Best lube for pedestal felts

[pnoboy]

For years, silicone spray has been considered to be the lube of choice for pedestal felts, but is it still the best?  To test this idea, I compared it to McLube Sail-Kote, microfine Teflon powder, and Protek CLP.  The test setup is shown in the picture.  A piece of piano felt is slid over a scrupulously cleaned piece of acrylic, while weighted down with a 500 gm weight.  A piece of string attached to the felt is directed over a ball-bearing race to an adjustable weight that hangs down out of sight of the picture.  The weight was adjusted until the felt just slowly started to slide over the acrylic.  I used acrylic because I had a piece, and the possibility of getting a piece of Cycolac of the same type used in the Rhodes' hammers was pretty remote.  Given that we're only interested in comparative results, the use of acrylic seemed justifiable.  Here are the results. 

Plain felt-- 190gm  The plain felt was tested as a control.

Microfine Teflon powder--200 gm.  I was not surprised that the powder made friction worse.  Every time I have tested it, no matter what the application, I have gotten the same result.  Instead of resulting in a slick, smooth feel, it creates a greasy, almost gummy feel.  Additionally, I wonder how safe it is to use.  The powder really is exceptionally fine, and some always gets in the air.  Should anyone be breathing it?  Well, I'm going to throw out my remaining supply.

McLube Sail-Kote--140 gm.  I had high hopes for this substance.  It works exceptionally well when sprayed on metals, but I guess felt is not its strong point.

Protek CLP--110 gm  Not bad at all, but I noticed that when slid over the acrylic, a thin oily layer was deposited.  It seems like this could attract dust and dirt, so I'm not inclined to use it.

Silicone spray--90 gm.  Silicone is still the winner.  I noticed that when initially slid over the acrylic, it didn't do so well, but after sliding it back and forth a few times, the friction decreased dramatically.  Clearly, some silicone was being transferred from the felt to the acrylic.  One has to wonder if both surfaces having the silicone made the difference or if it was mostly the plastic being coated that made the difference, and the felt was principally acting as a reservoir for the silicone.

One might ask why I used such a heavy weight on the felt (500 gm).  Well, especially if the piano has the bump mod, all the force of the pianist's finger is applied to a very small patch of felt, and therefore the pressure would be quite high.  In fact, come to think about it, I wonder if partial lubrication of the pedestal felt might be helpful.  The rear-most portion of the felt only touches the hammer at the end of the blow and acts as the stop lock, to prevent hammer bounce.  Maybe leaving the rear 1/2 of the felt unlubed would reduce hammer bounce.  I'm going to try it--it's always easy to add more silicone.

[David Aubke]

Thanks for doing this. I've been using the Teflon powder for a while now and I definitely share your concerns about inhaling it. I may switch back to silicone. Anyone know of a source that isn't combined with acetone? I don't like that it attacks glue so effectively (and the hammer cams if you reinstall too quickly). I use hide glue for damper felts so maybe the acetone isn't that big of an issue.

[laberge]

I'm sitting here at my desk thinking "damn I haven't even lubed my pedestal felts... no wonder my action feels heavy..."

oops. Thanks for doing the test! looks like I'll need to go get some silicon spray after work today...

[David Aubke]

looks like I'll need to go get some silicon spray after work today...

Don't reinstall those keys until it's good and dry.

[laberge]

looks like I'll need to go get some silicon spray after work today...

Don't reinstall those keys until it's good and dry.

Yeah, I might even do some tests with a few keys to see if it affects the glue on the felts/look to see how much is good to use. I'll let you know.

[Ben Bove]

A very cool thought out test.  Thanks for this.

[Fred]

Thank you for sharing! I'm not at all surprised about the Teflon powder. Another powder I've come across all too often looks like talcum or baby powder. It absolutely shreds the action centers enabling the hammers to wobble all over the place.

