Ahhhhhhhhh - miscommunication resolved! Yup, I remember now that your block is out. Yes, mine was mortised into the sides of the piano - my main reason for not replacing entire block. Being that yours is out, assuming the bottom of your block is flat, I would simply cut a piece of 3/4" plywood out to the shape of the pinblock, put a piece of plastic on top of the plywood and clamp the plywood to the pinblock with about eight or ten C-clamps. Sorry for the confusion. I wish I had a better picture, but you can see the inserts in this picture. Terry Farrell On Mar 31, 2010, at 10:04 AM, Dean May wrote: > Now I think I have a better picture. You are talking about doing it > with the pin block still mortised into the piano. You use the jacks > and plywood to provide a bottom then working from the top you epoxy > the insert in place. I actually have the pin block out so I was > having a hard time visualizing how I was going to employ the jacks > on the workbench. > > Communication is a beautiful thing when it happens. J > > Dean > > Dean W May (812) 235-5272 > > PianoRebuilders.com (888) DEAN-MAY > > Terre Haute IN 47802 > > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf Of Terry Farrell > Sent: Wednesday, March 31, 2010 1:17 AM > To: pianotech at ptg.org > Subject: Re: [pianotech] pin block inserts > > Do you mix up a new batch of resin and hardener for the filler, or > do you add it to the same batch that you just used for the wetting > coat? > > Doesn't matter. Just depends on how big an area you are doing and > what hardener you are using. The only rule is to apply the thickened > epoxy before the unthickened wetting-out coat has fully cured. If > I'm doing a small area (like maybe one of your treble pieces), maybe > I'd mix up - oh gosh, a hundred grams or so (I'm just guessing > here), paint the thin epoxy onto the edges of the insert and the cut- > out, then throw a bunch of #404 filler in there, mix it up and apply > to (in this case) both surfaces and push the insert into position. > But I'm using the slow or extra slow setting hardener, and it is > winter and my shop is cool. If it were summer, I might mix up > separate batches of epoxy for applying the first thin coat and a > second batch of thickened stuff - just depends on the working time > you have with the ambient conditions. > >> The part about the pin block jacks is a little confusing to me as >> well. Do you just use them as stands? Or are you actually pushing >> against something? If the latter, what is on the top side that you >> are pushing against? > > > Without the pinblock jacks, how are you going to hold the inserts in > position so that the bottom of the insert is level with the bottom > of the pinblock and the top of the insert is level with the top of > the pinblock? Simply position the pinblock jack under the section of > pinblock you are bonding - add a piece of plywood covered with > plastic if the jack doesn't cover the entire cut-out area. The > pinblock jack I have is from Pianotek and it is maybe 8" x 4" or so > - it has two machine screws to raise and lower a thick section on > pinblock material. The jack, with a piece of plywood and plastic > atop it is more than a stand, it defines the base of the pinblock. > It is pushing against the bottom of the pinblock. > > Again, put the pinblock jack on the keybed, slide it under the > pinblock, put a piece of plywood on top of the jack large enough to > cover the cut-out and put a piece of plastic on top of the plywood. > Raise the jack so that the plastic--covered piece of plywood is > snugly against the bottom of the pinblock. When that is done, your > cut-out now has a bottom - you could fill the cut-out with water and > have a very small swimming pool - if you were a very small > person..... Does that make sense? Now your cut-out has sides (like > it always did), but now it has a bottom (the top of the plastic/ > plywood topped jack). Now when you place your insert in the cut-out, > it won't fall through - because the jack assembly is there. > > I hope this clears things up - I wish I had a picture, but I don't > think that I do. Sorry. I think this is something that once you > understand what I am talking about it is very basic and obvious. But > before that I suppose it can be confusing. Let me know if I am still > not clear. > > Terry Farrell > > > > On Apr 1, 2010, at 7:43 PM, Dean May wrote: > > > Thanks, Terry, this is very helpful. I was a little concerned about > how much nominal gap to build into the system to provide room for > the glue, thinking maybe 1/32 per side, so hearing that up to 1/4” > is okay gives me some relief. > > The adding filler part from West System is a little confusing to me: > > Apply thickened epoxy to one bonding surface. Modify the resin/ > hardener mixture by stirring in the appropriate filler until it > becomes thick enough to bridge any gaps between the mating surfaces > and to prevent "resin-starved" joints. Apply