Summary for mil-std-171 finish 5.3.1.3 Discussion
MIL-STD-171 finish 5.3.1.3 or 5.3.2.3 refers to phosphate coatings listed in Table V of MIL-STD-171, not a separate mystery process. Dale Crawford asked what the protective finish meant because he could not find a description in the document. Ken Vlach answered that 5.3.1.3 is manganese phosphating under DOD-P-16232, now MIL-DTL-16232, and noted that a chromic acid rinse is required. Toby Padfield added that 5.3.2.3 designates zinc phosphate coating. David Presto cautioned that military phosphate work can be demanding: the plater’s procedure may need government review and approval, and the spec can require frequent bath and rinse testing, coating-weight checks, and salt-spray testing. The thread also points readers to DLA ASSIST for current specifications and qualified products.
Q. I’m quoting a part that calls out a protective finish 5.3.1.3 or
5.3.2.3 of MIL 171. Does anyone know exactly what this protective finish is? Any help would be greatly appreciated. I’ve been searching through the document and can’t find a description of the process.
Dale Crawford
Buyer – Shenandoah, Virginia, USA
2007
A. MIL 171 Finishing of Metal and Wood Surfaces unfortunately has similar paragraph and finish numbering. The finishes mentioned are in Table V on page 19.
Finish 5.3.1.3 is Manganese phosphating, DOD-P-16232 [ed. note: replaced by MIL-DTL-16232 [from
DLA]
], type M, Class 3, with no supplementary treatment.
Finish 5.3.2.3 is Zinc phosphating, DOD-P-16232, type Z, Class 3, with no supplementary treatment.
See MIL-DTL-16232G PHOSPHATE COATING, HEAVY, MANGANESE OR ZINC BASE [ed. note: replaced by MIL-DTL-16232 [from
DLA]
] for details. Note that a chromic acid rinse is required.
Ken Vlach [deceased]
– Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
A. 5.3.1.3 designates a manganese phosphate coating and 5.3.2.3 designates a zinc phosphate coating. See Table V in MIL 171.
Toby Padfield
Automotive module supplier – Michigan
A. Bidder beware! Mil spec phosphate MANDATES submittal of the plater’s phosphating procedure to the government’s ultimate procuring activity, typically Rock Island Arsenal, for review and approval prior to awarding of the contract. I would be hesitant to have any job shop phosphating house unfamiliar with such government specs, particularly phosphating, from submitting pricing. Requires testing of baths and rinses every 4 hours, coating weight tests for every 8 hours, salt spray testing both before and after application of preservative, and on and on. You need a house familiar with this spec!
Milt Stevenson, Jr.
Plating shop technical manager – Syracuse, New York
A. rev.E is soon to be replaced by rev. F.
Consider MIL-STD-171 a shopping list of finishes.
Finish 5.3.1.3 is a heavy manganese class 3 phosphate coating without supplemental oil and 5.3.2.3 is a heavy zinc class 3 phosphate coating without supplemental oil. MIL-DTL-16232 [from
DLA]
G for the phosphate coating process requirements.
Note that specifications may be obtained at the following web page:
assist.daps.dla.mil/quicksearch/
Type the number only (i.e., 16232, 171) of the spec in the second block “Document Number” and then hit return or click the “Submit” button… Note that supplementary treatments i.e., oil preservatives, dry film lubricants & CARC paints shall be traceable to the latest Qualified Products List (QPL) for the specifications or from the ASSIST Online Qualified Products Database (QPD).
Be advised that QPL’s are currently being transformed to a Qualified Products Database (QPD).
To obtain the latest qualified products, apply for an account and password at ASSIST Online:
assist.daps.dla.mil/online/start/
After logging in, click on “QPD” from the left-side list, then click
“Search” type in the “Document Number (i.e., 3150)” and hit return or click the “Submit” button. Click on the “Specification (i.e., MIL-PRF-3150)” and view the qualified products by clicking on the listed “Govt Designation” numbers.
To order specifications (i.e., FED-STD-595) apply for an account and password at the “Shopping Wizard.”
David Presto
– Rock Island, Illinois, USA
Ed. update Feb. 2023: We thank David for his posting, but links & instructions usually have a very limited life (which was the case here). We now do our best to directly link to all specs that are mentioned so you can get to it in a single click (and view it in two clicks if it’s free).