Gun surfboard - strength

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Linq
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Gun surfboard - strength

Post by Linq » Fri Aug 15, 2014 8:06 am

Hi, Been through a number of guns over the last few years - ranging from 7'8" to 8'6". Used in 8 to 15ft waves. Looking for some info on strength.. what is best glass thicknesses and stinger and blank. Also if there are other materials being used, other than the standard PU blanks and Fibre glass, that are stronger than conventional materials. I realize a board is not likely going to survive a thick lip landing on it no matter how strong - but would like to reduce the odds. Cheers

Natho
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Re: Gun surfboard - strength

Post by Natho » Tue Aug 26, 2014 12:02 pm

Just my own opinion.I don't think there is a 'best' option when it comes to strength. Like nearly all things in surfboard making and design there are always trade offs. As an example going more glass adds more weight. That said in big wave boards you normally want some weight. Lighter yet strong materials such as EPS and epoxy may not suit a big wave board as much as more traditional materials.

Many makers as an example will use something like 4oz x 6oz for top layer (or even 6x6) and 6oz on the bottom. Others will argue that by doing this you are in fact creating a weaker bottom in the board making it more likely to break through the bottom???. Who knows but I think you will find 4x6x6 or similar is pretty standard for such boards, with a thicker stringer. in guns you would also tend to have more thickness in the board relative to your other boards thus increasing relative strength. All boards however will break under certain conditions.

I watched a friend shape a big wave gun (8 footer) over the weekend for the upcoming Hawaii season. He was talking about adding strength when he glasses the board by increasing the amount of rail lap with the cloth (bringing the lap over the rail and further onto the deck than normal. I think he was then doing 4x4 top and 6 bottom. The idea was to add some additional strength via more lap while keeping the overall glassing down a bit. This was more about allowing the board to flex more I think. The board also had a pretty thick stringer.

sanded
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Re: Gun surfboard - strength

Post by sanded » Tue Aug 26, 2014 12:57 pm

Try nylextra between layers of fiberglass

so lay up would be

first layer from blank to outer skin

4oz or 6oz fibreglass
0.25 oz nylextra
4oz or 6oz fiberglass

Nyextra fibre thickens the laminate and makes it a lot stronger
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Elmako
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Re: Gun surfboard - strength

Post by Elmako » Thu Aug 28, 2014 7:54 am

Hi There, is someone shaping your guns or you are just buying off the rack? Your shaper will answer your question no worries.
J

cedric
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Re: Gun surfboard - strength

Post by cedric » Thu Aug 28, 2014 10:31 am

Carbon fibre strips are $6 per metre @ shapers so not a great expense to add to the cost of a gun, obviously
your glasser gets it a cheaper by the roll rate and well worth the extra cost for added board strength.

Nick Carroll
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Re: Gun surfboard - strength

Post by Nick Carroll » Thu Aug 28, 2014 7:39 pm

Solid wood stringer in PU foam with a good 6oz glass job gets the job done.

Quarter inch spruce stringer or double 3/8 marine ply should do it.

If you're going bigger in the 9'0" plus range a slightly thicker stringer really helps.

Anyone making that kind of board will know what to do. In fact it's kind of a weird question to be asking here.

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Re: Gun surfboard - strength

Post by Yuke Hunt » Thu Aug 28, 2014 8:35 pm

Nick Carroll wrote: In fact it's kind of a weird question to be asking here.
Fcuk yeah ... all things considered, 9 year old American girls seem to have a better grasp of gun strength.
The moving finger writes and having writ moves on ... now all thy piety nor wit shall lure it back to cancel even half a line ... nor all thy tears wash out a single word of it.

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swvic
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Re: Gun surfboard - strength

Post by swvic » Fri Aug 29, 2014 8:54 am

This guy make a few guns

http://instagram.com/easternlight

He mentions the stringer in one or two posts (grams, instas or whayever the fcuk you call 'em). They are thick

Everything he makes is all by hand, by him, start to finish. Board porn at its best. Made all my boards for years until I moved here. Top quality boards, top quality bloke and top quality surfer
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Yuke Hunt
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Re: Gun surfboard - strength

Post by Yuke Hunt » Fri Aug 29, 2014 10:06 am

The moving finger writes and having writ moves on ... now all thy piety nor wit shall lure it back to cancel even half a line ... nor all thy tears wash out a single word of it.

