Clementi Restoration

January 2014 – Rather than assemble a PDF of a restoration, let’s watch one in action now. Work will need to be start and stop for about 8 weeks as time allows from my real work on medical devices. So Patience Please as we get the pics shrunk to size and loaded.

Most square pianos look pretty good in pictures taken from a few feet away, and nothing is the same as a close physical examination, but occasionally a piano will come by way of an expert, and then you know ahead of time what you are dealing with. Here we have a Clementi piano of 1808, a piano not unlike one you might more frequently encounter if you were looking for a somewhat early one. The form was copied by everyone, and the approach here is good for Broadwood, Tomkison, Rolfe, Astor, and others from this period.

Looking it over, we can see right away what will need doing.

It has been restrung sometime in the 20th C, new large pins inserted, and the wire is tough music wire, so unsuited to what we are doing. The overspun are copper on brass, so we will save those in case they can be reused on cleaning. But that is not the heart of our problems. Weak glue and oversize wire have combined to break the wrest plank from the base of the piano. This one is missing its rear vent (a replacement is on hand though) so we can see what is going on, but usually unusual bumps and raised points at the pin block tell you things have let loose.

Here we see the separation. Other points are visible as well. So, the sound board must come out. The case has not separated from the base anywhere, and so this will not be a complex fix, but it cannot be done well without removing the sound board, which has been compressed and cracked in the treble as well.

Once again, we could fix this from up top, or possibly just ignore it, but since things must come apart, lets keep looking.

Those hammers look pretty reasonable, but the hinges are toast (brittle and many already broken), so count on the underlever hinges to be poor as well. Jacks are generally hinged in vellum and will last about 5000 years if not eaten or abused, so we can count on limited servicing needs there. The action cloth was eaten by the moths and only shreds remain, so out it all comes. This one will need a pedal to replace the one it lost many years ago, and the stand will need attention as well. The key levers are straight, the ivories and accidentals are serviceable or good, and the case has only the usual scuffs and finish loss. This was a plain sort of Clementi and will do well with a new finish. Nothing much historical to lose there, but if you are a purist and can live with a dullish look, then that much less to do. The silk is out of the name board vents so we will replace that in time.

The strings come off first, obviously, and the plain music wire is good for nothing, though we will hold onto those overspun for now. If they were older they would go as well, but being time consuming to make and expensive to buy, we can afford to experiment a bit before abandoning them.

Next, remove the screws from the mahogany strip at the left edge of the soundboard. They probably have never been removed before and will be tight, so prepare a screwdriver by thinning the tip so it COMPLETELY fits the screw slot (width and depth) snugly but without any clearance underneath between tip edge and slot base, then with a 140 watt soldering iron, give each screw about 30 sec of heating first.  With a wiggle motion and steady and meaningful pressure downward, loosen each screw and back it out.  Heating the screw first and having the right drive tip and technique means 100% success, the whole job done in 4 minutes. Something less (‘I grabbed a modern screwdriver and commenced to turning’ kind of story) means hours of agony and drilling out bits. Stop and get this right now. That modified driver will be your friend many times in this project. I keep three widths for all occasions. Occasionally a screw will break off from excessive corrosion, but not often if properly heated first.

Using shop wiping cloth strips, fluffy and absorbent, thoroughly wet them and start laying them around the perimeter of the soundboard. Overlap and press lightly to make sure there is good contact to the wood. Don’t wet the bridge and no water running down around the lower edge, just wet cloth at the soundboard perimeter.

Now cover in black plastic and go to another task.

We will check this daily but we are several days away still from success. Note that we followed the perimeter of the soundboard only. If the piano had exotic veneer inside, painters tape applied first is good to keep water off the sides. But these cloths need to be wet, not so the water runs out, but close.

OK, we have worked on other things the rest of that day and the next, so on the third day we come back. The front strip comes right off (sometimes it is not glued at all but in this case it was) and the first side strip now seems loose. Let’s lift it off.

Now we can add a little heat to the joints with heat lamps, and get the temp up to a point where it feels rather warm. With a thin spatula we feel under the whole strip, and the glue is loose all around. No? Then recover with wet cloth and return tomorrow. Yes, proceed! Using a broad spatula we lift up the long strips, which were nailed and glued, so carefully here, we don’t want a split strip.

Once all the edge strips are up, we reapply the wet cloths. Let this soak again overnight, we need that sound board joint to come free easily. The next day we return, and lifting up on the front edge of the soundboard, we can tell things are getting loose. Heat lamps all around and then lift carefully. We can see that the wrest plank has captured the sound board so we clamp it back flat to free things up. If a small area of the sound board is caught by the nut in the treble, we can saw that part free without concern, using a razor saw. In this case it was only about 3/4 inch that was impacted.