enough of the mixture > to one of the surfaces, so that a small amount will squeeze out when > the surfaces are joined together with a force equivalent to a firm > hand grip (Figure 10). > > Do you mix up a new batch of resin and hardener for the filler, or > do you add it to the same batch that you just used for the wetting > coat? > > The part about the pin block jacks is a little confusing to me as > well. Do you just use them as stands? Or are you actually pushing > against something? If the latter, what is on the top side that you > are pushing against? > > Dean > > Dean W May (812) 235-5272 > > PianoRebuilders.com (888) DEAN-MAY > > Terre Haute IN 47802 > > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf Of Terry Farrell > Sent: Tuesday, March 30, 2010 5:26 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] pin block inserts > > Hi Dean. Cut the inserts out to fit easily into the cut-outs - don't > worry about a perfect fit - you'll be using a good gap-filling high- > strength epoxy anyway. Even if there are quarter-inch gaps here and > there, no big deal. I'm not sure I understand the method of cutting > you describe below, but it appears you routed out the pinblock cut- > outs. Epoxy makes a mechanical bond with wood, so any roughening of > the surface you can will be good. If you are applying thin epoxy > resin to the wood, it would probably soak in enough that roughening > wouldn't matter - but since we don't really know how far it will > soak in, absolutely, IMHO, it would be a good idea to roughen the > wood bonding surface. I cut my pinblock cut-outs with a saws-all saw > - so it left me a nice rough surface anyway. > > Because of the stresses that will be applied to your pinblock, and > the relatively small bonding surface area you will have, you really > want to make sure you make the best epoxy bond possible. I used the > West System Two-Step Bonding Method, which I strongly suggest is the > best way to do this job. http://www.westsystem.com/ss/bonding-gluing-clamping/ > > Another good way to work thin epoxy into a surface that doesn't soak > up much this epoxy (this is how West System recommends bonding > metal), is described about half way down this page - point #3 http://www.westsystem.com/ss/bonding-hardware/ > Basically, they recommend sanding (with very coarse paper) the > thin epoxy into any non-porous surface to be bonded. I've even had > very good results using this method when I wanted to bond a plastic > pipe to something - and we all know that epoxy won't bond to plastic > - or at least we thought it wouldn't! > > After wetting out the two surfaces, I highly recommend using West > System #404 High Density filler - it is their highest strength filler. > > The method I used to align the inserts to the cut-outs was to first, > make sure my inserts are the same thickness as the block. Then I > used my pinblock jack (the thing you support the pinblock with when > driving tuning pins into the block), with a piece of flat plywood > (larger than your cut-out) on top of it and a piece of plastic on > top of that. Put it under the cut-out, snug it up to the bottom of > the block, and now you have an automatic insert leveling system and > also something to prevent any low-viscosity epoxy from oozing out > from the bonding area. > > Hope this helps. The last piano I used this method on I tune every > few months - and it holds it's tunings wonderfully. > > Terry Farrell > > On Mar 30, 2010, at 10:16 AM, Dean May wrote: > > > > This is the pin block from the piano tear down I just posted > pictures of. It is a rather complex shape with several different > levels- beyond my meager woodworking skills to duplicate. I could > have used plugs but borrowing from Terry Farrell, I decided to > router out the pin fields. I drew boxes around 3 pin field areas- > the two in the treble happened to come out so I could make them the > same size. I then transferred the dimensions of those boxes to a > piece of OSB board. I then drew a box 2.75” bigger all the way > around (6” router base, 1/2" cutting bit) and cut out the big box to > make my pattern. Since I was able to make the two treble cutouts the > same, I only had to make two patterns. Today I am going to a big > woodworking shop owned by a friend and I intend to cut out the > inserts on a good band saw. > > I plan on epoxying the inserts into place. I was wondering if > scoring the surfaces with a coarse rasp file, instead of leaving > them smooth, might give the epoxy better surfaces to bond. > > Dean W May (812) 235-5272 > PianoRebuilders.com (888) DEAN-MAY > > Terre Haute IN 47802 > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100401/9cf0386a/attachment-0001.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: image0002.jpg Type: image/jpeg Size: 42262 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100401/9cf0386a/attachment-0001.jpg>
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