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Door & fins

Posted: Tue Jun 13, 2006 4:23 pm
by rlander
Hi all!
I have been a lurker for a few weeks now, and I´ve finally decided to build a lightwind board, but despite all the research, I still got some questions. Also, I will be posting every step towards building the board in a blog, so that in the future people can learn from my mistakes/successes.
So, correct me if I´m wrong:

1) I found out that most of my local shops don´t sell 12mm marine plywood (probably because I live inland). Some do sell 15mm. Is it ok or will the board be too thick/heavy?

2) I´m building my board based on the Door. Can anyone post the measures?

3) How should the rails look like? Will rail design affect riding?

4) After i cut, sand and rock the board, I will apply epoxi. How many coats should I use? Why do a lot of people talk about "glassing"?

5) I will also stencil the board. Should I paint over the wood and then epoxi it, or should I give it one coat of epoxi, paint and then another coat?

6) I also found the fin prices to be wayy too high. Anyone have plans for fins?

Thanks for the help and sorry for the long post. I have done my homework, but I really don´t want to screw up and I will also contribute back to the community by posting everything on a blog.

Posted: Tue Jun 13, 2006 9:09 pm
by gbgreen59
I've found a material called G-10, or Garolite, which I believe most commercial fins are made from. A bar of it that is 3/8" thick works well for fins. You can make fins for between $3 and $5 each depending on how deep and wide you make them. G-10 machines very easily. I use a sanding disk on a table saw. Makes a big dust mess. You can find G-10 at MacMaster-Carr on-line. A 4" x 24" x 3/8" bar cost ~$30.

Posted: Tue Jun 13, 2006 9:18 pm
by bay surfer
D'ont over think, a door is a low tech board, any shape you want as long as you have a big plank. Marine plywood is not needed and is usually soft Okume, .5 in/13mm AC Ply is the cheapest high quility ply you need, Polyurathane, oil base paint, not epoxy is a better sealer for a BIG flexy board. any size 150+cm is good, the size 160X50cms is universal.
FINS ARE NOT NEEDED, AND HINDER RIDING IN 6IN OF WATER. If you need fin like feel, use a concaved sides, skatey feel striaght.
You get 2 doors out of a piece of ply, plus some wood for what your wife projects.

Don't bother about fins

Posted: Wed Jun 14, 2006 5:22 am
by hleeb9
I have a 2006 Door that was delivered without fins. It took some time to get used to rinding finless, especially on toeside. I got the fins a couple of days later, but I have not bothered to put them on.

The Door is extremely agile without fins, turns easily from heelside to toeside, and you can even turn the door 90 degrees to the direction you are riding, effectively sliding over the edge. You can also land with the board pointing the wrong way and still nail it.

You may loose some top-end without fins, but it's a light-wind board anyway. Even when well powered I do not miss the fins, because it is all about edging.

I have not ridden a home-made door or some of the door-like boards (Fat Berta or the MAX), and I do not know how these work without fins, but I'm really happy with my Door!

H.

Posted: Wed Jun 14, 2006 12:15 pm
by kitezilla
bay surfer wrote:D'ont over think, a door is a low tech board, any shape you want as long as you have a big plank. Marine plywood is not needed and is usually soft Okume, .5 in/13mm AC Ply is the cheapest high quility ply you need, Polyurathane, oil base paint, not epoxy is a better sealer for a BIG flexy board. any size 150+cm is good, the size 160X50cms is universal.
FINS ARE NOT NEEDED, AND HINDER RIDING IN 6IN OF WATER. If you need fin like feel, use a concaved sides, skatey feel striaght.
You get 2 doors out of a piece of ply, plus some wood for what your wife projects.
Bay Surfer,

This is the best post ever about plywood!!

AMEN

Re: Door & fins

Posted: Thu Jun 15, 2006 4:41 am
by munteruk
rlander wrote:Hi all!

1) I found out that most of my local shops don´t sell 12mm marine plywood (probably because I live inland). Some do sell 15mm. Is it ok or will the board be too thick/heavy?
I'd try for the 12mm if you can find it. Try other materials if you can't get marine ply.
rlander wrote:
2) I´m building my board based on the Door. Can anyone post the measures?
I can't help you with that one other than to suggest you grab a pic off the net and scale it up. Kiteboard outlines aren't to critical though - make a shape you're happy with and see how it goes!
rlander wrote:
3) How should the rails look like? Will rail design affect riding?
You can start with a square edge on the bottom surface (for clean water release) with either a small radius curve or a square edge on the top. Rail shape is developing, but there isn't anything too wrong with simple shapes IMHO.
rlander wrote:
4) After i cut, sand and rock the board, I will apply epoxi. How many coats should I use? Why do a lot of people talk about "glassing"?
"Glassing" is the process of putting layers of fiberglass and resin together over the outside of the board. It can be used to increase strength, add waterproofness, improve surface finish AND add weight. In an experimental board you could start without and then add fiberglass later if you decide the board is too flexible.
rlander wrote: 5) I will also stencil the board. Should I paint over the wood and then epoxi it, or should I give it one coat of epoxi, paint and then another coat?
Most epoxy isn't UV stable so I'd suggest epoxying it first and then painting it.

rlander wrote: 6) I also found the fin prices to be wayy too high. Anyone have plans for fins?
This is a hard one. I've made some vacuum bagged carbon & foam fins and there is no way it was worth the effort. What I'll do next time is simply make a mould and then cast them out of resin & glass. Hopefully I can cast in the bolts and unscrew then when it sets. Fins is one of the harder problems to solve IMHO.

Good luck and remember - if the first one doesn't work out then you can just make another one. I'm onto my fourth board now and each new board has been an improvement over the previous one!

Posted: Thu Jun 15, 2006 7:25 pm
by rlander
Thanks guys, top advices, as I expected! :thumb:
At that price I don´t see a big advantadge on building fins with G10. Unless I wanna have some real fun learning about fins. I saw somewhere a guy making fins out of a wax mold and liquid plastic, but I couldn´t find the link. Anyway, seemed a very interesting technique.
I did find 5.5mm ply. Can I just glue two sheets together with epoxi? And if I do use epoxi and paint the board, should I use polyurethane to coat it and achieve that glassy look?

Posted: Sat Jun 17, 2006 12:07 am
by bay surfer
Save the work of glueing two pieces of ply together for high performance boards. Do concave. rocker, ect, use rocker tables, vacume bagging, for the boards your going to use the most, Good wood boards cost 75 to 100$ to produce, with fins, pads, etc. Make a door for the low wind days, 40$ with pads/straps before you overthink.