would you buy a board built without sandwich construction

Windsurf? No way

Why?

Cos

Stronger for its weight
Stiffer too

Old poly waveboards didnt last and were heavy.
There isnt sufficient stiffness for proper fast boards we didnt go from 35kn to 50kn WR just on shaping and sails....boards bend n twist

For a beginner board yeah but not after that

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Imax1 said..
Cos

Lettuce?

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Mark _australia said..
Stronger for its weight
Stiffer too

Old poly waveboards didnt last and were heavy.
There isnt sufficient stiffness for proper fast boards we didnt go from 35kn to 50kn WR just on shaping and sails....boards bend n twist

For a beginner board yeah but not after that

Same as what Mark_australia said....

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Mark _australia said..
Stronger for its weight
Stiffer too

Old poly waveboards didnt last and were heavy.
There isnt sufficient stiffness for proper fast boards we didnt go from 35kn to 50kn WR just on shaping and sails....boards bend n twist
I
For a beginner board yeah but not after that

I'm not convinced stiffer equals better but strength maybe so. Especially for guys doing big moves.

it's a lot easier and cheaper to build Without sandwich, I'm of the feeling that sandwich construction may have lead us down an expensive high tech path that for most of us ain't needed.

ok Here's a choice

$4000 sandwich board or $2000 no sandwich board

I take it you are excluding the plastic rotomoulded boards of the past and the Patrik Airinside boards of the present.

If you mean a board with a polystyrene core and no sandwich, then no I wouldnt.

Yes I mean a board with an eps core , stringers and epoxy skin.

The science says that epoxy is about 20% stronger than polyester. So if we build an eps board like an old pu board it would be 20% stronger before even looking at improvements in other materials used in the build

Strength isn't everything. Epoxy is also soft. That board will dent like crazy, unless it's full carbon, and you use heavy foam. Not going to come out any/much cheaper, and it will be impact sensitive.

And the dents become delam very quickly especially with high air volume in styro.

Its not a case of unnecessarily flash....... sandwich is just light years ahead of non sandwich.
And stringers dont add strength as the tensile strength of the glass is far higher than the wood, the foam or the bond thereof. So if the glass fails the board breaks. Like adding a bit of string to a bridge wont make it stronger or hold longer during failure. Old surfers fallacy sorry.

Not to say you can't make a good board with foam n fibre ..... but it wont be as strong or light and certainly not the perfect blend we have achieved in the new construction say post c1990

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Mark _australia said..
And the dents become delam very quickly especially with high air volume in styro.

Its not a case of unnecessarily flash....... sandwich is just light years ahead of non sandwich.
And stringers dont add strength as the tensile strength of the glass is far higher than the wood, the foam or the bond thereof. So if the glass fails the board breaks. Like adding a bit of string to s bridge wont make it stronger or hold longer during failure. Old surfers fallacy sorry.

Not to say you can't make s good board with foam n fibre ..... but it wont be as strong or light and certainly not the perfect blend we have achieved in the new construction say post c1990

Stringers can be anything, wood, plywood, carbon, t stringer, uni cloth, rail bands.
I don't agree a stringer won't add strength. Question is how is it implemented.

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decrepit said..
Strength isn't everything. Epoxy is also soft. That board will dent like crazy, unless it's full carbon, and you use heavy foam. Not going to come out any/much cheaper, and it will be impact sensitive.

You may be right long term. Pu boards dented. My current single skin epoxy board with veneer patches feels pretty strong but I would expect long term dents. Sandwich boards eventually dent after heavy use.

prob with sandwich boards is they split. Single skin boards dent but don't split.

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Gestalt said..



I'm not convinced stiffer equals better

Why not convinced?

the less stiff a board is the more it can contort out of the intended shape. At best that means you're not getting the intended ride characteristics. at worst de lamination, or the foam could fracture through movement with time. I don't think EPS would be that great at holding together when it gets subjected to constant repetitive contortion (keeping in mind a windsurf board has to deal with loads outside of what a surf board does).

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Subsonic said.. >> I don't think EPS would be that great at holding together when it gets subjected to constant repetitive contortion.

I'm convinced you are correct. I had to fix a very badly delamned board, no sign of water in it, the sandwich resin penetrated the foam at least a cm, yet foam had completely broken down, and the pissy little sub stringers were broken.
I think the board was used in heavy chop by a big rider, the flexing of the foam caused it to just come apart.

no. I made a few (4) which were useful to try odd shapes that nobody was making, but they were heavy. I put my heel through one, (deck pad, veneer, glass the lot) and creased another. My next one(s) will be sandwich once i learn to vac bag.

Long time ago when sandwich boards did just conquer the marketplace a friend of mine was offered from a very experienced repair man and shaper to have a new slalom board custom made in the "traditional" way: wood stringer, eps foam core, epoxy, no sandwich, but oven care. The shaper was pretty well considered at the time, working closely with an important shop in Rome Italy. So unfortunately my friend agreed with the deal.
The result was a board that weighted much more than my similar volume RRD 281. The feel on the water was not nearly close: my RRD felt stiff and quick, his board felt soft and sluggish. Over time the stringer protruded slightly from the EPS core, so that it was possible to sense it bulging under the epoxy skin. In less than one season, that board, which was supposed to be aimed at an expert sailor, became of practically no value, as no one with the skill needed to sail it would ever consider to buy it.
On the water all the shortcomings showed even more boldly than onshore.
If everything is sandwich now, despite the high cost that make things hard for both those who sell boards and those who buy them, is for some reason.
And anyhow, if one looks at the WeOne and Tribal price lists, sandwich boards may be priced decently.