On another note, a properly set up Rhodes action (all aspects, key height, dip, hammer blow distance, escapement, etc.) with the bump modification (properly placed) is by no means spongy or sluggish when a pedestal lubricant is left out of the equation. Keep in mind, the pedestal (including the the edge of the bump farthest from the player) acts as a brake once the tine is struck.

Lubricants can introduce many unwanted side effects as well. Chemical additives can attack plastic and adhesives, and even pure silicone can compact the pedestal felt fibers (again hindering braking). Some Lubricants gum up in cold weather, or re-activate on a hot day.

All the above combined with properly smooth hammer cams, one questions the notion of a pedestal lubricant in the first place.

[pnoboy]

Thank you for sharing! I'm not at all surprised about the Teflon powder. Another powder I've come across all too often looks like talcum or baby powder. It absolutely shreds the action centers enabling the hammers to wobble all over the place.

On another note, a properly set up Rhodes action (all aspects, key height, dip, hammer blow distance, escapement, etc.) with the bump modification (properly placed) is by no means spongy or sluggish when a pedestal lubricant is left out of the equation. Keep in mind, the pedestal (including the the edge of the bump farthest from the player) acts as a brake once the tine is struck.

Lubricants can introduce many unwanted side effects as well. Chemical additives can attack plastic and adhesives, and even pure silicone can compact the pedestal felt fibers (again hindering braking). Some Lubricants gum up in cold weather, or re-activate on a hot day.

All the above combined with properly smooth hammer cams, one questions the notion of a pedestal lubricant in the first place.

Fred,

Do you have the specs for hammer blow distance and key height?  I haven't seen them.

Thanks

[Fred]

I do not think any Rhodes literature has a spec for this, as well as many other aspects of the piano, but it is a good idea to at least level the hammers across the compass once you've established height and dip to ensure a more consistent feel/response.

[bourniplus]

it is a good idea to at least level the hammers across the compass

I must ask, how do you level the hammers in a Rhodes?

[pnoboy]

it is a good idea to at least level the hammers across the compass

I must ask, how do you level the hammers in a Rhodes?

You could expand your question into two related questions.  How do you level each hammer with respect to its neighbors, and how do you level the hammers in general.  Let's consider the second question first.  The average hammer height across the compass can be adjusted by adding/subtracting the paper punchings used on the balance-rail pins.  Of course, adjusting the key height at the balance rail also affects key height, so if you want the keys to remain level, the punchings can only be adjusted very slightly, one next to another, but can provide a broad leveling across the compass. If one were up for it, you could try to use shims under the back-rail felt, but that's probably more trouble than it's worth. 

The first question is the more troublesome--Fender provided no individual, independent hammer height adjustment that I know of.  Maybe one of our readers can provide additional information.

[David Aubke]

I must ask, how do you level the hammers in a Rhodes?

I always thought the answer was "You don't".

If I was to try though, I'd probably adhere shims to the underside of the backs of the keys, then re-level the fronts with balance rail punchings. Since the keybed felt is a continuous strip, it would be difficult to isolate individual adjustments by shimming under the felt.

[Fred]

Yes, the hammer height can be adjusted by adhering paper punchings to the underside of the key where it rests on the back rail cloth. If the hammer is too high without any shims, the key can be planed to lower the hammer height.

[O.Lahoz]

Note that if you place paper shims in the balance rail, I think the scape distance will be modified. An action causes a reaction (or multiple)

[pnoboy]

O. Lahoz, please tell us about the piano pictured in your avatar.  It looks great!

[Student Rhodes]

I PM'd him about this quite some time ago, and I think he told me it was a photoshop creation.

[Fred]

I PM'd him about this quite some time ago, and I think he told me it was a photoshop creation.

That would be pretty cool if it where a real creation!

Note that if you place paper shims in the balance rail, I think the scape distance will be modified. An action causes a reaction (or multiple)

If I understand O.Lahoz correctly, yes, balance rail shims do affect the hammer height somewhat, but not to the extent that they affect the height of the front of the keys.

