(f)
Flush the surface with water until you get a water break-free surface.
NOTE: A water break-free surface will have a continuous layer
____
of water for 30 seconds.
(g)
Clean the surface with a mixture of magnesium oxide and water to remove the water break. Dry the surface with a clean gauze.
(h)
Flush the surface with a clean wet cloth or a sponge again.
S 377-003-B00
(3) Mix the Dow 19 conversion coating as follows:
(a)
In a clean 1 gallon glass or polyethylene container:
-
add 9/10 gallon of water
-
add 1 1/3 ounce chromic acid
-
add 1 ounce calcium sulfate powder
-
add water to fill the container to the 1 gallon level.
(b)
Mix the solution for a minimum of 15 minutes. Let particles in the solution go to the bottom of the container.
NOTE: The solution must be free of all particles when it
____
is applied.
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737-300/400/500MAINTENANCE MANUAL
(c) Measure the pH of the solution. The pH must be from 1.2 to
1.6. Use sulfuric acid to lower the pH or use sodium hydroxide to increase the pH.
S 377-004-B00
CAUTION:_______DO NOT USE FORCE TO RUB THE WET SURFACE. TOO MUCH FORCE CAN CAUSE DAMAGE TO THE COATING.
(4) Apply the conversion coating solution:
(a) Apply a large quantity of solution to the metal surface until the surface is gold to dark brown in color.
CAUTION: HIGH PRESSURE WATER SPRAY, RUBBING ABRASION, OR HIGH
_______ PRESSURE AIR BLAST CAN CAUSE DAMAGE TO THE NEW COATING.
(b)
Flush the surface with clean cold water.
(c)
Dry the surface with air that is no more than 180 degrees F.
(d)
Make sure all of the surface is coated.
(e)
Make sure there are no scratches, powder or lines on the surface.
(f)
To remove the powder, rub the surface with a clean cloth and apply the conversion coating again.
S 377-005-B00
(5) As soon as it is possible, apply the correct protective finish to prevent contamination of the surface or the start of corrosion.
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HYDRAULIC FLUID RESISTANT FINISH - CLEANING/PAINTING
____________________________________________________
1. General
_______
A. This procedure contains two tasks:
(1)
The first task is to clean the surface.
(2)
The second task is to apply the hydraulic fluid resistant finish.
TASK 51-21-61-107-008-B00
2. Clean the Surface
_________________
A. Consumable Materials
(1)
G00382 Paper, Abrasive - 280 grit (Minimum Grit
Number)
(a)
Aluminum Oxide, Scotchbrite, Type A
(b)
Aluminum Oxide, Bear Tex
(2)
B00083 Solvent, Aliphatic Naphtha - TT-N-95
(3)
B00130 Solvent, Isopropyl Alcohol - TT-I-735
(4)
B00151 Solvent, Methyl Isobutyl Ketone (MBIK) - TT-M-268
(5)
G00033 Cheesecloth, BMS15-5
B. Procedure
S 127-002-B00
(1) Remove the high gloss surface finish with 280 girt (minimum grit number) from the high gloss plastic and painted surfaces.
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