DIY downwind board - Advice wanted.

That lamination wont be anywhere near sufficient. Tracks need to be in a big block of pvc foam for a start and patching is more like 4 layers of 200gsm.
How much glass depends on foam density.

Also, its hard. Lots of things online are wrong like the homebuild foil board where the guy pours a litre of resin on the glass, then moved it with the squeegee blade - styro gonna suck half that resin up before u can move it. Basic errors like that abounds on yoochoob and stay away from the track installs with gorilla glue folks.

Common styro no good, need 28kg min, 35kg better. The 13-16kg stuff needs sandwich construction (a way better board, but thats not for newbie)

Have a go for sure but be aware its not just a surfboard with bigger boxes.
Watch more pro windsurf board build videos than surf ones.

I did this with a friend, was super fun, very technical and required a lot of reading, a complete pain in the and I'll never ever shape another board again I'm pretty certain, but the whole process was very interesting and rewarding and the board turned out usable. 100 hours easily sunk into the whole project.

I did it at the beginning of this year, prior to all the production boards hitting the market, and now that prices have settled I'm getting a nice price on exactly the dims I wanted. Beginning of the year that would have been double the price at least!

Unless you have a **** load of time I would suggest it isn't worth the effort, and you will be too busy to surf. You should also factor your budget probably in the region of USD500++ in expenses with the vacuum bag, mistakes, etc. If you get the build wrong, you could end up with a sponge that will suck up water and be useless.

I'd suggest if you are doing it to save money then it probably won't save much money, but this depends on how much you value your time, how much space you have to make a huge mess and how likely you are to build more than 5 boards.

Any question you may have will have been asked and answered many times here www.facebook.com/groups/232666917793846

What info is bad here so far?,

Thanks for your replies. I have tried to join the fb page however it's been pending for many days so not sure what's up with that.
I've done many stupid projects before- some successful, some I've thrown away or sold as parts so not worried if it goes bad - it's more an exercise for the mind & try something new. I've got heaps of time nowadays. The price of new DW boards is silly money over here - $3K plus shipping so if I can get away for something under a grand i'll be happy.

OK many issues there sorry

Firstly get real foam, cut to size, at a foam supplier. Seems you're in melbourne...? There will be polystyrene suppliers who use a CNC hotwire so you can order a block say 2000 x 500 x 300 ish for $150-$200 and starting with perfect square and parallel makes a massive difference. They should have 13kg (SL), 28kg (VH) as aussie standards. 13 will require sandwich / vac bag etc. 28 is OK for surf craft with enough fibre lam. I've made a LOT of kiteboards with it for jumping hard.
Advantage #2 there is you know the density, so then we can advise a lamination schedule.
#3 - if you glue bits together, the glue is harder than the foam and you will never sand the blank just right, without raised glue line and trust me its not fun. Make first board easy.


PVC foam - any composite boat builder will have offcuts they will sell, way easier to get some 20mm ish thick stuff than laying up bits n pieces of thinner foam. No no no to 2 part polyurethane foam, the common stuff in Oz is only about 35kg/m3 (same as a surf blank) and you need minimum 60kg... 80kg is standard in PVC here and 100kg even better if you can find it. Further, pour foams set with voids and you dunno where they are.

Styro soaks up every fluid like when you ding your board and it gets soaked inside. You need to laminate it carefully, by not pooling resin too long. Forget about how deep it may go, if your 1kg of resin becomes 1.5kg its not a help....
denser foam soaks less of course, but there is a marked difference from PU to styro glassing

I'm thinking about building one with paulownia. The thickness, flat deck and bottom seem like a potential good match for a wood board build. Foil box can go straight into a reinforced paulownia section. A much more pleasant experience than toxic eps board building to boot.

The first wing board I built worked great. I had built one windsurf board before, but that was more than 30 years earlier. The wing board ended up a bit heavy since I did not use vacuum and probably used more glass than needed, but that was not really a problem. I used PVC for the standing area; you'll definitely want to reinforce there and around the tracks, but there's no need to go full sandwich. For the rails, overlap the glass so there is plenty of coverage over the entire rail, or/and use rail tape.

The one thing I'd probably change for a DW board is to use vacuum, and perhaps thinner PVC and less glass, to keep the weight down.

Slyde im trying to keep it simple for a newbie ti get a desent result without bagging pvc all over a 13kg blank, and 20kg can be really hard to find so im trying to suggest what is reasonably achievable for a beginner to do, and get a good enough result.

But seeing as though a 6kg strong board cant be made with high density foam i will bow out from the discussion and go off to keep making them.
EDIT: looks like M grade is avail over east, here its very very hard to get