Thursday, January 08, 2009

S&G Night Heron Build Notes – Attaching the Panels

This was an interesting exercise. Handling the long hull panels is a difficult task and getting them to fit well is not trivial.

There were a few lessons here.

Alignment

Firstly, get a properly flat work surface to ensure the stations are positioned correctly.

Use a pencil to mark out a long straight edge down one side of the flat surface and mark out the perpendicular lines where the stations should sit.

In the S&G Night Heron instructions Nick suggests holding the stations vertical using a couple of quick clamps. I found that was painful as they’d move out of place whenever I pushed the kayak eg trying to knock an edge off; sand a bump off an edge or generally just touch it...

Instead, lock the stations into place using some scrap wood that’s wide enough to clamp securely into place. In the photo below you can see the deck on the stations and how they’re clamped to the table. (I wish I’d done this while building the hull:))Issues somewhat resolved, time to glue it up.

Bevelling

Next thing to remember is, bevel to the edge. Assuming you’ve cut the panels correctly this should ensure your boat stitches up as it is supposed to. Compare figure A to figure B… I naively would’ve thought that B was preferred to keep all fillets on the inside of the kayak, however, this might lead you to think differently.

bevel and station impact

Nick Schade’s instructions said to bevel so I worked on the idea it was figure B. Checking a station plan against the hull bottom confirms this, so, yes, you need to bevel completely to the outer edge (but not beyond). 001

The best way to ensure you don’t overdo it is to bevel most of the way with a plane or sanding block; loosely tie the panels together; then run a bit of sandpaper up and down the join until the panels close up together. Check the picture below.

How to get that bevel right. Run a bit of sandpaper up and down the connecting sheets to close up the gap.

Stitching

What sort of wire do you use??? I tried copper wire and galvanised steel tie wire. The tie wire worked fine. After reading various messages on the different kayak building boards on the net I was quite confused about what to use. Once you try it you realise you can use just about anything. The important this is that you’ve cut the panels correctly and there is a consistent internal bevel.

Gluing

I found this a bit confusing. Do you use plain epoxy or do you add an adhesive additive like West Systems 403. My current take on it is this: quickly wipe over plain epoxy because it will soak into the wood easily; then add a bit of the adhesive additive (made up of microfibres and colloidal silica I believe) and paint into the joint. You only want a minimal amount to actually glue the joint together. Don’t worry about forming a fillet during gluing.

If you have trouble removing stitches after the glue has set I found that the commonly repeated advice to use a soldering iron works great.

Filleting

For the filleting I used a lightweight filler (from Epiglass I think) and masking tape. Masking tape is great.

I tried lots of methods to apply the fillets: a plastic spoon worked great, a wooden stirring stick shaped like a doctor’s tongue depressor worked great and I think I could easily have cut any bit of plastic to a round shape to form an applicator. So all in all, it wasn’t very hard.

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