We are experiencing an unacceptable rate of paint failures of our crackle paint finish. We are applying animal glue to a primer coat and allowing it to dry to a tacky consistency. Next, we apply a waterbase paint and allow it to dry for 24 hours. Then, we apply a mix of gold and silver flakes and acrylic paint for toning. We topcoat it with a spray of a flat clear lacquer and after drying, we apply a wash and rub to the desired color. A paint adhesion test using an ASTM Test Method showed a failure of 15-30%. Is there another method of applying a crackle finish? J.C.
For the record, I answered a question from F.B. about crackle finishes in the December 1999, Painting Clinic. I gave the definition for crackle finish from two sources, The National Paint Dictionary and The Coatings Encyclopedic Dictionary.
The National Paint Dictionary, 2nd ed., published in 1942, described Crackle Finish as, “A finish usually produced by a lacquer, resulting from applying a top coat designed to shrink, crack and expose a more flexible undercoat, usually of a different color. This produces a novelty finish.”
The Coatings Encyclopedic Dictionary, published in 1995 by the Federation of Societies for Coatings Technology, describes Crackle Finish as, “Appearance resulting from applying a topcoat designed to shrink and crack and expose a more flexible undercoat, usually of a different color.”
The answer came from the Painting Clinic Department of Obscure Information. At that time I said, “This department is aware of a number of novelty finishes such as Crackle Finish, Hammertone, Jack Frost Lacquer, Leatherette, Plextone, Spatter, Suede, Wrinkle, etc. They were applied in many cases, because they provided optical interference to hide surface defects. My guess is that many of these novelty finishes were laboratory and production failures that some bright, enterprising salesman turned into commercial successes.”
The “weak link” in your present finish system is the animal glue. I don’t believe it has the moisture resistance and mechanical strength required of a durable finish. You must want a durable finish or you wouldn’t be concerned about an ASTM adhesion test.
You certainly go to a lot of trouble to produce a crackle finish that you can get in a spray can for $2.98 at a craft store. Furthermore, the commercial finish would be more durable than your present one. If the spray can finishes don’t give the desired effect, you can ask for a crackle finish from one of the paint companies listed under Chemical Coatings (page 320) or Coatings (pages 331-335) in the Products Finishing 2003 Directory and Technology Guide.