Here are the highlights from the forum regarding the maintenance, conditioning, cleaning, and lubricating of grand knuckles. Let me know if I missed anything. ++++++++++++ To clean the knuckles of old graphite or graphite grease, I've used Thoro or Energine (dry cleaning fluid) and a suede brush. There are probably other solvents that work also, but I don't have experience with them on knuckles. I apply the cleaning fluid with a syringe and brush as much as possible off with the suede brush, then let them dry. Afterwards, apply talc or powdered Teflon and rub into the knuckles with a spare treble hammer. ++++++++++ I scrub them with a little brass brush dipped in Naptha, with aluminum foil draped over the action to deflect the runoff onto the driveway. Wearing mask and gloves, and brushing in the appropriate direction to give the jack "bite" in the buckskin grain upon keystroke, I have seen many deeply compressed knuckles come out looking like new this way. Then Teflon powder. ++++++++++ I pull the grand action, put the front edge of the keyframe in my lap,then lift the back of the action till it's almost vertical and the hammers fall back. I use a brass brush (on most new pianos I'm more gentle and use a "hard" toothbrush with shortened bristles) to gently raise the nap of the knuckles. Then I apply micro-fine powdered teflon to the knuckles with an artist brush. I work it into the leather by brushing parallel to the shanks. I believe this pushes more powder into the leather, improving lubricity and how long it lasts. Don't use your fingers; they're oily and anyway you'll smudge teflon everywhere later. Next, gently place the action back down onto the keybed and gently putthe shanks back down onto the whippens. Playing the notes a few times burnishes the knuckle leather back down to its previous smoothness and seems to seal in the powder. I do this on almost every piano I service, new and old. I think it's a *big* improvement in the feeling of letoff for very little work. In some mid-level brands it's the only cure for squeeky knuckles. I also do a similar procedure to vertical hammer butts. Additionally, I sometimes like to put powdered teflon *into* (by raising the nap of the felt before applying) bearing felts, especially whippen cushions. I too use a large pipe cleaner to apply it to keybushings and balance holes (don't forget to use McLube on the keypins too). I rub powdered teflon into keybeds (rub perpendicular to the grain to get it in there) followed by painting (or spraying) McLube over the powdered teflon; it seems to make everything slicker and seal in the powder. Lastly, gently burnish with ScotchBrite. I've given up on aerosol cans (stinky and bad spray pattern) so I buy McLube by the quart and put it in small bottles with a finger-powered sprayer (like the ProLube bottles, except I don't really like ProLube as much -- takes too long to dry). As you can tell, I love teflon powder. It's WAY better than talc. As far as I know, micro fine powdered teflon is only available from Spurlock Specialty Tools (707-452-8564). Other powdered teflons (like Hoppe's) don't seem to work anywhere near as well; it's probably a different grain size. I buy teflon in all 3 bottle sizes Bill Spurlock offers: Smallest (.75 ounce) for tuning kit, medium (2.5 ounce) for supply kit, extra large (10 ounce) for shop. ++++++++++ Teflon powder can be brushed into the bushings for lubrication, Protek on the key pins. ++++++++++ I have used Spurlock teflon, thought it was expensive. Dupont sells powdered teflon, designated as MP-1100. It feels, acts, and looks exactly the same, but costs way, way less. Look up a distributor in you area, and ask for details. (4 microns, I believe is the grain size). ++++++++++ Some like Elmer's Slide-All, which is a Teflon-based lubricant, but it contains alcohol which can dry out leather. ++++++++++ Use a suade brush and clean and raise the knap on the knuckle. Brushing every third tuning should keep it nice and quiet. ++++++++++ The best lubrication I have found is a one two punch combination of teflon powder on the knuckles, and McLube spray on the rep levers/jacks. Raise the nap on the knuckles with a fine brass bristle brush, then apply generous amounts of the teflon powder sold by Bill Spurlock. I used to apply it sparingly, then observed a friend realiy pile it on and achieve lower friction levels. Transfer the powder to the knuckle leather using a spare piece of leather which has had the powder sprinkled onto it and spread out gently. Rub it in well. Any sloppy looking excess can be vacuumed off. Spray McLube 444A (clear, superslippery) on the rep levers/jack tops. It can be purchased directly from the company in case lots at 800 2 MCLUBE. ++++++++++++ After brushing with a brass brush (may not need to on new knuckles) I burnish it in with a rounded piece of wood. Charlotte Eschmann,RPT recently recommended burnishing with a piece of cork which I will try next. Brian DeTar,RPT also told me that a second application later may be needed to more fully cover the knuckles, but it will work great and last. Also spray the whippen tops with McLube 1725 - combination of both is slick stuff!! ++++++++++++ I don't like the dry-cleaning operation - problems with the fumes and not so wonderful results for all the work involved in my experience (the drycleaning fluid seems to work as much dirt, etc. into the buckskin as gets cleaned off). I prefer to simply scuff sand the knuckles to remove any glaze a brass brush won't take off, or any graphite grease etc. someone else may have used. The worst squeaks seem to come on newer knuckles with a glazed surface, though. Don't want to remove too much leather, obviously, so go easy on the sandpaper, and fairly low grit (120 tops). Applying the microfine teflon goes easiest with a makeup brush. I use one with about 1/4 inch diameter of bristles, probably camel hair or the like. Jab it into the jar of powder a couple times, and the bristles become loaded with powder. Then dab knuckles individually, gently for the first one, then more vigorously for subsequent ones. A brush full of powder covers about six knuckles very well. Then brush the knuckles you just tefloned to spread the teflon evenly. This is the most efficient way of getting the teflon on the knuckles I know, and with a minimum of mess and loss of material. A paint brush would work as well, I'm sure. ++++++++++++++
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