• Re: Paint Cans

    From jlarkin@highlandsniptechnology.com@21:1/5 to All on Sat Jul 23 09:10:54 2022
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spamme@not.com>
    wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The >film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >tedious job and not certain of removing every last scrap of film around the >lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Mike Monett on Sat Jul 23 12:07:07 2022
    Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very tedious job and not certain of removing every last scrap of film around the lid.

    Can anyone think of a better way?

    Thanks,

    Mike


    A torch and some sandpaper.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Mike Monett@21:1/5 to All on Sat Jul 23 15:38:48 2022
    Following Phill's superb suggestion to use a paint can for RFI shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very tedious job and not certain of removing every last scrap of film around the lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    --
    MRM

    --- SoupGate-Win32 v1.05
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  • From bitrex@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 23 12:23:32 2022
    On 7/23/2022 12:10 PM, jlarkin@highlandsniptechnology.com wrote:
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spamme@not.com>
    wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >> bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The >> film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >> tedious job and not certain of removing every last scrap of film around the >> lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.

    Altoids tins work great for homebrew RF filters and attenuators

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 23 12:36:38 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spamme@not.com>
    wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >> bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The >> film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >> tedious job and not certain of removing every last scrap of film around the >> lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.


    I've used those too, though I don't run antennas through the side of the
    can like that. ;)

    I have one that I use for testing photoreceiver protos--four BNC F-F
    bulkhead adapters and probably six 10 nF ex-Soviet feedthrough caps
    installed in the lid.

    They aren't as good as a clean (uncoated) paint can, though, and the RF shielding effectiveness depends critically on both the tin and the lid
    staying really circular. If they don't, you get slot antennas in the seal.

    Cheers

    Phil Hobbs
    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

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  • From Don@21:1/5 to bitrex on Sat Jul 23 17:40:19 2022
    bitrex wrote:
    jlarkin@highlandsniptechnology.com wrote:
    Mike Monett wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >>> bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The
    film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >>> tedious job and not certain of removing every last scrap of film around the >>> lid.

    Can anyone think of a better way?

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.

    Altoids tins work great for homebrew RF filters and attenuators

    https://crcomp.net/altoidsmixer/index.php

    And, if the Altoids is too small, there's always a Bud box:

    https://crcomp.net/mixeramp/index.php

    Danke,

    --
    Don, KB7RPU, https://www.qsl.net/kb7rpu
    There was a young lady named Bright Whose speed was far faster than light;
    She set out one day In a relative way And returned on the previous night.

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  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sat Jul 23 10:49:30 2022
    On Sat, 23 Jul 2022 12:36:38 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spamme@not.com>
    wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >>> bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The
    film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >>> tedious job and not certain of removing every last scrap of film around the >>> lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.


    I've used those too, though I don't run antennas through the side of the
    can like that. ;)

    It was good enough to tune my low-jitter phemt triggered Colpitts
    oscillator. My office is 2 miles from Sutro Tower and I suspect that
    the topography focusses the 22 Mwatts of RF specifically at me. I
    could probably light an LED.





    I have one that I use for testing photoreceiver protos--four BNC F-F
    bulkhead adapters and probably six 10 nF ex-Soviet feedthrough caps >installed in the lid.

    They aren't as good as a clean (uncoated) paint can, though, and the RF >shielding effectiveness depends critically on both the tin and the lid >staying really circular. If they don't, you get slot antennas in the seal.

    Cheers

    Phil Hobbs

    --- SoupGate-Win32 v1.05
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  • From Mike Monett@21:1/5 to Phil Hobbs on Sat Jul 23 18:35:36 2022
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The film completely isolates the lid from the can and prevents any
    RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very tedious job and not certain of removing every last scrap of film
    around the lid.

    Can anyone think of a better way?

    Thanks,

    Mike


    A torch and some sandpaper.

    Cheers

    Phil Hobbs

    Thanks. I'll look for a fine wire brush.



    --
    MRM

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to All on Sat Jul 23 14:41:18 2022
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spamme@not.com>
    wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I >bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The >film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >tedious job and not certain of removing every last scrap of film around the >lid.

    Yeah. It's to allow a steel can to contain latex (water-based) paint.

    The coating may be something like PVC, so I'd try a methylene-chloride
    paint stripper, like "5f5" (unless the EPA has ruined that too).

    You may also be able to solder through the lining film.


    Can anyone think of a better way?

    Somebody must make paint cans for solvent-based lacquers, which cannot
    tolerate such coatings. Google. Yes, look on Amazon for "unlined"
    cans.


    Joe Gwinn

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  • From rbowman@21:1/5 to Mike Monett on Sat Jul 23 13:05:57 2022
    On 07/23/2022 09:38 AM, Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very tedious job and not certain of removing every last scrap of film around the lid.

    Can anyone think of a better way?

