Thanks for the info David. I'm just investigating whether it's feasible to replace my existing wooden wedges with some sort of poured resin.

I'm not quite sure from reading the details of the Easy Composites resin what the maximum usable volume is. The spec seems to say 10 cubic cm at the thickest part of the casting. The gap between my partners and mast is about 25mm all round and 100mm deep.

Would vaseline be ok as a release agent or might the heat of the exotherm cause problems?

Yes, I'm faced with the problem of the step plug, if cast onto the mast permanently, being too big to pass through the partners when the time comes to remove the mast. However I seem to remember Jonathan Snodgrass mentioning that Lexia's Spartite plugs were easily slid up and down the mast as release agent had been applied to both mast and partners. I was hoping that a liberal smearing of vaseline on both step and mast base would be enough so I could tap the cast ring off the mast bottom when the crane had raised the mast up a few inches. I suppose it wouldn't be too much hassle to destroy the plug on the mast base and cast a new one each time the mast is removed and restepped.

David Tyler wrote:

The mast step and partners are now almost complete. The mast will have a heel plug with a tenon tapered at 5 degrees, smoothed and coated with release agent, and rigid polyurethane will be poured in through the hole and slot visible at the forward end of the step. Above decks, a deck ring for the mast coat has still to be added, and the conical hole for the mast has still to be faired and smoothed. Again, rigid polyurethane will be poured in. This obviates the need to get the step and partners exactly true with the centreline of the mast, and saves a lot of labour making wedges.

David, exactly which polyurethane will you be using? Is it a truly rigid resin, eg for making solid castings or something more like Spartite? Suppliers such as MB Fibreglass list a whole range of these products with varying shore hardness and cure times but which is most suitable?

Will the plugs permanently adhere to the mast or will you wax both mast and tapered surfaces to make the plugs removable from the mast?

Also is the chopped glass used in your mast step the finely milled variety or the short 6mm long strand type?

Annie Hill wrote:Remind us how you decided to do the camber.

I'm using a combination of hinged battens and barrel-cut. Either method on its own brings its own set of issues if a camber of 10% is aimed at; but used in combination, a little of one and a little of the other, each set of issues diminishes in importance. Hinges alone, with a total of 20 degrees articulation or more -  large changes in direction, "corners" for the air to go around, possibility of hinges popping apart by wedging action. Barrel-cut alone - difficult to avoid wrinkles and creasing, and broad seaming or darts are needed. My hinges have two double cones with a half-angle of 4 degrees, 16 degrees in total, and my panels have a depth of convexity on their top and bottom edges of only 43mm in 3380mm.

David Tyler wrote:

This week is Sailmaking Week.

Monday - marked out and cut six panels and the yard sleeve.

Tuesday and Wednesday - seamed the four lower panels together, with their batten pockets and luff and leech tablings, and made a start on seaming panel five.

For those new to sailmaking: it's enjoyable, but hard on the back and knees; factor into your costings a sufficient quantity of muscle relaxant. It's the Eskdale Beer Festival this weekend...

Oh David, what fun!  Remind how you decided to do the camber.

The Eskdale Beer Festival sounds like something not to be missed.  Ulverston had a fine brewery when I was a lass, but I'm not sure if it still exists.  However, no doubt others have arisen to take its place.  Have a good time!

This week is Sailmaking Week.

Monday - marked out and cut six panels and the yard sleeve.

Tuesday and Wednesday - seamed the four lower panels together, with their batten pockets and luff and leech tablings, and made a start on seaming panel five.

For those new to sailmaking: it's enjoyable, but hard on the back and knees; factor into your costings a sufficient quantity of muscle relaxant. It's the Eskdale Beer Festival this weekend...