Replasticizing hop balls

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  • Merl
    Hopper research dept.
    • Apr 2021
    • 697

    Replasticizing hop balls

    Idea credit goes to @Unicks.

    The goal is to see how much size increase I can get from an original Sun Hoppity Hop using acetyl tributyl citrate, a PVC plasticizer. The HH was made of thick PVC compared current cheaper, thinner hoppers so I ordered a large bottle to ensure I has enough.

    The HH is max rated at 20" for teens and adults, per original instruction sheet. Last year, I manage to heat stretch an un-replasticized HH to right at 24". This was the absolute max and didn't leave very much bounce.

    The current HH has been coated inside and out with ATBC, which the vinyl immediately soaked up as it vanished within a few minutes. The ball is now hanging in a closet under some pressure. It will be measured daily for any change in size and softness.

    Did the same to a new Hop! 66, which is of a different material and presumably not lacking in its original plasticizer. The maximum rated size is 26 inches. After coating the inside yesterday with ATBC and inflating, it is now near 28 in. but still somewhat bouncy. This may still be within the factory range of inflation so will keep watching.

    Unicks said it took about a week to see a real difference. End result for the HH and 66 is to see how much relaxation of the vinyl happens chemically leading to an increase in size, which then may or may not be followed up with heat stretching of the HH.
    Last edited by Merl; 09-06-2021, 17:43.
  • Merl
    Hopper research dept.
    • Apr 2021
    • 697

    #2
    Re: Replasticizing hop balls

    HH: up to 20.3" diameter from 19.8 yesterday with no added inflation.

    Comment

    • Merl
      Hopper research dept.
      • Apr 2021
      • 697

      #3
      Re: Replasticizing hop balls

      21.5" after another dose of ATBC late yesterday, a hot soak today to speed things up, and a top-off of air. No distortion and still flexy enough for comfortable use; firm but not rock hard. Bounces me a good 18" high....the cheap softer vinyl ones would have trouble doing that even fully inflated.
      Last edited by Merl; 12-06-2021, 16:12.

      Comment

      • Yen_D_Heart
        Member
        • Jan 2019
        • 47

        #4
        Re: Replasticizing hop balls

        That sounds really interesting!

        Can you explain how you did that? Do you have a step-by-step guide or general tips that you could share?
        I have a 32" hopper that I haven't inflated ever. I would love to have bigger hoppers than that, so maybe it's worth a shot?

        Comment

        • Merl
          Hopper research dept.
          • Apr 2021
          • 697

          #5
          Re: Replasticizing hop balls

          If you have ACTB, first step will be to thoroughly coat the entire inside, inflate it, thrn watch for any change as it soaks in.

          Comment

          • Merl
            Hopper research dept.
            • Apr 2021
            • 697

            #6
            Re: Replasticizing hop balls

            Some air was let out the other day after the top off but the ball is again at 21.5 (about same as a Hop! 55) but perhaps a bit bouncier than before. It's going to take some time to really see results from the ATBC.

            Comment

            • Merl
              Hopper research dept.
              • Apr 2021
              • 697

              #7
              Re: Replasticizing hop balls

              Haven't been too confident in the ATBC that came from China, so last week I ordered the softener from Sculpey (it's back in stock). It arrived today. Deflated the ball and dosed it with a 1 oz bottle of Sculpey's ATBC. Rubbed it in thoroughly and reinflated three hours ago. The ball is holding at 21.5 but is definitely not as firm as it was at the same size yesterday (remember that this is 53 year old vinyl already 1.5" above rated max...it SHOULD be tight as a drum). Maybe now we're starting to get somewhere.
              Last edited by Merl; 17-06-2021, 20:57.

              Comment

              • Merl
                Hopper research dept.
                • Apr 2021
                • 697

                #8
                Re: Replasticizing hop balls

                21.97" and still has decent bounce.
                Last edited by Merl; 18-06-2021, 13:52.

                Comment

                • Merl
                  Hopper research dept.
                  • Apr 2021
                  • 697

                  #9
                  Re: Replasticizing hop balls

                  22.5" after leaving inflated in the sun inside of a black contractor bag. Still bouncy enough.

                  Comment

                  • Unicks
                    Member
                    • Nov 2020
                    • 80

                    #10
                    Re: Replasticizing hop balls

                    @Merl For what it's worth, I've noticed that temperature cycling seems to speed up the absorption. I find that the vinyl seems softer when it's cold, then brought back to 80+F we get the soft-sticky vinyl again.

                    I've tried to poke a hole in the ball I have to see if the vinyl has lost it's strength or elasticity at full recommended inflation, but it remains soft and quite strong. Makes me leery when I see what ATBC does to vinyl items with pinch seams and how easily they come apart when you over do it. Maybe because these vinyl balls are seamless you can have a bit more fun with them before the pop.

                    Good luck!

                    U

                    Comment

                    • Merl
                      Hopper research dept.
                      • Apr 2021
                      • 697

                      #11
                      Re: Replasticizing hop balls

                      The HH is hanging in a closet will stay there for a few more weeks. If I don't see an undeniable difference by then, it's just not going to work on that type of vinyl. We'll see.

                      Comment

                      • Merl
                        Hopper research dept.
                        • Apr 2021
                        • 697

                        #12
                        Re: Replasticizing hop balls

                        Since you're familiar with this old vinyl, best-case scenario: what would you predict a 20" HH *could* end up like? Size, feel, appearance, bounce, durability, etc? Thanks.

                        Comment

                        • Merl
                          Hopper research dept.
                          • Apr 2021
                          • 697

                          #13
                          Re: Replasticizing hop balls

                          Haven't even looked at it at three days so I just took a measurement. 72" circumference, 22.9" diameter.

                          Comment

                          • frenchy
                            Senior Member
                            • Sep 2018
                            • 288

                            #14
                            Re: Replasticizing hop balls

                            I’m really fascinated by your classic hoppity hop experiment. How much ATBC did you use? How big is the ball now & have you noticed a change to the feel of the vinyl material?

                            Comment

                            • Merl
                              Hopper research dept.
                              • Apr 2021
                              • 697

                              #15
                              Re: Replasticizing hop balls

                              Used several ounces, btw the bulk bottle I got from Amazon and 2 bottles of the Sculpey softener, both inside and out. Can't say exactly how many ounces though.

                              Been over a week since I checked. The HH looks to have stabilized at 72" circumference (about 23"), the size of the original adult rated blue Great Space Hopper. It's bouncy enough for use but nothing really dramatic as far as size increase. Feels a bit softer but really not much. I got 24" out of another HH by using boiling water but it was pretty tight at that point and I knew not to push it any further. I'm trying to avoid using that on this one, tho it might make a difference with the added flex.

                              I also dosed the Hop 66. Need to add more air to see if there's a difference...it doesn't appear any bigger from sitting at normal rated size.
                              Last edited by Merl; 07-07-2021, 12:28.

                              Comment

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