Gun - Stongest materials to use

Linq's picture
Linq started the topic in Sunday, 5 Oct 2014 at 12:46pm

Gday

Looking for some advice on big wave boards (8'6 - 8'8) made from balsa. I have heard they could be a fair bit stronger than conventional PU foam with fibreglass.

Have broken quite a few standard guns around the 8’0 mark at our local bombie. Have been using 6x6 on deck and 6x4 on bottom with reasonably thick stringer. I realize most boards will break if a thick lip lands on it no matter how strong - just keen to get some feedback.

Any thoughts on balsa boards for surf around 10 -12 ft ? Will give me any extra strength. I also wonder about the weight – sometimes It can get reasonably windy with little extra weight helping cut through chop and wind.

Cheers,
Linq

quadzilla's picture
quadzilla's picture
quadzilla commented Tuesday, 7 Oct 2014 at 9:30am

Yes,balsa has more strength but 5x more costly and more weight....a better option IMO is a surfblanks gun blank reinforced with extra stringers and glass.The foam density can be altered to a heavier weight(less air)which adds more strength and they do pre shapes too.Balsa is not pleasant to work with.

mikehunt207's picture
mikehunt207's picture
mikehunt207 commented Tuesday, 7 Oct 2014 at 10:47am

Wide overlaps on glass make huge difference in strength also, a fair bit harder to sand hence the reason many glassers avoid doing them without being asked

stunet's picture
stunet's picture
stunet commented Tuesday, 7 Oct 2014 at 10:57am

I've got a self-shaped 7'6" balsa gun but haven't ridden it yet. Shaped it for bigger days though. Was told it was stronger then PU foam but couldn't say.

Quadzilla mentioned Surfblanks and that's a good option. You can customise stringers to whatever thickness you want. Order a blank with a wide Redwood cedar stringer.

http://surfblanksaustralia.com/blanks-info/wood-foam-stringers#.VDMq8CmSyaM

brutus's picture
brutus's picture
brutus commented Tuesday, 7 Oct 2014 at 1:23pm

heres a tip for a stronger bd......use 4-6 ply stringers...double them up so they are 8-12 ply.....these stringers are so much stronger than any others on the market.....most Blank Co's can get it from Briggs in Sydney.......

next tip use a lighter blanks so you can put a double 4 on the bottom and a double six on the deck and keep the Laps as wide as possible.

Balsa is heavy,really hard to shape........

udo's picture
udo's picture
udo commented Tuesday, 7 Oct 2014 at 2:50pm

@mikehunt how does glassing with a wide lap make sanding any harder ?

shaun's picture
shaun's picture
shaun commented Tuesday, 7 Oct 2014 at 4:55pm

No difference whatsoever to sand, just harder to glass more to rap around.

Redwood stringers are overrated, broken a few of them

I'm the scab you keep picking off and is there again the next day.

udo's picture
udo's picture
udo commented Tuesday, 7 Oct 2014 at 5:42pm

Yep what I thought just a bit harder to wrap the rail [6oz] but shouldn't be a problem to a pro glasser .

uplift's picture
uplift's picture
uplift commented Tuesday, 7 Oct 2014 at 5:45pm

The stringer thing is a good tip. A wide stringer is useless one piece, still has a weakness in the grain, and will easliy snap. Lots of opposing/different grains are good. Good shapers are fussy with the blanks. If you have to take too much off the outer, skin part of the blank, and get into the core too much, they are much weaker. Lap thing is good, helps stop the twist/crack starting through the rail. Obviously thinner/longer is a bad combo, same if rails are really thin, re twisting. Some guys try to do things with the weave direction in the cloth, similar idea to the layered stringers. A guy here makes a lot of windsurfers for Hawaii, and showed me new plastic/nylon looking stringers that would be hard to snap.

shaun's picture
shaun's picture
shaun commented Tuesday, 7 Oct 2014 at 9:02pm

Udu big laps are no problem but a little bit more work so unless you insist it ain't going to happen.

Don't know about plastic uplift, suspect it might be like the aluminium stringers they never broke just kinked. Spruce used to be popular in Hawaii a few years ago, but I think it can't be got now.

