Note: This is a cross posting under a new heading that came from the "Dope or not, Wiekert" subject line.
I agree with Fred. The protocols outline suggest a New York Steinway type lacquer treatment. I don't see the point then in worrying about whether it's Weikert felt, Bacon felt or Joe's felt. Once you soak the hammer with lacquer it lessens the importance of what the felt is to begin with. If you are going to reap the benefits of Weikert felt then it needs to be unadulterated, at least in my opinion. The problem continues to be too much bulk.
As I've mentioned and Fred alludes to, the profile of the hammer is very important and must work hand in hand with the overall density of the felt. A lower density felt either from pressing or from the starting point of the sheet must be profiled appropriately to match. These two aspects of hammer making must work hand in hand. A bulky lower density hammer will always need lacquer, always. However, a trim, lower density felt will not. (Similarly, a high density felt, say from heat pressing, will be uncontrollable in a low profile configuration. In that case a higher profile will be the more appropriate choice--more on this another time). The closer proximity of the molding to the strike point gives the hammer that bottom it needs without having to compensate by using lacquer and deal with the side effects associated with that. I've attached (or will attach) a series of photos from a presentation I did pointing out some stark differences in profile that exist between current iterations and historic hammers. One photo compares a 16 lb Weikert with an original Steinway hammer and another compares note 40 between a 16 lb hammer and the newly dimensioned hammers that I would advocate. These photos of the Weikert 16lb hammer are hammers that I removed from a piano (relatively new hammers) because they simply did not sound good (customer opinion and mine too). The hammers were very heavy, very bulky, infused with lacquer and sounded dead, lacking clarity throughout but especially in the upper part of the piano. I replaced them with another Weikert hammer that was made to my specifications (see below). Completely different response, clarity, power, high partial development as needed. Removing all that weight also reaped benefits in terms of touchweight dynamics.
The hammer design that I have been asking Ray to produce for me can be ordered from Ronsen. It is currently referred to as the Weikert Low Profile Hammer. If you simply contact Ray and ask him for that or the hammer that I have designed he will know what you are talking about and can make it. The features and important areas are as follows.
1. The hammers are profiled to a specific dimension through the set. This is designed to be matched with the overall density of the felt and the style of pressing. A match between these two aspects (sheet density and profile) is critical.
2. Hammers are cold pressed as standard on all Ronsen hammers. This is to maximize tension.
3. The felt sheets are skived to the final dimension prior to pressing so that minimal filing is done to the hammer after it comes out of the press. This is very important because the tensioned areas of the felt on the outside of the hammers need to be maintained and not removed. Hammers transition from tension in the outer layers to compression in the inner layers. Heavy filing can remove the tensioned outer areas of the hammer and reduce the overall tension in the hammers. Moreover, keeping the felt thin to begin with allows for maximum stretching of the felt which produces a more tensioned hammer and density that is achieved by stretching rather than pressing. This creates a hammer with more bounce, greater resilience, better resistance to hysteresis effect and greater stability in tone.
4. These hammers are designed to closely match in profile the original dimensions of the 1920's Steinway hammers. The original Steinway hammer was actually a lower density felt to begin with yet developed very nicely with plenty of power and brightness without chemicals. The sheet density on this current iteration is somewhat greater. Play in time is minimal if necessary at all. The top few notes may require some hardening depending but typically I am not advising that any hardeners are used and so far I have not found it necessary.
5. This hammer is best suited for low to medium impedance systems. High impedance systems such as concert instruments, certain Bosendorfer, Bechstein models (for example) may require something with slightly more weight and density. Work in this area is in process.
6. Profile dimensions should follow these specific guidelines (profile refers to the thickness of the felt above the underfelt):
#1 12mm
#26 9 mm
#40 7 mm
#55 5 mm
#70 4 mm
#88 3 mm
7 Light maple molding is used.
8. With light tapering and tailing the hammers are able to easily achieve the following weight. More weight can be taken if needed by more full tapering and adding weight is easy using lead solder techniques. I suggest that the tapering not extend all the way to the strikepoint of the hammer to protect felt at the strike point from being disturbed. #88 may benefit from even more reduction in weight.
#1: 9.5 grams,
#21: 8.1 grams,
#40: 7.2 grams,
#64: 6.0 grams
#72: 5.2 grams,
#88: 3.5 grams.
9. A like to do a fine polishing of the upper register hammers is recommended (above about note 55 or 60, though you can do the entire set as well). I do this to about 1000 grit. It is important to maintain the original shape of the hammer. Cutting through layers of felt can reduce overall hammer tension. While some play in can benefit the upper end, it can be measured in hours not years.
10. Needle work should be minimal. Low shoulder needling is not necessary at all. Hammers that are too loud will respond from minimal needling (full penetration) in the 10:30 - 11:30 area. I have my own needle techniques which I can elaborate on if necessary. Less is more.
I continue to work with Ray to get a hammer that will work without lacquer for high impedance systems and concert situations where power is the first priority. This particular iteration is designed to produce a wide range of dynamics. I also will be trying some slight variations in this particular theme with respect to underfelt and sheet shaping and pressing. But so far this particular hammer is working very well and I have put them on many pianos now starting at the end of last year.
(note: I will send the attachments that I mentioned of the hammer comparisons separately as the system is simply too unwieldy to do this easily I will also cross post this under a new subject heading the "Weikert Low Profile Hammer "
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David Love RPT
www.davidlovepianos.com davidlovepianos@comcast.net 415 407 8320
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