Hi everyone, I've been thinking about making my own high wind slalom board, and want to know any experienced builder's knowledge on the subject.

I'm thinking of doing an eps core, with a 5mm pvc foam laminate around that, followed by 3x 200gsm 3k plain carbon weaves at a 45 deg. offset to stop torsion and flexion, then another 4 layers of 4oz (~115g) sx glass for strength. in between the pvc and the eps there would be a sheet of glass, and a piece of carbon in the fin box and mast track area, and there would be additional glass reinforcements in the footstraps area between the pvc and the first layer of carbon.

the hull would be a double concave vee, with the rails being 5mm higher than the center, and the mast track would be recessed by 15mm as well. the recessed zone in deck and the double concave vee would be carved before laying the pvc. the eps block is 2400x600x100 so it will be about 62 wide when done, and will be cut to 2300 long so about 2320 finished . the rocker and shape will be similar to an av slalom 98 liter.

any thoughts?
cheers

Seems like way too much glass and carbon if im reading it correctly. I also wouldn't mix glass and carbon together in the same laminate unless you really know what your doing. Ill leave it to the experts to suggest laminates. Please post pics.

agree with imax overkill in the cloth department.
2 layers of carbon will give all the strength and stiffness required. But as you suspect will be subject to impact damage. I'm not sure how much glass over the top will protect the carbon.
Mixing glass and carbon like this should be OK, the problem with mixing glass and carbon is the huge difference in stiffness. It usually means the carbon does all the work. If there's not enough carbon to take the full load, there'll be a failure. But in your case, the glass is only for impact not longitudinal strength.

I suspect a carbon kevlar composite would do a better job, without the glass, but I can't be sure.

The other approach is to use the carbon under the pvc, that way it will give stiffness where needed, (between fin and front of mast track)

Then 2 layers of glass over most of the board, with a 3rd layer from rear of back strap to mast base. If you run the carbon at 45deg, it will give great twisting stiffness, but not be too much stiffer longitudinally than the glass. I have made speed boards mad like this 15 years old, without a problem

Agree with above re laminate, it's way too much fibre.
I will also add 5mm is overkill and especially on the deck
If you use carbon on a 45 there is so much waste and then it wants to deform lengthwise and suddenly it doesnt reach where you thought it did. Just use biax.
Some unidirectional carbon along rails and up the middle can add more to the board than a layer of glass all over.
And if it is your first board(?):
- the 5mm is too hard around complex curves.
- deck recess is not easy to shape, get pvc to confrm and then reshape. Leave that alone.

Agree again with Mark, I only use a deck recess on narrow boards, that I'm trying to keep some buoyancy in. Narrow boards tend to roll when water starting. 62 wide, shouldn't be a problem.
The hardest part of my board build is the recess.
Unless you can get Airex foam, that bends easily. normal 5mm PVC would be very hard to get round the rails, ( I last got some last century sometime). 3mm is adequate.

from what i've read here, would it be good to have biaxial between the 3mm pvc and eps, unidirectional along the rails, no deck recess, and have carbon/kevlar on the surface for impact resistance?
also what weights for all of it

For all of it, lot of weight! If it's your first board go with standard. For a "small" slalom board it can be 16kg/m3 eps core, bottom 3oz glass 3mm pvc with 6oz warp glass over. For top 3oz glass+ 4oz biax carbon from mast track to tail 3mm pvc 6oz biax carbon+3oz glass over and thick hot coat to have something to sand without touch fiber. You can simplify a lot build if you don't to wrap pvc on rails, stop it near rail apex and add couple strip of glass on rails when laminate.
For what is well explain by others, i avoid to use carbon and glass fibers in same direction because stiff carbon take all load. So i use biax carbon 45? with 0/90 glass.

From my garage board builder background, for personal flat water windsurf board i would stay with simple semi sandwich build: 20kg/m3 eps foam, 3mm stringer, bottom: 50mm UD carbon over stringer, 3oz glass+6oz biax carbon+3oz glass, all layers warp rails, top full 3oz glass 6oz biax carbon back + sandwich material up to rail apex then over 6oz biax carbon+3oz glass both warp rails. Sanded hot coat then spray varnish. All hand lam, only need simple vacuum for sandwich top.