I'm the scab you keep picking off and is there again the next day.

uplift's picture
uplift's picture
uplift commented Tuesday, 7 Oct 2014 at 10:53pm

'Don't know about plastic uplift, suspect it might be like the aluminium stringers they never broke just kinked. '
Yeh, will be interesting to see. Remember the phase with routed in glass rods around the rails? My mates Minamis all had them. When they broke it was horrific, skewers of splintered fibreglass would spring out. Weapons of mass destruction.

shaun's picture
shaun's picture
shaun commented Wednesday, 8 Oct 2014 at 7:17am

Now they were a pain in the arse, 6ft + of rovings, one false move and ya got shit everywhere. I didn't do enough of them to get a good system going and I don't reckon it worked that well.

There is a fine line between what works to give the board strength and luck.

I'm the scab you keep picking off and is there again the next day.

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 7:44am

@shaun the grooves that Stretch puts on the deck of his boards near each rail is that a extra strength thing, has been doing it for years now so is obviously worthwhile.

shaun's picture
shaun's picture
shaun commented Wednesday, 8 Oct 2014 at 9:39am

Back in my day we were doing it on the bottom, makes more sense on the top I suppose.

Just because someone has been doing it for a long time, doesn't necessarily make it a great idea :-)

I'm the scab you keep picking off and is there again the next day.

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 11:07am

You were doing the grooves in the bottom and filling with rovings before glassing.....Stretches is just a groove line in the deck I think and glassed normally....maybe an extra 4 oz strip in the groove ?
anyone else know anything about this ....Brutus why is this so ?

stunet's picture
stunet's picture
stunet commented Wednesday, 8 Oct 2014 at 11:13am

It adds strength as the fibreglass passes through a different plane of axis.

uplift's picture
uplift's picture
uplift commented Wednesday, 8 Oct 2014 at 11:14am

Maybe the idea is more surface area, strength on rail to spread the force, counteract twisting, splitting rails. The rods thing didn't stick around too long, as Shaun said, pain in the arse with all the rovings, but they still broke, and those resulting skewers were radical.

stunet's picture
stunet's picture
stunet commented Wednesday, 8 Oct 2014 at 12:06pm

Yep, the greater surface area would also help. 

In the late 80s Water Force surfboards at Cronulla were doing a similar thing except they had the grooves on the deck, just ahead of the front foot and running for a foot or so toward the nose. They were about six inches apart and looked like channels on the deck. Weird. But it didn't take much thought to realise how they worked. You can test it with paper: It's easy to fold when the sheet is flat, but put a kink running at 90 degrees to the fold and you'll feel some resistance.

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 12:21pm

look at the stiffness attained when a .5mm flat steel sheet is formed to corrugated iron profile.

stunet's picture
stunet's picture
stunet commented Wednesday, 8 Oct 2014 at 12:33pm

Exactly Udo. That's a bit better analogy than my piss poor paper example. It makes sense though, eh? Wonder why more manufacturers don't experiment with it.

caml's picture
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caml commented Wednesday, 8 Oct 2014 at 12:40pm

Yeah i know the grooves youre talking about . Last month jamie mitchell rocked up to surf an offshore bommie . I had a look at his boards 10"6 & 10"0 the bigger one had the grooves we're talking about . Not only may they be for strength but also for your hands to grip the rail easier .considering it was 3 7/8 thick that looked more feasible than for strength factor . Anyway seeing the surf was looking about 15-20ft & we were goin out on jetskis i decided one board would be eniugh of a hassle for me . Jamie took both his boards . Pretty much immediatly jamie had snapped the 10"6 with said grooves .my old faithful probably glassed with more layers is still going strong.

50young's picture
50young's picture
50young commented Wednesday, 8 Oct 2014 at 12:41pm

got to alter the flex in the board as well could be a bitch to get right

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 12:46pm

Is flex a concern on a rhino chaser ?

caml's picture
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caml commented Wednesday, 8 Oct 2014 at 12:47pm

Interesting to have brutus suggest using lightweight blank . I use heavier blank for more strength . Jamies board was lightweight compared to my standard boards . Recently going for 3x6 oz each side . Once again trying not to pollute with disposable surfboards . Why waste time n effort with a board likely to snap

50young's picture
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50young commented Wednesday, 8 Oct 2014 at 12:49pm

udo wrote: Is flex a concern on a rhino chaser ?

guess i wasnt refering to a rhino chaser, Diverse use the channels down the rails on top of their dynocores. was thinking more on shortboards
udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 12:55pm

Wasn't directed at you 50Y .....just wondering if caml and others worry about board flex in a gun in any way
Diverse still in aust or Bali based now?

shaun's picture
shaun's picture
shaun commented Wednesday, 8 Oct 2014 at 12:56pm

udo wrote: look at the stiffness attained when a .5mm flat steel sheet is formed to corrugated iron profile.

