I have the opportunity to get a heap of eps sheets 90 mm x 1mtr x 4mtr . And I have looked at every board making site possible I have a good understanding of the difficulty & time involved .
I have the shed & tools & skill with tools and I feel confidante that i should be able to do a reasonable job . I will have to make a hot knife but that's no problem. What I don't have is an understanding of the finer aspects of board design .
So I'm making this appeal in the hope I could be directed to a book or website or tech course that could give me a better understanding of this or the diminsions of current boards .
Even if I don't end up making boards out of it & I just use it to line the shed with I would still like to know more about board design so I can understand what happens when subtle changes are made with the new models. I would like to start with a board about 120ltr & then do a board about 70ltr .I'm 70kg I thought about doing the 70ltr 1st but it just wouldnt get used that much in sydney so I would have a long wait to be able to use it & I think that the smaller board would be less forgiving if the design was wrong I could be wrong thats just my thoughts. So any help would be greatly apreciated .
Thank you
Max
there is a lot in your question. and to much too handle on a forum, i say just go for it.
check out as many surfboard design webites as you can for info on rails, rocker and terminology.
there is a free 3d software package i use called boardcad. you can download it off the net.
the other item is the foam you've listed is almost too thin. you will struggle to get your volume with a reasonable width unless you laminate 2 sheets to make a 200 thick block. not ideal but very possible.
are you using polyester or epoxy? what resin is suitable for the foam you have? vac bag construction requires jigs to prevent the rocker from deforming while bagging.
keep asking questions here as you go and don't be afraid to take your straight edge and tape to the beach and measure every board you find.
Gesty's right, 90m is a bit thin, most of my boards come out of 150mm blocks. eps will bend but that gets a bit complicated.
I've been shaping boards for over 25 years now and I'm still learning what tiny little changes do to a boards performance.
When starting out I read a quote by an awesome shaper Jimmy Lewis who said get hold of the best board you can and copy it!
My first few boards were pigs to look at, went ok but rail shapes were very lumpy.
swaylocks.com would be your best bet for info and help it is for surboards but similar principles.
This is really, really basic generalization and is an example of extremes at two opposite ends, a flat ish rocker (which is the bottom curve of the board from nose to tail), planes early,stiff to turn and is fast, whereas a very curvey rocker is slow to plane, can be slow as it is pushing water but super easy to turn. a good board finds the balance between these two extreme to suit the characteristics you want from a board.
The outline also affects turning and planing as does the width.
The bottom or the rails determine how easily water is released from them and the thickness how easy or hard they can be pushed into the water during a turn depending on the riders weight.
It gets a lot more complex.
Just copy a board and go for it!
thanks people it will be epoxy i have some & probably 1mtr2 of carbon fiber already i also have klegi cell for fin box mast track foot straps . Don't mind about jigs I'm used to making jigs for jobs . I would glue the blocks together contact cement was a glue mentioned as it could still be cut with a hot knife & no have a hard spot for shaping. I was sort of wondering Is there a ratio between length of board & mast & fin & foot strap positions or is the track always set for the 1350mm mark . I like your suggestion gestalt I will start to measure boards . I might hire 1 just to measure when i get a bit closer to making it . I have a mike davis fiberglass tri fin that i feel is really close to the modern tri fin shape but the mast track is wrong position glass is pretty smashed & the foot straps are some cobre things i cant get so i might strip that & practice on that first . I will have to wait as work has been really slow so low in funds at the moment but it will come in time i just like to follow decartes theory throughly review the problem breaking it down into smaller pieces until the solution is clear & distince in my mind . I find the more i study the less problems I have. I did think that there might be a table of sizes of boards somewhere.
these are all approximates
rear of finbox - 100mm from tail
foot straps 500mm apart
strap plugs approx 150mm appart.
rear of mast track 1250mm from tail.
position of straps to finbox is dependant of rocker/fin/board type
important dimensions
wide point from tail
tail width at one foot off
aspects to focus on are rocker, 3d volume distribution, position/length of planing flat, rails.
edit,,,, i wanted add, when designing somehting from scratch, it's almost impossible to produce the perfect design first build. it takes a minimum of 2-3 protos to get close to the mark if you have a firm idea of what works and what doesn't. the best way forward is to design your board in 3d, do as many revisions as needed, then build your board and make tweaks to that model after sailing it so you are always moving in a forward direction and you have something to compare each change to on the water.
experienced shapers have templates they know work for particular conditions or design briefs and they make small tweaks from there to suit the individuals needs.
i dont believe everyone is encouraging actionmax to go ahead with this project it's like some gives you some windows and door's and you design a house because you got the stuff free
in my opinion the hole project is starting off on the wrong foot because the blank has to be joined, no matter what you call it that means extra weight, the whole idea is to keep the weight down not to mention how much stuff what ever your useing do you need to make sure you have a perfect bond, thats a lot of area to cover not to mention the glue line, no matter how hard you try your always going to get a high on the glue line,
i dont know what the answer is to the rest of your questions because i wouldnt even start the project
ok so one blank is 90 mm x 1mtr x 4mtr , what you do is make a high wind flat water speed board, get your blank and chop it too 90x500x4mt then you chop that to 250x4mts stand the blank on its edge and using some house bricks or anything you can get you bend the rocker into the blank
next step ......., mark out the thickness of speed board (tail to rocker) bet some 200gr uni carbon and make sure the grain is longitudinal using a wheel make the stringer
next step........ after that has set you have 250 blank with carbon stringer now get the other 250 stick it on the ground and put the bent blank on top and bend the bottom 1/2 to the same as the the top, get some resin and join the 2 blanks
next step now you have a blank with a carbon stringer and because the carbon grain is longitudinal the blank is incredibly stiff
next step.......all you need to do is sand down to your stringer remembering to keep every thing square
you will end up with a speed board that you dont want but its better than haveing a board that doomed for the tip
"edit" if you need a more thickness its easy to add it just where you need it but do it before do the stringer
honestly keef, that's shocking advice
boards aren't built that way.
