I know that many of you like myself are always on the lookout for old spalted wood logs. Many times we all have experienced when cutting into the log we find some nice spalting along with some soft punky wood. I found a product (which many may already know) for soft punky wood called Minwax Wood Hardener Professional Strength. I have tried it on some real pundy soft wood and this stuff works. What I do is take a acid brush and brush the product over the punky wood and I let it stay overnight. I can then sand it, turn it with no problems and when finished it does not leave a stain. A word of caution, be sure to read the warning labels and wear your PPE ie, Paint respirator for the flumes, eye protection and rubber gloves. I'm in no way affiliated Minwax, it's just a good product for soft wood. Happy Turning!