Geigenbauer Posted August 22, 2020 Report Share Posted August 22, 2020 1 minute ago, Don Noon said: Those values are after torrefying and many months of stabilization. The original properties were .355/5740/16.1 for the top, and .575/4415 for the back. Most of the mass loss is bound water Thank you Don. Very helpful! Quote Link to comment Share on other sites More sharing options...
avandesande Posted August 22, 2020 Report Share Posted August 22, 2020 Nice and smooth sounding without a lot of 'quack'. Did you glaze the color? It looks like there is some texture underneath. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted August 23, 2020 Author Report Share Posted August 23, 2020 6 hours ago, avandesande said: Did you glaze the color? It looks like there is some texture underneath. The color is all from iron rosinate varnish, with no other pigments. It's fairly thin, I think. Texture is either from crude woodworking underneaths, or on top later with gum arabic and heat gun. Quote Link to comment Share on other sites More sharing options...
Michael_Molnar Posted August 23, 2020 Report Share Posted August 23, 2020 Very nice photos. Quote Link to comment Share on other sites More sharing options...
Bodacious Cowboy Posted August 23, 2020 Report Share Posted August 23, 2020 On 8/22/2020 at 2:42 PM, Don Noon said: Top wood: .335 g/cc, speed of sound 6040 m/s, RR=18 Are you doing reinforcement in the sound post area with such low density wood? Quote Link to comment Share on other sites More sharing options...
Don Noon Posted August 24, 2020 Author Report Share Posted August 24, 2020 I use maple soundpost pads on all my instruments, even when I use higher density spruce, in addition to making thicker grads in the soundpost area. Quote Link to comment Share on other sites More sharing options...
Bodacious Cowboy Posted August 24, 2020 Report Share Posted August 24, 2020 Interesting, thank you. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted November 22, 2020 Author Report Share Posted November 22, 2020 The second viola of the new design is getting closer to the "finish" line. Varnish is on, soon to be assaulted to be made to look a bit more used. While varnish was drying, thoughts were given to the next instruments. As I have 2 commissions for my "large" 358 mm model and only had one form, I fired up the CNC and made another collapsible high-tech aerospace overkill form, with a few minor tweaks from the last one. I should have a more interesting post in the next few weeks when I finish the latest vioa. Quote Link to comment Share on other sites More sharing options...
scordatura Posted November 23, 2020 Report Share Posted November 23, 2020 23 hours ago, Don Noon said: The second viola of the new design is getting closer to the "finish" line. Varnish is on, soon to be assaulted to be made to look a bit more used. While varnish was drying, thoughts were given to the next instruments. As I have 2 commissions for my "large" 358 mm model and only had one form, I fired up the CNC and made another collapsible high-tech aerospace overkill form, with a few minor tweaks from the last one. I should have a more interesting post in the next few weeks when I finish the latest vioa. Don would you mind elaborating on the model concept you are using? Is it an expanded "Noon" violin? Rib heights? Arching? Like you I think that light wood is a good idea. Requiring less effort from the player to get the instrument to sound. Granted this is coming from a violinist who plays viola... Quote Link to comment Share on other sites More sharing options...
Don Noon Posted November 23, 2020 Author Report Share Posted November 23, 2020 3 hours ago, scordatura said: Don would you mind elaborating on the model concept you are using? Is it an expanded "Noon" violin? Rib heights? Arching? For the viola design, there are details in a previous post, which was the first one of the new design. I'm working on the second, basically identical, but the new one is constructed from slightly denser wood (but not much) for more all-around use, vs. a specific soloist instrument. All of my "new design" instruments are based on GdG outlines, with some tweaks... a little wider in the C-bouts, mostly. No specific instrument was copied, but I started from the ground up to look like a GdG. I did roughly copy the F-holes from the bass side F of the Plowden, but scaled up slightly. I thought the bass side F looked cooler. The 4 versions of the design (352, 355, 358, and 400 mm, with the last being the viola) use a lot of the same geometry. For the violins, the shape of the corners and C-bouts are all identical, with only the width changing 1mm for each size step. Stop lengths are nominally identical, but can be varied if necessary. The upper bout curve had to be diddled a bit for the width variation, and the lower bout also had to be diddled for width and length. For the viola, the corner and C-bout geometry was scaled up. Upper and lower bouts required some specific redesign... upper bout more rounded for high position access, and lower bout squashed in length to deal with the long stop and short body. F's were again scaled-up from Plowden, a bit oversize to keep the A0 resonance from getting too far below C. Arching is my own design, probably somewhere between Strad and Guarneri. Same with grads. The viola is just slightly fuller arching than the violins, but you'd never tell by looking. 3 hours ago, scordatura said: Like you I think that light wood is a good idea. Requiring less effort from the player to get the instrument to sound. Granted this is coming from a violinist who plays viola... I think it can be good for violas and larger instruments. For violins, the jury (me) is still out, but there is some evidence that denser (but not ridiculously so) wood can work fine. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted December 11, 2020 Author Report Share Posted December 11, 2020 At last, the semi-identical twin to my previous viola is now done. Same tree top wood, but the back wood is different. Similar sound, I think, but not exactly the same. I'm happy with the sound. Varnish is always a struggle, and mostly the varnish ends up deciding what it wants to look like. With the Covid19 lockdown locally, I don't want to have my usual gracious and talented test driver come out to play it... so I'll see what I can get. Quote Link to comment Share on other sites More sharing options...
