Archive for month: December, 2011

The Skinny on Thinners

 Coating manufacturers specially formulate lacquer thinners to reduce the viscosity of thier products. Becker formulates its thinners from a variety of solvents rather than just one in order to control how the solvent evaporates and the working characteristics of the coating. These solvent blends dissolve the resin quickly while maintaining the properties of coating and workability.

 Thinners are made with two categories of solvents, diluting solvents and dissolving solvents.  Dissolving solvents are the solvents which chemically dissolve the resins quickly, where as diluting solvents are solvents that dont dissolve the resin but merely mix into the coating to reduce the viscosity.  Dissolving solvents are generally more expensive that diluting solvents, therefore most lacquer thinner is a blend of the two categories of solvent to keep costs lower. 

 Some solvents are better environmentally than others as well.  To reduce the amounts of Volatile Organic Compounds (V.O.C.) or Hazardous Air Pollutants (H.A.Ps) some thinners are made with specific solvents that do not fall into either of these categories.  These thinners not only keep the air we breathe in the shop cleaner, they emit less pollution into the environment. 

 Using the proper thinners for the coating you are using will avoid many potential problems.  Most problems arise from evaporation rate of the thinners not being right for the conditions, or for the lacquer you’re using.  If the evaporation rate of thinner is too slow, the coating won’t dry quickly enough and you can get excessive dust that can settle into the coating from the atmosphere.  You can also have the surface film remain soft for an extended period, allowing for increased physical damage.  If the evaporation rate of the thinner is too fast the coating can have flow or blushing related problems.  It the coating forms a film before the surface has leveled, it can cause an orange peel effect on the finished piece.  Also, air can become entrapped in the coating from the atomization process if the coating skins over before the air can escape.  In extreme cases the coating can even dry while it is being sprayed between the spray gun and the work piece.  This is known as dry spray. 

 Not all thinners work in all products. Some thinners have solvents blended into them that do not mix with coatings.   These solvents can cause a chemical reaction in the coating, causing the coating to separate and form blobs in the coating.  This is generally referred to as “kicking out”. 

 Becker Acroma thinners are specially formulated to work with our products to gain the maximum performance from each coating.  Thinner 1309 and 140 have faster evaporation rates while thinner 219 and 419 are slower.  When a slower evaporating thinner is needed a retarder can be added.

 By using the proper solvent, the user can put less thinner in the coating to reduce the coating down to a desired viscosity.  Some thinners will reduce the viscosity of the resin in the coating in lesser amounts than others. 

 Utilizing the proper thinner the user can reap the benefits of higher solids while maintaining the workability of the coating.  Higher solids coatings allow the user to apply less coating to get an acceptable finish quality.  As well, higher solids material is more environmentally friendly, reducing the amounts of solvents being released into the atmosphere.

 Finally, a word of caution.  While it is tempting to use recycled thinners in order to reduce costs, doing so can prove to be a false economy.  The composition of these thinners is unknown, and can be the cause of complications that are more than difficult to trace.  For the relatively small cost saving for a complete coating system – hardly worth the risk!

 For more information please give us a call or drop us a line. We are always pleased to be of service!