Re: against the grain There could be several things coming together to create the problem you describe.
My first suggestion is when you reach the point of carving eyes, ears, and other details like beards etc. resharpen (or strop) your tools before beginning. We often try to carve details after carving all day with the same tools.
If you are doing most of your carving with a knife, you need to be very careful not to undercut. You must know how deep your cuts are going. Later when you try to do fine work, parts come loose.
Plan your carving so the grain direction supports the details like noses etc. Many old carvings are missing noses and fingers.
You can harden soft areas with superglue and other products.
Many of these methods restrict the finish you can apply later.
If it is an important carving, you can remove the surface until it is flat, and glue in a block and recarve it.
Finally, the wood could be 'punky' and will crumble under pressure.
Good luck, Rick |