This is a case that I'm sure will sound familiar to some.
I have a recently acquired customer the owns an old upright (1901). When I came out to inspect/tune the piano, I noticed that the action was so sluggish that it was unplayable. I also noticed the the wood was unnaturally stained a dark color. The skip to the end, I asked the customer if anyone had ever treated the piano with WD-40. "Yes," I was told. There were some sluggish keys and it was treated with WD-40 on the action. The entire action was treated, apparently. Everything was covered with WD-40... the stickers, the hammer shanks... everything. Either the whole action had been utterly soaked, or the WD-40 just migrated everywhere.
I decided to try a little ProTek CLP and come back another day. Though I really didn't expect it to work, I thought, "What harm can it do now?" When I returned, the parts of the action treated with ProTek were only slightly better. But overall, the whole action was still unplayable.
I have two questions:
1.) I thought WD-40 in pianos, especially on the actions, was a definite no-no. But, I did a little Googling around, and I found this toward the bottom of this page:
WD 40 doesn't contain what you'd think of as oil.
Also in the UK I did some background study of WD 40 before using it in damp sticky piano mechanisms.
I had a letter from the manufacturers of the patented product when they were owned by Cadulac Chemicals in the 1970s They informed me that the product contained
Animal Waxes (that is Tallow)
Petroleum based waxes (rather like Vaseline)
All borne up in a 3 to 1 concentration of White Spirit.
This is like a turpentine substitute.
The turps does most of the Surfactant work displacing water and the waxes do the lubrication.
It was safe to use in Piano actions, on wood, cloth and brass pivot pins and didn't dissolve any of the old fashioned Scotch Glue, or Animal Glue.
The company said I should be careful to make sure I didn't use it on any Cold-moulded plastics and there aren't any of those used even in modern pianos.
The lubricant was used to free up sticky components that the wooden parts had swollen with moist air or damp conditions. It was very effective and had no long term side effects.
So apparently the manufacturers of WD-40 recommend its use in piano actions. I thought that WD-40, over time, tended to gum up action centers, necessitating repinning and rebushing down the road. Am I wrong? Was I wrong to most strenuously discourage the use of WD-40 to the customer? Or, does anyone know if WD-40 has changed their position recently?
(Btw, if they are in fact advising the use of WD-40 in actions, perhaps they could be held liable for any damage done?)
2.) If I am correct and WD-40 is making things worse than would otherwise be the case, are there any cheap and dirty tricks I can use? I don't think I can justify the cost of completely repinning and rebushing. The only thing I can think of is to either wash the action centers with naptha or acetone. But, I really don't want to do this because of the danger of explosion as well as possible cancer risks to me and the customers over time. Also, I'm not sure it will work, anyhow. This action is pretty stiff. It may also attack the glue joints, too.
I realize this may be a lost cause, but I wanted to ask for other opinions before throwing in the towel.