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[ric_vidal]

Question fellows... for those migrating to EPS core boards, do you trim down the dimensions any?

My current dimensions (when the back allows) 6'10" x 19 3/4" x 2 5/8" pintail (hey, I’m getting older), but as a sometime maker now virtually full time repairer pretty much will have a dig at anything that floats me adequately.

Guy brought in a Gunther Rohn EPS/carbon rail for repair and feels very light but with the ubiquitous compressions of non-skinned boards and can’t see it standing the test of time. Bet it would be lively though.

Had a conversation with Dick Van Straalen recently about a repair and we was of the opinion most EPS manufacturers were making their boards TOO light, and if I understood him correctly, he said EPS surfed light even if glassed heavily (due presumably to its buoyancy)

Never ridden a Surtech or similar product but well aware of the corky/stiff reputation.

Also asking due to a bit of feedback I’ve had directly on Huie’s travelling CDD board, for those that look in on Realsurf and are aware of his project, and a lot have commented on the paddling/flotation. Now I know very little about the CDD blank but have assumed there might be some correlation.

Still yet to do a proper compsand after a couple of hashed attempts but feel the time is fast approaching, but have to learn how to chew Innegra first.

[lemat]

Two boards with same volume and same weight floats the same, even it's EPS or PU. If board is lighter and you want the same float you have to reduce volume.

[ric_vidal]

Isn’t that the point though, Lemat, a compsand I would have thought would normally be lighter?

[Kit Sidwell]

I've been making my last dozen or so just about as heavy as a PU, just to ensure durability. So I haven't been changing the dimensions at all.
I think if you are making them extremely light, say around 5 pounds or less, then maybe a slight adjustment in thickness.
I'm no expert, but my feelings are that that rail should be kept the same, as it is so crucial to how the board performs.
Lose a little bit of volume down the centre line if you want.

Surfboards are made with volume to mainly assist paddling, not the riding, right?
You can ride a piece of plywood if you can successfully get into the wave.
Makes me think that the rail should as the last 50 years of refinement has dictated.

The other thing is that some people claim that the overall design has to be changed to suit the different materials -
I used to believe this, but I was just repeating the ideas of others.....
I now feel that thinking like that ruined at least 15 or 20 of the early compsands I made, as I was making them really wide and really thin....
Now i've gone back to "standard" shapes that would be great in PU, and i'm much happier.
Not saying that the proponents of such boards are wrong, merely that I couldn't make it work.
By the same token, i'm about to do some really light boards and will not be changing the dimensions at all!
Looking forward to the extra float.

Huie has been making the lightest boards I've ever heard off, and has many different people riding them. Would love to hear his take on it.

[satch]

Don't forget your body weight. A surfboard does not only float itself but also the rider. So if you have a big breakfast or are in your winter wetsuit you  loose floatation too.
You will primarily notice the difference in weight between two boards that have same size and volume, when you are turning, because the second moment of inertia is lower on the lighter board.

[Offshore]

I agree with Kit on this one, I have done the same, started wide and thin, tweeked the design little by little and ended up with pretty standard PU type dimensions.... planshape rail and rocker. If you want it to ride like a PU build it the same dimensions, glass it heavy (So final weight is same as PU) or glass it light and maybe take 1/8 off the thickness. Dont change anything else.

 The real bonus with EPS is you are not constrained by stock standard blanks so experimental boards are easier to build, short, long, skinny, wide, huge concaves, crazy vees and hulls, rockered for africa or flat as a door. Whatever floats your boat !

[ric_vidal]

Thanks for the responses all, helps me crytalise in my mind how I should go.

OK, next question and realise there is probably a topic on it... using contour mats, can one still shape normally and expect the skin to conform?

[Kit Sidwell]

Don't forget your body weight

Just like getting somewhere warm and that feeling of lightness without your wetsuit.... oh so good!
The argument has be made before that the overall weight/buoyancy of the board an rider is the way to look at it, but I feel thats not really relelvant.
If a board is 30% lighter, you will really notice it! Doesn't matter that that is only a tiny percentage of the combined weight. I never understood peoples arguments the other way.

Ric,
Skins will conform to basic concaves, singles and doubles if not too abrupt. What is it you are trying to do?
I shape the concave into the board always - if i'm using a concave mat i'll just do it roughly, but some times I don't use a mat so i'll be accurate.
If not using a mat just weight the board onto the rocker table (I strap it down with roof-rack straps) rather than bag it to the table, but be careful to only have pressure over where the board touches the table, for example: a single concave I put some eps blocks out on the rails, so the straps only apply pressure there, and son't collapse the concave in the middle of the board. For a vee you have to have the block in the middle of the board, and I put wedges out under the rails to stop the board from rocking on the vee and thus twisting.
Hope this makes sense!

[lemat]

I never go wider and thiner because i want to keep my standard shape. First i didn't think flex was important, now i don't know.
So to keep a nice light new disposable PU flex, with same weight, and lot more durability, i make deck wood skin on 1.9# stringerless EPS with standard 1x6oz or 2x4oz bottom (or more if you want stronger  board), so you can make all type of bottom you want. Lam bottom first, it keep rocker when you bag so you don't need rocker bed, really simple.

Sorry for my french english 

[ric_vidal]

What is it you are trying to do?

Kit, dunno yet! Just want to find out the pitfalls... the beginner’s guide kind of died in the bum and sometimes reading info is hard to absorb (well for me anyhow) as opposed to physically seeing how something is done. Thanks mate.

To you too, Lemat, your Finglish is understood.

[huie]

soory i heare ya  ill be back   a s p

[huie]

ric  take the traveler for a padle for its low volume it may suprise you?

kity cat & i are doing a compsand with a diference will send you pics as we go
we will even use some innegra.

[ric_vidal]

ric  take the traveler for a padle for its low volume it may suprise you?

kity cat & i are doing a compsand with a diference will send you pics as we go
we will even use some innegra.

Will do H... looks like some swell is a coming.

[Jarrod]

I think there are too many variables changed between poly/poly and eps/epoxy to be able to attribute a difference in feel to weight only.    EVERYTHING is different, not just the core.

That said, I have always been firmly of the belief that claims of "more bouyant" EPS is pure horseshit. 

Same volume and same weight = same bouyancy.   Period.

Same volume and 20% lighter weight = slightly more bouyancy.  At first glance.   

Bear with me here.

Numbers simplified for math.   A 5kg board vs a 4kg board, same volume.  One would appear to have 20% more bouyancy due to 20% less weight.    Put a 95kg surfer sitting on top of those boards, however, and you only have a 1% difference in overall system weight/bouyancy.   You think you can feel a 1% difference?

A board never surfs by itself, there is always a surfer involved, so "HUGE" differences in board weight won't really make a huge difference in bouyancy.

Of course, there are MANY other variables involved, such as the very important moment of inertia mentioned above.   That's a HUGE factor when a board's weight is reduced by 20% at the end of meter-long levers (your legs).   But that doesn't have ANYTHING to do with bouyancy, which is only really a factor when you're paddling in or paddling out.

Epoxy feels different.  Adjust build schedule accordingly.   EPS/Epoxy is not "more bouyant".  Don't adjust shape/volume to accomodate it.

[lemat]

I feel more light weight when surfing and not a lot when paddeling. I find that my heavier board (same volume than my lightest) is better for take waves and paddeling in general. But on the wave ...

Entry rocker is important for paddeling.

Sorry for my english !