On Friday, December 6, 2013 4:04:18 PM UTC-6, Greg Guarino wrote:
So... naptha will thin Minwax; so will gasoline.

I've heard that people use mineral spirits as well. I flipped a mental coin.

Both naptha and mineral spirits are petroleum distillates, as is gasoline. Gasoline has both light and heavy naptha as its main ingredients, percentage-wise (to my knowledge, at least. That's what we blended at Placid Refinery, when I worked there. Back then, lead was added to the mix, also.). Gasoline contains more heavy naptha, than light naptha, volume-wise, in the blend.

I've always understood mineral spirits is (mainly) a blend of several different grades of naptha OR a particular grade of naptha. WikiP seems to confirm this (See "chemical Numbers" chart): http://en.wikipedia.org/wiki/White_spirit

Maybe today's "blends" (gasoline or mineral spirits) are different, than when I worked in this field.

In essence, I've agreed with Robert and DadiOH: Adding naptha to the mix only thinned your application.

One other thing I've done, befo Wipe down a project with mineral spirits prior to any finishing. This wiping (wash-coating) can reveal where there may be contaminates on the wood, that may affect the finish. The wash-coat allows you to see and remove any contaminates, before finishing. A naptha wash-coat will do the same thing and many folks do the wipe/wash with naptha, especially after stripping a previously finished piece.... to find where there is still old finish on the piece.

An aspect of oil applications that I try to follow: I've never blended an oil with something else, then apply it. With an oil application, not only do I wipe off any excess, but I rub it in, hard. Hard and fast, to produce heat, when rubbing. I learned this from studying piano makers techniques, who rubbed their oil applications to heat it up.... i.e., some aspect of "cooking" the oil onto the piece. Traditional piano makers used this technique, applying several oil coatings, before applying multiple coating of whatever topcoats were used, varnishes, black lacquers, etc. I've only applied lacquer to the oil coating I've applied.

Sonny