WHEN Magazine June 2013
Hey GrinderGuy, should I be using liquid colorant or dry powder colorant?
I had a call last month from a Colored Mulch Manufacturer whom had been using liquid colorant for several years, but saw a competitor just start using dry powder. This competitor was hanging a supersack of dry powder from an excavator bucket and sprinkling the powder over a pile of wood then grinding it all in a Tub Grinder with a fire hose of water spraying into the Tub while they were grinding. Not knowing much about the dry powder, he wanted to make sure he wasn’t missing a new improvement in the industry, so he asked me for my opinion.
What is dry powder colorant and liquid colorant? The powder colorants, called pigments, are essentially the raw color materials used to create a liquid. The powder pigment is what gives the liquid its color.
These days, anyone with a Trommel Screen and Saran™ Wrap can color mulch. Dry colorant is not a new development. I remember using dry powder back in the mid 90’s. While I did not use this method of application, it did work but the advancement of the liquid lines quickly made the dry application obsolete.
My opinion, and it’s just my opinion, was:
· While the powder is cheaper, this type of application does not allow for an accurate and consistent measurement of colorant application. So how do you know how much color you are applying and how much the mulch is costing?
· I would be concerned about color runoff since there are no other chemicals to adhere the colorant to the wood. Also, I would be concerned about the powder that was not broken down in the grinding process and could potentially runoff.
· The liquid color uses a much finer powder thus covering the wood much better with less actual color and lasts much longer do to the additional chemicals added to adhere the color to the wood
· I have seen operations mixing industrial ash with mulch to turn it black, and not use any colorant at all
With that being said, many operations use this sprinkle and grind technique today and swear by it.
After my call, I turned to a few Industry experts for their opinion. Some Colorant Manufacturing Companies sell both liquid and dry, others strictly liquid. Estimates are 95+% of the operations coloring mulch are using liquid colorant.
Those that sell only liquid had some common facts that were repeated:
· The process of creating a liquid provides the end user with a more effective product. Thus, a higher price per pound than the dry colorants.