: Don,

: Good question! I have heard various reasons and don't have a definitive
: answer. Some folks claim that being a wood product that it penetrates
: better, some folks claim that the gummy resins act as a sealer and are
: more compatible with oil, or that the gum solids and other natural
: compounds help to polymerize the oil (violin linseed oil/turps varnishes
: are based on this principle, but involve a specialized process. see
: http://www.scavm.com/Fulton.htm ). Gum turps has other beneficial
: properties for oil-based paints and protection of natural bristle brushes
: that make it popular. On the other hand, other folks claim mineral spirits
: works just as well.

: All the old-timers that I have talked to and at least one source on making
: canoe paddles strongly recommends gum turps (I don't have the book
: available, I'll look it up later, and see if it gives more information).
: Of course, it could be simply that good gum turps smells good and makes
: the finishing process much more pleasurable.

: Greg Stamer

All the information I have on hand (back issues of Fine Woodworking Magazine) say turpentine is more toxic, and is much more of a fire hazard than mineral spirits.

Most of the articles I've read suggest substituting ordorless mineral spirits if at all possible.

To thin paints, oils and varnishes you need a high quality pure thinner, so be aware there are different grades of mineral spirits. Some are intended for cleaning brushes (blue label) and the higher quality pure (more expensive) mineral spirits are meant to be used as a finish thinner.

All the best,

Rob Macks
Laughing Loon CC&K
www.LaughingLoon.com