Getting ready to order a 9,6 LB, and wanted to know what would be the best compromise as far as strength to weight? The board is going to be used in FL beach break so I want it to be as light as possible but I also dont want a board thats going to fall apart anytime soon. I am looking at either going with a Clark Super Green blank glassed with double 6oz top w/6oz bottom or a Clark Super Blue blank glassed with double 8oz Volan top w/8oz Volan bottom. Which would be better and I am also open to other suggestions? Thanks
if you want a board that’s lightweight AND strong, than a Clark blank with 6- or 8-oz. glass is NOT the way to go.
you need to talk to Steve Forstall about making a board for you…ride one of his boards and you’ll be hooked.
My favorite all around semi gun is 7’10", made with a Clark Super Blue, with a 1/8" Spruce stringer. It is glassed with triple 4oz on the deck, and single 6oz on the bottom. The board is 21 1/2" wide, and 3 1/2" thick, gloss & polish, with a Bahne FU box. The finished board weighs 12 1/2 pounds with the fin in. It has held up just fine, and has been exposed to some significant surf. I still have this board, but don’t surf it any more. (I gained 50#) The board was made in 1981, and glassed at the CASTER shop in San Diego. The point of telling all this is to point out a glassing schedule that surpassed my expectations for lighter weight, and strength, by a wide margin. My current board, an 8’ 10" X 23" has the same glassing schedule over a Clark Green blank. I’m very happy with it.
soulstice, I have an Island LB (eps/RR epoxy) and have spoken with Steve about his boards in the past. I want to add another polly board to my quiver.
Which would be the best combo to hold up against pressure dents and dings, lighter blank and heavier glass or heavier blank and lighter glass?
Use s-glass for a better strength to weight ratio, 30% stronger at the same weight, skip the volan.
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Use s-glass for a better strength to weight ratio, 30% stronger at the same weight, skip the volan.
Aloha Brant
I don’t mean to put you on the spot but… Tell us something about your experiences with S-Glass and why you feel it is 30% stronger. I have heard it mentioned here and there and was just wondering. Others feel free to weigh in on their experiences also.
30% is just the engineering reports I have read from various sources. It has been around for a long time and is well known to be stronger. S-glass is about 50% more expensive, behaves just like normal glass although it doesn’t sound like you will be doing the glassing.
edit: oops, meant that not glassing comment for gr8day not Bill.
the difference between S-glass and E-glass is in the quality of the silica. S-glass uses a higher grade silica in its production. it is said to have better elongation/flex characteristics…but as far as STRENGTH goes, there really is no difference. as with shaping…everything is a tradeoff. better flex of the glass gives the APPEARANCE of higher strength, but the limiting factor in compression strength is the resin…not the glass. poly doesn’t flex the way epoxy can, so regardless of the glass…the board’s resistance to dings is determined by how much of a beating the RESIN can take. also, if it were to flex more into a PU blank, the foam would compress, but wouldn’t bounce back the way EPS will…which is just asking for delams. if it ain’t broke, don’t fix it…poly blank + poly resin = good ol’ warp E-glass.
After doing some research on the Harbour web site, I found this.
Dents are a natural Bi-product of surfboards. The old balsa boards, when whacked really hard, will dent. I have been in this business since 1959 and have seen no production foam boards with more than a total of 20oz of glass per side. When using contemporary resins, the real problem in denting is the substrate or foam. Even with the early 60’s when foam weighed about 3.9 lbs. per cubic foot, surfboards still dented. Think of this: put one layer of 4oz glass on concrete and you will not dent it. To make a surfboard of reasonable weight, we cannot apply enough layers of glass to make it ridged enough to be dent resistant. Today’s longboard typically is made of CLARK “supergreen” foam. This name has nothing to do with anything but a name for foam that is approximately 2.44 lbs. per cubic foot. Supergreen is the standard of the longboard industry.
Wow. That mention of the Clark Supergreen being 2.44 lbs. per cubic foot changes things a bit. I’d never really thought about it but assumed it would be a lot heavier. At that weight, it’s awfully close to the 2# eps foam that Greg Loehr recommends.
