Touch upâs should be done minimum 4-6 weeks post the initial treatment. This allows time for eyebrows to heal fully before perfecting them for the second time. Free touch-ups are only valid up to 3 months from initial procedure date.
Re: The Tinny sound? Most folks that are concerned about a tinny noise with aluminum boats are referring to the noise generated by the hull moving through the water (which can be modulated/reduced through many different avenues). You mention vibration and rpms, so I'm guessing that you're not referring to that sound.
The tin whistle, also known as the penny whistle, Irish whistle, or just plain old whistle, is an instrument with a plastic or wooden fipple, or mouthpiece, and a metal body tube. They are fairly easy to play and the fingerings are similar to that of the saxophone, clarinet, and flute.