NOTE: The maximum cleaning time is 30 minutes.
(b)
Keep the part in the solution for 10 to 30 minutes. Refer to Table 201 for the chemistry and temperature limits of the solutions.
Table 201. Material Specifications
Chemical Concentration Temp F (C) Max Time Immersion Agitation
Duraclean 282 8 - 12 V/V Percent 140 to 160 (60 to 71) 30 Minutes Yes
Brulin 815GD 8 - 12 V/V Percent 140 to 160 (60 to 71) 30 Minutes Yes
WARNING: USE THE CORRECT PERSONAL PROTECTION. THIS CHEMICAL OR SOLUTION CAN CAUSE SKIN, EYE, AND LUNG DAMAGE. THE DANGER
AND PRECAUTIONS FOR EACH CHEMICAL IS DIFFERENT.
(c) Remove the part from the solution and let the unwanted solution drain into the tank.
(d) Flush the part with water for 10 seconds minimum.
(e) Flush the part in a double cascade rinse for 15 seconds minimum.
(f) Flush the part with water at 140 F (60 C) for 15 seconds minimum.
WARNING: USE THE CORRECT PERSONAL PROTECTION. COMPRESSED AIR WILL CAUSE LOOSE PARTICLES THAT CAN GET IN YOUR EYES. THE AIRSTREAM CAN CAUSE CUTS, DO NOT POINT IT AT YOUR SKIN.
(g)
Dry the part with compressed air. An alternate procedure for drying is included in the following step.
WARNING: USE THE CORRECT PERSONAL PROTECTION. HEATED PARTS WILL CAUSE BURNS.
(h)
Dry the part in an oven at 160 F (71 C) maximum.
Cleaning
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20-00-02/70-00-01
V. Method No. 203W: Plastic Media Blasting
(1)
The following procedure describes a mechanical method of removing coatings without harming the substrate. This method is an abrasive blasting process using a dry media of thermoset or thermoplastic plastic grit. Plastic media can be reused since it is not prone to break down and it retains its angular shape. It is necessary to clean the media before reuse.
NOTE: Plastic media can leave a film that can be detected during fluorescent penetrant inspection. Remove film with ethyl alcohol (SECTION VII).
(2)
Media used in plastic media blasting must be fabricated from virgin plastic (Grade A) with a particle size (U.S. Standard Sieve) and shape with sharp edges and corners. Plastic media are classified by type which specifies the hardness and material composition. Definitions of the different media types are as follows:
Type I A polyester plastic with a 3.0 mohs (34 to 42 Barcol) hardness. This media is recommended for use on delicate surfaces and is the least damaging of all media types.
Type II A urea formaldehyde based plastic with a 3.5 mohs (54 to 62 Barcol) hardness. This material may be used if the Type I material produces a less than desirable removal rate.
Type Ill A melamine formaldehyde plastic with a 4.0 mohs (64 to 74 Barcol) hardness. Type Ill media are very aggressive and are recommended for stripping iron based substances where residual stress is not a concern.
Type IV A phenol formaldehyde plastic with a 3.5 mohs (54 to 62 Barcol) hardness. This media is similar to Type II.
Type V An acrylic plastic with a 3.5 mohs (46 to 54 Barcol) hardness. Types I through IV are thermoset type plastics. This media is thermoplastic and tends to be softer and longer lasting.
(a)
Media Particle Size: Each type of blast media is available in a wide variety of size distributions. Blending of the different types/sizes is not permitted.
(b)
Media Material Restrictions: The media must be manufactured in accordance with the best commercial practice and supplied in accordance to the following restrictions.
1 No inorganic fillers are allowed in the media.
2 Media must not have or create an objectionable odor or affect the health of the personnel when used.
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