Turpentine, a product commonly used in paint and finish stripping, is a product of trees. This often harsh chemical is derived from pine wood chips. To produce turpentine, the chips are heated and the chemical is distilled. While still available in the marketplace, turpentine is no longer as commonly used as it once was, in part due to concerns that inhalation of turpentine fumes could have negative impacts on human health.
Turpentine is most commonly used to remove paint from wood or other surfaces. When applied to a painted wood surface, turpentine softens the paint and allows it to be wiped away. When used in this fashion, the turpentine itself has very little impact on the wood as the paint serves as a barrier between the turpentine and the wood.
Turpentine can also be used to soften varnished or shellacked finishes present on woods, allowing them to be, at least in part, wiped away. As with the paint removal process, turpentine used on wood surfaces for this function has little negative impact on the wood as the finish that is being stripped prevents the turpentine from coming into direct contact with the wood.
Turpentine can also be mixed with paint to thin the paint. Turpentine is most commonly used for this function within the art industry. Though turpentine-thinned paint can be applied to woods for processes such as antiquing, turpentine, when used in this fashion, has little negative impact on the wood as it is not at full strength when mixed with paint. Due to the potential dangers humans face by coming into repeated contact with turpentine, mineral spirits has now largely replaced turpentine for use in paint thinning.
If un-mixed turpentine is applied directly to an unfinished wood, it can have a negative impact on the hue and luster of the wood. The caustic nature of turpentine will harm the natural oils present in wood if wood is exposed to turpentine directly and for an extended period of time. The only purpose for applying turpentine to unfinished wood is to create a bleached and weathered look, though petroleum-based solvents intended specifically to weather wood will allow you to achieve this look without risking damage to the wood.