Building a Plywood Kiteboard - Blog

[cave_raver]

My board took few hits on Thursday night causing the board to flex the wrong way when I ended it into the sand! Consequently some of the wood filler has finally fallen out. The repair job is going to be some resin wood filler to replace the knackered stuff and then glass fibre tape along the rail to cover it up. I'm going to like this glass fibre tape

 

To all you fibre glass nuts out there - at the chandlers you can buy decent fibre glass matting. Instead of that matting that is just loads of fibres irregularly woven together, I've found proper glass matting that has a material weave. It looks much better but the downside is that it is more expensive. You guys have probably seen it before.

 

I'm quite looking to mark 3 which was going to be carbon fibre but I think may be fibre glass again but using this different matting.

 

CR

[jay1lk]

For a good supply of resins and matting try here http://www.homeblown.co.uk/

 

They also supply surfboard blanks. Has anyone tried shaping one of these to a kiteboard size??

[cave_raver]

I've often wondered where to get the foam from so that looks like a cool site. A bit of investigation is called for and perhaps a chat.

 

CR

[jay1lk]

There is a place in Newquay as well http://www.seabase.ltd.uk but they seem to sell kits only.

[8015]

Hey Cave_Raver - I'm sure I mentioned before to buy woven glass cloth if at all possible instead of chopped strand mat. The cloth is definitely not matting

 

The plain 90 degree alternate weave cloth is called woven rovings and is what you want. You can get other weaves (I've used twill and biaxial), but they can 'stretch' in certain directions if you aren't careful how you work them, woven rovings don't stretch. When it comes to tapes, you will notice that normal glass tape has strands of glass running lengthwise and then a single strand woven backwards and forwards accross the way, usually with some fine thread to hold it at the ends. On some tapes this fine thread can prove a real pain in the backside and will always create a ridge in the finished laminate or will keep liftin it up where you have to go round a curve - if the happens you can if very careful pull the thread out once the tape is roughly in place but you can't move it much aftwerwards as it will fall apart a bit!

 

Chopped strand mat has the strands organised higgeldy piggeldy to supposedly give roughly the same strength in every conceivable direction, but really it's just a cheap way of doing it Woven cloths have the strands oriented longitudinally and transversly which will be the directions most of your stresses are aligned in (mostly longitudinal) so is actually more efficient for almost all applications, plus its loads neater to work with! And I mean loads neater! You won't end up in half the mess you did working with chopped strands!

 

Your carbon will only come in woven cloths anyway, so better get used to working the stuff in glass first

 

JIM

[cave_raver]

Hey Cave_Raver - I'm sure I mentioned before to buy woven glass cloth if at all possible instead of chopped strand mat. The cloth is definitely not matting JIM

Just had a look through and you're right. I've just got to produce this thread as an article as it is becoming a nightmare!

 

CR

[shrimpo]

Hey Boater

Seen you give advice out before on glass work.

 

I have one for you.

 

I am in the process of MII wood baord, and want to make it a bit stiffer ( no joakes), so was going to put 2 layers of woven on the bottom side,as I have managed to get a rocker side to side as well as tip to tip and hope this will help keep it, plus the top with the grain looks good so I will keep that plain and just varnish it.

 

Now what I have never done is jell coat, so can you put a jell coat on after you have glassed, can you just brush it on, or am I going to be better off with some sort of paint???

Just wanted to make it look a bit cleaner than plain glass & resin.

 

Thanks in advance, and some of the other may be interested as well.

 

Shrimpo

[8015]

Gel coat is funny stuff in that it doesn't harden properly in the presence of air! usually it's painted into the mould first and left to set up butthe upper surface is still tacky when you start to laminate on top of it.