So weird to see the other trolls in theyre natural habitat

Decrepit ... chode fingers... fat cat ...

Good to see you all

Some brands give details of construction windsurf.star-board.com/windsurf-board-construction-technology/starlite-carbon-technology/

Starboard starlite, jp es, rrd etech, tabou mte etc all are cheaper tech buil, monolithic with more or less wood on deck. Can make good boards with far easier and cheaper build for garage builder.

Here is some reality fun facts. If this is your first build , your board will be very heavy , ugly , expensive and be OK at best . And that's if your handy with tools. If your not handy with tools forget it. There are a lot of set up costs at first , not to mention the noise and mess. A lot of mess. If your copying a board it will end up twice the cost of a really good second hand version. If your thinking of making something that you can't get, it's a option.
Should you do it .... absolutely ! It's a great hobby for a fun thing to do. It's a 50/50 that you enjoy the build. This forum will help you through the process and hold your hand during the build . I've done it , and do it , there are some good builders that will help. Please do it and post pics all the way. You may just get hooked and your second board will be so much better.

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Imax1 said..
Here is some reality fun facts. If this is your first build , your board will be very heavy , ugly , expensive and be OK at best . And that's if your handy with tools. If your not handy with tools forget it. There are a lot of set up costs at first , not to mention the noise and mess. A lot of mess. If your copying a board it will end up twice the cost of a really good second hand version. If your thinking of making something that you can't get, it's a option.
Should you do it .... absolutely ! It's a great hobby for a fun thing to do. It's a 50/50 that you enjoy the build. This forum will help you through the process and hold your hand during the build . I've done it , and do it , there are some good builders that will help. Please do it and post pics all the way. You may just get hooked and your second board will be so much better.

100% agree, so make the build process as simple as possible, at least for your first (couple of) boards. Chances are you'll sail them but not much. If you really want to try something that no manufacturer makes, go for it! I have made lots and lots of surfboards, which in comparison are cheap to make, and still sell well, however weird, but windsurfers, you might have to give them away.

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Imax1 said..
Here is some reality fun facts. If this is your first build , your board will be very heavy , ugly , expensive and be OK at best . And that's if your handy with tools. If your not handy with tools forget it. There are a lot of set up costs at first , not to mention the noise and mess. A lot of mess. If your copying a board it will end up twice the cost of a really good second hand version. If your thinking of making something that you can't get, it's a option.
Should you do it .... absolutely ! It's a great hobby for a fun thing to do. It's a 50/50 that you enjoy the build. This forum will help you through the process and hold your hand during the build . I've done it , and do it , there are some good builders that will help. Please do it and post pics all the way. You may just get hooked and your second board will be so much better.

Totally agree with this , there's so much to learn and tools you'll need. I'm a carpenter and been garage building wing boards for a couple of years and only now happy to build a windsurf board.

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Imax1 said..
Here is some reality fun facts. If this is your first build , your board will be very heavy , ugly , expensive and be OK at best . And tha if your handy with tools. If your not handy with tools forget it. There are a lot of set up costs at first , not to mention the noise and mess. A lot of mess. If your copying a board it will end up twice the cost of a really good second hand version. If your thinking of making something that you can't get, it's a option.
Should you do it .... absolutely ! It's a great hobby for a fun thing to do. It's a 50/50 that you enjoy the build. This forum will help you through the process and hold your hand during the build . I've done it , and do it , there are some good builders that will help. Please do it and post pics all the way. You may just get hooked and your second board will be so much better.

Strongly agree Imax.