Bodacious Cowboy Posted December 11, 2020 Report Share Posted December 11, 2020 varnish/antiquing looks really nice. Quote Link to comment Share on other sites More sharing options...
ctanzio Posted December 11, 2020 Report Share Posted December 11, 2020 Love the varnish. I noticed the subtle flair to the finish of the peg ends. Attention to the little details contributes to the overall visual impression, IMO. Mind if I steal that finish to the pegs? Quote Link to comment Share on other sites More sharing options...
ctanzio Posted December 11, 2020 Report Share Posted December 11, 2020 Also, what are the neck and stop lengths of the instrument and the height of the center of the bridge above the plate? I am struggling to find some correlation for violas to figure out if a bridge height is off or if the fingerboard has sunk. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted December 11, 2020 Author Report Share Posted December 11, 2020 1 hour ago, ctanzio said: I noticed the subtle flair to the finish of the peg ends. Attention to the little details contributes to the overall visual impression, IMO. Mind if I steal that finish to the pegs? The ring pattern on the end of the pegs is semi-accidental. I used a roundover router bit with the peg in a lathe, but the cheap router bit had a crappy grind, leaving the rings. It was horrid until I re-sharpened the bit, but there were still a couple of spots that I didn't grind out, leaving a few rings that I though looked nice... so I left it that way. Anyone is free to copy this accident. 1 hour ago, ctanzio said: Also, what are the neck and stop lengths of the instrument and the height of the center of the bridge above the plate? I am struggling to find some correlation for violas to figure out if a bridge height is off or if the fingerboard has sunk. The stop is 222 and neck 148, projection 33, overstand 8. This resulted in a free string length of 375. Bridge height is 39 after adjusting for 6 and 4 mm string clearance for C and A. My projection and bridge height are probably higher than most, but maybe less than some. You'd have to check with a viola expert, which I'm not. Quote Link to comment Share on other sites More sharing options...
ctanzio Posted December 12, 2020 Report Share Posted December 12, 2020 Thank you! Quote Link to comment Share on other sites More sharing options...
Don Noon Posted January 6, 2021 Author Report Share Posted January 6, 2021 Starting the next batch of violins... There's not often a need for the Big Bandsaw, but occasionally it comes in extremely handy... such as for slicing off the top of a thick 1-piece back for matching ribstock. Quote Link to comment Share on other sites More sharing options...
scordatura Posted January 6, 2021 Report Share Posted January 6, 2021 1 minute ago, Don Noon said: Starting the next batch of violins... There's not often a need for the Big Bandsaw, but occasionally it comes in extremely handy... such as for slicing off the top of a thick 1-piece back for matching ribstock. Have those been torrefied? I have been listening to a bunch of guitar luthier podcasts. Lots of use of torrefied wood in that world. Big makers and corporate enterprises using it. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted January 6, 2021 Author Report Share Posted January 6, 2021 Top, back, ribs, neck, scroll, pegs, and fingerboard are all torrefied on what I build these days. Unless someone orders mechanical pegs. Quote Link to comment Share on other sites More sharing options...
scordatura Posted January 6, 2021 Report Share Posted January 6, 2021 8 hours ago, Don Noon said: Top, back, ribs, neck, scroll, pegs, and fingerboard are all torrefied on what I build these days. Unless someone orders mechanical pegs. That is what I figured. The piece on the left is lighter than I would expect and the even lighter resawn rib wood made me think about how deep the color change goes after treatment. Perhaps it is the image. I have seen treated wood that on the outside is quite brown. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted January 6, 2021 Author Report Share Posted January 6, 2021 oh... I forgot to mention torrefied bass bar and blocks. The piece on the left is showing a planed surface that was planed a while ago. The piece on the right is showing a just-resawn face. So there's a light fuzziness that you get with a saw-cut surface. Also, I dial back the strength of the treatment for maple, so as not to get too dark. Spruce can tolerate stronger processing, and that's where I want to balance the treatment for maximum acoustic benefit. My torrefying process gives a uniform result through the thickness, but there is often surface darkening, depending on what's there. If the surface is old and oxidized, it can get extremely dark, also if the wood has been coated with something to bring out the flame, as wood suppliers often do with figured maple. Quote Link to comment Share on other sites More sharing options...
Sapiens Posted January 8, 2021 Report Share Posted January 8, 2021 I’ve tried once to torrefy in domestic oven at about 230F, spruce started to gently crack after a short moment. Do you torrefy for the color or to improve acoustic performance? Quote Link to comment Share on other sites More sharing options...
Don Noon Posted January 10, 2021 Author Report Share Posted January 10, 2021 According to my research, the best torrefaction requires oxygen-free steam under pressure, so a conventional oven falls far short. I started processing wood for acoustic reasons only, but the color I think is an important side benefit. My current processing has been developed to strike a balance between acoustic, aesthetic, and workability aspects. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted January 21, 2021 Author Report Share Posted January 21, 2021 I didn't know if this would work, but I was hopeful enough to make this vacuum fixture to hold down ribs and thickness them on the CNC with a surfacing tool. My old method of using a fixture on a spindle sander was OK, but tedious and slow, and left significant scratches to be scraped out. Thankfully, it worked better than I had hoped. So, in celebration, it's time to go on a bender... The 1-pc back in the middle has such tight flame that it looks washed out in the photo, so I spliced in a photo of a ground test on wood taken from that back. It will be good. Quote Link to comment Share on other sites More sharing options...
Bodacious Cowboy Posted January 21, 2021 Report Share Posted January 21, 2021 On 1/10/2021 at 5:39 AM, Don Noon said: According to my research, the best torrefaction requires oxygen-free steam under pressure, so a conventional oven falls far short. I started processing wood for acoustic reasons only, but the color I think is an important side benefit. My current processing has been developed to strike a balance between acoustic, aesthetic, and workability aspects. Do you have any concerns about possible long term implications of heat treating? Quote Link to comment Share on other sites More sharing options...
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