Christopher Jacoby Posted July 7, 2013 Report Posted July 7, 2013 Great photos, Trevor. Welcome to the timesink.
Roger Hargrave Posted July 8, 2013 Author Report Posted July 8, 2013 Trevor, I really do take my hat off to you. I am not sure that basses were built in this way in Cremona, although I don't see why not. I have only ever done cellos like this. The Amati bass was certainly very well balanced in the C bouts, so it could have been done this way. Keep us informed of the progress. I am sure that it will have a much better look of freedom than the one that Rene and I are building. But we are trying to work in the style of Amati and that will be my excuse. Thanks again.
Urban Luthier Posted July 8, 2013 Report Posted July 8, 2013 This is really cool Trevor, would you be up to starting a separate thread so we can see your progress? Many makers have a "bench" thread so we can look in and comment on what's going on in their work. Best Chris
Urban Luthier Posted July 8, 2013 Report Posted July 8, 2013 Also on the topic of construction methods -- your bass Trevor looks like a gamba shape. I've heard them described as corner less -- but that is crazy as this shape has corners also. At any rate gamba's like the shape of your bass were typically built without a form where the outline is traced on the back and the ribs are bent to the outline. I have no idea if gamba-shaped basses were built in Cremona and if they were what the construction method would have been. A part from what you've noted above Roger, would you know if the Cremonese ever used a form-less construction method for bass sized instruments? Chris
Roger Hargrave Posted July 9, 2013 Author Report Posted July 9, 2013 Roger, I made your Plaster of Paris ground. I used a plastic paint stirrer with my electric drill and it worked very well. It only took a day and a half to make. I changed the water several times, and it turned out almost like talcum power. I've used pumice and water for years but this stuff looks better, much finer. I put it on a fiddle with water and it worked in the pours much easier than pumice. I won't get a chance to put any varnish on it till later this week though. With pumice and water you have to be really careful not to tear the soft spruce up. If you rub to hard it's like sandpaper on wet wood. Thanks Yes I know that problem with pumice powder. But I am interested to know what kind of plaster you used, it sound about right.
David Burgess Posted July 9, 2013 Report Posted July 9, 2013 Gad zooks, Roger even antiqued his drying box!
actonern Posted July 9, 2013 Report Posted July 9, 2013 I'm surprised to see a dancer's pole in front of it...
Roger Hargrave Posted July 10, 2013 Author Report Posted July 10, 2013 I'm surprised to see a dancer's pole in front of it... My wife Claudia is a teacher, she has to have something to do in the long school holidays. David it is not antiqued, it is a subtle retouched that will enable it to blend into the garden when I move it. I only placed it under the terrace while I was making it because it was raining all the time. I have no idea what method would have been used in Cremona for basses. It may have been similar to systems used for Gambas making elsewhere. However, the fact that so many details, such as normal corners, overhangs and even the outline appears to mimic the Cremonese violin family suggests that the Cremonese method may have been used. Unfortunately I don't have enough information about this subject. Carlo Chiesa is the man to ask about this. Berl mentioned using a paint stirrer in the drill, to mix the plaster. I don't know if I mentioned this, but when I was washing linseed oil I had the cleaver Idea to use a paint stirrer in order to mix the oil and water. I was washing three liters of oil and shaking this with the added water was hard work. Unfortunately I must have had the mix exactly right, because the two emulsified and refused to separate. I tried heating it and I even left it standing for half a year; all to no avail.
David Burgess Posted July 10, 2013 Report Posted July 10, 2013 I'm surprised to see a dancer's pole in front of it... Put up a pole, and they will come. (photo credit to Martina Hawe)
Berl Mendenhall Posted July 10, 2013 Report Posted July 10, 2013 Yes I know that problem with pumice powder. But I am interested to know what kind of plaster you used, it sound about right. Hi Roger, The bag just says Plaster of Paris. It contains gypsum and lime stone. No other ingredients. I really don't think you would need to mix it as long as I did. Late in the afternoon of the first day I tested a small amount and it didn't set up. I thought I might get it finer if I mixed it another half day. I'm wondering if you could get it too fine by mixing it too long. I put two coats on a fiddle with water and used a fine scotch bright pad to remove the excess after it had dried. I put a coat of oil varnish on the fiddle and it looks like it soaked in a little. It's not shinny all over. After this dries I'm going to mix some P/P with oil varnish and work that in well. After I get it worked in, I'll go over it with a rag dampened with mineral spirits just enough to remove the excess. I'm sure that will seal it just fine. What would be great is if it just barely soaked in the very top part of the maple so you got that oil in maple effect. I don't think anything looks as good as oil varnish on bare maple. Just don't want it to soak in enough to kill the tone of the fiddle. I'll try to get some photos of it this afternoon.
