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Low VOC BMS 10-79 Corrosion-Resistant Primer
Subject:
Low-VOC BMS 10-79 Qualification
Purpose:
This page is designed to provide information on efforts to qualify a new, low-VOC corrosion-resistant primer to the BMS 10-79 specification.
Reference:
BMS 10-79 Urethane Compatible, Corrosion Resistant Primer, Revision M, 26-AUG-04
BMS 10-79 Qualified Products List, Revision 26-AUG-04
BMS 10-72 Exterior Decorative Paint System, Revision V, 03-NOV-04
BMS 10-72 Qualified Products List, Revision 3-NOV-04
BAC 5882 Application of Urethane Compatible Primer, Revision H, 13-JUL-2000
Note:
This does not supersede drawings or specification requirements. This information shall not be used for production, test, or acceptance processes.
Background:
In response to South Coast Air Quality Management District's tightening of Rule 1124, Boeing looked to qualify a low-VOC (<350 g/L as mixed) primer to BMS 10-79, Urethane Compatible, Corrosion Resistant Primer.
Results
In July of 2000, after much research, Boeing Materials Technology (BMT) qualified Dexter Aerospace's 10P20-44 low-VOC primer system to the BMS 10-79 specification. The "-44" primer system has been in use for several years at Boeing paint hangars as an exterior decorative primer (as qualified to BMS 10-72 Exterior Decorative paint System).
Comparision Between Low-VOC and Conventional BMS 10-79 Primer:
There are several differences between the new, low-VOC "-44" primer and the conventional (higher VOC) 515x349 primer from PRC-DeSoto:
- As required in BAC 5882, Application of Urethane Compatible Primer, the low-VOC BMS 10-79 primer must be mixed in full kits. Whether using a gallon kit or a quart kit of the low-VOC primer, the full contents (base, activator, thinner) must be entirely mixed. Previously, for small paint jobs, it was permissible to dip into gallon kits (unmixed), take the amount required of each component, and then mix those components to obtain the desired volume of primer for the paint job. No longer can you do this. The reason for this requirement is that the new primer is very sensitive to the 3:1:1 base:activator:thinner mix ratio. As little as 10% excess activator has caused adhesion failures. When mixing small amounts of primer, an excess of 10% activator represents a very small volume differential.
- The low-VOC 10-79 primer is more costly than the conventional primer. When comparing gallon kits to gallon kits, the new primer is roughly twice the cost. The same can be said when comparing quart kit prices. However, with the stipulation that entire kits must be mixed (see bullet above), suppliers are primarily using the quart kits now (because most jobs require less than one quart of primer). Quart kits of the new primer are 3 to 4 times as expensive (per unit volume) as the conventional gallon kits.
- The dry-to-tape and dry-to-stack times for the low-VOC primer are 2-3 times as long as they are for the conventional BMS 10-79 primer.
- The overcoat window for the low-VOC primer is 1 to 12 hours. For the conventional 10-79 primer, it is 15 minutes to 48 hours.
- The potlife for the low-VOC primer is 4 hours. For the conventional primer, it is 8 hours.
- The low-VOC primer is glossier than the conventional primer, and it is more of a yellow green (as compared to the darker green color of the conventional 10-79 primer).
Disclaimer: The information provided in this website is intended to assist suppliers to The Boeing Company. Although every effort has been made to ensure its accuracy, we cannot warrant its accuracy for use in environmental compliance matters. You should check with your local, state, or Federal regulatory agencies if you have questions regarding the proper procedures or other matter related to compliance.
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