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Polyurethane hose Rot

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  • Polyurethane hose Rot

    In the past I have extolled the virtues of Polyurethane air hoses:
    light weight, thinner profile, good cold weather flex
    and also its cons - cost and its weird twisting problems.
    Nonetheless I have exclusively used PU hoses for all but the overhead retracing reel. - a spool to lay out on the drive when airing car tires, and a roll on a hook inside the shop.

    This week I have discovered another possible downside: a Hitachi hose I repaired for a leak last year sprung another bad leak a few minutes after I pressured it up. Did my work with a spare and then fixed the hose (shortened it) and it sprung yet another leak. Took a good look at it and I see that the polyurethane has rotted - basically a tough plastic usually, it is simply crumbling and separating from the woven fibers in the wall. I could see other spots where the hose was white showing separation from the reinforcing fibers. I tossed the whole hose after I salvaged brass fittings and noted that it had an apparent date code of 9524 printed on the hose wall every couple of feet along with the name and pressure rating. For a lot of stuff a four digit code like that means 1995 24th week?

    So I'm thinking Polyurethane has a lifetime - anyone else had this issue with PU hoses?

    I hope my BT3000 belts are OK...
    Loring in Katy, TX USA
    If your only tool is a hammer, you tend to treat all problems as if they were nails.
    BT3 FAQ -

  • #2
    Iíve not had this experience with pu hoses, but with pu caster wheels. PU Shopping cart wheels look great until they donít, and it seems like they all come apart at one time. Iíve had Several sets of 6Ē caster wheels, the $35-$40 each wheel type with red pu tires all crack and fell off the tire within several months of each other. So it doesnít surprise me this happens with hose. Exposure to sunlight doesnít seem to be a factor either.


    • #3
      I only have one. Itís a ten year old Flexzilla hose that I use in the basement shop. No issues, but I donít use air a lot. Also have some Goodyear rubber air hoses for outside work. Checked the BT3000 & BT3100 belts when we moved in 2016 and no probs. Your post made me go down to the shop and look at the spare belts I have in a box. Also good to go.
      Last edited by Jim Frye; 07-18-2019, 06:57 PM.
      Jim Frye
      The Nut in the Cellar.


      • #4
        My 15 year old Harbor Freight hoses are still doing fine. No idea what they are made from, but probably not poly. They seem like the normal rubbery style. What are the advantages of poly?


        • #5
          Carlos, there's poly vinyl chloride (PVC) and there's polyurethane (PU),
          PVC hoses are cheap and stiff and bulky and really stiff when cold, like 50 degrees F or colder.

          PU hoses are much stronger with thin PU fiber reinforced walls that are much lighter, thinner and more flexible, even when cold. One thing they don't like is axial twist.
          If you have rubbery hoses they are probably rubber. HEavy, somewhat stiff but pretty rugged and reasonably priced. No cold problems.

          Theres a tutorial I wrote on these hoses... if not as hoses under the article on Pneumatic fittings.
          Loring in Katy, TX USA
          If your only tool is a hammer, you tend to treat all problems as if they were nails.
          BT3 FAQ -


          • #6
            I have polyurethane hoses that are 15 years old with no issues, one is Hitachi. PU does have some chemical compatibility issues, maybe yours got exposed to something.

            The newer ďhybridĒ hoses are superior to rubber and PU; soft like rubber but not bulky and doesnít rot.
            Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison