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

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

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.

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

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

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.

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

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

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

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.

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

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.

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)

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

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

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.

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.

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.

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.

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.

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