However, In the end just do it. So much can, and will, go wrong but so much will go right too.

my journey so far has been a little different so it depends on exposure and prep work. I managed to get 90% of the way there with my first build because I had been exposed to board design and building for many years, I then had some design ideas built by pros (which I'd also recommend) then leading up to my first solo build I had long detailed conversations with very experienced shapers in the surf industry, sup industry and windsurf industry (some great friends) about their approach and techniques. Reckon I spent at least a year researching. I also had long conversations with the materials and resins suppliers from the surfing and windsurfing industry about their thoughts on how to best use materials.

my builds take a while because at each stage I stop and spend time thinking through how I'm going to do the next bit of the build. Once I'm clear I dig in.

you'd be amazed how many helpful people there are that respect the process and offer great advice and help if you have the conversation. Other than this forum, when you buy materials ask the guy what his thoughts are. You never know. Last round of materials I bought turned out the guy I was speaking to. supplied cobra for many years and had insights beyond the norm.

i still get it wrong a lot, when i do I change my technique and go again. I've still only built limited numbers of boards and my boards aren't anywhere near the finish quality of the top shapers but I'm working on it. Thing is, board finish is directly tied to materials used which is also connected to construction technique.

building your own boards is significantly cheaper than buying new and significantly more expensive then a good used board deal as imax says. it's addictive if you are the type of person that enjoys a challenge.

the best advice is,
measure, measure again and measure again. Draw set out lines on you board and measure again
sand, sand and sand again. Every layer.

With every build those 2 things get the most attention

stuff needed,

Cheap sand paper from local hardware store. 80/120/240/400/800/1200/2000
Sanding block (cork)
straight edge, square, 60cm ruler, string, felt pen, pencils, pins
trim router with bits, hand saw, orbital sander or sander/polisher, plane (or cnc machine)
masking tape, masking paper, box knife
digital scales
squeegees, paint brushes, wood mixing sticks, face masks, mixing containers, cleaning chemicals, gloves, thongs
shaping stands, good lighting, good ventilation
plastic sheet under shaping stands
dusting brush
quality scissors
Board materials and fittings
Resin additives, tints, paint
work bench beside shaping stands

patience

layout table can be handy but not essential

that should cover most things

Another approach would be to reach out to a local shaper and ask them if they would be interested tutoring you to build a board at their factory. This does happen. Most shapers I know are more than happy to take on something slightly different just to change things up or gain new experiences

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Gestalt said..
stuff needed,

Cheap sand paper from local hardware store. 80/120/240/400/800/1200/2000
Sanding block (cork)
straight edge, square, 60cm ruler, string, felt pen, pencils, pins
trim router with bits, hand saw, orbital sander or sander/polisher, plane (or cnc machine)
masking tape, masking paper, box knife
digital scales
squeegees, paint brushes, wood mixing sticks, face masks, mixing containers, cleaning chemicals, gloves, thongs
shaping stands, good lighting, good ventilation
plastic sheet under shaping stands
dusting brush
quality scissors
Board materials and fittings
Resin additives, tints, paint
work bench beside shaping stands

patience

layout table can be handy but not essential

that should cover most things

Thongs ? I know it's good to feel comfortable, but shorts will work fine.

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Imax1 said..

Gestalt said..
stuff needed,

Cheap sand paper from local hardware store. 80/120/240/400/800/1200/2000
Sanding block (cork)
straight edge, square, 60cm ruler, string, felt pen, pencils, pins
trim router with bits, hand saw, orbital sander or sander/polisher, plane (or cnc machine)
masking tape, masking paper, box knife
digital scales
squeegees, paint brushes, wood mixing sticks, face masks, mixing containers, cleaning chemicals, gloves, thongs
shaping stands, good lighting, good ventilation
plastic sheet under shaping stands
dusting brush
quality scissors
Board materials and fittings
Resin additives, tints, paint
work bench beside shaping stands

patience

layout table can be handy but not essential

that should cover most things

Thongs ? I know it's good to feel comfortable, but shorts will work fine.

To the list i would add
1. Speedfile. Its a auto body tool, just a long sanding block that takes standard sized sheets. Not the rubbish that passes for a standard at Bunnings. Also a dense foam sanding block for wet sanding, the one that takes half a normal A4 sheet of sandpaper lengthwise. Go to a real paint that auto painters use to get this stuff.