    Wire brush in a drill motor? I'm not the greatest safety advocate but
    where eye protection. In addition to the film wire brushes have a nasty
    habit of shedding wires.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Lasse Langwadt Christensen@21:1/5 to All on Sat Jul 23 14:09:39 2022
    lørdag den 23. juli 2022 kl. 18.23.39 UTC+2 skrev bitrex:
    On 7/23/2022 12:10 PM, jla...@highlandsniptechnology.com wrote:
    On Sat, 23 Jul 2022 15:38:48 -0000 (UTC), Mike Monett <spa...@not.com> wrote:

    Following Phill's superb suggestion to use a paint can for RFI shielding, I
    bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The
    film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very
    tedious job and not certain of removing every last scrap of film around the
    lid.

    Can anyone think of a better way?

    Thanks,

    Mike

    https://www.dropbox.com/s/30c6aesh4tzjg56/Z496_Can.jpg?raw-1

    The seal is pretty good, metal to metal. It's shallow, easy to work
    in. Solderable too.

    Cookies good.

    Altoids tins work great for homebrew RF filters and attenuators

    there's a smaller version, https://www.adafruit.com/product/16

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From wmartin@21:1/5 to rbowman on Sat Jul 23 15:00:17 2022
    On 7/23/22 12:05, rbowman wrote:
    On 07/23/2022 09:38 AM, Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I
    bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The
    film completely isolates the lid from the can and prevents any RFI
    shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very
    tedious job and not certain of removing every last scrap of film
    around the
    lid.

    Can anyone think of a better way?

    Wire brush in a drill motor? I'm not the greatest safety advocate but
    where eye protection. In addition to the film wire brushes have a nasty
    habit of shedding wires.



    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like
    a wire brush wheel.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Mike Monett@21:1/5 to Lasse Langwadt Christensen on Sat Jul 23 23:46:44 2022
    Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

    fsøndag den 24. juli 2022 kl. 00.00.24 UTC+2 skrev wmartin:

    [...]

    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like

    a wire brush wheel.

    it also removes metal which the wire wheel doesn't (unless you go crazy
    with it)

    That was my thought also. I have lots of sandpaper. It would take a pretty coarse grit to remove the film, and it would take the metal also. But a touch with a wire wheel should do the job.

    Old wire wheels are more likely to shed wires, but new ones are pretty safe. I will use them in an electric drill where I can control the speed and direction. It will never reach the speeds and forces required to shed wires.

    I have a bunch of wheels on order that should arrive Monday.

    I looked at cookie jars. They a are horrible expensive (about $40), and most hve painted sides where the lid touches. Paint could be removed with paint remover, but that is a very toxic and messy operation the is best performed outside. I pass.




    --
    MRM

    --- SoupGate-Win32 v1.05
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  • From Lasse Langwadt Christensen@21:1/5 to All on Sat Jul 23 16:30:41 2022
    søndag den 24. juli 2022 kl. 00.00.24 UTC+2 skrev wmartin:
    On 7/23/22 12:05, rbowman wrote:
    On 07/23/2022 09:38 AM, Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I
    bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The
    film completely isolates the lid from the can and prevents any RFI
    shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very
    tedious job and not certain of removing every last scrap of film
    around the
    lid.

    Can anyone think of a better way?

    Wire brush in a drill motor? I'm not the greatest safety advocate but where eye protection. In addition to the film wire brushes have a nasty habit of shedding wires.



    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like
    a wire brush wheel.

    it also removes metal which the wire wheel doesn't (unless you go crazy with it)

    --- SoupGate-Win32 v1.05
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  • From Carl@21:1/5 to Mike Monett on Sat Jul 23 22:24:32 2022
    On 7/23/22 19:46, Mike Monett wrote:
    Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

    fsøndag den 24. juli 2022 kl. 00.00.24 UTC+2 skrev wmartin:

    [...]

    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like

    a wire brush wheel.

    it also removes metal which the wire wheel doesn't (unless you go crazy
    with it)

    That was my thought also. I have lots of sandpaper. It would take a pretty coarse grit to remove the film, and it would take the metal also. But a touch with a wire wheel should do the job.

    Old wire wheels are more likely to shed wires, but new ones are pretty safe. I
    will use them in an electric drill where I can control the speed and direction.
    It will never reach the speeds and forces required to shed wires.

    I have a bunch of wheels on order that should arrive Monday.

    I looked at cookie jars. They a are horrible expensive (about $40), and most hve painted sides where the lid touches. Paint could be removed with paint remover, but that is a very toxic and messy operation the is best performed outside. I pass.

    Go to amazon and search for galvanized garbage cans, may be too
    expensive but I spotted this one: https://www.amazon.com/All-States-Galvanized-Container-Gallon/dp/B085Q421RT
    Holds 6 gal so maybe too big.

