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Anyone have experience based results on how a pinblock will fair on CA treatment after it has had some dope used on it in the past(years ago). Are the residues of one incompatable with the other?

I have not done this myself, but I have heard technicians on the PTG list say CA after dope works fine.

You mean pin tight applied first, then CA? I'm sure I've applied CA in that situation and never had any issues.

I've used CA on a previously doped block in a console, and it worked perfectly. I don't know if it was Pin-Tite or another brand of dope, but whatever had been done many years before was a hot mess. The stuff was all over the plate and coils, and it obviously hadn't worked because overall the piano was 200 cents flat, some notes were a major 3rd flat, and my tuning lever was spinning like a propeller before I applied CA.

I discussed with the owner beforehand, and explained that it might not work, and she was fine with that. But it worked just like any other CA application I've done, it's been about a year and all is well...

Hi all - I'm a big believer in using C.A. in situations where repinning or a new pinblock is not an option, and have had much success with it, including a couple of pianos (a console and a small grand) which had been previously treated with either Lundsford's or Garfields - I'm not sure which but they had been done by me several decades ago and I used both when that was all that was available. The C.A. brought about a much better result.

If you would like to take a look at the brochure which I give out to my customers to explain the process,click on the following title: C.A. Treatment of a Loose Pinblock.

By the way, an effective demonstration of the chemical process which C.A. produces is to take a paper towel, crumple it and apply several drops of the glue to the surface. Within a matter of seconds the paper will be hot and stiff, because (I believe) of a reaction between the glue and the wood fiber in the towel. Depending on the brand of paper towel, you might even get a whiff of smoke. This is a very easy way to show that there is a real effect that takes place.

Best wishes, all. Chuck Behm

Greetings,
I am positive that the CA causes the wood to swell, and I know it cannot shrink the pin, since the pin is incompressible, so yes, there must be some compression of wood against wood. I also think that the CA serves to reduce the elasticity of the wood, and elasticity is required for compression to be effective, otherwise a few rotations of the pin could grind the surface and it would lose torque. Think of a metal pin rotated in stone as an extreme example.

However, I wonder if, perhaps, a significant factor in the increased torque is due to the increased effective surface area of the hole. If the CA actually is strong enough, on an intercellular scale, to create a lot more working surface for that pin to turn against.

In any case, it sure does work, I have several 5 year old jobs that still tune beautifully, whereas before, souping through a "Garfield's Restored" block was a miserable chore.
Regards,

it is also dramatic to squirt a dose on a cotton ball. Be ready for combustion.