Pianotech

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating. 

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating. 

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating. 

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating. 

Acetone works too, and will evaporate a bit quicker.

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating. 

It really depends on the lacquer and the amount of solids. I don't use off the shelf lacquer (nitro) because these are furniture lacquers and have hardening agents that rob the fiber of elasticity and can develop crystalline sounds that can be unpleasant. Neither do I advocate hardening only the strike point unless the foundation of the hammer is already stiff enough. Otherwise you can end up with a reverse gradient where the hammer is bright on soft blows but doesn't develop a fuller spectrum of partials on progressively firmer blows, which it should. So you first need to determine what part of the hammer needs stiffening. You do that by listening.  If it's been sugar coated excessively and the crown is too soft a light filling would be better to start with. If you have to harden, and  I've mentioned this before, the HammerLac product that Pianotek used to sell, now sold by Schaff, is "soft setting lacquer", meaning it stiffens the felt but remains flexible, almost rubbery, when it cures which is what you want. The solution strengths for this product are much stronger than you mention. A light application would be 15-20% solution by weight, a heavy application would be 40-45%. With new Steinway style hammers (Bacon Felt) I use a 30% in the tenor and bass and a 40% solution in the capo sections. In your case I would start out pretty light but only after a light filling and polishing of the hammer strike point with fine paper (600-800 grit) and double checking the hammer string mating.