Replies

1. 
   PhillGiles | Sep 22, 2003 08:03pm | #1

   In theory, a stain is supposed to be absorbed by the material thus changing its colour; a paint is a layer of colour bonded to the surface of a material. I believe that solid colour stains leave a layer of pigment on the surface as well as being absorbed, but the pigment is bonded to the surface rather than being suspended in a film (like a paint). I'm guessing that technology has blured the definitions to the point where they must overlap.

   .

   Phill Giles

   The Unionville Woodwright

   Unionville, Ontario

1. 
   DaveRicheson | Sep 22, 2003 10:39pm | #2

   Pretty good guess Phil.

   Solid color stains contain only enough vehicle (resin, either latex or oil base) to bind the pigment to the surface of the wood. There is some penetration of both resin and pigment into the wood. Advances in resin technologies have made them much better than the old solid color stains of 20 years ago. In direct weathering conditions and heavey foot traffic, I have not seen any of them last much more than about three years. They just wear or weather off.

   Paint/stain manufactures no longer seem to be putting the "solids by volume" content in an easily understood label on the cans. They list the information in a CAS number, which I don't have a clue about. Another way to muddie the waters for comparrison shopping.

   Paint, on the other hand, suspends the pigment in a film of resin that acts as a wear layer and gives more prtection to the substrate, i.e. wood, metal, dw, etc. Agian the solids by volume and percent pigment by volume to the resin is an important indicator of quality and perhaps performance. Beware those labels that have large amounts of "inerts" in them. Those are just fillers and profit builders for the manufacturers. They add nothing to the performance of the product, and in many cases may cause premature film failure.

   Dave

1. 
   Splinky | Sep 23, 2003 12:09am | #3

   Cabot Stain!!!

   The best around

2. 
   luvmuskoka | Sep 23, 2003 01:44am | #4

   Solid color stains contain only enough vehicle (resin, either latex or oil base) to bind the pigment to the surface of the wood.

   Dave,

   I believe "vehicle" and "resin" are two separate components.

   Unless floor finish is different: Vehicle is what carries the resin. The vehicle evaporates, leaving the resin behind. Water-borne products suspend resin molecules in water (and ether). Oil modified products suspend resin in solvent, usually mineral spirits.

    The amount of resin in relation to the amount of vehicle, is the solids content.

   A 40% solids rating means that 60% of the pail is vehicle and 40% is  resin....what's left behind.Ditch

1. 
   DaveRicheson | Sep 23, 2003 02:37am | #5

   I spent seven years formulating paint, so lay terminology and  formulation terminology may differ. Solvents are solvents and do not suspend or wet a pigments. It can not be a vehicle because it does not carry anything. It used for reducing and flow control, but must be compatable with the resinouse vehicle.

   Many oil based resins are "cooked" from a combination oils without the addition of any solvent in the process. Much like the cooking of crude oil, some of the lighter  natural oils are drawn off durring a resin cook. They are sometimes reintroduced into the latter stages of the process to rduce the finished viscosity of the final product without altering its' intended properities. Water is also a solvent, in that it is a reducing agent. It does not carry the resin or pigments, nor is it part of the finished film.

   The paint industry has over the years gotten away from true any description of thier products on the label. They started using solids by volume over thirty years ago as a consumer information/marketing ploy. Within the industry and for commercial end user the measure is solids by weight, a more meaningfull  description when talking about film formation.

   My point is that marketing and to some extent government regulation have changed what has to be identified on a paint label. I still have friends in the paint product development field and even they are confused when puchasing "trade sales" products. The best they can hope for is knowing a tradesman that has used the product and can reccomend it to them. Scarey isn't it?

   As my old boss, who had a PhD in chemistry used to say," Dave my boy, you have to learn the figures can lie, and liers can figure."

   Dave

2. 
   painterguy | Sep 23, 2003 03:19am | #6

   I've been in the residential repaint business for over 20 years in the Pittsburgh area.

   Many of the newer homes in my area have not only the cedar siding stained but also the trim.  House's i guess to be 15 - 20 years old were only stain has been used on the siding and/or trim usually have no or very little peeling. Even the very best prep and paint job cannot promise that.  I have ran into problems but blame them mostly on the painter then the stain.

   When re-staining we like PPG or Sherwin Williams acrylic latex stains. However if the trim or siding has been painted in the past, we stick with paint. A coat or two of stain over paint will not prevent peeling. 

   Stain is a soft surface though, not suited for traffic areas such as doors and door framers and yes like any coating it will wear from decking but at least it seldom peels from the decking like paint does..making it much easier to re-do.

   When using on new lumber some manufactures suggest priming with an oil solid stain or even oil primer.  This is a good idea when used on new cedar or redwood, since  "bleed" through latex paints or stains.