Took the words right outa my mouth you thievin bastard.

A classic example of this is that I have never seen a classic six channel break across the channels .

I'm the scab you keep picking off and is there again the next day.

shaun's picture
shaun's picture
shaun commented Wednesday, 8 Oct 2014 at 1:06pm

udo wrote: Is flex a concern on a rhino chaser ?

Rail to rail is important, as in the board being able to give in it by twisting a bit, makes the board feel alive when it springs back.
The thick stringers are good to take the flex out down the middle and can cut through big lumps of water without a big vibration going through the board.
Hope that's understandable.

I'm the scab you keep picking off and is there again the next day.

caml's picture
caml's picture
caml commented Wednesday, 8 Oct 2014 at 1:25pm

Yes i have been dabbling with flex for guns forever & all im goin to say is yes i do like a tiny bit of flex.

caml's picture
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caml commented Wednesday, 8 Oct 2014 at 1:28pm

Gary linden promotes his balsa guns as no flex . Each to their own

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 2:00pm

So could you leave the machine cut grooves in the deck of the blank......knock the top off the ridge that's left between each cut with the gauze just enough to make the glassing not to hard ? not sure but guessing each cut pass is 10mm wide ..that's a lot of added stiffening /strength to a blank.

uplift's picture
uplift's picture
uplift commented Wednesday, 8 Oct 2014 at 3:07pm

Flex is funny, what you get used to. I surfed really stiff epoxies for quite a while, Marty Littlewood's, Cal Liddle's etc, and got to love the instant response, no give. More unforgiving re the ocean though. React to chop, everything. So all your drive instantly goes somewhere, isn't lost in the forgivingness. Think cars with soft suspension. Pretty hard to break the thick, glassed up epoxies. One day Todd wanted to try one, and his pu felt like a wet rolled up, dead tea towel to me. But later I surfed some Mackie's, and got used to and like the flex again.

Agree with camel re weight. McCoy made me a couple of deluxe super lightweight, around 8'2 - 8'4". Snapped super quickly. Never did that again. Always went for strength. Mackie made me a glassed up 8'4", 3.5 thick, 21 wide, half inch wide glued up stringers, wide rail laps. Pretty hard to break. In the surf you want it for, weight is an advantage. Unless it hits you.

Udo if you 'knock the ridge off' you knock a lot of the sought after
strength re surface area/curve off, so why bother?

wellymon's picture
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wellymon commented Wednesday, 8 Oct 2014 at 3:25pm

Love flex

Our brains are too small at the moment to comprehend the reality of what's happening in our forests . We're only just waking up so to speak . The big problem is we think we know everything, we are specks of dust on a timeline and we know nothing .

shaun's picture
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shaun commented Wednesday, 8 Oct 2014 at 6:30pm

Udu are you talking about filling the groove with glass (gauze)?

I'm the scab you keep picking off and is there again the next day.

udo's picture
udo's picture
udo commented Wednesday, 8 Oct 2014 at 7:28pm

Glassing the board as per usual, the gauze -abrasive sheet was just to take the ridge off [mm] the machine cut lines, sandpaper will do.......just figured that the small concave corrugated lines left- 30 or 40 on the average deck ?
once they were glassed over would add heaps more strength ? going back to my post above re the flat steel sheet to corrugated ? then the smaller fluted version mini orb is much stiffer again...fucked if I know just thinking.

wellymon's picture
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wellymon commented Wednesday, 8 Oct 2014 at 7:20pm

