: Will nylon upholsterer's thread suffice for lashing or should I use something
: else? Also does it have to be waxed?

Artificial sinew is great to work with. Using it is one of the parts of making a SOF I like best. The wax makes it easy to tighten things because it sticks to itself, and it holds knots extremely well for the same reason. It's important to have a material that you like and is easy to work with, because lashing takes a long time and is hard on the hands. I sew the skin with 40lb braided dacron line and it's a killer on the hands, so I wouldn't choose to use a similar product for lashing. There's a lot more line in lashing than there is sewing the skin.

There are a couple of provisos with the artificial sinew, though, and they both have to do with the skin material. First is, if you don't do your lashing through holes in your chine and keel, the wax can and get on your skin and make it hard for some finishes to stick to the skin. Secondly, I live in the Great Lakes, and mildew is a problem with frames because we don't have salt water to discourage it, so everyone uses tung oil pretty liberally around here. In the past I used tung oil thinned with mineral spirits on the first coat, but if you use artificial sinew avoid it. It dissolves the wax and the resultant slurry stays a goopy mess for a long time, and again is bound to get on the skin.

There is a LOT to be said for using what's on hand, and there's a supplier of the artificial sinew two blocks from my house, but it's not hard to find through e-commerce. You can look at Jas. A Townsend.

Good luck!

m