[O.Lahoz]

O. Lahoz, please tell us about the piano pictured in your avatar.  It looks great!

Yes, is a "modified" student piano without the fishtail base. Of course, it is only in my imagination 

[groover]

Hi,
Wow this forum is very informative. I didn't even know about lubing the pedestal felts. I'm thinking that this would make for a much smoother action on the Rhodes. Is this correct and is it common practise? Anyone recommend any brands of this silicon spray that works well?
Thanks

[David Aubke]

All the above combined with properly smooth hammer cams, one questions the notion of a pedestal lubricant in the first place.

This is my new opinion on the subject. Although even the service manual recommends silicone spray, I think Fred makes some convincing arguments and I'll probably be skipping the lubrication step on my next job.

edit Wait a minute. The manual seems to be suggesting using silicone spray as a solvent for the glue, not as a lubricant. This seems like a terrible idea. The reason it would work as a solvent is because it's mixed with acetone which will damage the plastic hammer.

'nother edit OK, it also says to use it as a lubricant. I still wouldn't.

[pnoboy]

I appreciate the possibility of using no lube, but here's why I'm not ready to give up on it.  Do this simple experiment.  Find something in your house that has some hard, shiny plastic on it.  Often radios, TVs and computer accessories are housed in shiny cabinets.  Clean an area of the plastic very thoroughly using a spray detergent or the like.  Be sure it's squeaky clean, as the saying goes, and free from residues from the cleaner.  Now, lightly rub your finger across the plastic.  It will feel smooth and slick.  Now, press harder--pretty soon you'll start to experience a slip/stick phenomenon at which point the friction will feel much higher, and your finger may cause a squeaky sound as it rubs across the plastic.  If you put some sort of lube on the plastic--the tiniest bit of silicone, or something oily or greasy, the stick/slip phenomenon will go away and the friction will be noticeably lower.  The pressure between the pedestal felt and the plastic hammer is pretty high, and I suspect a bit of lube on the hammer will help quite a bit with friction.   For this reason, I'm planning to do some additional friction tests.

[theoriginalpol]

Yes, the hammer height can be adjusted by adhering paper punchings to the underside of the key where it rests on the back rail cloth. If the hammer is too high without any shims, the key can be planed to lower the hammer height.

I had one hammer that for some reason was significantly higher than the rest. I dropped its height by simply replacing the pedestal felt with some thinner (general purpose I guess) felt that I happened to have on hand. Was this a bad idea?

[theoriginalpol]

Also pnoboy out of curiosity what brand of silicone spray did you use in this test?

[Fred]

@ theoriginalpol

I'd be concerned with inconsistencies in feel, and wear in the long run.

@pnoboy

That all makes sense, but bear in mind that in the Rhodes action, the same component (pedestal and bump, if present) that sets the hammer in motion is also responsible for braking the hammer. The graduation of friction that you describe helps to stop the hammer under heavy playing. This can be especially handy in pianos that are set up for good response under a light touch as well, as with minimal escapement, you can use all the stopping power you can get to prevent double strikes.

[pnoboy]

Also pnoboy out of curiosity what brand of silicone spray did you use in this test?

I used KEL "Pure Silicone."  I don't think there's anything special about it, it was just a can that I had around.

[theoriginalpol]

Also pnoboy out of curiosity what brand of silicone spray did you use in this test?

I used KEL "Pure Silicone."  I don't think there's anything special about it, it was just a can that I had around.

Cool! That's the one I was considering, people seem to swear by it. Perhaps I'm being a little too paranoid about solvents — I read Kelloggs has some acetone in their sprays, but it evaporates quickly leaving pure silicone. So... a non-issue?

And thanks Fred, i'll keep an eye on that key. Although I've got VV's miracle mod coming in the mail, so I guess it's a moot point.

[pnoboy]

@ theoriginalpol

I'd be concerned with inconsistencies in feel, and wear in the long run.

