The other thing I notice is, often the horn isn’t done shrinking or curing yet when I first receive it. I let my horn sit out for a while before I even think of using it. It helps with warping I’ve found and having to trim wedges after the shrinking has stopped on finished sets of scales. It sure if that is wide spread among us or maybe the shrinking is due to my finishing process but I’d be surprised as the only sanding lubricant I use is water.