7696 Route 31
                                                                             Lyons NY 14489
                                                                             P: 315.946.1213
                                                                             F: 315.946.4456
                                                                             www.caswellplating.com
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                                        SSB370 Instructions

   Room Temperature Blackening Solution for Stainless
                        Steel
Stainless Steel Blackener 370 is an acidic liquid concentrate used full strength or
diluted with up to 3 parts distilled water to blacken stainless steel at room temperature. It is
recommended for color coding parts and blackening engravings on stainless steels. It produces a
pleasing dark gray/black finish. No sealer required.

Finishing Procedure

1. Clean:     Parts must be thoroughly cleaned and degreased
2. Rinse:    Thoroughly rinse using distilled water
3. Activate:  All stainless steel surfaces are passive by nature due to the chromium

            oxide present on the surface. This oxide must be removed prior to
            blackening by deoxidizing/activating the surface in one of the following
            Solutions:
             a.) For the 300 series alloys, immerse parts for 2 to 5 minutes in a 50% by
                 volume Muriatic Acid solution used at room temperature.
4. Rinse:    Thoroughly rinse using distilled water
5. Blacken: Some experimentation should be done with properly prepared parts to
            determine the optimum concentration of the SSB370 solution and length
            of immersion required to produce the desired depth of black. As a starting
            point, with 300 series alloys, try a 50% by volume solution A 33% or
            25% by volume solution should be evaluated with the 400 series alloys.
            Difficult to blacken surfaces may require the use of SSB370 at full strength.

                  Immersion times should be varied from 2 to 5 minutes maximum. Very
                  passive surfaces may require further activation to initiate the blackening
                  reaction by having plain steel in contact with the stainless steel parts
                  while immersed in the SSB370 solution. This can be accomplished by
                  using plain steel hooks or racks to suspend the stainless steel parts in the
                  solution or by including some plain steel wire in the plastic dip baskets or
                  rotating barrels used to contain the stainless steel parts.
6. Rinse:        Thoroughly rinse using distilled water.

Solution Replenishment and Maintenance

The SSB370 solution is gradually depleted through use, but may be replenished indefinitely with periodic additions of
SSB370 concentrate. The strength of the solution can also be fairly accurately maintained by the immersion time required
to produce the desired depth of black. As the time increases, add sufficient concentrate to reduce the time to your
established standard. The frequency of additions will depend upon the volume of work processed through the solution.
For optimum results, the strength of the solution should be maintained at 85% of its original strength or greater at all times
and frequent small additions are recommended.