Hi Susan, I've followed one tuner who applied CA from the bottom of a grand pin block. Not enough was used and now "one row" of pins is loose--so every second plain steel unison is suspect. The piano doesn't stay in tune very long--just long enough for the other tuner to collect his fee and leave. The client is loath to pay for a 2nd treatment, and is not particularly pleased. I'd love to here from other "bottom treators", to know how much glue they feel is sufficient. I am well aware of CA's ability to "wick" and it is "handy dandy" for "quick fixes" of loose hammers--when there is no time to use a more appropriate glue. I prefer to set pins if at all possible without the use of CA. However if I used it I prefer to use lots. I've tried the method where the piano is not tipped and find it unsatisfactory. I'd prefer all pins to have nearly the same torque if possible. Using "too much" is clearly impossible, and does result in very even pin torque. My directions to the client do suggest that good ventilation is a "must do". As to toxic I refer you to this link: http://www.ipmsstockholm.org/magazine/2004/10/stuff_eng_tech_ca_glue.htm The toxic part of CA gluing is much more from using accelerator on it. Something I don't recommend ever and in particular for pinblock treatment At 11:26 AM 2/5/2006 -0800, you wrote: > Hi, Don -- interspersed. > Surprise -- I've found I don't need to tip at all. Just slip a few drops > in near the seam, at the top of the pin, and it wicks in enough to hold. > Helpful to keep a shop towel handy, to catch any drips. You can just put > a corner of the towel in between the strings if you see CA dripping down > the plate. > > Do you really think that it is gravity getting the CA into the pinblock > holes? Try something -- take a board with a matching pair of hairline > cracks. (Be innovative -- figure out how to make identical cracks.) > Apply a few drops of CA to the end of one of the cracks, and hold the > board so that the treated end is toward the floor. Then do the same > thing for the other crack, but hold the board the other way around, so > that the treated surface is on top. Does the CA wick further than the > first time? > > Water-thin CA loves to creep into tight openings, one of its best >characteristics. > I think this accounts for being able to use it even when there are plate bushings > > It's nice that you ended up with fairly good torque, in spite of such a gross > > dose himself with some very harmful fumes. I hope you mentioned copious >ventilation! > Also after the job is done, as the stuff out-gasses over time. > > """" is, and how much bother and health >"""", or whether most of it goes here, there, and everywhere, including its >byproducts into your lungs and liver. > >"", while leaving those which were already all right. > > You want the CA to go where the pin meets the block. That is, the CA >itself is just coincidental to the real aim, which is to resize the >enlarged hole in the block to snugly contact the pin. I think some of the >fit is made by glue sticking to the pin, so it matches the hole. Any CA >which isn't lining the hole or following cracks radiating from the hole >(regluing laminations) is wasted, or maybe even actively harmful. The CA >dripping down onto the carpet. The CA gassing into your lungs, sticking to >your fingers, wandering over the plate or open pinblock, clogging the >bearings, seizing plate screws of grands, etc. There are lots of places you >don't want the CA to go. The more you use, the harder (or more impossible) >it is to keep the CA confined to its task. > > "" are the lucky ones, like the people who get ill and throw up when they >try to get drunk. People can get cirrhosis of the liver or cancer without >feeling bad till the very latest stages, when it's too late for effective >treatment. The fumes are bad news, especially repeatedly, in large >quantity. You should also consider, if you think your own liver is made of >titanium, whether your customers (and their pets) are equally fortunate. >They will have to live in the house during the hours or days after you soak >their pianos with CA. > > Sorry if I sound strident -- I feel very strongly about both the health >aspect, and about what all the extra CA does to a piano. It all seems so >unnecessary. > > Just consider what might explain the good results I've seen from two >applications, as opposed to one. Wish I had the time and energy to do some >experimenting on a tired old pinblock, but I don't have any tired old >pinblocks, just tired old me. But the mental picture I have is this: there >is the loose pin in a hole no longer quite round, with delaminations of the >block in the deeper layers. So you add CA glue. It wicks in, where the hole >is almost but not quite in contact with the pin, possibly just at the edges >of the gap at the top of the pin, which is pulling hard against the bottom >of the hole (toward the bridge.) It wicks best where there is JUST enough >room. Okay, it hits those cracks between the laminations, and has a field >day. Here are cracks the right size in abundance, for inches and inches! It >rushes in there, we've made its day. However, it is rushing away from the >loose tuning pin, and it hasn't closed that hole at the top (too wide, it >is not a gap-filler.) Hey! Susan must have been wrong, I only used a >little, and the pin is still loose! Maybe not quite AS loose as it was, but >it's STILL LOOSE! > > Well, if that happens, I think it's because the CA has wandered deep into >the block, where it is doing good things like gluing pinblock layers back >together. > > Now, we come back, in a spirit of investigation, and give it a few more >drops of CA. Still not a ton. It seeps in slightly higher up in the gap, >because the part which has pretty good contact is full of set-up CA. It >creeps back along the pin, comes to where the delaminations used to be -- >and they are sealed by the first application! It doesn't wick inches along >the cracks, because it can't get into them any more! They are fixed! So, >more of it stays right at the pin -- which is no longer so loose. > > Well, that's how I _want_ it to work, and it seems fairly consistent with >the results I've observed a few times. Let's say this -- I haven't seen any >results which are NOT consistent with this pleasing mental visualization. >Certainly worth trying -- wish some of you guys would, especially the ones >who will remove old tired pinblocks in your rebuilding, which you could >treat with less and more, once, twice, thrice, and then saw apart after you >removed them. > > Susan Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T. Non calor sed umor est qui nobis incommodat mailto:pianotuna@yahoo.com http://us.geocities.com/drpt1948/ 3004 Grant Rd. REGINA, SK, S4S 5G7 306-539-0716 or 1-888-29t-uner
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