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Questions re: Aluminum Oxidization

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  • Questions re: Aluminum Oxidization

    I want to prep an aluminum surface for epoxy application using Caswell’s de-smutting solution.

    My question is how long will the surface stay clean (no oxidization)? My sense is that it will begin oxidizing immediately. Is that ok?

  • #2
    It will, you can avoid it by doing the etch in an inert atmosphere, like argon, a sandblasting cabinet makes a good standby glove box!
    Mark

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    • #3
      You will get enough oxidation in five seconds to offset the effect of the cleaning. If you wait a full minute, you've wasted the effort to clean the surface.
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #4
        In my past life in aerospace job we used a chamber with inert gas to give enough working time to apply a conductive sealant containing a high concentration of silver powder. As others have noted the oxidation occurs rapidly.
        Byron Boucher
        Burnet, TX

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        • #5
          Originally posted by darryl View Post
          You will get enough oxidation in five seconds to offset the effect of the cleaning. If you wait a full minute, you've wasted the effort to clean the surface.
          I have no way to create an inert atmosphere. It has been previously suggested to apply some epoxy and scratch it in, then apply the sealing coat. Do you think this will work to seal the joint? Will it last?

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          • #6
            Sounds like you need an etching type glue.

            Anyone have thoughts?

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            • #7
              Originally posted by Horst View Post
              I have no way to create an inert atmosphere. It has been previously suggested to apply some epoxy and scratch it in, then apply the sealing coat. Do you think this will work to seal the joint? Will it last?
              You have a good chance of success. Just make a puddle of epoxy so that you can do the scratching without exposing the surface to air.

              The same principle can be used to solder aluminium by scratching the surface with a hot copper bit while under a puddle of molten flux.

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              • #8
                You can 'wet sand' the area using epoxy, then with fresh epoxy ready to apply, wipe the previous clean then apply the fresh right away. I've had pretty good luck with that.
                I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                • #9
                  We used to spray truck bodies with a yellow etch primer before painting, worked well, if the paint went on where it hadn't been primed the steam cleaner used to fetch it straight off again.
                  .

                  Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                  • #10
                    Originally posted by darryl View Post
                    You can 'wet sand' the area using epoxy, then with fresh epoxy ready to apply, wipe the previous clean then apply the fresh right away. I've had pretty good luck with that.
                    Why wipe it clean? seems to me that would encourage oxides.
                    And as far as contaminating the glue, people are always selling fancy 'filled' epoxys. Just call it aluminum oxide filled epoxy!
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      Fair enough. By wipe it clean all I mean is to remove the grit-filled swarf so the parts can come together without an extra compound in between- just fresh epoxy. The grit that is generated as you sand is oxidization in large part- something that you're trying to remove- ?
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                      Comment


                      • #12
                        Originally posted by darryl View Post
                        Fair enough. By wipe it clean all I mean is to remove the grit-filled swarf so the parts can come together without an extra compound in between- just fresh epoxy. The grit that is generated as you sand is oxidization in large part- something that you're trying to remove- ?
                        Something your trying to get under. Once its in the epoxy its likey not doing much harm. Although any larger bits of grit I guess you might wanna remove. Maybe 'scrap' clean once, leaving a good layer of epoxy residue while removing as much of the excess as you can.

                        I think I would be more worried about bits of sandpaper grit falling out into the epoxy.
                        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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