TM 9-3990-260-14&P
10-7.
GENERAL WELDING MAINTENANCE (CONT).
c.
Galvanized Coating Replacement. To replace the galvanized coating, use Zinc Stick
(95% zinc, 5% tin with flux) that will melt at less than 750F (398C), followed by a primer and top coat (CARC
paint). This is recommended repair for galvanized CROPs prior to primer and CARC paint. If the spray metalizing
(Zinc) method is available, it is the preferred method. The galvanizing method is in accordance with ASTM A780
and the thickness will be in accordance with ASTM E376. If there are questions about the repair method OR the
application of one of these processes, contact the American Galvanizers Association at 1-800-468-7732 or Mr.
George Shaw at the U.S. Army Tank-automotive and Armaments Command's Materials & Coating Group, 1-800-
325-2920, extension 45083.
CAUTION
Do not weld the CROP while on trailer or truck or damage to equipment may result.
d.
CROP Welding.
(1)
Welding on the CROP must be performed off the trailer or truck. Different areas of the
CROP require different weld electrodes and preheat. Use the following guidelines to deter-
mine the correct weld and/or preheat. The bail bar center wear plate should be accom-
plished using 300F (149C) preheat and ER110S-1 with gas metal are welding (wire fed
welder with argon and oxygen shielding gas) or E11018-M with submerged metal arc
welding (E11018-M stick electrode and arc welder). All other areas of the CROP should
be welded using ER70S-6 welding wire. The following applies:
Weld Area
Wire
Preheat Temperature
300F (149C)
Bail Bar Center Wear Repair
ER110S-1
300F (149C)
E11018-M
400F (204C)
Pin Support Plate to End
ER70S-6
Structure Assembly Tubes
200F (93C)
Pin Block to Main Beams
ER70S-6
450F (232C)
D-Ring Bar to Side Beam
ER70S-6
300F (149C)
Bracing Mechanism Nut to
ER70S-6
Side Beam
Areas not listed above do not require preheat.
(2)
Painting Instructions. Refer to TB 43-0209 and TM 43-0139 for painting instructions for the
M3A1 CROP.