I mean, a 6’2" C is 2 cubic feet prior to shaping so that would mean it weighs only .8 lbs. more than a 2# eps blank the same size, right? And from the catalog it looks like a 9’5 S blank is 3 cubic feet, meaning a shaped longboard would weigh within 1.2 lbs more than a 2# eps blank, right?
From all the posts about it I thought the difference was much more. It would be much easier for most of us to shape from a clark blank so if the weight difference is that little, it’s tempting to just go that way.
6,4 oz top with a 6 oz bottom. That will give you good strength to weight ratio. If you put the cloth in a bi directional lay out. Put the cloth on the board like a big cross, then cut it out. If you don’t care about weight then do the double 6 deck with a 6 bottom. I do my long boards that way, but its slightly over kill for the wave. Long Boards 6,6 x 6. Guns & resin work boards 6,4,x 6. Disposable Short boards 4,4 x 4.
-Jay
alot of 220-240lb friends are getting long boards with double 6 deck and 6 bottom some even with patches that are lighter than some 6/4 top 4 bottom layups…
They are getting boards with “polished” sandcoats versus a gloss coat layer that helps cut down the weight.
As far as strength I don’t see any softening in these boards with the “polished” sand coat finishes versus the gloss coat ones and they still are just as pretty and glossy as the ones with the extra resin layer…
I guess a good glasser can cut down on the amount of resin coats added after the initial lamination to reduce the final weight of the product but still end up with a “lightweight” but strong board.
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30% is just the engineering reports I have read from various sources. It has been around for a long time and is well known to be stronger. S-glass is about 50% more expensive, behaves just like normal glass although it doesn't sound like you will be doing the glassing.
That is what I thought. I have heard and read similar claims.
I can tell you from actual experience that the difference from E to S glass is nowhere near 30%.
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the difference between S-glass and E-glass is in the quality of the silica. S-glass uses a higher grade silica in its production. it is said to have better elongation/flex characteristics....but as far as STRENGTH goes, there really is no difference. as with shaping...everything is a tradeoff. better flex of the glass gives the APPEARANCE of higher strength, but the limiting factor in compression strength is the resin...not the glass. poly doesn't flex the way epoxy can, so regardless of the glass...the board's resistance to dings is determined by how much of a beating the RESIN can take. also, if it were to flex more into a PU blank, the foam would compress, but wouldn't bounce back the way EPS will...which is just asking for delams. if it ain't broke, don't fix it.....poly blank + poly resin = good ol' warp E-glass.
Aloha Soulstice
I agree. No apprecialbe difference. In fact, I would say it makes a weaker board. Have you ever sanded a board glassed with S-Glass. If so, or if anyone else on this forum has, please tell us all if the sanding of the hotcoat feels any different.
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I had a conversation with a shaper who also glasses his own boards. I brought up S-Glass because I had heard it's a stronger glass. He told me he didn't like using it because it's a pain in the rear to sand, and if I remember correctly mentioned something about if you're not careful it will splinter on you. I could be wrong about the splinter part but I think that was part of the conversation.
Have you ever sanded a board glassed with S-Glass. If so, or if anyone else on this forum has, please tell us all if the sanding of the hotcoat feels any different.
Not recent, but years ago I worked on boards with s glass quite a bit.
I understand it has been treated in some chemical way to enhance adhesion. You could feel some sort of difference when cutting out, even with gloves . It did eveything the other glass did as far as workability, seemed to stay a little flatter.
As far as sanding goes, a filler coat is a filler coat. I didn’t, and don’t, sand through to the fabric most of the time, so I can’t say if the sanded fibres are splintery or not, and I have no recollection of feeling anything like that.
As far as strength goes, they lasted the same as eveything else but seemed more resistant to dings. A story I’ve told before is with some boards bottom up while going through a heavy hailstorm. The one with the e glass had hundreds of small shatters, some small dents, the s glass had not a single mark.
