Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Using varnish when restringing

When you are restringing (with new pins) using the original block, do you swab the tuning pin holes with varnish beforehand? (Or dip the pins in varnish before tapping them in?) I seem to recall reading a PTG thread in which a respected tech was convinced that doing so not only made for a consistent-feeling torque, but that over time the same torque was more likely to hold up when using the varnish. If I recall correctly this tech was scientific about recording his torque readings and remeasuring each year for several years, comparing pianos he'd restrung with and without the varnish prep.

For those that have experience with this, any preferred brand/type of varnish? Do you simply apply it with a Q-tip?

And of course I'd like to hear from anyone who thinks (based on real experience) that using varnish is not a good idea.

I'm also curious to know what other kinds of prep or techniques you use when restringing. What kind of prep work do you do with the pinblock, if any? Do you wash the new pins with mineral spirits before using them? Do you measure all pin diameters to ensure uniformity? Klinke seems to be the highest quality manufacturer out there, are there any others? Thanks for your thoughts...

Back in the 70's, when I apprenticed, the shop I worked at didn't varnish the pins/holes - never heard of it before.

Dear James,

I'll be curious to see what others have to say. There are a lot of opinions on this subject.

I have used 'spar varnish' for 30 years in my restringing. A quick swizzle with a hammershank down the tuning-pin hole; a very light coating. I don't let it dry, I swizzle 10, string them, and then hit the next 10, etc. I want the slightly sticky varnish to serve as a 'pin-driving fluid' to prevent damage to the wood of the pinblock as the pin is whacked into place.

Rebuilds where the tech simply whacks the pins into a dry hole always feel 'jumpy' to me. Imprecise and 'clicky', which may get better with time...but often does not.

Using the spar-varnish gives you a smooth and solid feel to the pin. Predictable and nice. It actually improves with time. When I first used this I was not pleased...I thought the pin was lower torque than it should be. It took about a year to understand that the varnish is still 'curing' down there and just got a little tighter as time went by. Pianos restrung with the varnish have remained solid and predictable. It really takes about a year...maybe a year and a half...to see where the torque will finally be.

Not at the shop today, so I can't give you the manufacturer. But, a 'marine spar varnish' is the label.

I look forward to other's comments!

Sipping Costa Rican today,
I am,
In the armchair,

During my university years, I worked at one of the top shops in the country. Using a driving fluid was standard practice there, so it is what I have always done.

However, to take it beyond individual experience, the Appleton Chapter of PTG did a controlled test of restringing with and without driving fluid. In all cases, the results were that there was lower initial pin torque using the driving fluid and a higher pin torque after the fluid dissipated compared to the tuning pins that were driven dry.

I recommend lacquer sanding sealer or shellac over varnish. You really want something that will dissipate more easily. There's no need to have a "coating" on the inside of the pin holes like a layer of finish on the cabinet.

We use a hammer shank to swab the hole before driving the pin. Usually we swab 6 tuning pin holes at a time. More than that and the fluid starts to dissipate or dry. I think using a driving fluid also minimizes/eliminates tuning pins jumping or snapping. It seems to give the pins a real smooth feel as they turn.

There is a bit of interest in this right now, I think there was something about this in the Journal lately. Some of the components of spar varnish (at least the traditional kind) are natural tree resins. I am currently bringing in some some resin from Europe on request from a high profile technician who wants to try it out.

I'd be inclined to think that varnish or resin could work favourably within a certain window of compression/torque on the pin. If the pin hole sizes vary where they get a bit too tight (over 110 in/lbs) I think it would magnify the problem of sticky creepy pins. On the other side of the coin, it wont help too much if the hole is too big to properly hold the pin. Is the application of varnish or rosin meant to compensate for poorly drilled holes as far as size consistancy? I only mention this because I've seen wonderfully responsive tuning pins without the need for chemical additives between it and the wood.

Colophonium or Colophium, (gum rosen) is readily available in N. America. This product can also be used as a hammer hardener for clients who don’t want their hammer sets soaked in chemical solutions such as lacquer or colodium.