 

Now obviously this sucks if you have to do repairs, the simple way around it is to put weatherproof sellotape over the patch but the styrene still has to evaporate so this doesn't work well wither. The next solution is to add a little liquid wax (2% by weight seems to ring a bell) - the wax floats to the surface, the styrene evaporates through it but it keeps the air off the gel (I believe gel coat fillers basically use this approach!). Now this leads to a possibility, you could attempt to mix gel with wax and coat your board, but it is horrible stuff to paint, there is a real knack to it and even then you don't generally get a smooth surface on the non-mould side (you laminate on it so no-one ever knows).

 

What you want is to use a flow coat. You can buy it ready made, basically just ordinary polyester resin thickened a little so it flows to a fairly even surface (building canal boats we had stuff that was fire retardent to do fuel lockers and things, so it's not all ordinary polyester). If you are using epoxy to laminate the board, polyester doesn't bond very well to it, so what you will in fact be best doing, is making an epoxy flow coat yourself. I suggest adding a little colloidal silica to thicken it (wear a mask and keep stirring) - best to experiment with quantities and consistency before adding hardener (remember to add the right amount extra to go with the volume of hardener when you have decided!).

 

Note that I mentioned polyester doesn't bond well to epoxy, well nothing bonds well to epoxy if you just leave it, even epoxy! As it sets it forms a waxy top layer which you need to get rid of before flowcoating. The easy way to do this is a bit expensive - you need to get some stuff called peel ply. You lay this over the wet underside of your board and rub (using a bit of peel ply is ideal) it down so that the resin soaks through from below. When the epoxy is set the peel ply miraculously peels off very easily and takes that waxy top coat with it! The cheap way is to use sandpaper and elbow grease, it works but takes longer.

 

Anyway, your flow coat will give you a smoother surface but it probably still won't be perfect, there will be a slight feel of the cloth pattern. The way to minimise, or perhaps you could eliminate it, is to put a layer of much finer cloth on last, or perhaps a layer of fine cloth and then a layer of glassfibre tissue. To be honest board builders make smooth boards and they lay up on the outside so must have some tricks of the trade that I don't know (having always laid up in moulds), I suspect a lot of sanding and polishing is involved though?

 

HTH, if not find someone who has built surfboards!

 

JIM

[shrimpo]

Jim

 

Thanks for your reply, as always very in-depth and loads of good points ( you are becoming the "font of knowledge" on the forums for glassfibre work).

 

 

I am going to a boat builders today to get some glass & resin, so may ask them as well, they may have some other ideas, but it looks like loads of work just for the bottom of a home made wooden board, so may end up going with plain glass/resin finish, if I can get hold of the tissue glassfibre I will use this, and a spot of paint on top, I will see how much time I get, trouble is once made I'm then itching to try it out.

 

Shrimpo

[cave_raver]

Boater - you really are the man that know stuff about glass etc.!

 

Last night I replaced all the cacky wood filler on the edge of the board with resin wood filler. Just got to say that this is great stuff. It comes in the form of a resin mixed with wood filler and you add harner in the usual manner. When it goes off you are left with an hard wood coloured/texture surface which can be sanded or carved. One point to note is that it does exactly as it says on the tin - 10 mins after mixig and it is set! I found this to my cost when it set before I had finished using it. Went all hot and then rock hard.

 

Only done one side of the board, the other tonight and then glass fibre tape tomorrow. Varnish on the next night and then all I need is wind for the weekend. Hopefully this repair will make the board a little tougher so no repairs will be necessary for the while.

 

CR

[bushflyer]

this thread is really good.

 

my boards have matured into a mk1 (simple ply job) and a mk2 composite jobbie which is a bit smaller.

 

just wanted to suggest laying carbon fibre tows on the board edges and wrapping the cloth over, these can be sanded down to as sharp as you wish and are very tough. used it a lot on model glider wings.

 

now, where can i get aramid cloth and carbon tows cheaply?

[cave_raver]

What's a tow or is that a silly question?

 

Used the fibre glass tape last night. It took longer than I expected so I have only done the ends. I will try and do the edges tonight. Looks like it will do the job though. Just got a problem making sure that the tape stays on the board edge and doesn't peel off before the resin goes off. Think I'm just going to have to hold it on.

