TT-C-490F
thickness (see 6.6) after the gage has been standardized using the same surface (indexing) as that over which the organic finish has been applied.
4.7.6.2 Adhesion test for CARC. After the complete specified paint finish has been applied and cured, three samples from each day's production shall be selected for paint adhesion testing (see 4.7.2).
Adhesion testing on the painted test specimens/coupons shall be performed after the complete paint finish has fully cured for a minimum of 168 hours at ambient conditions or by force-curing. A two coat paint system shall be tested after drying in accordance with applicable paint specifications. Each sample shall
be tested using ASTM D3359, method B using any commercially available tape (1 inch width) that will yield a minimum of 80 oz of adhesive resistance over the tested coating when tested in accordance with ASTM D3330/D3330M. CARC adhesion shall not be less than scale 4B with any layer of the system. Where CARC dry film thickness has exceeded 5 mils (125 microns), method A of ASTM D3359 shall be used if permitted by the procuring authority. Nonconformance to 3.6.2 shall constitute failure of this test. All items processed since last acceptance shall be rejected and corrective action shall be taken. Contact the CARC Commodity Item Manager at ARL, ATTN: RDRL-WMM-C, Building 4600, APG, MD
21005-5069 for a current listing of approved adhesion test tapes.
4.7.6.3 Paint adhesion test for non CARC. Unless otherwise specified, a minimum of two test specimens/coupons (see 4.7.2) from each day's production shall be run through all steps of the regular production process including painting. Adhesion testing on the painted test specimens/coupons shall be performed after the coating has dried in accordance with the applicable paint specification. Press a 2
inch length of a somewhat longer piece of pressure sensitive adhesive tape (1 inch width) conforming to ASTM D5486/D5486M type I or type II firmly onto a flat or cylindrical surface of the item, rubbing out all air bubbles under the tape. Allow approximately 10 seconds for the test area to return to room temperature. Grasp a free end of the tape and at a rapid speed strip it from the item by pulling the tape back upon itself at 180 degrees in such a manner that the tape is folded back to back during the procedure. Observe for bared areas where the paint is removed. Disregard flecks of paint on tape where the underlying metal or phosphate coating is not visibly exposed. Nonconformance to 3.5.6.2 shall constitute failure of this test, and all items processed since last acceptance shall be rejected and corrective action shall be taken.
4.7.7 Accelerated corrosion resistance. Prior to initiation of production on a contract, or whenever a change in the production process or coating system occurs, or when required by the procuring activity, a minimum of three test specimens/coupons (see 4.7.2), shall be run through all steps of the regular production process including primer application. The specimens/coupons shall be coated and cured for the time and temperature recommended for use in production. When approved by the procuring activity, an alternate test shall be used, which allows one of the organic coatings listed in table II, to be substituted for that used in production. The painted specimens/coupons shall be scribed with two intersecting lines using the scribe tool as described in ASTM D1654. In instances where more than one metal is used, each metal shall be rated for corrosion resistance pertaining to the requirements of the specification of the primer being used. During production, one specimen/coupon (see 4.7.2) from each day's production shall be subjected to the accelerated corrosion test specified below until five consecutive day's productions have successfully passed the test. Sampling may then be reduced to one sample twice a week. If failure occurs, all items processed since last acceptance shall be rejected and corrective action taken. Sampling shall revert to one specimen/coupon from each day's production until five consecutive day's productions have again successfully passed the test. For the purpose of this test, the significant surface on cylindrical items shall be an area 60° on either side of a scribe mark. Production shall not be initiated until results of the salt spray test are received, except at the contractor's
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