Inadequate knife sharpness, or too much moisture. Ugly "drag line"

[DwightT]

FWIW: If I have to take a long break during tooling, I will spray the project and my stone work surface with a misting sprayer (light mist), then cover the project with plastic wrap.  The wrap will seal to the wet stone and hold the moisture in the project for at least a day.

[YinTx]

On 12/24/2025 at 3:37 AM, DieselTech said:

I have also seen belly leather do this. 

This!  The sample you show looked a bit loose.  Another trick I've learned is to make casing solution with some saddle soap, it really helps to lubricate the surface and allow for cleaner/smoother more controlled cuts.  Give it a try.  Also, sometimes I'll run a glass slicker over the surface a bit to help even the compression of the fibers.  At any rate, after I've cut for a bit, almost inevitably material builds up on the blade and I will begin to feel a bit of drag, so strop again... and again.

Casing solution done right can help prevent any mold forming.  I live in a very humid environment, and have had work on the bench for days with no issues.  Heck, the first thing I ever tooled got interrupted by a hurricane, stayed in a zip loc bag with no air conditioning in hot conditions for over a week before I could come back.  It is now a 3 ring binder with an eagle.  Do some experimenting with scraps to see if you have any issues.

Edited January 23 by YinTx