Decanted Alkyd Resin
With the VOC concerns around solvents in general, oil based paint is getting harder to find. In fact most locations only have oil base paint for rust preventative finishes. Because of the EPA regulations they name these products rust preventative and don’t even use the name paint in the product name. Also, the number of colors available for these pants is rather limited now as the waterborne paints are taking over the market. I like to use these on my metal sculptures and I preferred to spray them on to get a smooth finish. When I use the sprayer I can mix colors to any shade or finish I want. I deliberately mix up too much paint because I have found a way to recycle the alkyd resin that makes up the adhesive of oil based paints. With this, I can add the oil to a dry pigment of my choosing and reuse it to paint other sculptures.
Let Sit So Pigment Will Settle
The process to do this is extremely simple and straightforward. After you have spray applied or brush applied your alkyd paint, The remaining paint simply gets thinned more so with a volatile solvent such as VM&P Naptha or Acetone. Then you allow the mixture to set a week or two and the pigment will sink to the bottom. You can pour off liquid portion and filter with cheese cloth if necessary. Or, you also can leave everything together while the more volatile components evaporate. If need be, you can speed up evaporation with a shop crock pot no longer used for cooking to drive off solvent.
Separated And Concentrated Alkyd Medium
The photo above with the dark reddish brown liquid demonstrates what a clean alkyd medium will look like after pigment separation and solvent evaporation. The manufacturers somewhat pre-send the pains so this alkyd medium undoubtedly has less volatile solvents and it already such as heavy mineral spirits etc. even with additives is still comes out as a fairly viscous liquid.
Testing As A Simple Varnish
I found a piece of pine scrap wood and just simply get up some paint thinner in a brush to apply the Alkyd oil as a varnish. It really does not need to be thinned as this mixture has some thinner already on it. I purposely overthinned first coat so wood would absorb it. Then I brushed on straight Alkyd on top. Interesting that when applied, it seems nearly colorless. Next, I will attempt to disperse a pigment into the Alkyd oil.