what if...

now that we got all different cored boards with different skins and stuff, what if we could mess around with what gas was inside them?

I mean there’s lots of air in a surfburger, but what if you replaced this with say helium? further reducing the weight?

I’d be hard to vent becauase of the fact that all you’re helium would excape, but there could be ways to overcome that…burton’s making helium filled snowboards, why not surfboards too? is there a weight limit where lightness just becomes unpractical?

search…archives…answer there!

And, being something of a math freak, I’ll take a stab at it anyways.

Take a board. Say, it’ll displace ( float when it’s completely under water ) some 230 lbs - call it a bit over 100 kilograms. This is more than a little high, but it’ll serve and it’ll make the math easy.

So, it has a volume of about 0.1 cubic meters. And lets say ( pulling a figure out of my hat, but it’s not too far off) that something like 80% of the volume of said board is gas. So, that’s 0.08 cubic meters of gas, call it 80 liters.

Note that I said ‘gas’ and not ‘air’ - the process of expanding the foam from a solid plastic to a foam is not necessarily done by adding air, rather it may be a chemical process which causes bubbles of gas to be trapped inside the plastic. We are not talking about whisking up egg whites for mousse au chocolat, y’know?

Typically, that gas will be carbon dioxide ( CO2 ) or nitrogen and it may not be possible to substitute helium. But, lets keep going. Like I said, I’m a math freak. It’s a personal problem, like…

Looking around for some good values for gas densities, I bumped into this

 Density of Gases at STP in grams per cubic centimeter:    Air  0.001293  Carbon dioxide  .001977  Carbon monoxide  0.00125  Hydrogen  0.00009  Helium  0.000178  Nitrogen  0.001251 

Not done yet, we need to change that to grams per liter so we multiply by 1000

Air - 1.293 grams per liter

CO2 - 1.977

Helium - 0.178

Nitrogen - 1.251

So, how much less weight are we talking about for a board that has around 80 liters of gas in it if we were somehow able to substitute helium for the CO2, air or Nitrogen in the foam?

Well, doing the math ( my favorite part, by the way )

1.293 ( air) grams/liter * 80 liters = 103.44 grams

1.977 ( CO2) grams/liter * 80 liters = 158.16 grams

1.251 ( nitrogen ) grams/liter * 80 liters = 100.08 grams

now, figure in helium -

0.178 grams/liter*80 liters = 14.24 grams

That is a considerable difference… but only if it’s a balloon with one hell of a lot of helium in it. The difference between a board with CO2 as the gas ( why not, it’s the heaviest ) and the same board using helium is about 144 grams. Around 4 1/2 ounces, if you’re going with US units, around a quarter pound. Say, less than the weight of a bar of wax. And it gives you an idea of how much volume there is in a helium balloon, for it to pick up a useful load.

And there’s more. See, helium is kinda like one of my ex-girlfriends used to describe me: it’s insidious. Though she used to say that almost everything else was insidious too - anyhow…

Put it in an even faintly permeable container under pressure and it makes its way out. Say, a permeable container like a fiberglass and resin skin that won’t let relatively large water molecules in…but a wee, bitty atom ( ‘cos Helium doesn’t form compounds, it’s a fairly noble gas like neon, argon and such ) like Helium, it can sneak out between the holes in those big ol’ resin molecules and plastic molecules that make up the foam like the breeze going through a screen door. Air is relatively big stuff, O2 molecules, N2, a few trace constituents like CO2 and such, it won’ go back in nearly as easily, or at all.

But the board isn’t under pressure… or is it? Put it on your rack, or on the beach, on a hot day, and there’s pressure in there, cos it heats up. Out goes the helium… and when the board hits the water and the gas inside cools off, well, lets just say it sucks, y’know? Boyles Law of Gases bites you. If, for instance, you go with a 20 degree F difference, air temp to water temp, the volume is gonna decrease by 1/20th - remember, it’s a 100 liter board, so about 5 liters ( think of it as 5 quarts) ain’t there any more, and suddenly the board looks like Starvin’ Marvin.

In case you were thinking about balloons - well, ever notice those kinda flat things on the shore, baloons and ribbons all together? I do. Those are rubber ( neoprene) balloons that were full of helium under a little pressure and the helium made its way out through the balloon itself, nobody put any holes in it. The Great Big helium baloons that they use to try to float around the world with have almost no pressure differerential between the helium inside and the air outside - that’s why they look kinda baggy when they take off.

And a 20 degree F difference isn’t a big deal - here, we get 40 degree F differences, 100 F air and 60 F water isn’t that odd in, say, August.

So - maybe helium isn’t such a good move, not for a few ounces… instead, skip that before-surf Quarter Pounder and you’ll be ahead of the game for much less effort.

hope that’s of use

doc…

Howzit doc, Funny thing about the weight of wax which alot of people don’t take in to account. I have a friend who has talked to me about a process he’s working on that could make wax obsolete on surfboards. He brought me a sample and when it was dry it had no grip but when it’s wet your hand wouldn’t slide on it. Very interesting idea. Aloha,Kokua

what if you make a board that weighs five pounds , but you weigh 200lbs ?

“there’s a lot of air in a surfburger”

[hahahah …CLAAAASSSSIC , mate !]