@pnoboy

That all makes sense, but bear in mind that in the Rhodes action, the same component (pedestal and bump, if present) that sets the hammer in motion is also responsible for braking the hammer. The graduation of friction that you describe helps to stop the hammer under heavy playing. This can be especially handy in pianos that are set up for good response under a light touch as well, as with minimal escapement, you can use all the stopping power you can get to prevent double strikes.

Fred, I appreciate your point, and I started out using no lube on my pedestal felts.  However, the action felt a bit heavy, and on one note I discovered that plastic from the hammer ended up on the pedestal felt, right on the bump mod.  Clearly, excess friction was causing the hammer plastic to wear and some of the plastic was effectively rubbing off onto the felt.  That particular hammer was not as smooth and slick feeling as the others, and I ended up polishing it with some ultra-fine lapping paper. 

Of course, with the bump mod installed, all the force generated between the hammer and key is applied between the bump and the small portion of the hammer that slides over the bump as the key is pressed.  Because the key and hammer are not coaxially pivoted, there is necessarily rubbing between hammer and bump.  Because of this experience, I took all the keys out of the piano, put wide masking tape over all the pedestal felts, leaving just the bump area uncovered.  I sprayed silicone on the bump area, but used a bit too much, as some of the spray wicked into the covered part of the felts. 

The action felt markedly lighter after lubing, but alas, some notes ended up double striking.  Fortunately, I discovered through some testing that mineral spirits easily dissolves the silicone grease that is left behind after the solvents in silicone spray evaporate.   Because I used wood glue to attach the pedestal felts, which did not dissolve from mineral spirits, I found I could saturate the offending pedestal felts with mineral spirits and then repeatedly blot them with paper towels until the paper towel absorbed no more liquid.  Also, I used a paper towel dampened with mineral spirits to remove any silicone that ended up on the hammer.  This procedure fixed the double-strike problem.

However, I now, once again, had no lubrication on those notes.  So, this time, I took out the affected keys, and sprayed silicone spray on a clean piece of glass.  Then, after letting a bit of the solvents in the spray evaporate, with a fingertip, I could transfer a bit of silicone to just the bump area—without the silicone migrating into the rest of the pedestal felt.  At this point, I felt I had about the best option—lube at the bump to help eliminate friction and wear, and dry felt on the rest of the pedestal for good braking action.

[prtarrell]

Silicon never sleeps.  It will pass from the felt, through the glue, and into the wooden key. I agree that the unlubricated pedestal felt helps the stop block.  The force to move the key down (the downweight) is related to the upward force of the key returning to rest positin,( the upweight).   Heavier downweight results in heavier upweight and faster return to rest position to permit the next blow.   The relationship between these two determines the ability of the aaction to repeat (repetition).  So the lightest feeling action is not necessarily best the best.  There is a  trade off.

[rhodesjuzz]

Silicon never sleeps.  It will pass from the felt, through the glue, and into the wooden key. I agree that the unlubricated pedestal felt helps the stop block.  The force to move the key down (the downweight) is related to the upward force of the key returning to rest positin,( the upweight).   Heavier downweight results in heavier upweight and faster return to rest position to permit the next blow.   The relationship between these two determines the ability of the aaction to repeat (repetition).  So the lightest feeling action is not necessarily best the best.  There is a  trade off.

I agree. It think it is never good to overdo with sprays, silicon, etc. The same goes for waxing screws that mount the tonebar to the harp. It may be very tempting to do and for the first few years you might benefit from it. But I'm afraid on the long term it might harm the wood. Of course I'm not certain about this and how about spraying key pins? What are the long term effects?

--Roy

[Fred]

IMO introducing lubricants to the pedestal (or part of it) creates an effect that is potentially damaging (compacted felts, compromises in adhesion, reactions with plastics, etc.), temporary (as lubricants disperse and evaporate), and temperature sensitive (adding yet another variable that can affect all previously mentioned points). If there seems to be a need to lubricate the Rhodes action in this manner, there is usually an underlying issue in the set up of the action.

