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About Mike_Danielson

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  • Birthday 10/22/1942

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    Materials scientist--PhD

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  1. Voirin bows probably predate any engineering standards for screw diameters and thread pitches. The bow owner needs to measure the screw diameter and the pitch as a starting point. There may be more to it though; such as, depth of the thread and shape of the thread. At first "cracker out of the box", you are trying to find an "off the shelf" tap that will work. It might not be a perfect fit, though, but good enough. Mike D
  2. Salts of nitrates and nitrites are too dangerous for you guys. You should stick to coating the wood with horse piss--a much safer substance. OR use nothing while you sun tan the wood--that works, also. Mike D.
  3. Chris Burt, thank you for the great idea of using gravers as knife blanks. I had no idea these existed. A search shows that they are made in a large array of sizes and steels. They do not appear to be very expensive. Mike D
  4. Squeak, squeak---just a tiny reminder--we have no idea how this bow worked before the animal gnawed on it. Mike D
  5. Just do the Lucchi repair. It does work, is not hard to do; thus, is not too expensive. The trick that makes this possible is the G-2 epoxy which makes a strong joint in the wood. Restore the wood dimensions to the original size. Playability should not significantly change since the repair is over a small region. Get the box of water colors out and this fix can be made invisible. French polish. Mike D
  6. I have tried washing the linseed oil (Barlean's food grade flax seed oil) and not washing it--it made no difference. Now days, I use both Barlean's and the cold pressed oil from Kremer. Both oils work for me. I do not see how washing the oil would hurt anything; so, keep doing it if you wish. The varnish problem appears to be dirt or some introduced dirt or particulate into the varnish. Here are a couple of ideas: 1) Let the varnish settle--never shake it. Pour the varnish off the top. 2) Filter the oil if there is still a problem--this will take out the particulates and the "worms'. 3) Use a fairly stiff brush to apply the varnish, and then use the 'tip off' technique to level and break the fine bubbles. Do a search if you do not know what 'tip off' means. I never use a thumb to apply varnish--how will you get varnish into the corners? Mike D
  7. Before you get overexcited with a new idea, you should always do some homework; such as, Ralph Mayer's "The Artists Handbook....." Saffron gets an F on its report card. So does Dragons Blood. Old wood develops a yellowish patina all on its own. Suntanning can accelerate this process before you put the finish on. Mike D
  8. Frank Pallister is the fellow doing the demo. Anyone see a fire extinguisher in that dump of a kitchen? If the beaker cracks or he knocks it over, fire everywhere. This is a bonehead. Basic chemistry technique is that you never stir using the thermometer. For these temperatures, you should be using a thermocouple. This cooking should be done outside , and he should be wearing some protective clothing. Mike D
  9. Years ago, I purchased a new Record joining plane of 22". It warped after a few years, and because it was cast from some silicon-type of cast iron, it was as "hard as the hubs of hell." Almost impossible to grind to flatness. So, I made a 22" wood plane like Krenov would have made. Worked like a champ for those long joints. When it goes wacko, you can fix it with a scrapper. A friend gave me an old No 7 Bailey/Stanley plane--it works like a champ, and it never has needed any flattening. Mike D
  10. I use Speedball India Ink. Two coats on each side. Check to make sure it fully penetrates. Mike D
  11. I think this method has the potential of being something that the masters could have done to create the initial color along with some sun-tanning. But there can be a real simplification to what Roubo has proposed. In the boarding of houses, the pee falls on the manure; so the manure already contains all the ingredients that you need (along with straw to keep it porous). Just put the horse manure into a bucket and add enough water to just cover it, and let it sit. It would benefit from being warm so the fermentation can take place (brave people can bring it into their house during the winter). Skim the juice after a few weeks and coat the instrument. The ammonia odor and general stink will require airing out of the instrument, but it will eventually go away. Fermentation will convert the nitrogenous compounds into nitrates, nitrites, and ammonia--just what you need for suntanning. Who knows, the brownish color of the solution may even be permanent. Mike D
  12. For these temperatures, you should be using a thermocouple. Go on ebay and buy the thermocouple and the associated electronics. Either a K or J will work. They are more compact and more robust than a thermometer. Mike D
  13. If you look at youtube, you can find a number of autopsies of various LED bulbs that have failed. They all seem to have a full wave rectifier with some filtering and voltage control. The large filter capacitor is considered the weak link, and when it goes out, there will be an increase in flicker. I found one engineer that measured the ripple on one particular LED bulb, and it was very low--maybe 30 mV on top of the DC--this is really small. LED behavior varies among the manufacturers because quality of the power supply is all over the place. Placing a battery in parallel with the power supply and bulbs should help to buffer out the voltage fluctuations when a AC to DC power supply is used. Mike D
  14. I looked up the A19 soraa lights (as you recommended) and something does not look right. Percent flicker is less than 30%--what does that mean? Why not 0% flicker which a DC powered bulb would provide? If flicker triggers some health problem, can you trust a bulb that has approximately 30%? The color temperature is 2700K and they give it a CRI of 95--this seems impossible. I would not trust these for work with varnish. You need 6500K for good color rendering. I do not have a dog in this fight. Mike D
  15. Hold on about the Soraa LED lights. The MR16 are supposed to be flicker-free. They require 12 volts AC; so, you will have to provide a stepdown transformer, and a special connector. MR16 appear to be flood lights; suggested use appears to be restaurants. Color temperature is too low to get a correct color rendering for varnishing or matching. The lowest is 2700K. Cost is about $20/bulb. You just as well go with the 12 volt DC bulbs that the campers use since you will have to provide a power supply in any case. These bulbs seem to be widely available. I have not checked on the color temperature of the DC bulbs which might be an issue. They look to be more conventional in shape (not floods), use the Edison base, and are cheaper. Mike D