Surface Preparation Techniques for Adhesive Bonding by Wegman Raymond F. Van Twisk James & James Van Twisk

Author:Wegman, Raymond F., Van Twisk, James & James Van Twisk
Language: eng
Format: epub
ISBN: 9781455731282
Publisher: Elsevier Science
Published: 2012-11-09T16:00:00+00:00

4.7.4 Storage

1. Sol–gel kits are considered to be time- and temperature-sensitive and shall be stored in accordance with the supplier’s recommendations.

4.7.5 Processing

1. Precleaning: Remove all foreign materials from the surface as needed.

2. Prepare the AC-130 or 130-2 in accordance with the manufacturer’s instructions provided in each kit. Scale up for the size of the part as necessary, e.g., 1 liter of solution per 0.9 m2 (10 ft2) to be coated. Do not treat the surface with the AC-130 or 130-2 before 30 min induction time is complete. (Induction time is defined as the time period after all the AC-130 components have been mixed, but before the mixed solution is active.) Do not treat surfaces after the 10-hour maximum pot-lifetime has expired.

3. Deoxidation of the surface may be accomplished by grit blasting, sanding, mechanical Scotch-Brite, or manual Scotch-Brite.

a. Grit Blasting: Using alumina grit, grit blast an area slightly larger than the bond area. Use 2–5 atm (30–80 psig) oil-free compressed air or nitrogen. Slightly overlap the blast area with each pass across the surface until a uniform matte appearance has been achieved.

b. Sanding: Using a sander or high-speed grinder connected to oil-free nitrogen or compressed air line, thoroughly abrade the surface with abrasive paper for 1–2 min over a 15×15 cm (6×6 in) section covering the entire surface uniformly, following the manufacturer’s instructions.

c. Mechanical Scotch-Brite Abrading: Replace the abrasive paper as described in Section 4.7.1.3 with a Scotch-Brite abrasive disc and abrade surface as described in Section 4.7.1.4

d. Manual Scotch-Brite: Thoroughly abrade the surface with a very fine Scotch-Brite pad for a minimum of 1–2 min as described in Section 4.7.1. Remove loose grit residue with a clean, dry, natural bristle brush or with clean oil-free compressed air or nitrogen.

4. Application of AC-130: Apply AC-130 or 130-2 solution as soon as possible after completion of the deoxidization process. The time between completion of deoxidization and application of AC-130 shall not exceed 30 min. The application of the AC-130 or 130-2 may be accomplished by any of the following methods: spray application, manual application using a clean natural bristle brush or swabbing with a clean wiper, cheesecloth or gauze, or by immersion. Apply solution generously, keeping the surface continuously wet with the solution for a minimum period of one minute. Surface must not be allowed to dry and should be covered with fresh solution at least one time during the solution application period. Allow the coated surface to drain for 5–10 min. If there is any surplus AC-130 solution collected in crevices, pockets, or other contained areas, use filter compressed air to lightly blow off excess solution while leaving a wet film behind. Do not splatter this excess onto adjoining surfaces.

5. Drying: Allow the coated part to dry under ambient conditions for a minimum of 60 min. Minimize contact with the part during this time, as the coating may be easily damaged until fully cured. Exact drying time will depend on the configuration of the part and room conditions (temperature and humidity).

6. Bonding: Apply primer and/or adhesive within 24 hours of AC-130 or 130-2 application.

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