Mackie
Uplift! Seen Mick surfing the most weirdest board I ever seen down south of Ullas a few months ago
Looked like 7-8 ft big arse nose and real slimmed out in the tail with the hughe ist swallow tail with a twin fin, the back of the deck was half the thickness off the boArd and beyond ???
It suited the wave, fat left hander at 5 ft and it was just flowing so smooth, he got all the best waves?
Mackie is out there for sure , I've ridden a few of his short boards and geez they have gone off pretty quick
He shapes some pretty good shit and has a step out of the realm style of thinking
Top bloke as well;)

Our brains are too small at the moment to comprehend the reality of what's happening in our forests . We're only just waking up so to speak . The big problem is we think we know everything, we are specks of dust on a timeline and we know nothing .

shaun's picture
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shaun commented Wednesday, 8 Oct 2014 at 7:47pm

udo wrote: Glassing the board as per usual, the gauze -abrasive sheet was just to take the ridge off [mm] the machine cut lines, sandpaper will do.......just figured that the small concave corrugated lines left- 30 or 40 on the average deck ?
once they were glassed over would add heaps more strength ? going back to my post above re the flat steel sheet to corrugated ? then the smaller fluted version mini orb is much stiffer again...fucked if I know just thinking.

It's the bottom that is the weak part of the board, the deck has two layers of glass and curved rail giving it strength 99 out of 100 boards break from the bottom, never seen one crease on the deck

I'm the scab you keep picking off and is there again the next day.

uplift's picture
uplift's picture
uplift commented Wednesday, 8 Oct 2014 at 11:14pm

Gidday welly, yeh Mackie is into his snow board influenced things. Awesome craftsman, and deluxe all round shaper. Can do pretty much anything. I got a custom quiver from him, 6'8", 7'4", and 8'4". Perfectly matched, so easy to jump from one to the other. Spud's he called them. That was maybe 6 years ago, and funny now how my friends show me their 'new' boards, which are similar idea, even the firewires. That area has some similar setups to here, so I like it when the shapers know first hand what you are after. So well made, still in great condition, and I surfed the 6'8" almost everyday os. Its so good all round, I can trust it from 3- 4 foot to double/ triple overhead. I've got some burger fins in it. Have to get the rear fin custom done.

Have you mucked around with kevlar much shaun? Back in the late seventies a guy in Bali showed me a kevlar kneeboard that he was belting with a hammer, looked pretty indestructable. Pain to work with though, without the right gear. And the colour. Roger Matthews made a kevlar beast for blacks ages and ages ago, and hooked into some real big bombs on it. It looked pretty rugged too.

shaun's picture
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shaun commented Thursday, 9 Oct 2014 at 6:25am

No Uplift I haven't touched it, did a couple of years sanding then glassing in the early to mid 80's. First time I seen kevlar was late 80's, but I reckon unless the board was glassed kevlar all over it doesn't really work. Over the years you see board with with strips going down guts, round the rail or on the tail, by making those strong points you create weaker points.
If you were to glass a board to make it as strong as possible it would be a messy task, boards are still and always will be popped out they are glassed to be cost efficient, at least with big guns they're harder to pop out but I see there are some that are trying. Not to many shapers outside of hawaii that shape AND ride rhino chasers, personally I can't see how they can shape really good ones if the don't get the feel for them from both a shaping perspective and flex from different glassing and stringers, there is only so much data that a "team" rider can pass on.

More importantly uplift, you mentioned that you had friends. What's that like? You know, to have friends.

I'm the scab you keep picking off and is there again the next day.

udo's picture
udo's picture
udo commented Saturday, 11 Oct 2014 at 10:55am

GEO Blanks did they ever go into production ?

stunet's picture
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stunet commented Monday, 13 Oct 2014 at 8:48am

udo wrote: GEO Blanks did they ever go into production ?

Yeah, we may even get the opportunity to test one soon. See Luke Dorrington is selling them:

http://ldcreationsurfboards.com/products/geo-blank

udo's picture
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udo commented Monday, 13 Oct 2014 at 8:53am

Not cheap @$200 more than his other shapes .

Roy Stuart's picture
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Roy Stuart commented Sunday, 7 Dec 2014 at 7:10am

The strongest material is undoubtedly 3D glass: http://youtu.be/FSAgsiFp_G4

indo-dreaming's picture
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indo-dreaming commented Tuesday, 4 Nov 2014 at 12:00pm

stunet wrote:

udo wrote: GEO Blanks did they ever go into production ?

