Are these Marcel pedestals?

[David Aubke]

If the pedestals on this KMC 1 have the Marcel curve, they'll be the first set I've seen in person. So I'm not certain whether they are.


It's a very subtle curve.

I'm trying to decide whether to proceed with a Miracle Mod but..
1. The consensus appears to say it may be unnecessary.
2. The action doesn't feel too bad as-is.
3. A quick check suggests I'd have to place the bump forward of the flat part. That is, the hammer cam sits right at the front edge when at stop-lock.


So I'm likely to leave well enough alone.

[Student Rhodes]

They appear to have the Marcel curve.   Certainly in that 1970 era, they were common on the Rhodes.
I have a Student Model with that curve from late '69, but I haven't really torn into it yet.  I'm somewhere in the process of replacing the felt cubes. 

Anyway, the consensus seems to be that you shouldn't need a bump mod, rather a refurbishing, or replacement of the felt seems to be the remedy.

Ray

[pianotuner steveo]

Hmmm...I could be wrong, but I always thought that the early pedestal shown on page 8-2 of theRhodes service manual was the marcel curve. If not, what was that one called?

[David Aubke]

Hmmm...I could be wrong, but I always thought that the early pedestal shown on page 8-2 of theRhodes service manual was the marcel curve. If not, what was that one called?

The pedestal on that page does appear to have a differently shaped and very pronounced curve.


The curve on my pedestals is so slight, I'm surprised it could have a meaningful effect. But it does appear to be intentional, not just a loose tolerance.

[pianotuner steveo]

David, I have seen pictures of the pedestal you have before. It was intentional. I'm just not sure which one is the Marcel.

Ben or Cormac, do you know for sure?

[David Aubke]

Now, the trick is going to be developing a clamping caul for gluing felt.

I may try some "Friendly Plastic".

[Peter Hayes]

Use contact cement on both the wood and the felt. Wait a few minutes and press them together.

Here's a pretty good video from our good friends at Vintage Vibe.

https://www.youtube.com/watch?v=D7dqqxvTYRQ

[David Aubke]

Thanks Peter.

I've been using hot hide glue for my pedestal felts. I suppose I don't have a good reason to favor it over contact cement except that it's a more traditional adhesive.

Will the contact cement release when the next technician applies acetone?

[Peter Hayes]

Yes.

[pianotuner steveo]

I'm pretty sure that mineral spirits will release contact cement, and its also plastic friendly if any spills. I know I've used mineral spirits to remove excess contact cement within hours of applying. Just not 100% sure about fully cured contact cement.

Haha, I was typing this while Peter replied....

[David Aubke]

Can anyone give me a good reason to continue using hide glue?

Probably not.

I've already got a quart of that gel contact cement.

[pianotuner steveo]

I know several piano techs that still use hide glue. I opened my business 36 years ago and have never used hide glue. I guess it's all just personal preference. I've been told that it's better when gluing leather, but again, I've never needed to use it.

[Fred]

Hide glue is excellent for a bond that can last for years, yet be undone with little to no damage to the parts it adheres. Acoustic piano hammers are a great example, as there may be a want to replace them without scrapping the shanks. I can see felt application, but contact cement has similar characteristics in the "undo-ing" dept., AND can adhere to tricky shapes, like the bump mod, upon application without clamping.

[Max Brink]

Why are so many people using contact cement on the pedestal felts? PVC-E Glue is fume free and it doesn't matter if you get it on your hands. It seems like the obvious choice for felts on a piano key, no?

[pianotuner steveo]

I've had bad luck with it on felt probably because felt is so porous.It sticks initially, but I've seen it lose its tack- especially in hot dry situations, like having a music room in an attic for example.

[rhodesjuzz]

I've had bad luck with it on felt probably because felt is so porous.It sticks initially, but I've seen it lose its tack- especially in hot dry situations, like having a music room in an attic for example.

I can confirm this....

--Roy

[pnoboy]

I used PCV-E on wood-to-felt bonds and it bonded very strongly both to the felt and to the wood.  I think the trick is to use enough so the glue can slightly infiltrate the felt fibers, but not so much that it renders the felt stiff.  I've also used it for gluing on keytops, for which it is almost universally used, and it created a strong bond in that application, also.  I'm a bit leery of contact cement.  I don't think ordinary mineral spirits will dissolve it when fully cured and aged, and if it doesn't, then you're stuck with acetone, which can create explosive fumes when used in a closed space.  Acetone will also dissolve the plastic that is used for the bump mod, which is a real negative IMO.

Hot hide glue is an excellent choice--it has been used historically with acoustic pianos, so there's a long history--well over a century-- of its application with wood-to-wood and wood-to-felt joints.  It also bonds strongly to itself.  So, if pedestal felts need to be changed in the future, you don't have to worry about getting all the old hide glue off.  I assume liquid hide glue would work much like hot-hide glue, and it doesn't require mixing and heat.