Several composite engineers I know agree up to 30%, but that’s in extreme situations, and probably not in a situation where it’s spread thinly over a foam beam like surfboards are.
In a sandwich situation it would be another small enhancement.
Necessary? Not really, but how fussy are you?
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gr8day said....."He told me he didn't like using it because it's a pain in the rear to sand,"
EXACTLY!!
I was hoping someone could share from actual experience and if they did it would contain a quote similar to the one above.
S-Glass was not created for the surfboard market, nor the particular resins we use. You will notice that actual weave of the fabric on an S-Glass board is slightly visible compared to E-GLass. This is due to what is called “incidence of refraction”. Normally the resin and the fabric are designed to be used together and as such they tune things like the incidence of refraction, elongation, etc so the the materials are a complimentary as possible.
Your first clue is that you can see the S-Glass fibers. Indicating that it wasn’t made for the resin system you are using.
The second clue is the hardness of the hotcoat when you try to sand it. I have heard dozens glassers explain how good S-Glass is because the board is so much stronger…especially its impact strength. Like in the case of the hail that Wildy mentioned.
No one ever seems to get message that if you aren’t hitting the glass fibers, why is it so hard to sand. Clearly this isn’t the S-Glass, it is something totally different. And it is!! The finish on S-Glass is not designed for polyester surfboard resin and something in the finish is causing the resin to cure differently. And it is telegraphing all the way up through into the hotcoat! It is curing extremely hard and brittle. Kind of like laminating your board with finishing resin. It is made to cure very hard and crispy so that it will polish up to a nice shine. The downside of course is the stress fractures you see in the finish coat around dents and nearly broken boards.
I went around and around with the people at Hexcel about this S-Glass issue and they wouldn’t own up. In fact, they were surprised that I brought it up to them. Not suprised that the problem existed. So…I concluded that they were maybe adding something that would boost their test numbers (30%??? stronger) and therefore sales of the product.
I found S-Glass to produce boards that were much more resistant to impacts but that were much more brittle and broke in half much more often. Using it in small patches were feet go on sailboards was a reasonable use. But I don’t think it has any practicle use in surfboards.
Also keep in mind that most uses of fiberglass are not in thin single or double layer skins like we use in surfboards. So most of the test data is for much thicker laminates which function more like a sandwich where the outer layers take all the stresses and the inner layers are just there to keep the outer layers separated. Consequently the data is generally useless to us surfboard guys.
I also pulled this off of Harbour’s design page.
S-Glass has great memory, but this may be its undoing. It won’t stay bonded to the foam as well when severe denting occurs.
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Quote:Use s-glass for a better strength to weight ratio, 30% stronger at the same weight, skip the volan.
…Tell us something about your experiences with S-Glass and why you feel it is 30% stronger. I have heard it mentioned here and there and was just wondering. Others feel free to weigh in on their experiences also.
IMHO, S-glass is better. It makes for a longer lasting board. But whether it is cost effective for you to pay twice as much for glass is up to you. It’s not twice as good as E-glass, but I feel it’s better.
IMO, S-glass is a little stronger, resists dents better, and has a longer fatigue life – i.e. when a board (glass) looses its flex, and flex memory and starts to feel ‘dead’.
{Quoting FiberglassSupply }
S-2 Glass Surfboard Fabrics, are industry standard for high performance surfboards and sailboard fabrication. When compared to E-glass, S-2 laminates show significant improvements in tensile strength, flexural strength, flexural modulus and compressive strength. S-2 Glass Laminates also exhibit improved impact resistance and toughness.
{End Quote}
S-glass uses a more complicated production process. http://www.azom.com/details.asp?ArticleID=769
Bill - I glassed a board recently with Aerialite S-2 glass. My experience with it includes, a) perhaps slightly harder to sand, but not that big of a deal from my perspective, b) have not yet had any heel dings or normal impacts show, c) however when I slammed the board into the reef at Makaha, ding repair was required.
This is 2x4 oz deck, 1x 4oz bottom.
All told, I’d use it again. Your mileage may vary.