Thread: Goat Island Skiff building in Denmark :-) Sejl-jolle bygges i Danmark

Peter Lord!

Thankyou for putting some supplier information here for the region!! Thankyou. Thankyou!

Bjarne,

I missed the reference to polyester resin. Peter is right ... don't use it because it doesn't stick to wood reliably and it is brittle.

If you can get the glass that he is talking about for the hull, or even lighter then that will be excellent. That weight or up to 200gsm or a bit more will be good for foils.

MIK

Bjarne, My experience with polyester resin in the 70s (and it's still the same stuff) was a disaster over plywood. In two years it had delaminated and cracked and water had leaked in under it. All comments I have read when people ask about polyester resin say the same as Mik and me. It sticks only to other polyester as in reparing a fibreglass boat. In autobody repairs it sticks long enough for you to sell the car. Better not to cover with 'glass cloth than use it with polyester resin. Don't try to save on quality of these materials. Your time must be worth much more. Mik explains where you can save, on blocks for the rigging, for example. Why use expensive epoxy paint over cheap polyester resin? It won't protect it for long. Save on paint, not on the structure, and use latex or other house paint.

Peter

Polyester resin over wood is worse than no resin at all. Paint sticks better than polyester resin to timber.

MIK

Good info! I did not know that.
what goes for the epoxy paint its cheat, i get it from a friend that's working on a shipyard
I do need to give it some glass, we have very rocky beaches in the bay. Is there any other solution that can be used instead for epoxy glue, as i have told before, its damn expensive here in denmark!

Bjarne

Originally Posted by Glug

Bjarne, if you mean polyester resin to stick the cloth to the plywood, DON'T USE POLYESTER RESIN anywhere. It doesn't stick for long, but separates from the wood and water gets under it and the wood rots. I learned the hard way 30 years ago. Use epoxy, and the stuff I use is NM epoxy from http://www.nilsmalmgren.se/. It's great,and it's SWEDISH, so easy to buy. It cures hard in a longer time than WEST which is much too fast setting, but if it is getting to be cold weather, or you want it to harden fast, you can add an accelerator, which can be bought separately in a plastic bottle.

Nils Malmgren also sells glass cloth in 160gm/m2 which I think is fairly light. When you get to applying the glass to the bottom email me and I'll give you some tips about laying it out and filling it with the minimum amount of resin, which does not add strength, only weight. This kayak building site is one of many with PICTURES that show you how to apply glass cloth to plywood with the best technique and minimum amount of resin. http://www.oneoceankayaks.com/Shop.htm#plydex , Kayak builders know how to maximize strength and crush resistance with light weight. They go into rock gardens all the time. My kayaks have 2 layers of light cloth on the bottom for abrasion resistance.

Peter Lord, in Uppsala, Sweden

Peter, can you help me with a link to both parts ?
And if you have an idea of the price for it. I intend to put 2 layers on my buttom.

Bjarne

Howdy Bjarne,

the lighter the weight of glass you use, the less epoxy you will need. Also Peter gave a link on how to reduce the amount of epoxy you need to fill the weave of the cloth so the surface becomes smooth.

MIK

The links are there in the text. To use the least amount of epoxy, I use a Squeegee, don't know what it is called in Danish or Swedish, but it's a slightly flexible plastic flat tool that you use to spread joint compound onto interior walls with to fill the joins between the boards. All hardware shops sell them. The cloth should cover not only the bottom but the chines and up the sides 30mm or whatever the GIS instructions tell you.You lay on the cloth cut to size, and carefully spread it out, pour on a small bit of mixed epoxy and spread it out with the squeegee, back and forth slowly, so it doesn't form too many bubbles, and the resin is filling the weave but has no pools above the weave. The plywood might soak up some resin while you are doing a new surface so go back and make sure that the cloth has enough. The weave should not be white, as that indicates too little resin. Keep going like this all over the cloth with small amounts of poured on epoxy. After the resin has begun to harden and no longer sticky but still soft, you can put on your second layer of cloth if you want extra protection. When hard, then you can sand the tops off the resin onthe weave, but not into the cloth, and roll with a roller on a new final layer of resin to get it smooth. You might want to practice on a small piece of ply first. The kayak web sites have pictures. Try a search for kayak and fiberglassing for others than the one I gave you.

Here is a little picture of my progress. There is some small error, but i must live with them
Tomorrow im gonna glue the bulkheads, its starting to be fun now. It look like boat now

Bjarne

Hey Bjarne,

Great to see your progress! Thanks for sharing. You will be on the water before you know it (and I will be jealous).

-Jamie

Oh WOW a GIS in Denmark!!!

Well done Bjarne.

It looks like you are about to clamp or screw the gunwales in position temporarily (ie no glue) this is a good idea before the bottom goes on and the seat tops are fitted.

Best wishes
Michael.

Thx guys

And yes, Mik, i'm gonna put the gunwales on with some screw before i glue the buttom. I had it on shortly and it do a big difference on the shape of the boat - a huge difference!
I only have one 19 x 45 mm left for now, but i have some leftover from when i splitted the timber, im gonna use that for the other side. Then ill go for glueing the bulkheads.
When the buttoms goes on i dont know - as you can see i have to it outside and they promise some very bad weather next week. Rain, cold and windy, not the best weather for building boat and def. not the best for glueing with epoxy.
And i could really use some more space to build on

Bjarne

If if rains keep the boat off the ground and cover it with a polytarp. Make sure the water will run off.

If you put the boat upside down and just put the two extra sheets of ply on the bottom and the polytarp on top of them and some weights on the polytarp it will be very dry and secure.

MIK

I have been out looking for some wood to the hollow mast and it's impossible to get something that even get close to the measurement in the plans
The closest i can get is 16mm - its *impossible* to get 12 mm, if it shall down to 12 mm i have to get somebody to bevel it and thats expensive, damn expensive, it will cost a lot more than the wood itself.
So can 16 mm be used instead of 12mm ??

And what is "Gunwale cappings" ?

Bjarne

Just got an account at flickr and have put up some picture:
http://www.flickr.com/photos/3103340...7607586047897/

Bjarne