SS best water tank material?

Discussion in 'Materials' started by abosely, Sep 20, 2015.

  1. abosely
    Joined: Mar 2015
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    Location: Big Island Hawaii

    abosely Senior Member

    Is SS the best drinking water tank material from long term health & ability to be cleaned stand point?

    If using SS for tanks, which grade or alloy of SS would be best, considering
    it will be in a saltwater environment.

    Probably will have at least two tanks in each hull (catamaran) built to fit area and be removable for maintenance if needed.

    Thought about using 1/4" ply and glassing inside, outside and using an epoxy paint to finish inside, but unsure about the health aspects of epoxy paint coatings or if there even is any available for small tanks. Other than material cost, don't see any real advantage to building a composite water tank. They won't be particularly difficult or complicated shapes to build.

    So guessing SS would be the best material choice health & safety wise? Is there any negative aspects to SS potable water tanks?

    Cheers, Allen
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I like plastic tanks. They are easy to inspect for algae growth because they are translucent.
     
  3. abosely
    Joined: Mar 2015
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    abosely Senior Member

    Plastic would be nice but I need a material that I can fabricate the tanks so they can be built to fit in available spaces.

    Will definitely build them with a good size inspection/cleaning plate with a well reinforced mounting ring that can be solidly bolted down and not leak.

    From what I have been researching, it looks like 304 SS sheet with a good epoxy paint on exterior to protect the outside of tanks from saltwater since 304 isn't as corrosion resistant to saltwater as 316.

    Cheers, Allen
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Bladders ?
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Plastic tanks can be fabricated. Just by a welder and some material and have at it. Bladders work well too.
     
  6. abosely
    Joined: Mar 2015
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    abosely Senior Member

    Thanks PAR, I thought that plastic tanks had to be molded. That's great news.

    I did some searching and most molded tanks seem to have 3/8" thick walls. When using HDPE sheet and welding up tank, would 1/4" sheet be thick enough or should use 3/8"? Didn't know if the the 3/8" was nominal thickness since it is rotation molded.

    Tanks will be 25 gals or less. Maybe weld stiffeners across wide sections for extra stiffness if needed?

    Being able to weld plastic tanks means I can make a few small tanks to fit in small spaces to store some extra water, since they can be made to fit spaces available, there will be a few triangular areas.

    Cheers, Allen
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Tank shell thickness depends on how big it is and to a lesser degree its shape.
     

  8. abosely
    Joined: Mar 2015
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    abosely Senior Member

    Ok, that makes sense. I'll figure out tanks wall thickness when ready to build tanks since won't know size/dimensions till then. They will be a few different sizes and shapes depending available space and such.

    But good to know material and building method for tanks.

    Trying to do as much research and systems detailing & designing as I can well ahead of time as feasible.

    Cheers, Allen
     
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