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Michael Doran

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Everything posted by Michael Doran

  1. I varnish my cellos before attaching the neck. I think this makes my neck projection more stable in the long run. It's a little extra work retouching the neck heel, but it's not that bad. I have a background in repair, so I'm comfortable with it. Also on an antique instrument it's not a big deal if the neck heel doesn't match 'perfectly.' I do this for my violins as well, but I'm not sure it's worth the trouble. -Michael
  2. Wow Mike C, I've never seen linseed oil so dark! I think in Celsius for varnish cooking, so 400-500 F is 205-260, which is hot but not crazy. My rudimentary understanding is that more cooking above a certain temperature kick-starts the polymerization process that occurs when it dries. I'm still not sure how much is enough and what is desirable. Joe- your linseed color looks more like what I'm used to seeing after light cooking. M
  3. We had a nice Bergonzi com through the shop where I worked. I made a few Bergonzi models after that, but I felt like it was difficult to get enough power from so narrow a waist. They were very sweet, but I wanted more growl. On my last one, when I took the ribs off the mold I pushed the c-bouts wider and it was more in the direction I wanted the sound to go. The proportions ended up being similar to a Guarneri; since then I've just made Guarneris. That Bergonzi scroll sure was fun though. M
  4. Also, I'm not a fan of the idea of adding burnt umber. It's very opaque. It's dirt after all.
  5. When I'm cooking resin to check the color I put a drop of the cooking resin on a white tile (like you would use for mixing touch-up, less than a dollar at Home Depot) and grind it with a pallate knife. Then you will be able to see what color the dust is. I found that there was too much color variation with different thicknesses to be reliable on the dipsticks. Usually I go for dust somewhere in the neighborhood of burnt sienna and not darker than burnt umber. I don think it's a bad idea to add mastic, but it's also not necessary. It depends on how chippy you want your varnish to be. M
  6. I've never regretted stripping an instrument and re-varnishing, or popping a top. It's always better and you will learn something. I had a particular violin that I think I stripped and varnished 5 or 6 times. The last time was the best. That said I don't advocate that degree of sillyness; at some point it's better to move on and just make another violin. M
  7. As far as violin books go, it is not very expensive. The photos alone make it indispensable. Just buy the book. (Ascending soapbox) Also, don't copy it and steal from them. It's hard enough to break even on books of this quality for such a limited market. If you steal this book it will make it less likely that others will be made. (Climbing down from soapbox) -Michael
  8. I wouldn't use olive oil for anything woodwork related. It is not a drying oil; if an oil doesn't dry it goes rancid eventually. If you must use oil, use linseed oil. Water will most likely take off the neck funk. Listen to Steven.
  9. Hi Joe, It was nice to meet you at the VSA. I just discovered your thread here and I'm excited to follow along. I'm just starting two new cellos myself. Regarding warping in the ribs- I LOVE warping in the ribs. Granted, I'm antiqueing, but I try to get as much flame bump, and texture, and warping as I can. Cello ribs take up a lot of real estate and if you don't have something interesting going on it they can turn out flat and boring. If you look at old cellos, the ribs are all over the place anyway. Best of luck, Michael Doran
  10. I was taught at school to glue in the back set of linings, then glue the back onto the ribs. The next step was to remove the inside mold and then fit and glue the top linings in. At this point the top was already made and one had to be careful when fitting the top linings to avoid changing the shape. Now I put both sets of linings in before removing the mold, take the outlines from the ribs then remove the mold and glue on the plates, back first. At school we were told it was not possible to get the mold out if you put all the linings in. It was a leap of faith the first time I tried it, but I assure you it works just fine. Michael
  11. Linings add a tremendous amount of strength and rigidity to the rib structure. On two occasions for repair I have had to remove all the linings from a free rib structure and it is amazing how flexible it gets without that support. In general I think linings should be smaller rather than larger. For violin 6 x 2 is my standard, and I would not go under 5mm. 8 is what I was taught in school and that seems a bit large now. For cello I do about 16 x 3, but I have seen them up to 22. It just adds unnecessary weight, in my humble opinion. Personally I like willow better than spruce, but I don't believe it is that important. I get the feeling that the old masters used whatever was handy and worked easily. My experience has been that willow bends extremely easily, while spruce takes more concentration. Usually I over bend the linings on the bending iron and relax them with my fingers to the desired shape. -Michael
  12. Also- I don't even strain my touch up varnish or polish, I just wait for the crud to settle and take the clear stuff off the top. I waste a little this way, but that's okay with me.
