Home Cosmetic Science Talk Formulating Weird Rust Spots Appear when conditoner is touching metal???

  • Weird Rust Spots Appear when conditoner is touching metal???

    Posted by dmtcbrands on July 10, 2014 at 2:21 pm

    Hi all-

    Gerry with DMTCBrands. We are working on a new conditioner here and we are stumped on why rust appeared on our metal emulsion blender when we left some conditioner on for a few hours.  We used Tocopherol in the mix and  the ph was 5.5.  Any thoughts?  Any help would be appreciated.
    Microformulation replied 10 years ago 5 Members · 9 Replies
  • 9 Replies
  • Microformulation

    July 10, 2014 at 5:12 pm

    What grade Stainless Steel is the mixer constructed of? SS 316?

  • Microformulation

    July 10, 2014 at 5:13 pm


    See the description of SS 316 grade. Generally this is preferred in processining in Cosmetics.

  • dmtcbrands

    July 10, 2014 at 6:38 pm

    Thank you Mark. I will check that out to see what grade it is. I assumed it was to acidic but it doesn’t seem so. We also noticed it on metal spring on the pump. 

  • Bobzchemist

    July 10, 2014 at 8:35 pm

    It’s possible that the stainless steel wasn’t passivated properly.

  • Microformulation

    July 10, 2014 at 10:53 pm

    Passivated. Sadly enough I was able to recall what that meant. Does SS 316 even need passivating?

    “Type 316 is considerably more resistant to solutions of sulfuric acid,
    chlorides, bromides, iodides and fatty acids at high temperature.  In
    the manufacture of certain pharmaceuticals, stainless steels containing
    molybdenum are required in order to avoid excessive metallic

    “The addtion of 2% molybdenum makes 316 considerably more resistant to corrosion and oxidation than the 304 family of alloys.” An engineer at Lee Groen once told me that this eliminates the need for passivation.

  • Bill_Toge

    July 11, 2014 at 4:00 am

    @Microformulation, we only passivate 316 grade steel if it’s coming into contact with reactive or metal-sensitive materials, e.g. hydrogen peroxide or thioglycolic acid

  • vitalys

    July 11, 2014 at 6:29 am

    @dmtcbrands, if you use quats in your formulation - it may cause the rust easily

  • Microformulation

    July 11, 2014 at 9:46 am

    @Bill_Toge That was what I thought. Thanks for the confirmation. Doesn’t Food service (professional) generally use SS 316 also?

    My thought is if they have adapted equipment (no offense dmtcbrands, I don’t know your manufacturing size or capabilities), they may have “re-purposed” equipment that isn’t SS 316. I have seen this happen with some start-ups. For example, some smaller process settings will utilize mortar or “squirrel” mixers (look that last one up, it exists) that they have purchased at Home Depot/Lowes. After several months they will notice marked corrosion on the mixers. I have seen the same on re-purposed mixers used in the lab.


  • Microformulation

    July 11, 2014 at 9:58 am

    I pulled this out of my notes from one site visit. Here is the mixer blade they “re-purposed.” If you note, it says it is galvanized steel. This is not SS 316.


    They were smaller and it was performing “like a champ” per the owner. They were attaching it to a smaller Lightnin’ Mixer in Manufacturing (small batch manufacturer). If you looked closely you could see rust building up.

    @DMTCBrands If you are using any innovative (and that is common, no insult intended) you would need to confirm the grade of steel. Another issue I sometimes see with re-purposed equipment is it is harder to breakdown and clean sometimes.

    Lastly, get into the habit of cleaning your equipment as quickly as possible. At one plant I worked early on the Plant Manager  was very strict on this. We would sometimes get the employee who finished a batch at 4:30 and would try to “hide” the equipment until the next day rather than at least do an initial cleaning (remove all residual product). When this ever happened, it would be entertaining. It wasn’t until later when I was in the Military that I would meet someone who could match that Plant Manager in the grasp, depth and creativity in his use of the curse word.

Log in to reply.