Bondo Rotted Wood Restorer will solidify soft and spongy wood by penetrating into the wood surface to create a solid base and stop rot quickly.Bondo Rotted Wood Restorer will solidify soft and spongy wood by penetrating into the wood surface to create a solid base and stop rot quickly. Wood rot is a common issue for most homeowners, regardless of where you live. It can be easily repaired with this restoration product. It is excellent for use with Bondo Wood Filler (sold separately).