  13. Combining all the ingredients and shaking it once in a while is how I make polish and touch up varnish as well. I was told to avoid heating at all costs because it makes it less transparent. Usually my resins dissolve in a few days to a week with occasional shaking. I also find the polish gets stickier after a year or so, so I try to only make what I can use relatively soon. I should try the tuxedo shirt polish cloth sometime. Being a violin maker I'm not exactly familiar with tuxedo shirts, so it never occurred to me. I've been using 100% cotton sheets from the thrift store. I like them because the repeated washing removes the lint and they are inexpensive. I go through a lot of polish cloths when I'm removing varnish for antiqueing. -Michael
  14. Are you heating it to 500 Celsius? I have fused Baltic Amber a couple of times and it took a lot of heat to get all of it to melt. There were some stubborn pieces that were solid right up to 400 C. -Michael
  15. Hello all, I took the top off a modern factory cello a few weeks ago and I noticed that the edges of the upper and lower blocks had been chamfered on the sides. It was only on the upper surface- the part of the block that glues to the top. It was only chamfered on the sides and not on the long side of the block. (Hope that makes sense.) I can only assume the idea is to guide the opening knife to the glue joint smoothly when you're removing the top. I've never seen this before. The top came off fine. I've also removed lots of tops without this, so it's clearly not necessary. I'm not used to taking cues from factory instruments about my own making, but this seems like a good idea. Has anyone else seen this, or does anyone do this on their own instruments? Are there any drawbacks I'm not considering? -Michael Ps. The chamfer on the factory cello was kind of large, maybe 5mm. I'm thinking you wouldn't need it that big for it to work. I was thinking something on the order of 1-1.5mm.
  16. I've used silk to reinforce rib repairs. I think it works well. I have several thicknesses I bought to try out, but I don't think there is much difference. Wedding dress shops often have a good selection of silk. I think it might be called tafatta? I like that the silk adds a lot of support at almost no weight or thickness. -Michael Ps. I've used silk mainly to reinforce cracks. I'm not sure if you need something more for this situation.
  17. I use .4 for the G and D, .35 for the A, and .3 for the E. I use a handy set of feeler gauges that I got from Lee Valley; they are wider than the normal machinest/automotive ones I have seen. I hold the proper feeler gauge flat on the fingerboard and file the groove in the nut down until I just barely touch it with the slotting file. -Michael
  18. I saw a trade instrument once at a shop where I worked with two similar ebony pins in both the top and bottom block, as well as another in each corner block. They were on both the top and back. When I asked about them I was told it was a French trade instrument made for export to warm and humid environments. (The Caribbean or somewhere similar comes to mind.) Apparently it was done with the idea they would keep the thing from falling apart. Not sure if that is fact or fiction, but it's what I was told. -Michael
  19. I've never seen spruce linings cut on the slab, that is with the slab face as the glueing surface. I've successfully used basswood as well. I use the same procedure whatever the material- willow, spruce, or basswood. I cut my cello linings to size, 3 mm x 16-17 mm x whatever length, then stand them up in a jar of water for a half hour or so. With a bending iron heated so that water droplets bounce off the surface when dropped and a bending strap, I over-bend them and then relax the linings into shape either with no heat or a little re-bending as needed. Sometimes I get little compression lines on the inside surface of tight bends, but I don't think it matters since you carve that off when you shape the linings. -Michael
  20. Hi Tim,I like the low tech solution of a bicycle inner tube, but this gadget works really well. I think I got it from Howard Core right after I graduated VMSA. As I recall it was $20-30. It works wonderfully. When I was working on the 24-hour fiddle in Oberlin I had to turn an end button without it and- ouch! I also have a no-moving-parts bridge planning jig like Jeffrey's, but I seldom use it. -Michael
  21. I can reccomend Sten Olsen in Seattle. He is an honest and straightforward guy who deals mostly in instruments under 10K. Go take a look and see what he has in your price range. -Michael
  22. Hi Fred- whatever works is what works I'm reminded of the old saying: A man with a thermometer knows the temperature, a man with two thermometers is merely confused. -Michael
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