Gary Young master of the vacuum bagged wood laminated surfboard has an updated take on his original article with some addtional insights to some of the stuff he sees happening today.
interesting read you can see it here:
http://www.wetsand.com/category.asp?locationid=5&tabid=850&subtabid=2190&catid=2184&prodid=0&resourceid=[=1]
some clips I found interesting:
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After over 10 years of bamboo board making, I would estimate that each layer of rotary bamboo veneer is roughly as strong as one layer of 4 ounce unidirectional fiberglass.
Two layers of bamboo veneer with grains crossed, epoxy laminated and vacuum bagged uses less resin than a hand laid-up 8 oz. fiberglass.
On bamboo NFC surfboard decks I use as many as five layers of bamboo in high stress areas.
In the fin box area, up to three layers of bamboo are used.
These are truly “green” boards - the sanding dust is not itchy, the foam dust is recyclable, and the renewable bamboo fiber trimmings decompose into soil.
Performance? Durability? Lightweight? Most Green? Reasonable Cost?
I think I’ve got ‘em all covered.
Let’s be realistic – there are ‘surf animals’ who can destroy almost anything. Every material or construction technique has shortcomings.
In general, if we are talking custom boards: [indent]
Hollow boards, no matter how strong, can get water inside, are usually heavier and they take forever to make or are molded.
EPS (Expanded) and XPS (eXtruded) foams can melt with heat or polyester resin, EPS can absorb water.
Urethane foams are not recyclable, are weight challenged for their strength and can shrink back over time.
Carbon and synthetic fibers are expensive because of the energy required to make them and have production problems.
The trick is to make an affordable board that has a reasonable balance of these important elements. [/indent]
Some of the reasons I think bamboo could be the ultimate fiber in a surfboard: [indent] [indent]
Performance - bamboo has a unique flex and can be made in most custom shapes.
Durability – bamboo boards have a longer fatigue life, have greater impact resistant skins and strong fin box mounting.
Weight – bamboo can be made as light as a glass board, while far stronger.
Cost –bamboo surfboards are now cost competitive with high-end glass boards.
Esthetics – Bamboo surfboards look naturally beautiful
Environmental elements - Bamboo is a renewable fiber, worker friendly, scraps decompose.[/indent][/indent]
Shaped blanks were as light as 4 pounds for a 6-8 Clark with a 1/8th stringer to 7 - 9 pounds for a longer, thicker blank with a wider stringer.Conventional wisdom said a bigger stringer made a stronger, less likely to break board.
My thoughts were that if the wood in the stringer were in the skin and rails, the weight spent on the stringer would do double duty: provide a less dentable skin yet still contribute to breaking strength.
This has proven to be a valid approach - in 1978 I said “Put the stringer in the rails.”
This worked well, but made the boards rigid, and really hurt you if you got a rail in the shin.
Today my motto is “Put the stringer in the skin!”
Fin box reinforcing techniques are unique – I use a higher strength Extruded Styrene (XPS) foam under the skin in the fin box areas that has a compressive strength six times higher than normal polyurethane foam.
While the rails are also hi-compressive strength Extruded Styrene foam, I have compromised a little compared to earlier bamboo board methods by using a small amount of fiberglass with epoxy on the rails which enhances flex, is easier to make, easier to repair and not quite so brutal if the rail thumps you when getting worked.
Once again: XPS foam does not absorb water.
So if you do get a ding, keep surfing and fix it in the first 3 months if you want to minimize discoloration of the bamboo. There is no measurable weight gain from water absorption.
Be aware that some are making “bamboo surfboards” with pre-laminated woven bamboo panels.
Others are taking woven bamboo mats, gluing to foam and fiberglassing with polyester resin.
If ANY other adhesive gets in between the epoxy and the bamboo, it will interrupt the bond and eventually delaminate.
Polyester resin does NOT bond well to bamboo.
Pre-laminated bamboo panels have water absorbing problems too[/]
sounds to me like he’s not applying exterior glass to any part of his boards other than the rails…
also of you use his 4oz cloth estimate as to the strength benefit of the 0.3mm bamboo veneer lam and the other estimate that the bamboo jersey is equivalent to 6oz cloth, then a bamboo laminated shape glassed with one layer of bamboo jersey and epoxy is equivalent to 10oz of glass with polyester resin.
“Put the stringer in the skin”…
that’s a good one
Looks like the current trend of parabola/perimeter stringers are now passee’ on the big island.
I’ll end it with this other hilarious clip…
I paddled into my local lineup on the rocky, reef deficient East side Big Island today. A haole kid saw my bamboo board and in slight pidgin, asked: “Eh, brah! Nice board! How long you been shaping?”
In preparation for this article I had been looking at lots of old photos. I had just seen the first board I had “shaped” in 1963 - an old Walker blank from San Clemente. My “shaping” consisted of scrapping off the hard foam crust. It wasn’t a close tolerance blank - but hey, I shaped it - didn’t I?
So I told the kid “I started in 1963…” expecting him to figure it out .
“Brah, I go Pahoa, I no can do da math.” he said.
I replied “I have been shaping over 40 years.”
“Wow, dats a long time. Anyway, da bamboo THEORY kinda’ cool!” he remarked.
“THEORY!” I gasped. “This is NO THEORY, it is real! It is not just an idea, this is a real board.”
“Well mabbe if dey moa popular…” he said.
gotta love that one…
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