 

CR

[bushflyer]

carbon tows look like little bits of black cotton. they're the black lines you see running down the centre of a surfboard. they come in packed strands and you lay them as youre moulding, just make sure the epoxy penetrates the weave or they'll peel away from the board edge. lay next to the rail as you fold over the bottom skin, press so flush, add top skin and then sand to shape once cured. ill scan a pic in from an old model plane mag later.

 

also a note for those worried about the amount of dust sanding, try wet rubbing. just avoid the house sink or the girlfriend/wife will KILL you! and make sure the boards sealed

[ned1710]

Well it's finally finished (almost!) just got to put a handle in the middle.

 

I went for foam core and glass/epoxy skin. The board is 140 long and about 40 wide in the middle. not sure on the weight though- more than the kitchen scales can weigh anyway!

 

It looks ok. I seemed to spend ages trying to sand everything completly smooth and flat but figured it might not make that much difference in the end and just painted it. It seems pretty strong; i cand stand in the foot straps and bounce up and down a bit and nothing creaks or groans so fingers crossed!

 

I don't know how far I'll get with the blade. Me thinks i'll need a f'king windy day so I had better take someone else with me just in case:eek:

 

I guess cost wise it came to around £100 after i got all the paint, sandpaper filler and the foot straps.

 

I'll post after it's maiden voyage (unless it comes home in two pieces!)

 

Ned

[cave_raver]

That looks well cool! I'm going to have to remake mine to catch up

 

Out of interest where did you get the foam, what sort is it and how much does it cost?

 

I tried to use my Blades on water but it got so complicated trying to keep it out of the water, having it depowered and getting your feet in straps that I gave up and went for the G. I don't know if you've done it before but if you do use the Blades on handles have a strop hooked into a harness. Also make sure the footstraps are REALLY loose because it saves so much hassle. Mine are very loose and the board doesn't come off.

 

Good luck and let us know how the board behaves.

 

CR

[ned1710]

Hi cave_raver

 

 

I got the foam (and most other bits and bobs I needed) from Scott Bader. The guys in there are really helpful. They are just off embankment road. The best way to get there is to dirve along embankment rd towards the city centre. It's probably about 1/4 mile past the rowing club. After you go under the bridge with the seagulls it's on the left down embankment lane. I got a 10mm thick sheet which cost around £35 + vat i think (cant find the receipt). It's called Airex and it comes in 1x2m sheets. I cut the sheet in half lengthways and then cut out both sheets to the shape of the board. Both sheets were sandwiched together with a bit of wovern roving in the middle. (hope that makes sense!) This made it alot stiffer and helped to keep the rocker in place. The glass i used was quite heavy; around 500-600gsm i rekon.

 

I fly the blade on a 60cm bar with a crossover so hooking in is no problem. Once i get a proper job (i am starting to realise that there will be no more uni next year) a nice depowerable foil is the first thing on the list. Still can't decide between a flysurfer or a G though. I think the g's look so cool in the air and i have heard so many good things about them it looks like that might be the one.

 

I'll let you know how the maiden voyage goes. Fingers crossed!!

 

Cheers

 

Ned

[cave_raver]

That's just round the corner from me. I may pop down.

 

If ever you want to meet up to have a go on my G to help you decide, just shout. I can also drool over your board

 

CR

[ned1710]

that would be awesome i'd love a go on the G (drooling as i am typing!!) Trouble is i work weekends so it would have to be an evening session. Let me know if you are heading to bigbury, bantham or whitsands and i'll jump in the car. I need to sort out a wetsuit that fits and a buyoancy aid of some kind. Just as well i get paid next week:D

 

 

I found the receipt for the foam and it was a bit cheaper than i thought (but not much!). £27.60 + vat for a 2x1m sheet. If you pop in they have a price list of all the stuff they sell. Great place for resin, brushes, tubs and anything else you would probably need!