Berl Mendenhall Posted July 10, 2013 Report Posted July 10, 2013 Here are a few shots of the fiddle. It's a fairly high quality Chinese fiddle. I had it varnished with spirit but striped it and sanded it down to bare wood. You can't tell much by the photos but this is two coats of Plaster of Paris and one coat of oil varnish. I don't know if you can tell, it soaked in just a bit. The varnish is colored some (that really doesn't tell you much). You can see the varnish didn't soak in much as it's not blotchy where the end grain would have sucked it in.
Urban Luthier Posted July 10, 2013 Report Posted July 10, 2013 Roger, Berl and anyone else who's used the Plaster of Paris as a ground, Can you share more info on the type of product you used? All i can get access to locally in Canada is stuff from the building store -- marketed as "fast drying" or from the art store Called Burma casting plaster which has volcanic ash added Would either of these work? Chris
Berl Mendenhall Posted July 11, 2013 Report Posted July 11, 2013 I'm no expert on this stuff, but if it says Plaster of Paris and contains only gypsum and limestone it's probably okay. To make P of P they heat gypsum to a high temp. That's all. After it's been heated, when you add water it sets up. When you add water and keep it moving and not allow it to set, it does like Roger says, it takes all the heat out of it. Pretty cool actually.
Roger Hargrave Posted July 11, 2013 Author Report Posted July 11, 2013 Hi Berl, I would say that this looks about right. Roger, All i can get access to locally in Canada is stuff from the building store -- marketed as "fast drying" or from the art store Called Burma casting plaster which has volcanic ash added Would either of these work? Chris Give it a small scale try. The stuff that I usually use has a setting time of about 15 to 20 minutes. The volcanic ash might even be an advantage. The Romans used it in their cement. Berl the violin looks about right. I am just a little concerned that some of what was already on the instrument might have sealed the pores. This can actually happen too much. As I said on this blog, I usually take extra care to seal the edges and end grain areas, but even here some porosity is required. Too much and the varnish will not stick too little and the varnish will sink in until the area goes black.
NewNewbie Posted July 11, 2013 Report Posted July 11, 2013 As I said on this blog, I usually take extra care to seal the edges and end grain areas, but even here some porosity is required. Too much and the varnish will not stick too little and the varnish will sink in until the area goes black. Sounds like walking a tightrope. Do you see evidence in Classic Cremonese instruments, of the failure to meet these tight requirements, or did they get it right always?
NewNewbie Posted July 11, 2013 Report Posted July 11, 2013 All i can get access to locally in Canada is stuff from the building store -- marketed as "fast drying" or from the art store Called Burma casting plaster which has volcanic ash added Screw-up on my part. Missed other quote.
NewNewbie Posted July 11, 2013 Report Posted July 11, 2013 marketed as "fast drying" or from the art store Called Burma casting plaster which has volcanic ash added Give it a small scale try. The stuff that I usually use has a setting time of about 15 to 20 minutes. The volcanic ash might even be an advantage. The Romans used it in their cement. If you want to pursue this more, then this might help. Pozzolana
actonern Posted July 11, 2013 Report Posted July 11, 2013 "Do you see evidence in Classic Cremonese instruments, of the failure to meet these tight requirements, or did they get it right always?" It doesn't look in this photo like they always did... http://www.flickr.com/photos/mdarnton/5719685550/lightbox/
CarloBartolini Posted July 14, 2013 Report Posted July 14, 2013 Come on then, make one. You can also use it as an additional jolly boat, although you might need to varnish it with boat varnish. I think a few people have been inspired by your post ... Sorry Roger, they beat me to it.... Double Bass Boat even guitar players...
NewNewbie Posted July 14, 2013 Report Posted July 14, 2013 "Do you see evidence in Classic Cremonese instruments, of the failure to meet these tight requirements, or did they get it right always?" It doesn't look in this photo like they always did... http://www.flickr.com/photos/mdarnton/5719685550/lightbox/ So looks like a case of too little here, so the end-grain has soaked up colour. Thanks!!!
NewNewbie Posted July 14, 2013 Report Posted July 14, 2013 I think a few people have been inspired by your post ... Sorry Roger, they beat me to it.... Double Bass Boat even guitar players... I wonder if they are playing "Row row your boat"?
fiddlecollector Posted July 14, 2013 Report Posted July 14, 2013 "Do you see evidence in Classic Cremonese instruments, of the failure to meet these tight requirements, or did they get it right always?" It doesn't look in this photo like they always did... http://www.flickr.com/photos/mdarnton/5719685550/lightbox/ Do you not think thats just dirt/rosin build up inbetween the hard growth lines ?
actonern Posted July 14, 2013 Report Posted July 14, 2013 Its all very interesting, but to my thinking, if that summer growth was porous enough to soak up dirt and rosin, it was porous enough as well to soak up varnish even before that... and I don't know what kind of color varnish one could apply that would not also react the same way... soak into and darken the wood. E
fiddlecollector Posted July 14, 2013 Report Posted July 14, 2013 Who said it needs to soak in? It may be just on the surface. Rosin will stick to almost anything if left for long enough.
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