Stirred, Not Shaken

Q. I recently read your column in the December 2011 issue of Products Finishing and noticed that there was a question from an American corporation with operations in India pertaining to process specification BAC5736 regarding mixing of an epoxy primer. If this corporation still has questions pertaining to BAC5736, please direct them to me as my group has responsibility for this process specification.

Regarding their question, my interpretation of BAC5736 is as follows:

1. The base material, Component I, which is a pigmented polyamide, must be thoroughly mixed so that all solids are sufficiently incorporated. Subjecting this material to a paint shaker for 10 to 15 minutes is a recommended method for accomplishing this.
2. The curing solution material, Component II, which is an epoxy resin solution without pigmentation, is added to the base material and must be subjected to a paint shaker or mixer for 3 to 5 minutes.
3. Water is added to the base/curing solution mixture and must be stirred mechanically or by hand. Use of a paint shaker after water addition is prohibited.

Please let me know if there are any future inquiries pertaining to Boeing specifications. I always enjoy reading your column, as there is always useful information associated with organic finishes. E.S.

A. E.S. is referring to the question titled “Shaken, Not Stirred” in the December 2011 issue. Not having a copy of the specification, I couldn’t give a definite answer to that question. My guess is that the prohibition against using a paint shaker after adding the additional water is because it would result in foaming of the mixed paint. Thank you for your input, E.S.