Back in the late 80's I purchased a "windsufer" slalom board it was 120 liters the core wasn't eps but it was built light around 7kg from memory, board didn't last dented so easily but was so nice on the water.

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Gestalt said..
would you buy a board built without sandwich construction

Yea if price was right.
A few friends have built and sailed single skin wave boards cos it was cheap and quick and they wanted to try something different out. Good groundswell conditions, good level sailors, lasted a couple of years.

NO!!! Non of my boards from the 90s survived and they were all single skin/ stringer epoxy/polly. A well built composite board will be stronger, hold its rocker line and resist damage far better. Build at your peril

Out of interesting and I am aware that this is the windsurfing forum.
I just checked out the NSP website and at random looked at one of their foil boards which looks like it is foam, a carbon stringer, carbon on the standing area, fiberglass, and EVA on top.
Foil boards go through a fair bit of abuse how can a foil board get produced without being a sandwich production?
I thought it might also be a length thing but this board comes in a 7"2'

Most wing foil boards ( not all) are non sandwich. I cant ever recall seeing so many damaged boards on the beach its at least a weekly occurrence that I see a knee of hip through a deck or rail. Sandwich for me all the way

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geoITA said..
Long time ago when sandwich boards did just conquer the marketplace a friend of mine was offered from a very experienced repair man and shaper to have a new slalom board custom made in the "traditional" way: wood stringer, eps foam core, epoxy, no sandwich, but oven care. The shaper was pretty well considered at the time, working closely with an important shop in Rome Italy. So unfortunately my friend agreed with the deal.
The result was a board that weighted much more than my similar volume RRD 281. The feel on the water was not nearly close: my RRD felt stiff and quick, his board felt soft and sluggish. Over time the stringer protruded slightly from the EPS core, so that it was possible to sense it bulging under the epoxy skin. In less than one season, that board, which was supposed to be aimed at an expert sailor, became of practically no value, as no one with the skill needed to sail it would ever consider to buy it.
On the water all the shortcomings showed even more boldly than onshore.
If everything is sandwich now, despite the high cost that make things hard for both those who sell boards and those who buy them, is for some reason.
And anyhow, if one looks at the WeOne and Tribal price lists, sandwich boards may be priced decently.

something sounds odd here. I never considered my pu boards back in the day to be soft and sluggish. i still got a speed board in the garage from the early 90's that doesn't suffer from any of those traits. An eps board should not be like that either. so i'm thinking the wrong density foam was used for the build.

i currently sail an eps board built without sandwich and it's stiff and fast. i race friends on similar gear and i'm not slower.

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jontyh said..
no. I made a few (4) which were useful to try odd shapes that nobody was making, but they were heavy. I put my heel through one, (deck pad, veneer, glass the lot) and creased another. My next one(s) will be sandwich once i learn to vac bag.

this is my biggest concern.

what density eps did you use?

great to read everyone's thoughts and experiences.

i agree that sandwich construction is stronger, stiffer and lighter but...... there's more than one way to skin a cat and i'm of the mind the current cost of kit will kill windsurfing.

i'm a big believer of lighter being better and this is the one area where single skin boards can't compete.
but stiffer? I dunno if that's a good thing. I'm not a fan of full carbon boards in bumpy conditions. A bit of flex to me works better.

I've built a board without sandwich construction and so far not experienced some of the stuff above. Although when i embarked on that journey i thought the comments above would have been the outcome. granted it's not my daily driver.

The science says that eps is indeed more prone to delamination than PU. However i think the science says EPS is stiffer than PU when comparing like for like densities. My feeling is that what's missing from the conversation is what density foams are used in the boards getting easily damaged.

would we consider a single skin with veneer in it to be sandwich or does sandwich need a pvc or similar core.

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decrepit said..

Subsonic said.. >> I don't think EPS would be that great at holding together when it gets subjected to constant repetitive contortion.

I'm convinced you are correct. I had to fix a very badly delamned board, no sign of water in it, the sandwich resin penetrated the foam at least a cm, yet foam had completely broken down, and the pissy little sub stringers were broken.
I think the board was used in heavy chop by a big rider, the flexing of the foam caused it to just come apart.

from what i understand, EPS has a worse bond strength than PU. i don;t know how density effects this tho.

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sheddweller said..

Gestalt said..
would you buy a board built without sandwich construction

Yea if price was right.
A few friends have built and sailed single skin wave boards cos it was cheap and quick and they wanted to try something different out. Good groundswell conditions, good level sailors, lasted a couple of years.

the next board build will include a sandwich but after that i'm going to have a crack at a wave board idea and get someone whos a much better sailor than me to push it. i like the feel through the turns through with my single skin board which was a surprise so i'd like to take this idea further

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Gestalt said..

sheddweller said..

Gestalt said..
would you buy a board built without sandwich construction

Yea if price was right.
A few friends have built and sailed single skin wave boards cos it was cheap and quick and they wanted to try something different out. Good groundswell conditions, good level sailors, lasted a couple of years.

the next boards build will include a sandwich but after that i'm going to have a crack at a wave board idea and get someone whos a much better sailor than me to push it. i like the feel through the turns through with my single skin board which was a surprise so i'd like to take this idea further

I reckon have a go! I have an idea for a hand lam'ed wave board using basalt and doing it differently using eps with a structured expanding eps foam we developed on the deck - instead of a sandwich construction

When get a chance/ time to do it we might post it up here as we go along.. this could be a way for backyardies to make a board with single skins instead of the vac bag sandwich route.. just need the time to play around..