Announcement

Collapse
No announcement yet.

Passivating Chinese Tanks

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Passivating Chinese Tanks

    I have been in this industry for almost 30 years and have commissioned many tanks. I am now stumped with an oily white film on the inside of these Chinese tanks that nothing seems to cut. It will emulsify with hot caustic but will still coat the stainless and not rinse out. Any suggestions?

  • #2
    My Guess !!!

    Maybe a thin coating of White Grease, White Lithium, food grade grease, could have been used during mfg, or in the polish or finish of your SS tank, we use it on some of our big molding machines, it's FDA approved, really sticks well, hard to remove, it's a great grease.

    Just one thought.

    Gregg

    Comment


    • #3
      This is probably the oil / grease used during rolling / spinning the sheet steel. Degrease with potassium hydroxide - 2 % at 65 to 80 C, or 5% NaOH at 80 deg C for 30 minutes +. I had to manually clean some Chinese kit with hot domestic detergent and a scrubbing brush before using caustic, and even then there was still a bit of a film, but degreasing swabs showed completely clear, and the beer produced was OK. I was tempted to use some car engine degreasant first, but I would then have wanted to strip out every seal, manually clean and replace with fresh valve rubbers etc - so we didn't. Fortunately as a 15 US brl setup, we could manually clean with detergent and brushes
      dick

      Comment


      • #4
        Oh yes I meant to add - then for security, passivate properly. My preferred method is hot nitric acid, but I know plenty of people used tartaric.
        dick

        Comment


        • #5
          I have had luck with Birko's BruREze cleaning that kind of mess out, it's my go to alkali cleaner anyway. Can't stand caustic, nasty, dangerous stuff, won't use it unless I have to.

          Comment

          Working...
          X