Technical data
3.1.18 Mixing MIL-C-81706/MIL-DTL-81706 Solu-
tion. The use of MIL-C-81706/MIL-DTL-81706 requires
that the following precautions be observed.
• MIL-C-81706/MIL-DTL-81706 conversion
coating materials are toxic and require the use
of rubber gloves and eye protection (goggles
and face shield) by personnel mixing or ap-
plying. If the material (which is an acid)
accidentally contacts the skin or eyes, flush
immediately with plenty of clean water. Re-
port to dispensary and/or consult a physician if
eyes are effected or skin is burned.
• Mixing and application shall be done in an
adequately ventilated area. Avoid prolonged
breathing of vapors.
• Do not permit specification MIL-C-81706/
MIL-DTL-81706 materials to come into con-
tact with paint thinner, acetone, or other com-
bustible material; fire may result. Also, any
absorbent materials, i.e., rags, sponges, paper
or nylon matting, etc., used in or exposed to
these materials shall be rinsed in water before
discarding. They are an extreme fire hazard if
allowed to dry otherwise.
• Do not use MIL-DTL-5541 or MIL-C-81706/
MIL-DTL-81706 treatment on magnesium al-
loy, high strength steel, or on cadmium or zinc
plated surfaces. If these materials are present
in adjacent areas, they must be protected.
• Conversion coating material should not be
allowed to enter faying surface areas or other
areas where the solution can not be adequately
removed by rinsing.
NOTE
• The solution will usually turn green during
application if dirt or corrosion is present on the
surface. The color green will not have the
iridescent quality that a properly applied and
dried solution will display.
• Select an area for mixing so spillage or splatter
from solution will not cause damage to other
equipment. Use only a stainless steel, plastic
or rubber container to mix solution in. Mix
only enough solution to coincide with the
immediate job requirements in order that fresh
materials will be available for each use.
a. If specification MIL-C-81706/MIL-DTL-81706, Form
II - Powder, is being used and it is not finely divided,
crush by rolling on a clean piece of paper. This will
improve mixing efficiency.
Nitric acid is highly toxic to skin, eyes, and
respiratory tract. Eye and skin protection is re-
quired. Use only in a well-ventilated area. In case
of eye or skin contact, flush immediately with
water and report to dispensary.
b. Preparation and use of MIL-C-81706/MIL-DTL-81706,
Form II - Powder, will be done in accordance with
vendors technical instructions. This solution should be
analyzed prior to use for pH value and hexavalent
chromium content by the base chemical laboratory at
depot facilities. Solutions used in field operations can be
analyzed using pH paper or a pH meter and visual
performance characteristics. Solution matter should be
retested every five days and the chemical laboratory
should be consulted should difficulties arise. Field
operations prepare solutions as per vendors instructions
and test per example below. Mix three ounces of
MIL-C-81706/MIL-DTL-81706 powder to one gallon
of clean water in an approved container. Add nitric acid,
Federal Specification O-N-350 and check pH for range
of 1.6 - 1.9. Five ml will usually adjust pH to this range
however, it could require up to 15 ml. Mix solution well
with a clean plastic or aluminum paddle. Check the time
it takes to form an iridescent yellow to brown color on
a sample of the same alloy the solution will be used on.
If the time is more than 5 minutes, retest the pH and
make the following adjustments:
(1) A pH greater than 1.9 will require addition of 2 ml
portions of nitric acid until desired pH is achieved.
(2) A pH less than 1.6 will require addition of 2 ml
portions of ammonium hydroxide until the desired
pH is achieved. After pH adjustment the solution
reaction time should fall within the range of 1 to 5
minutes.
c. If powder material is being used, allow the solution to
stand approximately 1 hour prior to application. A small
amount of powder may not dissolve; however, this is not
objectionable.
3.1.19 Application of MIL-C-81706/MIL-DTL-81706
Solutions.
a. Apply the coating solution with a fiber brush, clean rag,
sponge, applicator bottle (plastic), or low pressure
stream (flow-on, do not atomize). The method used for
application should be selected depending on the specific
job requirement. If pumping is required, pumps, valves,
and fittings shall be manufactured from 18-8 stainless
steel, polypropylene or polyvinyl chloride (PVC). Flow
TO 1-1-8
Change 3 3-11