Yeah, we may even get the opportunity to test one soon. See Luke Dorrington is selling them:

http://ldcreationsurfboards.com/products/geo-blank

I guess that would be one of Gary's Dorringtons sons, makes me feel old seeing his son shapes too i remember when they were toddlers, i use to get boards from Gary had some good boards from him.

Roy Stuart's picture
Roy Stuart's picture
Roy Stuart commented Sunday, 7 Dec 2014 at 7:10am

udo wrote: look at the stiffness attained when a .5mm flat steel sheet is formed to corrugated iron profile.

Not a good analogy since corrugations in iron increase the thickness of the beam by a factor of about 50 which is the main reason for the increase in stiffness. Deck channels in surfboards don't increase the thickness of the board at all, although they will improve resistance to skin buckling under compression.

Roy Stuart's picture
Roy Stuart's picture
Roy Stuart commented Sunday, 7 Dec 2014 at 7:12am

shaun wrote: No Uplift I haven't touched it, did a couple of years sanding then glassing in the early to mid 80's. First time I seen kevlar was late 80's, but I reckon unless the board was glassed kevlar all over it doesn't really work. Over the years you see board with with strips going down guts, round the rail or on the tail, by making those strong points you create weaker points.
If you were to glass a board to make it as strong as possible it would be a messy task, boards are still and always will be popped out they are glassed to be cost efficient, at least with big guns they're harder to pop out but I see there are some that are trying. Not to many shapers outside of hawaii that shape AND ride rhino chasers, personally I can't see how they can shape really good ones if the don't get the feel for them from both a shaping perspective and flex from different glassing and stringers, there is only so much data that a "team" rider can pass on.

More importantly uplift, you mentioned that you had friends. What's that like? You know, to have friends.

Kevlar is weak in compression and it's compression which causes boards to break. It also breaks down in sunlight.

brutus's picture
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brutus commented Sunday, 7 Dec 2014 at 5:04pm

put a 14 ply laminated stringer down the middle of the board and 6" off the stringer run another 7 ply stringer parallel to the central stringer...glass the board with a 4 + 6 oz top and bottom in Epoxy resin and bd will be pretty strong....

actually Kevlar is strong on compression and weak in rigidity.......carbon is rigid and Kevlar is used in bullet proof vests because of its ability to absorb the compression of a bullet hitting the vets.

Roy Stuart's picture
Roy Stuart's picture
Roy Stuart commented Sunday, 7 Dec 2014 at 6:55pm

hi Brutus,

Apologies for contradicting you but kevlar is very low in compressive strength, this is well known.Compressive strength isn't needed for bulletproof vests, it's kevlar's tensile strength and flexibility which makes it suitable for that application.

"Kevlar® reacts well under a tensile force (stretching force) but badly under a compressive force. It is not used where compression resistance is needed" http://www.technologystudent.com/joints/kevlar2.html

There are plenty of studies around which confirm this.

Because of its low strength under compression kevlar isn't suitable for surfboard laminates where resistance to snapping is required. It also absorbs water and breaks down in sunlight. I made a few kevlar boards in the 90's before we had access to the relevant information.

Stringers are not an efficient use of material for surfboard strength as much of the stringer is close to the neutral axis where it adds very little to strength. It's the outer skins which count.

Linq's picture
Linq's picture
Linq commented Sunday, 7 Dec 2014 at 7:06pm

Cheers Brutus : Do you make your own 3 stinger blanks or order them elsewhere ?

trippergreenfeet's picture
trippergreenfeet's picture
trippergreenfeet commented Sunday, 7 Dec 2014 at 9:57pm

Another option for a super strong board is balsa laminate like Sunova produces. Glassed to bring the weight up for a gun makes them almost indestructible...e.g. turn em deck down on the ground, step on and bounce, the board will flex and rebound straight back, no chance of creasing let alone snapping. Not too many boards that can handle that. Not the cheapest but will surf the same in 10 yrs time as the day ya got it.

This is a 7'2...knocked a bit of length off it (4") and put that extra volume under the chest and did some refining of the entry rocker for good paddling/quick planing ability. Goes off like a frog in a sock.
Had a couple extra layers of 4/6oz on both deck and bottom to get the weight up as these things can come in a bit lightweight with standard glass.