johnms

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About johnms

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  1. Cleaning your violin

    I am currently in the process of cleaning my early 1800s German factory instrument. This was very dirty when it came into my possession some years ago and at that time I sent it to a luthier for a clean and set it up. It came back about 30% cleaner but still very dirty. I could see maybe 2/3rds of the perfling after that clean. Subsequently I had a go myself using a non-solvent based hand washing cream which was a method recommended by a contributor here on Maestronet. With much elbow grease I did get further improvement but it was a long way from a good result so I never finished that task. Just 2 days ago I had a sudden thought about another possible cleaning fluid and did a small trial and found it was way, way better than both previous efforts but still not 100% as over a century of dirt takes a bit of removing. It is a water-based cream that leaves no residue and produces scratch free gloss finish (but not high gloss). What I using this time is toothpaste. Its main ingredient is Baking Soda, which is the basis of most household cleaning products. Handled with care toothpaste is absolutely harmless to you or your instrument. I apply using a wet squeezed out cloth (so no liquid water is present) putting a small dab of paste on the cloth and then quietly working using one finger on a very small area wiping off with a damp sponge and then a dry soft cloth. Still needs the addition of elbow grease. Try it for serious dirt and report back. Will almost certainly also work on bows including the metal work. But do not use either a budget toothpaste (they can have non-soluble powders added to bulk them up and that might cause scratching, or ones sold for tooth whitening as they usually have a bleaching agent added.
  2. Degraded Mother-of-Pearl in Frogs

    While I'm not a bow technician and this is not exactly the same problem, I had a frog with deeply set mother-of pearl that I suspect was the end result of sweat corrosion from the previous owner, and when I asked my bow expert about fixing this I was anticipating the mother-of-pearl would be replaced. Instead she carefully put several coats of clear varnish over the eye and while this didn't completely flush things off, it made a big improvement visually, and this varnish has been fine for about 18 months but then I don't have corrosive sweat. Nevertheless a coat or two of varnish might well offer protection to the mother-of-pearl against sweat.
  3. New Workshop

    One good window is all you need. I recommend something like a picture window. For optimum lighting I suggest north, you will have the most light and you won't have the intense sun rise or set to blind you. For those of you in the Southern hemisphere your workshop window should face South
  4. Bottom and Top Block Depth (Thickness?)

    If you look very carefully at old instruments with flat-faced end blocks you will find that the block faces are never parallel to each other. Like so much of Cemonese violin design the little things are often subtly different from what you think. In this case I can only assume this avoidance of parallel faces is intended to prevent standing waves being set-up.
  5. Lord Wilton

    I have read a lot of comments that indicate a mismatch between cross and longitudinal arch height is normal. From the drawings I have seen it appears that arch height is simply measured from the underside of the top plate at the location the arch height is required. One factor that might be producing this lack of correlation in top arch height measurements is a failure to account for rib height variation. I have yet to see a comment about making this adjustment. From what I what I have observed the bottom of a rib usually follows a straight line while the top edge is effectively a curve with its maximum height in the area of the C bout. Simply measuring arch heights relative to the underside of the top plate means you are taking measurements off different datum points. No matter what object you are measuring you cannot compare height measurements unless the measurements are adjusted back to a common datum. You have to either set up a common datum measuring line or else adjust individual measurements back to a common datum. For violins this means either increasing cross arch height measurement by the rise in height in the rib or deducting that measurement from the longitudinal arch. Without making this adjustment it is impossible for the measurements to match. Keep in mind that rib heights are often different on each side. I hope this first time poster is not telling experts how to suck eggs.