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(15) Method No. 204Q: Effectiveness of Cleaning Magnesium Alloys Prior to Painting Test.
(a)
Four AZ31 magnesium panels shall be processed in accordance with AMS-M-3171, Type VI. After coating and prior to painting, the panels shall be dipped in lubrication oil such as Farbest 7220, or any other product approved in accordance with MIL-C-16173, Grade 3, and allowed to set for a minimum of 24 hours prior to cleaning. Clean two of the panels with the test cleaner and two panels with methyl ethyl ketone (MEK).
(b)
Seal and paint panels in accordance with maintenance manual sealing and painting procedures for components for which cleaner is being tested. (Use sealant, primer, and topcoat, which are currently being used to coat Honeywell production hardware.)
(c)
After processing, dry tape adhesion test shall be performed as follows:
1 Make two parallel, scratch marks on test panel approximately 1 inch (25,4 mm) apart from one another.
2 Wipe test panel clean using isopropyl alcohol in accordance with ASTM D 770. Allow the test area to dry completely (approximately 30 seconds).
3 Remove two complete laps of approximately 1-inch (25,4 mm) wide tape. Remove an additional length at a steady (not jerked) rate and cut a piece of tape approximately 4 inches (101,6 mm) long.
NOTE: Tape used for testing shall be rubber or acrylic adhesive backed tape with a minimum peel adhesion of 60 oz/inch (16,68 joules/meter) width when tested according to ASTM D 3330, Method A.
4 Fold the last inch (25,4 mm) of one end of the tape back upon itself (adhesive against adhesive) to create a tab approximately .5 inch (12,7 mm) long.
5 Apply tape to test panel so that tape is aligned perpendicular to scratch marks. Smooth tape into place with finger. Use firm hand pressure to assure good contact has been made.
6 Within 1-2 minutes, remove tape by pulling it rapidly (but not jerked) at an angle of approximately 180o to test panel.
(16)
Method No. 204R: Dissimilar Metals Corrosion Test
(a)
Cleaning product shall be tested in accordance with MIL-R-81294.
(b)
Following testing, panels shall be free from pitting, etching, and corrosion.
(17)
Method No. 204S: Sodium Hydroxide Base Rust Remover.
(a) Cleaning product shall meet requirements specified in AMS 1380.
Cleaning
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SECTION III – INSPECTION
TABLE OF CONTENTS
SECTION PAGE
1. Standard Inspection Practices ..................................................................................................... 301
A. General..................................................................................................................................301
B. General Inspection Procedures.............................................................................................301
C. Magnetic Particle Inspection ................................................................................................. 302 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：标准施工手册 STANDARD PRACTICES MANUAL 20-00-02/70-00-01(40)