…and LOTS of OTHER people here , too …

but , on the other hand …if you were to use hot air …is THAT lighter than normal air , I wonder ? [It certainly seems to make things a bit HEAVY here at times !]

cheers !

ben

lighten up and enjoy life …you’re not six foot under yet . [“any day 6’ above ground is generally better than 6’ under”]

you’ve done some experimenting with methane, haven’t you Mr. fish ?

welcome back chinga dear, how’s the tight fitting wetsuits going? Actuaally , "Chip " was just asking after yoiu the other day . He couldn’t decide whether he wanted you or rubberlove to size him up for a new tight fitting wettsuit. He is one sick puppy. And I thought I was bad.

cecil b. de skinflicks star

what a coincidence - on the MSN Surfmat BB a couple days ago i was asking if anyone had ever surfed with their surfmat filled with helium. Evidentally, IAW what Docs view were - the helium wouldn’t lighten the mat up that much - and would probably leak out… dale’s view.

Some guy however in that MSN group (Inflateable-Dream Speed) has rode a helium filled mat - but hasn’t chimed in yet.

I’d have thought the surfmat would float off - but I guess not. I was wondering about boards m’self.

Quote:

you’ve done some experimenting with methane, haven’t you Mr. fish ?

if brain farts count , I believe there’s a guy here who could power his windsurfer around the world in a week

Hey, Kokua,

Yeah, I love seeing these guys who went absolutely bonkers wanting a super-light board and then they go and cover it with a quarter inch of wax… adding at least couple pounds to the weight by the time you add in random sand, crud and the back-of-the-car random dog hair.

Gawd…remember hot waxing boards? Brushing on a nice, thick coat of paraffin wax to act as a base and then going from there?

No-wax surface? Interesting - wonder how it would do with, say wetsuit boot soles.

Best regards

doc…

You go Doc, I used to argue this crap with my old factory manager. I tried to explain to him that the helium tank at the grocery store didn’t float away and it had one hell of a lot of compressed helium in it, how much could you possibly get inside of even a hollow board before it split at the seams. Now I know why the helium “leaks” out of the mylar balloons so easily, sort of like osmosis. Learn something new everyday

Hi Jim,

Yeah, exactly like osmosis, really - the mylar ( see it’s actually nylon - see http://en.wikipedia.org/wiki/Nylon … gawd, Wiki is cool ) is just this big ol’ string of carbon and other groups that really doesn’t hold much back when ( if you look at that diagram) you think of the individual helium atoms as just a little tiny dot that can slip on through that lattice.

Latex is similar in structure ( another polymer) … but the Wiki latex page refers to some stuff that only Ben could love.

Damn, I miss the lab…

doc…

A vaccume is lighter than any gas.

Glass.

Drill.

suck.

Plug.

Later…Osmosis?

If not, still not too significant, or even noticable I’d imagine.

-A

Howzit doc, Oh yes I remember hot waxing boards, when you think about it a lot of todays surfers have never used parafin wax. I used it up to about 94 then switched to Sticky bumps I think. Another thing I remember about melting parafin was my Mom yelling at me for using her good sauce pans to melt it in and getting a slap across the back of my head. Aloha,Kokua

what about a honecomb CORED board where the honeycomb is about 95% air by volume. Just adding a new spin to the discussion…

Howzit Turbo, Do you mean the honeycomb being 95% in it’s structual form alone. I worked with honeycomb boards back when they were in their infancy and even though they looked great they had a big tendecy to delam when your foot pressed down on hard turns. Also there can be no pin air in the lay up of they just turn into big cardboard sponges. But this was years ago and hopefully they have improved the technology over the years. One problem was the Aqua jet owner sold us a bunch of materials that he found didn’t work so he just ripped us off.Aloha,Kokua

well, I guess if I was going to make a honeycomb board it would be aluminum and cut on 2 axis. So the honeycomb would be flat top, bottom, and sides and then use other materials for the top, bottom skins, and rails, this way you could shape in contours and your rails. I think the way most honeycombs manufacturers measure the amount of air is taking the honey comb in say a square foot block and then measuring how much air is inside by volume. Usually it’s around 90% or more. A board made that way would be extremely light and strong, but incredibly stiff and expensive. I was jsut talking in theory and was wondering how much more weigth you would actually shave off by replacing the air inside with helium. It would already be light, probably in the 2lb range with most of the weight coming from the skins, fiberglass, and resin. Then you could go the other way and make it heavier, and say make a really stiff, strong board,that is heavy enough for big waves.

Just wondering, what honeycomb did you used in the past? Were the boards vaccum bagged? How did they ride besides the delams?

Well- the main problem with a vaccum is this.

See, when you take air pressure out of the inside of something, that doesn’t mean it goes away on the outside.

For instance, lets say you want to remove 2/3 of the weight of the gas by removing 2/3 of the gas. Call it a 9’ board, around 22" wide. Well, the outside air is going to be pushing in at around 2/3 of an atmosphere- about 10 lbs per square inch.

And there’s a lot of square inches on something that size - around 4600 - so the force on the board is about the same as parking one of these on it.

Somehow, I think the glass job you’d need to hold that would weigh in at more than the 100 grams or so ( four ounces ) you’d save by eliminating the air.

Oh well

doc…

Howzit Turbo, So long ago I can’t remember the details on the honeycomb other than it came from Aquajet guy,but it seemed like it was cardboard or a like composite. The boards weren’t vaccum bagged, they were hand laid up in the mold by another of the glassers since I was in training at the time. They rode pretty good until the delam which was during the testing, but the rider was one of the owners and he weighed about 200 lbs.Aloha,Kokua

how does helium react when it heats up ?, what if the helium as inside a cylinder container and then resined over ???