Design & Illustration

Fiberglass – epoxy

I recommend an initial (and minimal) coating of epoxy before laying out the cloth. The reason is that with a filled wooden structure it is much easier to control the wetting out of the cloth.

The cloth is quite flexible and can be shaped over most hulls without any wrinkles. Then pour a small batch of mixed epoxy on top of the keel and work it over the surface with a rubber squeegee. Repeat until the cloth is wetted out - i e invisible.

When the epoxy has set (normally overnight), lift the hull from the molds, turn it right side up on a couple of supports - ideally the leftovers from the particleboard you cut the molds from

The inside is then treated the same way as the outside: sanding, coating, applying and wetting out the cloth (on the wall in the left you can see two of my longboards).

That done, and the epoxy cured, it is time to start building the deck…

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Should the weave be aligned fore & aft or on the bias? For & aft would have half the fibres running in the same direction as the wood fibres, half at right angles. Bias would have half the fibres at +45 degrees and half at -45 degrees to the wood fibres. Half the fore & aft fibres appear to be wasted weight, merely duplicating the strength already present in the wood. Bias seams better because none of the cloth fibres are parallel to the wood fibres. Given that no fibres are wasted in the "bias" approach a lighter cloth could perhaps be used, which would also require less epoxy to wet out resulting in a weight saving. So is biased fibre alignment better than fore & aft?

See comments c4442-c4445-c4450...

But why not test...

A small note from the moaning char.

I am building my kayak in the garden, and with a very good summer in Denmark, it is very zen like to work under the fruit trees.

Up until the moment, when I put on the fiber and epoxy.

I was a day with temperature around 28-30 degrees celcius. I finished the epoxy work around 1 pm. Everything looked nice. Had to do some rolling, to get rid of some air bubbles but it looked smooth before i left the project for the next 6 hours.

When I came back it looked like a battlefield.

Björn has made a note, not to raise the temperature.

I have to say - yes! be aware. Do not do this in sunlight.

Right now I have not settled on, whether to cut the boat with the chainsaw or to sand off all of the fiber and epoxy.

It is not an option to try to fix the bubbles. Too many, too big.

Any good ideas?

Yes, there are a lot of blisters, and they are pretty big! My mentioning of temperature came from personal experience. Been there, done that.

Normally this comes naturally: you laminate late in the afternoon and spend the epoxy curing time sleeping – and during the night it gets a little colder in the air.

Which is a good thing in most situations in life – work with nature, not against!

There is no standard recommendation for a lamination looking like yours.

You can, of course, with the help of a chainsaw make the problem go away – and go buy a kayak. But that would be a failure that will stay with you for a very long time.

You can also sand off most of the glass (at least where it is damaged) and add a new layer – this time to coincide with a decreasing temperature.

You can also cut off the blisters, sand the edges lightly and add pieces of glass to cover.

Or you can slice the blisters with one or two cuts perpendicular to the strips (so you don't cut the important athwartships strands), force a little epoxy into them, lay a piece of plastic over and press them flat with duct tape.

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