Transferring mould patterns

[gusblake]

Hi,
I was wondering if anyone could tell me how you usually transfer the outline of a mould pattern onto the plywood/chipboard to cut out the mould?

The patterns I've got are for Iain Oughtred's Wee Rob (12ft glued clinker canoe).

I've tried nails through the plank land marks but can't seem to get a batten to take the curve and am worried that this method isn't precise enough.

Cheers,
Gus

[peter radclyffe]

Originally Posted by gusblake

Hi,
I was wondering if anyone could tell me how you usually transfer the outline of a mould pattern onto the plywood/chipboard to cut out the mould?

The patterns I've got are for Iain Oughtred's Wee Rob (12ft glued clinker canoe).

I've tried nails through the plank land marks but can't seem to get a batten to take the curve and am worried that this method isn't precise enough.

Cheers,
Gus

get a thinner batten

[gonzo]

Are you trying to transfer the lines from a loft board or are you lofting the lines?

[PAR]

Use a joggle stick.

[Steve W]

You are doing it right but as Peter said,get a thinner batten,the batten will fair out any errors although i would assume that the designer has lofted it out and corrected any errors from his table of offsets before selling the plans.Of course it was probably done on a computer these days,although i think Ian has been doing this since before computers took over.
Steve.

[longfellow]

Gus,
If you are asking how to ultimately get a lofted body plan section of a station on to your mold material, I have a simple process that works for me and takes some of what you would read in boatbuilding texts and other techniques that will not b found anywhere. it also does not require the intermediate step of creating patterns as does stem and keel work.
1. Traditional nail head impression technique described everywhere. My twist is to sharpen the edge of the nails (spin the nail in your hand while running it against the fine wheel on your grinder or belt sander)- this makes things easier and more exact.
2. I preassemble the required number of planks to cover half of the lofted section. My twist here is to edge glue them - no cleats which will prevent you from either putting the wood blanks right down on the lines or putting them right down on your band saw (neither is good). Edge gluing holds fine while you shape the two halves. I then temporarily nail the two halves together for the entire shaping and labeling process. When you have the section half shaped, make enough marks up both halves (water lines, buttocks, sheer, center line), separate, and lay them on your lofted grid exactly according to your marked lines.
3. NOW cleat the halves together however you see fit given their size and your building technique. I take the time to use glue at all cleats and cross members.