The thing went so and so since we used an excessively thick putty (resin + silica) which could not flow freely in the space between the bolts and the oversize holes, so we had to recoat several holes (two more hours last evening). Here are a couple of pics of the rig. However, the bolts came out (relatively) easily thanks to the plastic tape wrap.
And here's a pic of one of the coated holes
At least, now we know how to do it for the next set of aka beams.
Three hours of work yesterday, in which we prepared the bolt holes in the aka beams with resin thickened with silica. The holes were drilled oversized (12 mm dia for 10 mm bolts, 15 mm dia for 12 mm bolts). We then covered the bolts with plastic tape, put them in the holes and filled the space with resin. Hope it works...
Three more hours today. While Cinzia was fighting with the sander, I drilled the oversized bolt holes which will be coated with thickened resin.
I have some reservations towards those akas. First one is that those planks have several knots, a few of those being quite large. Are those knots going to be a problem, structurally speaking?
Second: they are heavy. I haven't measured the weight but based on sizes and specific weight of the fir, we should be close to 100 kg! I'm wondering if one could design a lighter system: nothing complicated, like a box section made of plywood and lumber. I sent an email to John Marples, we'll see what he replies.
I really regret not having used a router from the beginning to smooth those edges, this is taking ages... Anyway, we're getting there. Three more hours today: we glued the doubler on the rear aka (300 grams of thickened resin) and continued to round down the edges.