 

Cheers

 

Ned

[bushflyer]

just wanted to suggest laying carbon fibre tows on the board edges and wrapping the cloth over, these can be sanded down to as sharp as you wish and are very tough. used it a lot on model glider wings.

 

heres the pic i promised. it may be a model glider wing, but the construction is identical to the average kiteboard- foam core wrapped in composite.

 

any questions drop me a line at malink@foils.nl

[carlos_climber]

Woody no 3 - built and tested this weekend.....best one yet 140 x 36, 3 layers of 3.5 marine ply with a coat of 200g/m2 glass sealed with sp 106 epoxy.

 

What can I say - rides like a dream both in flat water and chop and rollsa in at just under 3.5 kg

 

I think you definately need peel ply and an absorbsion sheet else you have a lot of sanding to do

[cave_raver]

Well I have to finish my board repairs off but I reckon that weather and tides permitting I will be going down sometime this week.

 

For Bantham or Bigbury while I am learning I am looking at a southerly (plus SW or SE) wind around 15mph and the tide one to two hours of low tide. Fussy I know but it guarantees a bit more success in the water. If I can get these conditions after work (around 18:00 there) or at weekends then thats where I head.

 

If you just want to have a go on land which is probably best, we just need a low tide one evening but it can be a bit gusty from other directions. Chuck me a mobile and I'll text you when I'm next going. Usually I know 12-24 hours beforehand. Buoyancy is not entirely necessary for down there in the shallows but I can lend you mine if you need it.

 

CR

 

that would be awesome i'd love a go on the G (drooling as i am typing!!) Trouble is i work weekends so it would have to be an evening session. Let me know if you are heading to bigbury, bantham or whitsands and i'll jump in the car. I need to sort out a wetsuit that fits and a buyoancy aid of some kind. Just as well i get paid next week:D

 

 

I found the receipt for the foam and it was a bit cheaper than i thought (but not much!). £27.60 + vat for a 2x1m sheet. If you pop in they have a price list of all the stuff they sell. Great place for resin, brushes, tubs and anything else you would probably need!

 

Cheers

 

Ned

[shrimpo]

Hey Cave_Raver

 

Finished MII board now.

 

It's 156 by 40cm, 3 layers of 4 mm ply, going down to 2 layers at the tips,

 

Managed to get a rocker front to back around 10mm, as well as end-to-end rocker.

 

One layer of Kevlar on bottom, and resin on top.

 

Didn't by footpads this time, used part of an old camping mat, so spent it on new fins, only two on the back edge.

 

Still went for Prolimt adjustable straps, as you only have to worry about fixing once then, and used blind rivets for this, next time I will put these in before any glass, but did not find them till after.

 

Total cost £70, so not to bad.

 

Hope to give it a try at the weekend so will let you know how it goes.

 

 

Some photos attached.

[Ned1599968590]

That is lush good on ya mate

[cave_raver]

Hey Shrimpo, board look cool. While I was varnishing mine last night I was thinking that I should have some kind of graphics on it but perhaps I'll leave it until the mark 3. I especially like the idea of the kevlar. Tough or what!

 

Let us know how it rides.

 

CR

[john malone]

just seen this , we started with the plywood , but now are making glass/foam boards using vacuume bagging for a bit more money than some of you guy have spent on the ply's . its not as hard as you think , boards are coming out at 2kgs for a 140x40 !!!

I notice that some are using glass to rap the ply up in - go for 3 sheets of 5mm high density foam ( cost £30 ) and set the rocker with some glass inbetween and you will have a better lighter board

 

click on

http://groups.msn.com/KiteSportsCorner/shoebox.msnw

HOTROD CUSTOM KITEBOARDING

check out our rocker table - we can set any rocker profile we want .

also Bill at SPORTS CORNER http://www.performancefoils.co.uk has fins, straps etc etc in stock ready to post for the home builder - and he's cheap

say john malone sent you ..... and ask him what our proto 140 hotrod goes like

any more info on suppliers etc mail me on johnmalone25@hotmail.com

 

 

john