FWIW,….in my years of woodworking, I have had to steam a dent ot two. I found that if multiple applications are required. it is best to let the dinged area dry completely between applications. it is the reaction of the dry wood to the steam that causes the swelling you want. if the wood is not thoroughly dry when steam is applied it's reaction is much reduced. several steamings can take a long time if you allow the area to dry completely, but if done correctly, will remove pretty severe dents.