In the early 70's I was taught to use rosin for violin bows, rubbed into the pin threads.
Later I was taught and learned by experience that drilling the block correctly gave the best results weather drilling a new block or re-drilling an old one for a larger pin size.
I do not use driving lubricants any longer.
Also, I find that torque alone is not so much of a priority as the feel of the pin moving in the block.

I believe the main purpose of the rosin was to keep the pin from being contaminated with finger oils. It does not accomplish the same kind of thing as using driving fluid which minimizes destruction of the pin hole that happens with the manipulation of the pin during stringing. I believe the use of driving fluid is a superior approach to a superior feel of tuning pin.

Thanks everyone, still hoping to hear from more techs.

Jurgen, I must have missed the article in the Journal. If anyone knows which issue it was in I'd appreciate it.

Just sitting here rebushing a keyset and waiting for the hurricane to arrive....

Actually, kpenbrook, the process of drilling does not leave a fine surface nor one that is consistant in size (incomparison to reaming or boring processes). The hole is nowhere as close to consistancy in size as that pin is on its diameter. The driving of the pin with its lightly threaded surface and the initial rotations to bring up to pitch evens out the walls irregular surface to provide more contact with the pin.... I would regard this as a beneficial thing and not a destructive one, as you mentioned. A few inch lbs of torque might be lost in the process but that is easily compensated for with the initial tool sizing.

I highly suspect that using a driving fluid would interfere with this final sizing of the hole in the same way as using specialized lubricants on an engine before it runs for several thousand miles and the rings properly wear into the cylinders.

Agreed on the drilling.

This was confirmed to me years ago by a long time machinist when he overheard my conversation at a supply house regarding drill bits and what my application was.

The machinist industry does not view twist drills as accurate; twist drills tear the walls of the hole and once that begins there is no way to prevent it or stop it from continuing.

It was recommended to use a Forstner bit for new holes and adjustable reamers or dedicated reamers for the existing holes being enlarged.

Also any liquid that is put into the hole will fill the wood grain making for a more even wall structure. How far it permeates the wood fibers or how long it lasts is the unknown.

When we used rosin, the intent was driving fluid, not protection from finger oils.

I haven’t used any fluids on tuning pins for years now. As you mentioned previously a properly sized hole is yields best results.

If finger oils are a problem for some drop the tuning pins in alcohol or Methyl Hydrate. That’ll clean them up fast.

Just to be clear, I wasn't offering an opinion but experience.

We all know that one way to loosen a tight tuning pin is simply to move it back and forth a dozen times or so. It doesn't matter if you have a "really tight" tuning pin or a "somewhat tight" tuning pin. If you move the pin back and forth several times it WILL be looser than it was. Thus, no real potential for "evening out" the torque from pin to pin.

That is the same kind of manipulation pins get in the stringing process. Regardless of the individual starting torque, manipulation of the pin will always reduce that torque. Always. Addressing variations in hole diameter is a separate issue.

Using a driving fluid has been demonstrated -- by scientific testing and by experience of many top rebuilders -- to reduce the initial wear.

This might be a new concept to some and there certainly are other approaches. I don't really care who uses which procedure. However, there is no question that this approach works and works very well. It has a track record running into multiple decades.

Hmm, different story than what I heard. That is why it was used in some factories.

In any case, the rosin wouldn't do the same thing as the driving fluid because it doesn't dissipate. It stays there -- which may or may not be helpful.

I had always associated rosin with snapping tuning pins. That's its function in a violin bow -- to have that drag and release action that results in the string being activated. However, I don't have any direct experience or awareness of studies or tests one way or the other.

I will add this, there are many top rebuilders that have worked on and improved their drilling techniques such that they do not use driving fluids and track records are there as well.

I am betting that snapping tuning pins are from glazed holes caused by a drill bit being too hot, probably from being dull. Ever notice how they tend to be in the upper end of the piano?

Yup!

High speed glazing is especially problematic with multi laminate blocks( read Delignit) as the resins overheat.