Correct glue to fix new key covers

[Spadger1944]

Hi, everyone,

I wish to replace the white key covers on an old Challen baby grand piano, and although I know how to carry out this task, there seems to be much confusion regarding the correct glue for the job.

Can anyone tell me of the best glue which is available here in the UK?

I intend to use white plastic covers rather than stimulated ivory. The instructional videos on YouTube are all American and the recommended PVC "E" glue is not available here, or so I believe.

Would standard Woodworking PVA glue be suitable?

Would appreciate any help on this subject.

[Colin Nicholson]

Some general advice here..... assuming you have removed the action, key slip rail, and each key can be removed and numbered/ working them in your hand, and not in-situ in the key frame??


PVA doesn't work for me as the plastic is not porous, & will peel off plastic when dry. Best to use impact adhesive like Evostick. Work on one octave at a time using a palette knife.
Make sure you also use a vice (protected with cloth) to clamp the tops down & ooze out the glue, then after 24 hrs cut off/ file excess.

KEY TOPS WITHOUT FRONTS - USE A JIG FOR CORRECT OVERHANG (LIP)

(Edited 25/3/16) ..... Apply impact adhesive evenly to BOTH surfaces - leave for a few minutes so it goes tacky, then secure one key at a time in your jig, then press key top on so overhang is correct.... you get one shot at it, so use a jig. Gluing simulated ivory is a similar plastic/ shiny smooth at the bottom - so needs impact glue. A small tube is no good, you need a small tin size.

You are also best rebushing the keys as the gaps between each key may be uneven. (Edited) - best done by a piano technician, using hot animal glue and plastic/ wooden key wedges - bushing cloth will be different gauge for tops and underside. If the keys wobble side to side, they will look awful with new key tops on,as all uneven.... so a lot of prep work needed. Keys then need to be eased with special pliers.

That's the easy bit!
Once done, you'll need some grand lead weights to level the keys (without the action on top). When you sit the action back on, just watch every white key pop up at different heights, like a Mexican wave. The weights are used to simulate the weight of the action pressing down on the key capstans, and you need the fronts UP, in the "ready to play" position. Add/ subtract paper washers to get the keys level by removing one key at a time. This can't be done with the action screwed down. Leads weights (52) are quite expensive, so may be worth getting if you are going to do a few pianos.


If the weight of the new key tops are heavier than the old ivory, you may need to readjust the rep springs. (Edited), also depending on the difference in thickness between old ivory & new tops, you may need to remove about 1mm (plane) of wood from the underside of the fallboard, removing the felt first.... then glue on new felt.

Also knock up a quick jig so you get the overhang lip exactly the same (about 2mm), and only one go at impacting them together. Use a padded vice to clamp together to get plastic as near as possible to key.

KEY TOPS WITH FRONTS
I prefer not to use these if possible, unless loads are damaged. You may get away with PVA, don't know, never tried it.... but there is more surface area to glue - if it fails, then use impact. If you use the tops & fronts (combined), always remove the old celluloid fronts so they don't snag against the front rail later.

With using tops & fronts combined, at the T or L section of the head of the key (where the black key starts), they often need filing down here as they overhang.... not an easy job to get them symmetrical, (and requires a lot of practise) and you will lose that nice curved profile.... that's why I prefer to replace any odd damaged front (even with ivory), use tops only - and align the T or L perfectly which may change the overhang, then paint the fronts (if needed) with model paint.

See this video for some ideas when I refurbished an Erard last year
https://www.youtube.com/watch?v=4--2PK-uy5c

Old key tops 3:20
New tops 5:00
Fronts 15:00
Key regulation & levelling 16:45

[Spadger1944]

Thanks for your advice Colin.

[KevinBull]

The other possibility for gluing keytops on is to use contact cement, which is something I have used, but I much prefer the PVC-E glue. We can ship the PVC-E glue to customers in the UK. The only items we can't ship internationally is the Protek lubricants.

[Colin Nicholson]

Like a kid with a new toy this forum?

[Barrie Heaton]

The other possibility for gluing keytops on is to use contact cement, which is something I have used, but I much prefer the PVC-E glue. We can ship the PVC-E glue to customers in the UK. The only items we can't ship internationally is the Protek lubricants.

We can get Protek lubricants in the UK from F&N

Barrie

[raquelcruzjazz]

Hi, everyone,

I wish to replace the white key covers on an old Challen baby grand piano, and although I know how to carry out this task, there seems to be much confusion regarding the correct glue for the job.

Can anyone tell me of the best glue which is available here in the UK?

I intend to use white plastic covers rather than stimulated ivory. The instructional videos on YouTube are all American and the recommended PVC "E" glue is not available here, or so I believe.

Would standard Woodworking PVA glue be suitable?

Would appreciate any help on this subject.

Where do you find these key covers?

[Barrie Heaton]

Trade
https://www.fletcher-newman.co.uk
if not eBay


Barrie