Slobadan Madicubich
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Re: Gun surfboard - strength

Post by Slobadan Madicubich » Fri Aug 29, 2014 11:11 am

Linq wrote:Hi, Been through a number of guns over the last few years - ranging from 7'8" to 8'6". Used in 8 to 15ft waves. Looking for some info on strength.. what is best glass thicknesses and stinger and blank. Also if there are other materials being used, other than the standard PU blanks and Fibre glass, that are stronger than conventional materials. I realize a board is not likely going to survive a thick lip landing on it no matter how strong - but would like to reduce the odds. Cheers
Nick Carroll wrote: In fact it's kind of a weird question to be asking here.
Yeah, what do you think this is? a surfing forum? How dare you try to increase your knowledge. You should take as gospel any information given to you by anyone that you're intending to give at least $600 to.
The absolute hide of you to think you may garner information elsewhere & possibly use it to contribute to any meaningful discussion with an all knowing guru on the manufacture of your board is an alarming indication of your potential as a troublemaker and before you know it you will be offering opinions on what legropes; fin size, shape & configuration; plan/tail shapes; rocker & rail outline work best for you in these conditions.
If you were a genuine contributor you would be revealing what kind of obscure music you listen to before you ride your fancy push bike to the beach via a bush track 37km out of your way accompanied by your cat then blaming Tony Abbot for any deficiencies in your life whilst bemoaning how inadequate the rest of the worlds population is yet at the same time wondering why a good coffee bean is so hard to find to complement your grinder.
I hope this helps

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marauding mullet
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Re: Gun surfboard - strength

Post by marauding mullet » Fri Aug 29, 2014 11:19 am

Womble wrote:
Noice.
X 2
Love a leg rope bridge too.
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Rocket
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Re: Gun surfboard - strength

Post by Rocket » Wed Sep 03, 2014 7:54 am

fongss wrote:Im seeing Alot expoxy in the Gun making here, i asked if it was a strength issue and was told :arrow:

No...its just cheaper than Poly and we can Charge more :idea: :roll:
Thought epoxy allowed for more glass laminates with the same weight overall Fong?

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Re: Gun surfboard - strength

Post by Nick Carroll » Wed Sep 03, 2014 5:43 pm

poor slobodan.

I was implying that maybe a good gun making surfboard guy would know way more about big gun surfboard production than anyone here and if he's getting good guns made by someone, then that's the person to be talking to.

fongss epoxy is stronger than polyester, the matrix is way sturdier, it also flexes where poly cracks. If you really wanted to swing for the fences you'd use vinyl ester resin. That shit is ridiculous but it costs.

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Re: Gun surfboard - strength

Post by sanded » Thu Sep 04, 2014 2:46 pm

Epoxy resin is known in the marine industry for its incredible toughness and bonding strength.
Quality epoxy resins stick to other materials with very strong bond (2,000-p.s.i. vs. only 500-p.s.i. for vinylester and a lot less for polyester resins). In areas that must be able to flex and strain WITH the fibres without micro-fracturing, epoxy resins offer much greater capability.
Cured epoxy tends to be very resistant to moisture absorption.
Epoxy resin will bond with already-cured materials, which makes repair work easy, reliable and strong. It actually bonds strongly to all sorts of fibres

Vinylester resins are a compromise between the low cost polyester and higher cost of epoxy resins, it utilises a polyester resin type of cross-linking molecules in the bonding process. Vinylester is a hybrid form of polyester resin which has been toughened with epoxy molecules within the main molecular structure. It offers a better resistance to moisture absorption than polyester resins but its downside is in the use of liquid styrene to thin it out (not good to breath that stuff) and its sensitivity to atmospheric moisture and temperature.
Sometimes it won't cure if the atmospheric conditions are not right. It also has difficulty in bonding dissimilar and already-cured materials. Due to the touchy nature of vinylester resin, careful surface preparation is necessary if reasonable adhesion is desired for any repair work.

Polyester resin is the most cost effective resin available in the marine industry and offers the least adhesion, has the highest water absorption, has high shrinkage and high VOC's.
Polyester resin is mainly compatible with fibreglass fibres (though has been tried with other skins with some success) and is best suited to building things that are not weight sensitive.
It is also fractures easily, though for surfboard making this is the preferred resin as it keeps the cost down and easy to use with measurements not needing to be so accurate as vinylester and epoxy resins
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Natho
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Re: Gun surfboard - strength

Post by Natho » Thu Sep 11, 2014 4:45 pm

Great stuff. Does vinylester go under any other name in the surfboard industry?.

sanded
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Re: Gun surfboard - strength

Post by sanded » Mon Sep 15, 2014 12:49 pm

Natho wrote:Great stuff. Does vinylester go under any other name in the surfboard industry?.
Hey Natho - Thanks - work in the industry and it cracks me up the miss-information out there!
Vinylester usually goes under that name - A few surfboard builders do use it, though it has a short shelf life about 3 months once opened (unless kept in fridge) so most backyard builders go for poly or epoxy. It smells as much as poly but a bit stronger (feels strong though its still a bit brittle - compared to Epoxy with its elastic properties).

Epoxy is heaps stronger (and dearer), less smell and new resins are probably the safest health wise (always use a mask with all 3 and dont use acetone on your skin!! if using epoxy white vinger works a treat!)
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