the stringers we use are all sitka spruce from robbins timber in bristol. they come in a lenght of ca. 5500mm ready machined to a thickness of 35x25mm and in good quality with very few defects and nice straight grain. we only have to thickness them down to 35x22mm and scarph them to the required length. before scarphing the lengths together we coat them in epoxy and round off the corners that are going to be facing inwards. doing this before scarphing makes handling much easier.
we find the quickest way to coat a lot of stringers at once is to clamp them flat together, apply resin with a roller or brush and take them apart once the epoxy is gelled so they do not get bonded together. don’t wait too long… we coat on face side (35mm) first, coat the opposite 35mm side, then round of the corners and do the rounded side at last. the second narrow side is left bare and gets a quick saturation coat before the planking sheets get glued on with spabond.
routering the corners where easy on a simple router table set up but even easier freehanded with this priceless little fella :
for the scarph joints we used a 1:12 ratio which were easily cut on the radial arm saw with a little jig.
shame that none of that wood will be seen in the finished boat…