yeah in the 80's board were hand shaped from pre rockered blanks and finished in polyester.
now blanks are cut from foam blocks with hot wire and templates, rails, concaves are hand finished then the whole thing gets vacuum bagged on a jig.
this is one of the fallacies in windsurfing. that custom boards are not as accurate as production boards. when in fact they are all made the same way. to template or on 3d cutting machines. only difference being laminate makeup and resin amounts.
stringers are not really laid between 2 halves of a blank anymore either. wave boards still use them but most slalom/speed boards the stringer is a carbon strip laminated to the bottom or deck of the board.
i don't like stiff, i prefer veneer, the board feels nicer and is more forgiving.
so if actionmax wants to build a board. he would laminate 2 pieces of 90mm thick foam together giving him a 180x1000x4000 piece of foam and then use plywood stencils to hot wire the rocker and plan shapes. or 3 pieces and end up with 270mm
if the resin joint of the board is a problem then use a knife to trim it back. the only issue you get is the joint between the 2 blocks of foam can loose some of the foam during shaping. you can use some filler to make it true again.
other than that, he can do what some on this forum do. design the board and get a recognised shaper to build it.
think of the foam as permanent formwork. it has no real structural integrity.
edit, anyways, the foam is the cheap part. just buy another block if it's that much of an issue.
If you want to glue 2 pieces of eps together use water based contact adhesive. Not the most ideal way to do it but it will be okay. The hot wire will go through it no worries.
You can bend the rocker into an eps blank but it it will always be a whole lot easier and more accurate if you have enough foam to cut it exactly.
Get into it and have some fun doing it. Riding a board you have created your self is a cool thing to do.
As an exercise, it could be quite interesting to do, but i wouldn't hold out much hope of the board working well.
There are several grades of EPS. When I built a board from it I used a higher density fire-retardant grade because it was much better for sanding. The lightest grades tend to rip bits out of the surface when you sand and would retain a lot of resin during layup due to the coarse grain. I got them to tilt a block up and feed it horizontally past the hot wire to give me two wedge shaped blocks.
Epoxy needs about 20 to 25C and you need to have the core at that temperature for a while before layup otherwise air will expand out of the core under the layup if you put the heat on too late - like I did.
I've made a couple of boards with joins and have to agree with keef on this one gesty.
Unless there's a hot wire-able glue that doesn't melt eps!
Guess with a bit of inventiveness you could hot wire the bits separately then glue them together, but that doesn't seem all that easy.
And sanding across the join is always a pain. there's bound to be a difference in abrasive resistance.
I've also made boards by bending the foam, and the rocker hasn't come out quite as I wanted.
Keef's idea of a carbon stringer could be the answer.
I'd taper the front off first, that should make bending easier, as would getting some heat into it, boiling water probably the safest, (for the foam anyway).
A 120 litre board should be possible at 98mm thick, just needs to be wide and long enough.
it's posibble to use a combination of hand saw and hotwire.
or use the glue that hoops recomended.
another question is what density is the eps? isn't 14kg/m2 what should be used.
keef, depending on how much rocker the board has you "may" be able to position the rocker template so that the join in the foam doesn't require cutting at all.
then you use a saw to cut out the outline.
with respect, it's certainly more accurate then using car tyres. at least if you are going to use car tyres use a jig to ensure your rocker is fair.
carbon strips in the horizontal plane work as stringers when under tension. like when landing a jump
Keef, it's just a personal thing with me, I don't like stringers and try to avoid them, even if my alternative doesn't seem as efficient.
Gestie, can't see how you could add extra foam thickness, without having to cut the rocker line through it.?
OK, I think I see, would have to be a line between bottom of tail and end of nose I guess, not very intuitive, bit of lateral thinking there mate.
I think you may have solved it!!!! But it is a big join, glue weight is going to be a factor.
My joins have just been through a small section of the nose.
I didn't think that gluing the blocks together would be such a massive problem after all I have just seen a board widened on this forum & I imagined that it was glued in some way . Starting to look to hard for me now Ill wait until I get the eps & then see how I feel . I've got blocks of the fire retardant stuff I've used that to line the walls of the shed & its heaps heavier . When they metal skin the eps for roofing they use contact cement well that's what it looks like . And just a small note if i was building a house & someone gave me the windows I would design around that as glass is much more expensive than brick. I will strip & do the glass board I've got & see how that goes first . If it totally sucks well that will be the end of my board building . Thank you for the advice everybody
I've joined EPS with the thinnest layer of epoxy and qcell (vac bagged)I made i very very thick mix.
Just held my breath when the hot wire cut through it, as the epoxy stinks and is probably toxic at that heat.
That fire retardant styrofoam is probably about 45kg/m whereas the eps is usually 12 to 15kg/m I've used a contact cement designed for the fire retardant foam.
Rider, how did you apply the epoxy/qcell?
Every time I've tried a thin stiff mix, it's dragged the cells out of the foam.