I got the belly patch glued last night using Resintite. The patch was held in place with masking tape to stop it slipping and then bound with rubber strapping.To stop the glue filling the hole of the small knot I stuffed a bit of twisted paper towel into it.
By the way, it took 3 tries to get the patch the right shape and grain alignment, first bit was too small, second bit was perfect until I realised I got the grain edge on... damn.
It was a relief to see it looked good this morning. A quick clean up with my big bastard file revealed the result. The small hole cleaned out easily by running a drill up though it and then cleaning it out with a file.
If you compare the result with the pencil lines I drew on the stave you will see I didn't take off as much wood as I had been contemplating, this is mainly because a thinner patch is slightly flexible and will conform to the shape of the cut out, and also the knot was very clean and solid inside.
It looks slightly odd with the line of the patch cutting through the knot, but there wasn't really any other way to do it, short of slicing off half the width of the bow which would have been a bit drastic and would have spoilt the back.
There comes a point where you think, if I'm going to cut away every discontinuity or imperfection I might as well laminate a stave.
The patch hopefully will do the job of bulking up the heart wood in that area and preventing any movement around the knot whilst retaining some of the knot which shows the character and keeping the integrity of the back.
I may be able to reduce the sapwood a little during tillering rather than removing heartwood as I don't want to end up back at square one with almost all sapwood and the knot showing on the belly.
You can see I decided to patch first and then plug the small knot, this was more about impatience than aesthetics or mechanics, but I do think it adds to the integrity of the piece. (Hmmm sounding a bit like an art critic there. "The rigid lines of the patch juxtaposed with the roundness of the knot symbolising man's struggle against nature" ;) )
I'll peg the small hole today, but I won't flex it on the tiller until it's had a few days for the glue to really cure.
I should add that the remaining black area in the knot will be excavated and filled later.
Wow, that looks real tight. How did you layout and cut the patch? (How) would this be doable with hand tools?
ReplyDeleteCheers,
ReplyDeleteI rasped out the knot to give a smooth flat curve all by hand. The patch was trimmed from an off-cut of the same log as an oversize square section using a spokeshave, then rough cut to the curve on the band-saw (tricky because the curve is sort of diagonal across the square cross section. I then offered up the patch with my bench light shining from behind so I could see the gaps which I then relieved the high spots with a fine rasp/coarse file, checked again and repeated the process. Once it was about right I held it in position and filed off as much excess as I dared to get it thinner so it would flex as it was strapped down. I marked a pencil line at each end across the patch and limb to keep the alignment as I repeatedly tried it.
It was rather tricky, which is why it took three goes to get the patch right, but after the first two I was getting better at it!
It's all down to patience and perseverance really. I was tempted to stick the second patch down, but I thought for the sake of another 30 minutes I might as well get it right.
I didn't do that much with the band saw, but it did save a bit of time.