Other choices for felt-to-wood bonding might be Aleene's Tacky Glue or Sobo, but I haven't tried them.  I know of some piano techs that use Sobo.  There are many adhesives that should work well on felt and wood.  The key is to pick one that can removed in the future

On the topic of the marcel curve.  I once had a Rhodes that had this feature in the action, and I thought the action was excellent.  The hammers never double struck, and it was also possible to play softly.  The action response also seemed more linear in that the volume increased smoothly with how hard the key was struck.  With my '78 stage piano with the bump mode, the volume seems to stay low, and then jumps up to loud somewhat abruptly.  The marcel action was not as light as a bump-mod action, but I thought that was a plus, because it felt more like an acoustic piano.  I wish I still had that piano, but like a dope I sold it some years ago--big mistake.

[Ben Bove]

Pno - yes, the bump mod on a later piano is quicker to escalate from soft to loud.  The angle of the hammer curve is sharper, so it interacts more sharply with the bump being a fulcrum point.  On pianos with a more rounded hammer curve, there's a slightly better ability to control different velocities, because there is still a touch of roll happening over the bump.



Yes the pics at the top of this thread are the marcel curve.  There was only one iteration, and you can tell just like how was demonstrated - holding a flat edge to it will show a little dip.  I believe the diagrams in the service manual intentionally went way out of their way to show the surface was curved, otherwise a service tech would miss it.  it's a subtle curve, and trying to draw that subtle dip on paper probably wouldn't show well.

The 8.2 diagram is from the mid-late 60s, where the "bump mod" was actually a pre-set metal tab on a flat pedestal, with a felt strip on the hammer.  This pic isn't factory with the felt on the wrong surface, but it shows the flat pedestal with metal tab.

[pianotuner steveo]

-ok, so
I guess there never was a "wavy" shaped pedestal- just a bad drawing in fig. 8.4

[Ben Bove]

Figures 8.3 and 8.4 from the scanned manual are supposed to represent the pictures at the top of this post, they're both the marcel curve.  The manual drawings really aren't that great... another thing I notice is that they don't have the 45 degree angle notch-out in the front of the key pedestal.  So that's deceiving as well... it's sort of a poor drawing, but also was probably made in the midst of a lot of design changes they were trying to keep up with.  The best visual example is the real world example above ... it looks like a normal early 70's pedestal with a little scoop out of the center.

Another good picture of a marcel pedestal is on the vintage vibe page for purchasing keys.  Picture 2 in this link is a great up-close pic.
http://www.vintagevibe.com/collections/fender-rhodes-action-parts/products/fender-rhodes-keys-vintage-curved-marcel-pedestal?variant=1264406215

Speaking of manual drawings, this example shows how the dimensions are completely off for the front lip of the piano.  Press down a key in this picture, and see where the front of the key would disappear to... haha.

[David Aubke]

Hot hide glue is an excellent choice--it has been used historically with acoustic pianos, so there's a long history--well over a century-- of its application with wood-to-wood and wood-to-felt joints.  It also bonds strongly to itself.  So, if pedestal felts need to be changed in the future, you don't have to worry about getting all the old hide glue off.

Yer killin' me. I just did this piano with contact cement. It sure is easy and effective.

The truth is, I mainly used hide glue because I have easy access to the stuff and the necessary equipment and because it's traditional - though not for a Rhodes. The 'removable by future techs' aspect was just gravy and the reason I would give to avoid sounding pretentious.

After reading an article on the Spurlock Specialty Tools site, I remain convinced that hot hide glue is the way to go for key bushings but I'll have to make a decision about these pedestal felts.

[goldphinga]

I use contact cement for pedestal felt replacement. No problems with it at all. Can be easily removed if necessary with a little scrape without need for chemicals and allows movement of the bumps for ideal placement before it sets up. When doing the mod, I put some on the felt and some on the pedestal. Just done the bump mod on a late 75 with flat pedestals and left the hammer cam felts in place and just bumped the peds. Did each one by hand for optimum response, especially as the felts were all different lengths and placed pretty haphazardly at the factory. The piano is totally transformed and well worth the effort. I was going to remove all the under cam felts but its a huge job and if you do each bump by hand it's unnecessary. 

[pnoboy]

I tried using contact cement on some extra felt and a scrap piece of wood.  It seemed to work well, but I noticed that it soaked into the felt like a sponge.  How did you control it?  Presumably, too little would result in weak bonding, and too much would infiltrate the felt and make it stiff or kind of gummy.

[pianotuner steveo]

If I remember correctly, Naphtha removes the cam felts quickly and easily....

[Ben Bove]

I guess it would be a conversation on what type of contact cement, ones off the shelf like "Goop" at Home Depot have a thicker consistency, so it doesn't really leech into the felt fibers.

[pianotuner steveo]

I always use Weldwood when I am referring to contact cement.

[David Aubke]

I always use Weldwood when I am referring to contact cement.

Me too.

As mentioned in the Vintage Vibe video, they sell a thick gel formula that won't soak into the felt.