Summary for wash primer hexavalent chrome Discussion
Wash primer and hexavalent chrome are discussed in the context of obsolete military coatings and possible replacements. The original question asks when Sherwin-Williams removed Cr 6+ from wash primer under MIL-C-8514. In the excerpt, Adam Westhoff says his company stopped using DOD-P-15328 because of the hexavalent chromium in it and is looking for a replacement that will etch metal, create a profile for topcoats, and dry fast. Ted Mooney replies that DOD-P-15328 is long cancelled and was superseded by TT-C-490. The excerpt then shows Adam noting they have been using formula 84, Molybdate, which is covered by TT-C-490, but the thread cuts off before further guidance appears. Based on the visible text, the practical takeaway is that the old specification is obsolete and users should look to TT-C-490-based alternatives rather than the cancelled product.
Q. WHEN DID SHERWIN WILLIAMS REMOVE Cr 6+ FROM WASH PRIMER PER MIL-C-8514
[from DLA]
?
Randy Matuskey
– Glendale, California
October 19, 2018
A. Hi Randy. According to https://www.paintdocs.com/docs/webPDF.jsp?SITEID=SWOEM&doctype=EDS&prodno=E90G16, it currently contains 0.8% by weight of Chromium, and 9.0 by weight chromium compounds. I am not familiar enough with their Environmental Data Sheets to be able to say whether this indicates that it is or is not free of hexavalent chromium.
The sheets do state –in capital letters — “AS CURRENTLY FORMULATED”, which is certainly an indication that they feel entitled to change the formulation of their product at will. Consequently, if the answer is important, the only safe thing to do is inquire directly of Sherwin-Williams with batch numbers, etc.
Your situation is probably interesting. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
October 2018
Q. Is there a current replacement for DOD-P-15328? We had to stop using it due to the Hexavalent Chromium component within its mix. We have been struggling to find a suitable replacement that etches the surface of the metal to create a profile accepting to our top-coat and that has a fast dry time. Is there such a solution? Thanks for the input if there is any.
ADAM WESTHOFF
Comsaco Inc. – Norfolk, Virginia U.S.A.
March 18, 2019
A. Hi Adam. DOD-P-15328 is long cancelled and was superceded by TT-C-490
[from DLA]
. This actually now covers 8 different types of conversion coatings and pretreatments for metallic surfaces, and three different classes. Type III is hex chrome free, and sounds to me like it describes wash primers. While hex chrome contributed corrosion resistance, it doesn’t seem to me that chrome would have contributed to the etching you are seeking, so it sounds like there should be a suitable replacement that can etch the surface while being hex chrome free. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
March 2019
Q. Ted, Yes I realize that 15328 has been canceled. We have been using formula 84, Molybdate, which is covered by TT-C-490
[from DLA]
. It does not perform as well as the wash primer did as a base primer for our enclosures. We are not getting the adherence that we were used to with the wash primer. Plus we have to wait hours before top coating. I am looking for a primer/pre-treatment, that will create a surface more accepting to our top coats without having to blast prior to. Years ago I found a company that claimed to have a wash primer without the harmful Hex-6. They have since fallen off the earth. Do you know of said sorcery? Any help you can offer is greatly appreciated.Thanks, Adam
ADAM WESTHOFF [returning]
Comsaco Inc. – Norfolk, Virginia U.S.A.
March 19, 2019
July 17, 2019
We use – DOD-P-15328D Metal Wash Primer Pretreatment Green (Part A)
Green (Part A) by Sherwin Williams – no hex chrome and no problems Product code E90G4
Sincerely,
Micheline Forth
Edwards Interiors – Rincon, Georgia
A. Sorry to say that all DoD P 15328 wash primers do contain hexavalent chrome. That product mentioned from SW contains pentazinc chromium octahydroxide.
Chrome-free wash primers are available, at this moment there is no adequate specification to cover them but that will arrive this year.
Megadex CF2020 is a fully chrome free washprimer.
Jim Rowbotham
Pexa Ltd. – Holywell Green, West Yorks, UK
December 5, 2019