At 00:12 +0100 7/6/08, Allen Wright wrote: >What's the solution of oxalic acid you mention below (how >saturated?) and where does one find this stuff? This looks like a >good way to clean old parts.... > >I enjoyed your damper article - thanks for sharing that. Hello Allen, Normally the French polish suppliers have it but here is a link I found using Google Shopping: <http://www.jpennyltd.co.uk/shopping/pgm-more_information.php?id=158&=SID> It shouldn't really cost that much, but I can't find who I got my last lot from, cheaper than that for 5 kg. A saturated solution is one where the water will not hold any more crystals in solution. A dessert-spoonful in a cup of water would be beyond the saturation point I think. Just use a bit too much of the crystals. As to the poisonous nature of the stuff, use your common sense and try not to drink too much of it or let the cat do so. It can indeed be absorbed through the skin, and if you worked a whole day with it without washing your hands you'd notice a slight stinging sensation. In the article I stress the importance of a good scrub-up after using it. I, my wife and many others have used the stuff regularly for 30 years, and I never bother with gloves. Read <http://ptcl.chem.ox.ac.uk/~hmc/hsci/chemicals/oxalic_acid.html> -- "Protective equipment : Safety glasses. Gloves are not generally required, but if they are to be worn most types of gloves material (e.g., nitrile, butyl rubber, neoprene or PVC) are suitable. PVA gloves are not suitable for handling oxalic acid or its solutions." Another piece of misinformation I've found parroted in a few places on the WWW is that it "dissolves a layer of dry wood...". So far as I can tell, this is perfect nonsense. Oxalic acid will also completely remove the black stains caused by the contact of rusty iron with wood, for example at the base of a check wire. Several applications are needed, but the effect is astonishing. For its effect on metals, there's nothing like trying it. On those Schiedmayer dampers there was no effect of the damper wires and they came up like new with a light rubbing with fine steel wool. If there is exposed iron, the surface will turn a light grey. It has little effect on brass and practically none on nickel. Here are my recommendations for the super-sensitive and the superstitious: 1. Don't use shark-infested water to dissolve the crystals. 2. If you're working in town, especially in America, wear a full rubber suit, and an oxygen mask if you need to breathe. Use an umbrella if acid rain is forecast. 3. Scrape some barrier cream from the palm of the hand into the nails and round the cuticles before working. If you want further protection and can afford it, use a small amount of silicone barrier cream on the hands. 4. Wash the hands and nails thoroughly after use. 5. Don't leave it in a dish where animals can get to drink it. JD -- ______________________________________________________________________ Delacour Pianos * Silo * Deverel Farm * Milborne St. Andrew Dorset DT11 0HX * England Phone: +44 1202 731031 Mobile: +44 7801 310 689 * Fax: +44 870 705 3241 ______________________________________________________________________
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