zenguitar wrote:At this rate I'll be making a truss rod cover rather than playing it.
Andy
An inverted white 'U' with a pheasantwood veneer?
By the way, do you normally have a logo on your handbuilt instruments?
zenguitar wrote:At this rate I'll be making a truss rod cover rather than playing it.
Andy
dwebb wrote:I won't argue about the damned silly instrument bit, but I did think that the tuning was effectively the top four strings of a guitar capoed at the 5th fret?
zenguitar wrote:Thanks Kev.
Nothing magical or mystical about the polishing mixture. I just read the instructions that came with the Rottenstone I bought from Luthiers Mercantile and used those as a starting point.
As I mentioned much earlier in the thread, these are the first instruments I've finished with shellac so I am learning as I go.
The instructions basically pointed to using the Rottenstone with a mineral oil as a lubricant and applied with felt pads. There was also a recipe for a polish based on methanol that scared me (as that would soften the shellac) but was more directed at restoring old finishes.
So I searched online, and found some more articles. Read through them, and then bit the bullet and came up with something that made sense to me. I took some Rottenstone, added a drop of washing up liquid as an antistatic/antisurficant and then added White Spirit (mineral oil) until it was the consistency of pancake batter.
So, basically, I relied on existing knowledge and experience, did some reading, and came at it from 1st principles. It worked well, and there was nothing in the mix that could have done any harm.
Andy
Folderol wrote:I was about to offer to take the dear little thing off your hands
zenguitar wrote:So, the afternoon started fine, added another drop of water to the glue in the jar as it had all been absorbed. Then we fired up the gas stove and brought the water close to boiling point.
That's when I put the jar of glue into the water.
Remembering first to remove the lid. You don't want it exploding when you heat it!! And when you finish, make sure to leave the lid off/loose until it cools. You don't want it imploding, or seizing the lid on with the vacuum. Here's a closer look, see how it's gone all liquid.
However, before getting on with the glueing I needed to take some precautions. So I put a sheet of greaseproof paper over the baseboard, and then glued some more greaseproof paper to the top boards I made.
And then left them all to dry.
But eventually I had to bite the bullet and start glueing. And I'm afraid there was no time to take pics as I went. I had one clean break and 4 splits to get glued. However, the method is straightforward enough... use small paintbrush and dip into the liquid glue, paint glue along split/wood to be joined. I applied glue from both sides, and worked the wood a little to draw as much as possible into the repair.
Then it was straight into the jig for clamping. And the clamping pressure comes from the loops of string you can see.
The secret is to tighten the loops like a Spanish Windlass. It's a very old woodworker's technique that can apply a LOT of pressure with remarkable control. I use a variation of the technique to glue broken headstocks and the only real problem is that it is incredibly easy to put too much pressure on the joint.
The wooden blocks are there to make sure that there is plenty of downward pressure to ensure that the back remains flat, as well as the cauls applying the sideways pressure to clamp the glue joints tight.
And now I am just waiting. Hide glue dries initially by gelling, and then by evaporation. With the baseboard and top plates, it will definitely need to be left for close to 24 hours to dry properly. And open, or rubbed, hide glue joints can dry fully in a few hours.
So, fingers crossed. Of the 5 joints required, 4 looked fine. But one was visibly gapping, although less than 1/2th a mm, and I couldn't tell how well it would close without giving it a go.
I'll have no idea whether or not I've been able to save the back until I remove it from the clamping jig tomorrow...
Andy