and transformer, waiting on the vac pump. Need to get all of the consumables still.

My thoughts were to possibly make a board in the traditional hand layup style, then duplicate it in a vac formed version to get a better idea of the differences in performance, flex and general characteristics.

Thanks again for the info- I’ll keep you posted.

4

You could split the difference and do balsa rails and a corecell deck and bottom. It has better characteristics than dcell. Its the way that Bert is currently going.

5

That may have to be one of the design variants I’ll try! Thanks for the tip.

I saw Bert’s Corecell board in the archives somewhere (vac bagging thread I think), but I didn’t notice balsa rails… hmmmmm. =)

Tom

6

He paints them so they blend in

7

Hey PC,

Here’s a shot from the project ASH thread.

…just look at that gloss!

Rio

8

Petrochem, Don’t use D-cell, use Core-cell or Airex. People often refer to these foams if they were the same product with different brand names, but they aren’t. They are actually different materials with different properties. Core-cell is more flexible and springy than D-cell. My compsand board is Core-cell, balsa rails, 2.5 oz inside with 4 oz top 2.5 oz bottom glassed with fairly flexy epoxy resin (6% elongation). It feels like PU but more responsive and move lively.

9

I was surprised that there are also different weights of corecell. I’m pretty sure that Bert uses the 450 plain.

10

In the past with PVC I have joined it with diagonal cuts to get the length I want.

I lamed the bottom to the EPS then shaped the blank, before puting on deck I have used a heat gun to pre bend the PVC around the shaped EPS rails.

I seal outside PVC with a vey thick mix of q cell and resin about 100mls for each side 8’6" and then glass straight over this wet mix, it’s so thick and dry that my fingers really hurt after squeegeeing it into the PVC.

11

Hi Pinhead-

It’s simply a supply chain issue. I found info on Airex online, that brand came in what appeared to be the perfect desities for what I’m trying to accomplish. I sent a few emails regarding distribution networks but have not heard back yet.

The D-cell is available thru Fiberglass Supply, so if the other materials end up being unavailble to me, I’ll go with that (eventually I’ll get to the balsa…)

If anyone has info on where I can get Corecell or Airex in the USA, it would be greatly appreciated.

My other thought was to try calling the local boatyards, they may be able to help me find the goods. (?)

Tom

12

Where are you located?

13

Chicago, Great Lakes surfer… =)

14

This should work great for you http://www.noahsboatbuilding.com/noahsusa/AMAZING/index.asp?CartId={CF1C83B8-F00A-4C21-96E4-44990EVEREST79BB82F}

It was given to me from cmphawaii. There clearance corecell is very inexpensive!

15

Hi DanB-

OK, that’s a frustrasting website… can’t view anything without a login, but there’s no way to create one (login & password)…

…and no telephone number. GAH!!!

16

Recheck the link. I gave a more direct link (when you get to the webpage click on the link to start a new cart)

17

Hi Dan-

That one worked just fine; thanks a million!!

Tom