That said, if you have come up with a set up that you are comfortable playing, that is what matters at the end of the day - Just be on the lookout for any of the adverse effects that could crop up, especially if your piano is subject to extremes in temperatures.

I would strongly recommend against the use of wood glue for pedestal felts, however. These felts are what we would call a "consumable" component in the action, and years later may require replacement as they will wear, with or without lubrication. Most wood glues are designed to provide a bond "stronger than the wood itself", making removal of worn felts very difficult while trying not to distort the shape of the pedestal, bump, and placement of the bump.   

[rhodesjuzz]

IMO introducing lubricants to the pedestal (or part of it) creates an effect that is potentially damaging (compacted felts, compromises in adhesion, reactions with plastics, etc.), temporary (as lubricants disperse and evaporate), and temperature sensitive (adding yet another variable that can affect all previously mentioned points). If there seems to be a need to lubricate the Rhodes action in this manner, there is usually an underlying issue in the set up of the action.

That said, if you have come up with a set up that you are comfortable playing, that is what matters at the end of the day - Just be on the lookout for any of the adverse effects that could crop up, especially if your piano is subject to extremes in temperatures.

I would strongly recommend against the use of wood glue for pedestal felts, however. These felts are what we would call a "consumable" component in the action, and years later may require replacement as they will wear, with or without lubrication. Most wood glues are designed to provide a bond "stronger than the wood itself", making removal of worn felts very difficult while trying not to distort the shape of the pedestal, bump, and placement of the bump.

Thank you Fred! But how about lubricating key pins and the glue (and perhaps the key's wood) that holds the key bushings in place?

--Roy

[pnoboy]

IMO introducing lubricants to the pedestal (or part of it) creates an effect that is potentially damaging (compacted felts, compromises in adhesion, reactions with plastics, etc.), temporary (as lubricants disperse and evaporate), and temperature sensitive (adding yet another variable that can affect all previously mentioned points). If there seems to be a need to lubricate the Rhodes action in this manner, there is usually an underlying issue in the set up of the action.

That said, if you have come up with a set up that you are comfortable playing, that is what matters at the end of the day - Just be on the lookout for any of the adverse effects that could crop up, especially if your piano is subject to extremes in temperatures.

I would strongly recommend against the use of wood glue for pedestal felts, however. These felts are what we would call a "consumable" component in the action, and years later may require replacement as they will wear, with or without lubrication. Most wood glues are designed to provide a bond "stronger than the wood itself", making removal of worn felts very difficult while trying not to distort the shape of the pedestal, bump, and placement of the bump.

It is certainly true that many wood glues are hard to remove, but not all of them.  Acoustic pianos have used hot hide glue to attach felts to wood for hundreds of years.  With some heat and moisture the glue softens and felts can be removed, and new ones applied.  The same is true for Titebond's liquid hide glue.  The glue I used, PVC-e is also water soluble and is not hard to remove.

I don't agree that requiring lubrication indicates an action setup problem.  As I mentioned in my post, there will necessarily be rubbing between key and bump.  This can be minimized if the Rhodes action was designed such that the contact point between bump and hammer intersects an imaginary line drawn between the key pivot and the hammer pivot when the hammer is halfway up.  I've never checked to see if the Rhodes action was so designed.

I also am very skeptical of poster prtarrell's claim that silicone will continue to travel and go through the glue layer.  If that were the case, it would destroy the glue and the glue bond.  Silicone spray would become worthless because it would destroy or compromise everything in sight.  The grease left behind after all the solvents in silicone spray have evaporated is very thick, and it's hard to imagine it traveling.  I will set up an experiment.  I will take a piece of glass, clean it very thoroughly, put masking tape on all but a narrow strip, and spray a heavy coat of silicone spray on it.  After the silicone spray dries, I will remove the tape, set aside the glass for about a month, and then check it for silicone creep.  I will report what I find.  Talk is cheap, and real data priceless.

