Had a thought about the balsa-skin eps boards...

General Discussion
1

been thinking about how they go together, along with how Bert taught us to do the D-cell vacuumed board. The part that I have the hardest time mind-shaping is the balsa rails, especially since there would necessarily be so much waste (wasted $) involved with cutting rocker into them…

What if you were to the bottom with balsa in the style shown by Bert on the d-cell board, along with the simultaneous lay-up of the rails… But instead of the rails being solid strips of balsa (layers and layers of money!), make just the rails of D-cell, and the bottom and deck skins of balsa.

If a board skinned entirely with D-cell will ride well, and a fully balsa-skinned one is worlds better, then what if you just take the balsa rails out of the equation and replace them with D-cell?

this was my brainstorm for the day, and as soon as I have the time, I will try it. It would make the balsa part very nearly affordable.

2

from benny1’s comments it looks like balsa may be cheaper than d-cell. My calculation is about $45 for enough balsa skins and rails for a 10’. That combined with the saving of EPS and it seems like you can have a blasa/eps sandwich for the same price as a clark blank board. Maybe my estimate on materials is way off but we’ll see.

The d-cell rails do sound like less work, but not sure they provide the benefit of the paremeter string idear. I’m going balsa for both the look and flex characteristics (a live board). Again we’ll see.

3

J

already working on this angle…

both a sheet of 1/2" corecell from Fiberglass Hawaii 2 weeks ago

The stuffs expensive though

I like the idea that Bert showed of cutting the entire rail band out in one clean stroke of the box cutter.

I figure that and a band of kevar with the corecel and the balsa lams will give me Greg PPS blank solution.

Gonna have to wait though as I got other things to worry about.

-B

4

I’ve got my balsa costs down to about $20-$25 per board. It pays to buy in volume

5

the balsa rails are kind of the key to the whole project… doing a pvc deck and bottom seems ok…

$12 a blank when you buy a “cube” of eps

$40 give or take for the balsa…

glass is a bit more due to the extra layers…

time is the big problem, but that always seems to be a problem no matter what i build…

but that also what is cool about the vac bag… you can throw all sorts of stuff into it… give it a try and let us know what you think.

6

Maybe I went about it wrong, but when I tried to do full balsa rail wraps it was a real pain to get a clean wrap all the way along the rail. There were a number of areas that needed to be patched up. Doing solid balsa rails eliminates this problem.

If you wanted to leave the dcell showing on the rails it might not be so bad, but you could run into problems when you try to taper the balsa at the seams. Not sure which sands easier, balsa or dcell, but one of them has to and you might end up with some uneveness on the rails.

Would someone that does their boards with solid balsa rails be able to put up a step-by-step sequence of the process they use? I’m intimidated more by the amount of work it would seem to take than the money.

7

Isn’t the parabolic stringers kind of a key element in Berts (and Gregs new blank) designs?

regards,

Håvard

8

superman same price aa a clark kent…do include the labor please.the effort difference though a pleasure is still an expense that well offsets the clark foam investment.

include free delivery.predictable diminished waste,variety of adjustable rockers all driving down production -effort time

the adventure of making 1 off rockers from raw ingredients is stellar .

reworking methods in place at the begining of foam and wood-lam construction of the late 40’s and early 50’s will indeed reveal new subtle nuances in the refining of these constructions.driving effort down is and should clearly be considered an expense,and not passed over as though it

was not a factor.

…ambrose… just a thought

include all the steps and filler coats in epoxy const

while using poly,including vac bagging

would the end product be as strong or stronger than …epoxy and poly [contemporary methods]?

wasnt there a clark foam newsletter to that effect ten+ years ago?

styrofoam -epoxy isnt new…it has come along way, yet its still kinda a hassle

9

hi shuwz

i posted this the other day. seems pretty sinple to me with little waste .

step 1 , get enough 2.5mm thick strips of balsa to make two ,2 meter by 1 meter

sheets ( or how ever lomg you want)

step 2 layout so edges are staggerd and tape together both sheets… paint one sheet with elmers or titebond

step 3 glue the two sheets together using vacumm bag

U now have a sheet of 5mm balsa plywood long and wide enough to cut rails as per berts d cell method

step 4 cut rails using rocker template I use threee each side…

taper stringers at the ends of board so they are neat and dont squash out when under vacum…

step 5 glue three rails together and loosely hold together with a few bits of tape

step 6 clamp it with tape to the foam offcut u have leftover when u cut the outline of board out

heres a few pics i posted the other night

this is a sheet of balsa ply wood

three stringers

glue still wet .lightly tied to gether with tape

then clamped down to the offcut…

let dry.

u can see the other rail clamped down with masking tape

total time about an hour or less

ready to use with a perfect fit

hope this helps

anyone got any other methods ???

i tried using shorter pieces individually but relised it was a total drag

cheers all


10

Bravo, Paul, what an elegant solution! And that way, you’d be able to lay up shorter (translate: cheaper) sections of 2.5mm balsa to make the ply that you cut out into rocker.

I like that very much, being able to cut the rocker in the way that bert showed with the D-cell is a huge bonus, I will certainly be doing it that way when I get ready to make my own. Thanks!

11

Would you gain anything by using [=1][ 2]silly’s [/][/]method and sticking a 2oz layer of glass inbetween the balsa? Whould it help the flex or just make it too dificult to work with?[=1][ 2] [/][/]

12

thanx shwuz hope it works for you . second time was a bit easier.

maybe could just glue the peices straight up to the blank with gorilla glue (Will probably do this with my fish board)

hey garage .

i thought about doing that as well .as thats what i did for my fins .

maybe it would be to stiff … the fins are quite stiff.

would stiffer rails be good or bad??

I was thinking say a 5 ` 10" fish wouldnt even need stringers

where a 10 mal might need to have 1 inch stringers with glass in the layers.

I guess the best way to put glass in, would be when making the plywood sheet??

i thought about doing the deck skin the same way as well

cause im not an engineer, more an artist i dont really know how thing relate

but i guess il find out by surfing the boards…

i surfed my 6 8 wide ass balsa in waist high waves yesterday and it ripped.

usually id have trouble just to float on that size surf…

not sure why it works so good

could be wide ass

or thick big fins

more float from eps

lighter

flex return

it deffinately is not from my shaping skills …cause i know my shaping is crap

good luck with the stringers

im saving offcuts as well

trying gorilla glue this time …and gluing rails on before i bag for bottom skin

anyone else tried this it seems a bit neater… as sorting things out and linning up in the bag in hurry, is a bit stressful