Wim en Debby wrote: > > Hi List, > l know this method for several years. l have also good experiance with > it . Here in Belgium its called Metalock. lt was made to repair cast > iron peaces like huge waterpumps and engine-blocks. But cast-iron > frames from piano's and grands, are easy to fix. It is cheap and there > is no risc, like there is with welding, that your plate breaks at > another place. > best regards, > Wim Vermeyen > Wim's Piano Service > Ekeren, Belgium > wim.debby@village.uunet.be > > -----Oorspronkelijk bericht----- > Van: Robert Goodale <Robert.Goodale@NAU.EDU> > Aan: pianotech@ptg.org <pianotech@ptg.org> > Datum: woensdag 16 december 1998 7:04 > Onderwerp: EXTRA! EXTRA! Plate Repairs- THIS COULD BE IT! > > While at Yamaha an amazing new method for repairing cracked > piano was shared by another member of the group. This is a > completely new technique and is unlike anything previously > discussed. This group member also brought a video tape for > show and tell which put everyone in awe. Even LeRoy was > dumbfounded and is now wanting more information. > > This is no joke folks, read on... > > This crack repair method was developed originally for > repairing cracked cast iron engine blocks and other heavy > machinery. It involves no welding whatsoever. Instead a > series of very specially designed screws are inserted into > the crack which quite literally pull the crack together > stronger than it was before. When the repair is complete it > is almost invisable. This may sound to good to be true but > the tape demonstrates this clearly. Two flat pieces of cast > iron were fastened together in a butt joint by a single one > of these screws, and was then hooked on each end with a > heavy chain. The chain was then connected to a wench which > lifted a 350 pound engine block. The bond held perfectly. > A complete series of pins overlapping in a crack seals the > crack permanently and stronger than it was originally. On > bench tests these repairs were shown to be completely air > tight at 80 PSI. > > Ok, so here's how it works. The screws are designed to dig > in to the cast iron. They must go into a pre-drilled hole > using a special bit. The holes are also taped. The secrete > is in the screw threads which are cupped sharply upward. > The top half of the screw has a countersunk collar which > pulls tightly into the hole in the opposing direction of the > cupped threads. The screw is driven into the cast iron > using an air drill until the torque breaks of the head. The > result is that the cast iron is clamped tightly together > *internally*. A series of these screws are installed to > follow the crack side by side. Then an overlapping series > of screws are inserted in a second pass. The remains of the > torqued-off heads are ground away smooth. No welding, no > mess. This type of repair can even be made inside the piano > without plate removal. There are several types of these > special screws which can be used on various types of cracks, > even on angles or in corners. They are also available in > various lengths. The video presentation was extremely > convincing and had us talking about it for the remainder of > the week. > > This group member's local chapter recently decided to try > this repair as a joint project. The inventor of this > technique was personally present and assisted in explaining > and then demonstrated the repair. This proceedure is brand > new and this was the first such repair made on a piano. I > think we can all pretty much expect to hear a lot about this > very soon. > > This repair system is called the "CastMaster" by a company > called Lock-N-Stitch. They do have a web page. Check it > out and be amazed. > > Lock-N-Stitch > > Follow the link to "Information about Cast Master". After > you've read the text and looked at the pics, go to the link > that demonstrates the complete repair. > > Enjoy! > > Rob Goodale, RPT I will be doing a LockNstitch on a 1906 Conover plate sometime in the next two weeks. Cracks are in (2) the pinblock struts, which load in tension. Piano has four individual pinblocks. I live in Central Ill (Clinton) and would welcome any one wanting to join the experience. Richard O. Snelson Phone 217-935-4215
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