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plastic bin for alodyneing the center ribs

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  • plastic bin for alodyneing the center ribs

    Anyone found a plastic bin to hold the acid cleaner and chromic acid big enough to do the center ribs ?
    Found a sterilite one but it was a swindle. Label said it was 35 inches long. Rib is 31.5. label was for lid--- NOT what fits inside- ( that was like 29 inches)

    If I made a box from MDF and coated the inside with polyester resin--- would that resist the acids ?????
    Polyurethane varnish ????

    Tim

  • #2
    2x4 or 2x6 "box" on your benchtop with a visqueen liner? Build it as large as you need it that way.
    Christopher Owens
    Bearhawk 4-Place Scratch Built, Plans 991
    Bearhawk Patrol Scratch Built, Plans P313
    Germantown, Wisconsin, USA

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    • #3
      I think vinyl ester is better than poly or epoxy for solvents, at least some solvents. How about a glass fish tank, or cut a old 55 gallon drum or propane tank in half?

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      • #4
        Originally posted by Chris In Milwaukee View Post
        2x4 or 2x6 "box" on your benchtop with a visqueen liner? Build it as large as you need it that way.
        when I was working on my RV build I did something similar...just plastic lined a long box with clips holding the plastic at the edges. But I didn't know the chemicals could burn through the plastic. is there any off the shelf stuff that meets this protection level....or is this special order stuff? is this something Aircraft spruce sells?
        Last edited by way_up_north; 01-04-2019, 10:18 PM.

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        • #5
          I've had my acid and alodyne bath solutions in 15 gallon poly barrels for years in a completely dark room without troubles. One end cut out, 6 mil poly sheet over end to cap (depress center and double bungee cords around barrel to seal for storage between uses.) Double dip the center ribs, longer items constant reapplying (best done with warm days and solution to speed it up).
          Last edited by marcusofcotton; 01-05-2019, 12:57 PM.

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          • Sir Newton
            Sir Newton commented
            Editing a comment
            100% Keep the solution warm & mix it strong.

        • #6
          The best material for containing acids including hydrofluoric is nalgene. This outfit offers 85 gallon tanks... perhaps they’re tall enough to be cut in half?
          Find the right tank to meet your application needs with cylinders ranging in size from 19L to 757L.

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          • #7
            I found a place here on the other side of town -- in the ritzy mall area-- called "the container store". They have EVERYTHING !
            I found the Iris brand plastic boxes for storing wrapping paper rolls. They are about 1/4 inch longer than the ribs and about 2 inches wider and 6 inches tall-- with a snap-down lit.
            PERFECT !!!!!! The stores are all over the country so there might be one near you. I had never hear of them before...……

            Tim

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            • #8
              I think you should find good crates or containers that might be suitable for this acid. Maybe you could use the garbage cans I rented when I was renovating from this company https://www.186needabin.com/disposal-bins/. It kept a lot of trash from piling near and in the house itself and made it easy to move around. Also, the trash didn't spoil the appearance of our garden. So you should contact them and find out if these trash cans are suitable for your needs. You are lucky if they do because it costs pretty inexpensive to rent such a dumpster. If you do so, write here, I would be interested to know.
              Last edited by Cristhanbur; 01-17-2022, 01:31 AM.

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              • #9
                I used some roof flashing bent in the shape of a center rib to make several tanks for acid,water, alodine.
                d.jpg line with plastic sheet.

                The above shape was to make use of a limited amount of alodine or acid.