2. Make a shaping square for rails. Its easier than checking with a t-square and sanding here n there but not all along the rail.
Everything starts with a perfectly square rail once the outline is cut. If you dont get outline right, then square the rails right, you will be chasing that with fill all through the build and that gives u the weight. Will do a pic when i am next in shaping room

^ I may need to look into a speed file as my large shaping blocks keep delaminating.

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i think imma practice techniques on a smaller scale such as a board for skurfing or whatever, then when i get better imma make a proper windsurfing board

(also what pvc do i use in the sandwich, divinycell h100 looks really good but i cant find any sellers for a normal price or the right size. any alternatives?)

80kG/M3^ 3mm thick is fine. Afraid you have to live with whatever size sheet it comes in. I can normally get a board out of 1 sheet. But it may require a join or two. But joining the pvc is ok as long as the join is filled with resin. The PVC is only in compression, the cloth takes care of tension.

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kasra said..
i think imma practice techniques on a smaller scale such as a board for skurfing or whatever, then when i get better imma make a proper windsurfing board

(also what pvc do i use in the sandwich, divinycell h100 looks really good but i cant find any sellers for a normal price or the right size. any alternatives?)

For a first garage windsurf build you should stay with a starboard starlite carbon like tech. Buy a pre shape eps blank so you only have to finish sanding it slowly with simple tools, and start with a good shape. Seal top and bottom with epoxy micro slurry. Set fin box. Hand lam 6oz biax carbon+ 6oz warp glass on bottom warping rails. Sand laps. Hand lam 6oz biax + patch on top, warping rails, vaccum bag wood veneer on deck, fair wood at rails, set mast and straps boxes, then lam 6oz warp over warping rails. Sand laps. Hotcoat, sand, finish coat, sand. Enjoy your board, dream of next one...

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decrepit said..
80kG/M3^ 3mm thick is fine. Afraid you have to live with whatever size sheet it comes in. I can normally get a board out of 1 sheet. But it may require a join or two. But joining the pvc is ok as long as the join is filled with resin. The PVC is only in compression, the cloth takes care of tension.

so any closed cell pvc foam with 80kg/m3 density or heavier is fine, and joining with resin is fine. got it.

Great topic, how about some photos?
As a guy who likes reviewing a few decades of W. Surf mags I'm often amazed how the 'current' overall outlines change - and always claim to be the Cats meow.

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Andy1712 said..
Great topic, how about some photos?
As a guy who likes reviewing a few decades of W. Surf mags I'm often amazed how the 'current' overall outlines change - and always claim to be the Cats meow.

I don't have any photos, haven't started it yet. I will start it when i have some spare money, my wallet is quite restrictive right now.

Select to expand quote

Imax1 said..
Here is some reality fun facts. If this is your first build , your board will be very heavy , ugly , expensive and be OK at best . And that's if your handy with tools. If your not handy with tools forget it. There are a lot of set up costs at first , not to mention the noise and mess. A lot of mess. If your copying a board it will end up twice the cost of a really good second hand version. If your thinking of making something that you can't get, it's a option.
Should you do it .... absolutely ! It's a great hobby for a fun thing to do. It's a 50/50 that you enjoy the build. This forum will help you through the process and hold your hand during the build . I've done it , and do it , there are some good builders that will help. Please do it and post pics all the way. You may just get hooked and your second board will be so much better.

That has been my experience and I am so glad for it!

If time was not money....fun question , would overlapping rails at each lam layer one layer at a time , be better ? Am I missing something, Surely a mini overlap has got to be better than a butt join ? A overlapping join has to be its weight in gold ?. Whenever I fix a mast crunch nose damage , its because there is no cloth overlap and the board suffers sideways damage along the butt seam. If board construction was overlapped, a soft crunched nose would would most likely survive and not leak water and be happy with itself. It's not like it's doing anything. Except leaking.