The quest for a 2 pound board

I was just mentioning in another thread my compulsion with crafting a 2 pound board that doesn't self-destruct. I'm am attempting to achieve a final weight with fin boxes of 2 pounds 15 oz, at most.

My fin boxes, in total, weight 3 oz, so I'll need to have a finished, laminated and painted board at 44 oz.

I'm going to wrap a 1 pound EPS core with H-45 divinycell. This is a 3 pound density foam - the same density that Lakewakes uses in their production boards. Althoughm I'll only have about 3 mm covering the 1 pound EPS.

My rail material, before being shaped is 3 oz in total. The EPS core 15 oz before being "whittled" down to the final shape.

I attached the rail material to the core using .5 oz of epoxy on a side. I mixed up several ounces, but lightly brushed the rail material with epoxy using a paint brush.

Then I tossed the whole thing in the bag to clamp it down and get the rocker set. I believe that the board at this stage will come out of the bag at 18 oz, but that after trimming close to shape it will be 9 oz. That's my goal at least, 9 oz or less before attaching the skins.

It came out of the bag at just a shade under 19 oz. I didn't shape it fully, but was able to trim it down to just about 13 oz. I do believe that there is 4 oz left in the residual. I added the bottom skin and it's in the bag now. The d-cell skin weighs 3.5 oz, I used 2 oz e-glass and the section I cut weighs in at 1.5 oz.

I mixed up 3 oz of Resin Research, which is the smallest amount I can mix accurately. I reserved 1/2 of that mixture and then wet out the e-glass with the other half. I spread the eglass on the bottom and smoothed that out. Then with the reserved epoxy I brushed .5 oz along the outline of the skin to insure good adhesion along the rails. It's cooking now and my hope is that it comes out at 20 oz. The skin would then calculate out at adding 7 oz.

That should give me a final shaped and skinned blank at 23 oz. On target for a 2'ish pound board.

It came out at slightly below 23 oz. I have a slight tear in the skin that I forgot about. I had to glue that together with some extra epoxy, and I'm just a bit over on my actual weights from my calculations. I'm estimating that I can trim maybe 1 oz from the bottom skin that extends beyond the rails. So that would leave the board at 22 oz +/-. My next weigh-in will be after shaping the deck, hopefully it will hit 18 oz.

I shaped the deck before bagging and it was at 18 oz, so...I'm back on target.

Out of the bag this morning and it weighs in at 24 oz. With final trimming, I am estimating a weight before external lamination of 22 oz.

looks great keep up the good work , are you finishing the boards or just enough to ride , as more time = more $

Thanks brewkettle. I mostly just take them through a hotcoat, especially on experimental stuff like this. The cost is one reason, another is it makes me sick to spend 2 weeks painting and glossing to have it break! I mostly don't have an interest in the graphics, so it feels like a chore and I don't learn anything...so...I don't bother.

I can't wait to see how this one turns out, and if it is strong enough to ride. Looks like a fun challenge.

Dad, can you please take a picture of all the boards you've ever made, lined up...like in a surf shop?

We wanna see.

DTTO

Hey dtw and Petr - yeah, I'll dig them all out over the weekend when I pull the boat out. Right now most of them are in the nooks and crannies of the shop on the far side of the boat.

Thanks ragboy - it's still on target. I laminated the deck last night and it now weighs 28 oz - 1.75 pounds.

Hey Jeff,

How much lighter will this be than a regular model?

James' contest boards are in the 4 pound range without traction or fins. So I'm shooting for 1.5 pounds lighter. Typical production boards are in the 6 to 8 pound range so in comparison to them: 3.5 to 5.5 pounds lighter. The weight savings numbers aren't too impresive, but expressed as a percentage it's interesting - the range is from a minimum of 38% to 69%.

Saving 1.5 pounds probably isn't a big deal for most of us, but I'm interested to see how light I can go without catastrophic failure. I know that once the board is airborne, manipulating it is impacted significantly by a pound.

The first test is will it NOT self-destruct.

Bottom laminated, I am hoping that it pops out at exactly 2 pounds!!!!

I call that "close enough!" 2 pounds and a "smidgen" which in this case is 1/8 oz.

now will you vent this core because of the 1# eps

I should, but most likely won't on this board. If I do another one, now that I know the procedure and where I can trim weight, I will.

Per your request dtw, this isn't quite all of them There are a few on the walls - like the board that James won the Amateur's at the Centurion contest and the first board James ever won - I didn't think he'd be too pleased with me waking his teenager-self up for this photo op.

That is pretty cool. You should really think about the Surfdad Camp idea.

Can someone explain Venting the core?

Jeff, Nice quiver! How many years have you been designing/building building boards for?

@ dtw - it's a great idea, I just don't want to make this a business. Wakesurfing is how I escape business!

Hey Jon...Thanks! I think that "pile" has been amassed over 5 to 6 years. I've messed with making boards for that 5 or 6 years plus another 5 as a kid.

The venting issue deals with low density foam that off-gasses. As Brewkettle was asking me since the core of this board is 1 pound EPS and it's not really sealed with loads of resin.

With the low denisty foam, as it heats up OR the beads get crushed from heel dents the gas that's used to blow the foam (typically pentane) escapes and is trapped under the glass. As that gas is heated it expands aganist the exterior lamination and often times causes delamination (separation of the fiberglass and foam).

A vent is typically a semi permeable membrane like gortex that will allow any gas inside the board to escape out, but prevents fluids from getting in to the core. As the pentane escapes from the crushed foam beads and heats it just exits out the vent harmlessly.

You may also see vents on hollow boards. Those vents don't breath. The air that is trapped inside the hollow board helps support the skins during use and most manufacturers suggest equalizing the pressure by opening the vent out in the water and then sealing it back tight. They also allow water to be drained from a hollow board that has been punctured.

Omg Jeff you have around 40 boards?!?
Very impressive, thank for taking this photo of your collection.

Maybe I'll run the business for you and you can just be yourself.

time for a yard sale

SD if those boards were shoes that would be half of my wifes closet.

btw there is that same old dirt in upper right corner of you camera lense Jeff. (aprox there where is SS logo on longboard)

You guys are funny. I was laughing to myself after I had all the board in front of the boat - I looked into the shop and chuckled - HEY! I have room for more boards now!

Petr thanks! I just checked my lens and it's an epoxy finger print! Sheesh. I'll try and remove it without messing up the lens itself...well I mean, any worse than it is.

With fins and enough traction to ride, the board weighs 3 pounds and 1 oz. The fins I used for the weigh in are 5.5 oz, so the board sans fins is 2 pounds 10.5 oz...I have some 3 oz fins, so I can get the board fully ready-to-ride at 2 pounds 15 oz.

Thanks for the info on vents. I will have to do some more research on this.

We got a chance to ride it today - it's really easy to toss around. It also seemed to have more float, I don't think that it does, it's just the lack of weight.

I'm doubtful that this will have any longevity, but it didn't self destruct when it got wet!

Backside switch, Nice.