                For the capstips I glued 10 foot long pvc pipes cut in half the long way. I added the ability to drain the tanks at the end.
                pipe1.jpg
                water entering tank as a steady stream






                pipe2.jpg

                My setup had continual flowing water that entered on one end and drained on the other end so I did not have to change water during process


                For the spars I used a pvc sheeting from one of the box stores. The material is in the plumbing department. It was meant for shower pan.
                It can be bought in any length by the foot.

                pvcsheet.jpgm1.jpg
                built in drain at one end of the tank




                Some times I used my vacuum to recover liquid from tray.
                vacuum bottle to reclaim acid, or alodine

                bottle.jpg
                Stan
                Austin Tx

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                • #10
                  I also used a 6 gallon bucket and flipped the main ribs around end for end. I only used these tanks made from 6" sc40 pvc pipe for longer stuff like spars, cap strips, cheers

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                  • #11
                    You can buy them in specialized stores. As a rule, such bunkers are made of plastic and used to store substances of various structures. They have specific characteristics depending on the type of stored substances. Btw, I started using https://www.dumpsterrentalslafayette.com/ last week. It has significantly saved me the cost of removing garbage from my store. Previously, I spent a lot of money on renting specialized cars and fines for late disposal of garbage.
                    Last edited by geraxaneca; 09-09-2022, 04:26 AM.

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                    • #12
                      Was just at my Lowes in eastern TN.---- and they had a plastic bin that looked long enough for the long center ribs. FYI----

                      Tim

                      PS----- I have decided to not do any more alodineing--- as it reduces the fatigue life of the parts a little. Not so much an issue on the ribs but maybe of more import in the main spar. I will just use 2 part water based epoxy - chromate.
                      Last edited by fairchild1934; 02-01-2023, 01:30 PM.

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                      • #13
                        Originally posted by fairchild1934 View Post
                        Was just at my Lowes in eastern TN.---- and they had a plastic bin that looked long enough for the long center ribs. FYI----

                        Tim

                        PS----- I have decided to not do any more alodineing--- as it reduces the fatigue life of the parts a little. Not so much an issue on the ribs but maybe of more import in the main spar. I will just use 2 part water based epoxy - chromate.
                        Do you have a reference for that Tim? Some folks confuse Alodine with anodize, anodizing has the reputation for reducing fatigue life but I've not found references to support that in alodine treatment.

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                        • #14
                          cant remember where I read it---- but when I was reading up on alodining---- it seemed to be the same basic conversion as anodising---- the only difference seemed to be that one uses electricity to drive the process and the other uses a "downhill energy" process that requires no external electricity be applied.
                          the difference seemed to be the same as electroplated nickel vs. electroless nickel. It appeared that the deposited aluminum oxide was the same when it was done depositing. it was said--- reasonably i would say---- that you created a hard shell on top of the softer aluminum core--- and the threshold for cracking that hard shell is much lower (or sooner in terms of fatigue) than for the softer AL core. However because they are intimately bonded--- a crack in the hard shell continues to propagate into the softer core. So my reasoning was/is that for parts that we expect to flex-- (spar) it might be better to use only epoxy chromate. I would not expect the ribs to flex in a direct way under load as much as the spars. and--- you might survive a cracked rib but not so much a cracked spar. (maybe yall phD engineers out there my not go that far---)

                          Plus it is some inconvenience and expense to alodine. in the long run -- an epoxy chromate might be just as good. Maybe diminishing returns for alodine.
                          I understand just plain non-epoxy chromate did very well on the cessna bird dogs. That was 70 years ago !!!!!

                          Thats my understanding of alodine vs. anodize. Maybe someone with plating background can correct me if my understanding is doo-doo :-)

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                          • Sir Newton
                            Sir Newton commented
                            Editing a comment
                            Until it was discovered that alodine is pure poison! Chemically etching followed by a generous dip in alodine was the industry standard preparation before primer was applied. So basically what I am saying is those 70yr old planes were all prepared using alodine 1st.

                        • #15
                          Tim, you are correct that anodizing forms a hard aluminum oxide and that there are similarities in process. But alodine leaves a thinner soft gelatinous chromate coating. Following link is a good short read on the difference.

                          Alodine finish is one of the best surface finishes for aluminum in precision machining. This guide delves into it, and why it is critical.


                          Mark

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