    --
    Regards,
    Carl

    --- SoupGate-Win32 v1.05
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  • From rbowman@21:1/5 to Mike Monett on Sat Jul 23 22:06:22 2022
    On 07/23/2022 05:46 PM, Mike Monett wrote:
    Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

    fsøndag den 24. juli 2022 kl. 00.00.24 UTC+2 skrev wmartin:

    [...]

    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like

    a wire brush wheel.

    it also removes metal which the wire wheel doesn't (unless you go crazy
    with it)

    That was my thought also. I have lots of sandpaper. It would take a pretty coarse grit to remove the film, and it would take the metal also. But a touch with a wire wheel should do the job.

    Old wire wheels are more likely to shed wires, but new ones are pretty safe. I
    will use them in an electric drill where I can control the speed and direction.
    It will never reach the speeds and forces required to shed wires.

    I have a bunch of wheels on order that should arrive Monday.

    Too late to mention a brass wheel then :) Bring a magnet if you go
    shopping for one. There are a lot out there that are brass colored, to
    put it kindly.

    --- SoupGate-Win32 v1.05
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  • From Jasen Betts@21:1/5 to Mike Monett on Mon Jul 25 12:06:06 2022
    On 2022-07-23, Mike Monett <spamme@not.com> wrote:
    Following Phill's superb suggestion to use a paint can for RFI shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very tedious job and not certain of removing every last scrap of film around the lid.

    All that low VOC paint that rusts cans is to blame, they used to make
    them metal on metal.

    Can anyone think of a better way?

    Wire brush wheel driven by a suitable power tool.

    --
    Jasen.

    --- SoupGate-Win32 v1.05
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  • From Jasen Betts@21:1/5 to wmartin on Mon Jul 25 12:12:24 2022
    On 2022-07-23, wmartin <wwm@wwmartin.net> wrote:
    On 7/23/22 12:05, rbowman wrote:
    On 07/23/2022 09:38 AM, Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I
    bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The
    film completely isolates the lid from the can and prevents any RFI
    shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very
    tedious job and not certain of removing every last scrap of film
    around the
    lid.

    Can anyone think of a better way?

    Wire brush in a drill motor? I'm not the greatest safety advocate but
    where eye protection. In addition to the film wire brushes have a nasty
    habit of shedding wires.



    abrasive grit wheel, it sheds crud, but not skin-penetrating barbs like
    a wire brush wheel.

    yeah, but they eat metal better than they eat plastic. wire brush is
    the other way round.


    --
    Jasen.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jasen Betts@21:1/5 to rbowman on Mon Jul 25 12:11:11 2022
    On 2022-07-23, rbowman <bowman@montana.com> wrote:
    On 07/23/2022 09:38 AM, Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI shielding, I >> bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the lid. The >> film completely isolates the lid from the can and prevents any RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a very >> tedious job and not certain of removing every last scrap of film around the >> lid.

    Can anyone think of a better way?

    Wire brush in a drill motor? I'm not the greatest safety advocate but
    where eye protection. In addition to the film wire brushes have a nasty
    habit of shedding wires.

    Wear full face protection, else you may wind up picking a few stray
    metal bristles out of your face.

    --
    Jasen.

    --- SoupGate-Win32 v1.05
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  • From John S@21:1/5 to Mike Monett on Thu Jul 28 18:34:07 2022
    On 7/23/2022 2:35 PM, Mike Monett wrote:
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The film completely isolates the lid from the can and prevents any
    RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very tedious job and not certain of removing every last scrap of film
    around the lid.

    Can anyone think of a better way?

    Thanks,

    Mike


    A torch and some sandpaper.

    Cheers

    Phil Hobbs

    Thanks. I'll look for a fine wire brush.


    But don't breathe the smoke.

    --- SoupGate-Win32 v1.05
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  • From amdx@21:1/5 to John S on Fri Jul 29 12:32:45 2022
    On 7/28/2022 5:34 PM, John S wrote:
    On 7/23/2022 2:35 PM, Mike Monett wrote:
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Mike Monett wrote:
    Following Phill's superb suggestion to use a paint can for RFI
    shielding, I bought two - one from Amazon and one from Home Hardware.

    Unfortunately, both of them have a gray film lining the can and the
    lid. The film completely isolates the lid from the can and prevents
    any
    RFI shielding.

    The film is tough but thin. It can be scraped off, but this will be a
    very tedious job and not certain of removing every last scrap of film
    around the lid.

    Can anyone think of a better way?

    Thanks,

    Mike


    A torch and some sandpaper.

    Cheers

    Phil Hobbs

    Thanks. I'll look for a fine wire brush.


    But don't breathe the smoke.

    Seems like it would be wise to just make a few phone calls and get what
    you need. I would call automotive paint suppliers.

    --
    This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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