Sticky Pigments

Newer varieties of paste colorant may need a special solvent in order to be stirred into stain base. October 9, 2006

Question
Has anyone had any experience with HULS 844 pigments blended into Woodsong B10 stain base? I recently started with a new shop that does all commercial and casino work. They like to send color matches out to finish supplier for matches and this works out well as I have used the same company previously with no notable problems except this one. Whenever a stain is matched to a dark color, the pigment sticks like glue to the bottom of the can and will not stir in to the stain base evenly. I don't care what you do; the stuff is like molasses fudge. I questioned the rep and he questioned the HULS rep and got the reply that the base was overpigmented. I don't buy it. I have used stains from Conestoga doors in PA. (I believe it was a Lilly product) and there would be 3/4" of pigment in the bottom of a gallon yet it would stir up as smooth as silk. Any feedback is appreciated.

Forum Responses
(Finishing Forum)
From contributor A:
I am guessing a bit here but I think that your supplier may have used glycol base tinters that did not disperse well in the stain base that you are using. I have run into this problem while tinting my own products and can usually solve it by using a bit of lacquer thinner to help break up the glycol so that I can get good dispersion. Try this with a small sample of your stain. If it works then at least you'll know what the problem is. Perhaps a bit of lacquer thinner will solve it for you but if you get too thin before you get the dispersion solved then you'll need a different stain base or a UTC or equivalent tinter setup; perhaps your suppliers will already have this or can recommend a different stain base that will work better with their tinters.

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From contributor B:
A lot of strange things are happening with pigmented colorants. Most manufacturers of paste colorants are using synthetics resins to mill and grind their pigments. Because of all the changes in the VOC and HAPS regulations, the "normal" solvents that were used to turn these colorants in the stains, toners, glazes, and shading stains may not work the same any more. As contributor A mentioned, he uses a little lacquer thinners to break it down, whereas some shops are using Acetone.

Many manufacturers are now blending their own solvents and reducers to be used with their products, because the regular solvents that were used in finishing shops do not work any more like they did at one time. You can ask the rep if they have a special solvent for the pigmented colorants. These blended solvents usually work very well. The reason the Lilly colorants worked was because they used different resins to mill and grind the iron oxide pigments into the paste colorants.