thanks JD and Paul, It sounds like something very useful indeed, and safe enough to use with a little caution (I'd probably wear gloves). I may have used this years ago to lighten a dirty soundboard, come to think of it (probably called wood bleach). I'll give it a try on action parts. Allen On Jun 10, 2008, at 12:17 AM, paul bruesch wrote: > I've bought Oxalic Acid at the local Ace Hardware. It's called Wood > Bleach. The label doesn't say if there are any other ingredients in > it, but it was quite effective for cleaning up the geode stones I > found in SE Iowa a few years back. > > Paul Bruesch > Stillwater, MN > > On Mon, Jun 9, 2008 at 2:41 PM, John Delacour <JD at pianomaker.co.uk> > wrote: > 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 > ______________________________________________________________________ > Allen Wright London, UK http://www.broadjam.com/akwright -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20080610/d5b88b50/attachment.html
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