OK, you have it out and mostly intact. The edge that had cracked under the former pressure came away separately but we can fix that later. Now we clean up the remains of the mouse nest and mess under the soundboard. Come back at the next update later in January to see what becomes of a the soundboard, fixing that wrest plank, and getting started on the action.

February 2014 – Addressing that sound board, we see that it is hardly quarter sawn fir, but appears to be white pine and cut at whatever angle could be planked out! This is typical of post-fire Clementi pianos (1807) when the need for volume outweighed all else and so much prime wood had been lost. They used what they had, and it still sounds fine, though perhaps slightly less stable than quarter sawn wood.

It was shellacked when made, and we will go ahead and remove this now. It gets in the way of repair and it has held the dirt nicely, so a fresh clean coat will be better for moisture control and more pleasing to look at.

There are several splits and cracks, some old and repaired, and some a little later. In general the hardest crack to repair is one where someone has been there before. Frequently, if the cracks are all as-found, then in a soundboard out restoration we can soak things and bring them back together. In this case we have some work to do. Let’s look at what we have.

The rear is detached and has an old fix, but it still matches closely and we will be able to repair this without more than a thin shim.

The front right corner is a simple split. Clamped back and reinforced with linen from behind, this is the easiest crack to repair.

Old crack, badly repaired, and now open again. This type takes a little work to make right.

First, we soak out the old repair. We cannot do anything useful on top of that bit. Wet towel for about an hour is sufficient to get the old glue swollen, them warm it up a little and the old piece lifts out.

I need two good parallel sides though, and this was fixed in place so it is shaped like an American football. Let’s take a scalpel and clamp a straight edge to the board, then carefully cut two good edges in a “V’ shape, both tapered into the depth and from the outside to the inside.

Good enough. Now we will fabricate some pine wedges with a matching taper, but thicker than the widest part of the gap , and having glued those up, we slip them in for a few hours to dry in.

Clean up the glue, then apply tape at each side (masking or painter’s tape is fine, we will not have it down for any real time) so that as we saw, we stay just above the surface of the board.

Now we can saw out the wedge. Thin wedges are easily cut with our scalpel but this thick one needs careful sawing. A saw with flat teeth is best, and of course thin curf is easier to manage.

Once cut out, we remove the tape and with out scraper just pull it down the splice until the splice is at board level (just a few good curls should do it). We can tone in the splices later.

The cracks that were not spliced are simply brought together and glued. Doing this on an irregular thin board is a challenge, but easily met by clamping wood blocks fore and aft of the split, and then bringing the split together under a little clamping pressure. If alignment is difficult, then separately clamp a thick plastic ruler or similar under things as well which will align the board but which the glue excess will not stick to. We can clean up hide glue after the fact without leaving any trace behind.

Next – fixing the wrest plank and case separation.

June 2014 – Plenty of distractions and things to do, but now with warm and steady weather, and a good gluing season ahead, we bring the wrest plank back into good contact with the base boards. The key is to make a notched 2X4 that will allow you to clamp things at an angle. The exact angle you cut the 2X4 can match the angle of the wrest plank in the piano, but a 45 deg V cut into the board in four places is quite sufficient and easy with a circular saw, with the depth set so that you only cut perhaps 60% into the thickness of the timber. Cork sheet stuck to the side that will face the piano (uncut side) keeps it from slipping forward under the clamps.

The wrest plank needs to go down and backwards to meet the back, seen here before and then immediately after. Heat lamps are used to keep the glue wood warm while working.

Let the glue pool around the edges for now, as we can and will easily clean this up later. For now we will let things set for a day and then take it apart.

Now with the wrest plank solid in the case, we can reinstall the repaired soundboard. It’s mid June now so no need for heat lamps anymore, the workshop is a comfortable 85 F. The glue goes around the edges and the moldings have been prepared already with the original nails set such that we can tack it all back in in less than 10 minutes.

Things are back in and fitting just right. The SB immediately gives a good response to the tuning fork, so we expect success from this sound board when complete. While that is drying we take a moment to clean off the left hand side of the piano hitch pin plank and cheek block using watered down methanol (50/50). Don’t use this to clean the notes at the wrest plank as it can fade the note runes, but for the rest it takes the grime and old shellac off nicely.

OK, we can now address the wrest pins. We have some decisions to make, so more on that later this week.





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