[Fred]

It is certainly true that many wood glues are hard to remove, but not all of them.  Acoustic pianos have used hot hide glue to attach felts to wood for hundreds of years.  With some heat and moisture the glue softens and felts can be removed, and new ones applied.  The same is true for Titebond's liquid hide glue.  The glue I used, PVC-e is also water soluble and is not hard to remove.

Yes, PVC-E and hide glues offer ease of component removal in the future. In your original post however, you only refer to it as "wood glue". Without further description, one could conceivably grab the ol' bottle of Elmer's and proceed to cause a lot of headaches in the future ; )

I also am very skeptical of poster prtarrell's claim that silicone will continue to travel and go through the glue layer.  If that were the case, it would destroy the glue and the glue bond.  Silicone spray would become worthless because it would destroy or compromise everything in sight.  The grease left behind after all the solvents in silicone spray have evaporated is very thick, and it's hard to imagine it traveling.  I will set up an experiment.  I will take a piece of glass, clean it very thoroughly, put masking tape on all but a narrow strip, and spray a heavy coat of silicone spray on it.  After the silicone spray dries, I will remove the tape, set aside the glass for about a month, and then check it for silicone creep.  I will report what I find.  Talk is cheap, and real data priceless.

The problem I see with your experiment is that it lacks any type of mechanical movement of the silicone on the glass (other than gravity, if left upright). The rubbing of the hammer cam against the pedestal will surely agitate any substrate or chemical more than gravity alone. For the most accurate results, why not try in the actual application?

I agree, if one where to lubricate with silicone spray, the proper way would be to spray elsewhere (not directly on action components) to allow solvents/propellants to evaporate, followed by careful application to the bump only. As far as silicone travelling, it would at least be spread across the area of the hammer cam that glides across the lubricated bump. This in turn could affect the hammer's ability to brake. Another thought - I know some acoustic techs who cringe at the thought of using it anywhere near a piano, for fear that the silicone will travel to the tuning pins. I'll, admit, I've always been puzzled by that school of thought, but perhaps they're not taking into account careful application, as opposed to spray-bombing the whole lot.

All that being said (typed?), with proper set up all notes will sound under the lightest touch. Feel of the action is very subjective, however. I've had many clients who, coming off an acoustic grand, find the bump mod too light for their preference. Others, used to digital pianos, organs, etc., may be on the opposite end of the spectrum. One does need to realize these are mechanical actions - A period of time to acclimate to that fact may be in order for some, but I have yet to encounter a client who returns with the complaint that the action feels too heavy after a proper set up, without pedestal felt lubrication. That said, if you find a set up you prefer on your particular piano, stick with it and enjoy.

[pnoboy]

Fred,

I agree that the Rhodes action feels fine even without lubrication, and your point about wood glues is correct--one has to be careful to select one that is water soluble.  My only reason for applying any lubrication to the pedestal felt was the observation that the hammer plastic seemed to be rubbing off onto the felt, perhaps due to local heating.  It occurs to me that a nifty solution to the lubrication problem might be to apply a short piece of Teflon tape to the hammer cam only along the small portion of the cam that contacts the bump.  That would leave the bulk of the cam untouched, there's nothing to creep, and the tape would be easily replaced if it wore out.  I've got some Teflon tape--if it's wide enough I'll give it a try on one note, just for fun.

Yes, my silicone test wouldn't have any mechanical movement, but, I believe the other poster was suggesting something beyond just mechanical spreading--that the silicone has some unusual property to creep on its own, and not just be spread around mechanically.  I'm going to set up the test this weekend--it's just a matter of 10 minutes of time, and it would be interesting to know for sure if silicone has some unusual property that we all should know about.

[Fred]

...the hammer plastic seemed to be rubbing off onto the felt, perhaps due to local heating

I have seen that before. It may also be the result of the plastic oxidizing or degrading over time. I noted that you polished the dull hammer cams with an ultra-fine paper. After that step, try Mother's Mag and Aluminum polish - you should be able to restore that smooth, shiny surface the cam(s) had when new...