Polycarbonate as an encosure material

Frequent question about finishing your stompbox: painting, etching, clearcoating, lettering, etc...

Polycarbonate as an encosure material

Postby ZONGONGO » 02 Jul 2012, 23:41

Greetings everyone and anyone !
I was considering a clear polyycarbonate, (LEXAN) enclosure for a circuit, but was warned of grounding problems and RF interference.
Does anyone have more insight on this and insight on possible remedies.
The idea is to see the circuitry. I'd like to avoid lining the interior with metal tape.

Thanks to anyone and everyone that responds to my question !
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Re: Polycarbonate as an encosure material

Postby jmraney317 » 03 Jul 2012, 00:58

Lexan wouldn't be my first choice for an enclosure, but it can be done. Some things you'll want to keep in mind:

The input and output jacks aren't going to be able to ground through the case, so pay attention to proper grounding techniques. The same applies to the metal cases on the potentiometers. Those are hard to solder to; best practice there would be to carefully bend the little tabs that hold the backs on the pots off, remove them, use a heavy-duty iron to solder a grounding wire on, then reattach. Kind of like brain surgery...

Also, it might be wise to consider using a sheet of blank copper-clad board under the solder side of the board. It needs to be grounded, and not touching the bottom of the board. This should provide some shielding, without compromising the visual appearance of the enclosure.
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Re: Polycarbonate as an encosure material

Postby ZONGONGO » 03 Jul 2012, 02:06

Thanks for the great insight, jmraney317. As a novice, I'm not sure I can claim to have common sense, Grounding can't just be overlooked.

I think the visual aspect of a plate below the PCB may be a necessary compromise. ??
I would appreciate keeping the subject open. Thanks again !
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Re: Polycarbonate as an encosure material

Postby Nocentelli » 03 Jul 2012, 13:56

You could investigate incorporating ferrite beads and small value capacitors (100p?) to ground at the input and output, like on the EHX nano LPB-1 and Muff overdrive: They both have a metal case but it is not grounded:

viewtopic.php?f=1&t=13013&hilit=ferrite+beads
viewtopic.php?f=1&t=15969
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Re: Polycarbonate as an encosure material

Postby Ice-9 » 13 Jul 2012, 16:55

If you are having a footswitch there could be problems with the durability of the enclosure as plastic enclosures are not that sturdy, I doubt it will survive very long with a size 9 boot stomping on it.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?
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Re: Polycarbonate as an encosure material

Postby ZONGONGO » 13 Jul 2012, 17:21

To Ice 9
Thanks for the concern and the heads up !
Polycarbonate is exceptionally strong. I have experience working with LEXAN and believe me, a pedal shape at 3/16" thickness will take multiple blows with a 22 oz. framing hammer and survive. It's what they make bulletproof glass with. I have no worry in that regard. I would say it's bulletproof in every sense of the term but the literal ! (3/16" wont stop a bullet).
Thanks again for the input !!!!!!
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Re: Polycarbonate as an encosure material

Postby Prostheta » 14 Jul 2012, 08:57

If you have some fine copper mesh it is feasible to build a Faraday cage inside the case using scissors and insulating tape to stop the seams conducting. One for the pedantic only, perhaps.
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Re: Polycarbonate as an encosure material

Postby ZONGONGO » 14 Jul 2012, 13:08

To Prostheta;
I don't know what a Faraday Cage is But I can look that up.
Could you elaborate ? I'm not sure What you mean when you refer to the seams conducting ?? .
Thank you for the feedback !
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Re: Polycarbonate as an encosure material

Postby Prostheta » 14 Jul 2012, 13:56

Okay, well I'll do my best. Google'em!

A Faraday cage is an electrically conductive shield, although this is a very blunt and imprecise explanation. A specific example I can think of is an active EMG pickup as the coils are encased within a simple copper mesh shield. The insulated edges part is so it acts more like a star ground with one common location (or area I guess) connected to ground. Probably not too important. I made a bunch of in-instrument pre-amps where I used a simple "C" of copper mesh connected to ground at the front, curled under the PCB, over the back and over the top and then inserted into a deep potting box. Very quiet little device.

The cage that performers reside within when playing with Tesla coils is also a Faraday cage. Just in case you think your pedal will be subject to noise, struck by lightning or a massive discharge from a resonant transformer circuit. :D
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Re: Polycarbonate as an encosure material

Postby ZONGONGO » 15 Jul 2012, 23:44

Thanks Prostheta !
I'll do a little research. Perhaps the Faraday cage will be an interesting addition to the visual aspect of a pedal in polycarbonate, if it proves necessary.
Thanks for your interest in answering my noob questions !!
Cheers !
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Re: Polycarbonate as an encosure material

Postby Prostheta » 16 Jul 2012, 08:41

I'm no expert! Just concerned that shielding (or the lack of it) will make polycarbonate a difficult choice.
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:21

ZONGONGO wrote:Greetings everyone and anyone !
I was considering a clear polyycarbonate, (LEXAN) enclosure for a circuit, but was warned of grounding problems and RF interference.
Does anyone have more insight on this and insight on possible remedies.
The idea is to see the circuitry. I'd like to avoid lining the interior with metal tape.

Thanks to anyone and everyone that responds to my question !



I made a HM2 and HM3 seriusly plexiglas or policarbonalte, youo choose, 2mm thickness; and melt with clorophorm; is great!!! i´m from PERÚ and it is easy to do, cutting and melted!!!

Here is the pictures I demostrate that I´m writting here, no hummmm no noise no anithing!!!
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:25

As you see these are great; I will copy all pedals enclosures atmy personal constructions and sizes; these pedal copy of BOSS is 1cm more at all sizes.

here is wen I prepare to paint it:
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:32

The electronics is other cuestion, it may to be exactly you calculate, the freespace is critical, maximun space internal and other complements, the pots is limiting, in PERÚ no 9mm pots; is the 16mm korean pots. This limits you enclosure so big!

here is the photos of the enclosure plus pedal electronics:
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:41

If you waná do this, I strongly recomended to sand first to paint it.

I used a paint wather acrilyc based paint it is easy to do, to buy in all the world you find it in bricolage stores to paint in wood!! I prove then to paint in plastic, in metal and it is great!!!, usd by hand painting or using AIR BRUSH is great.

First I made hand painting to cover all the enclosure, then the air brush paint total 6 covers tree days total!!

Here is the product only painting; BLACK in the out; aluminium based internal; finaly The adhesive mask and my mark on it GodSaveMetal:
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:46

If you love to see this, I have a mirror finish with a resin in the external and internal it is great.

Here is the finish:
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 04 Nov 2013, 23:55

AND for finally the brothers jointed!!! HM-2 plus HM-3:
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Re: Polycarbonate as an encosure material

Postby ZONGONGO » 05 Nov 2013, 00:19

Awesome job. very cleanly done. I'm impressed !
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Re: Polycarbonate as an encosure material

Postby GodSaveMetal » 05 Nov 2013, 01:46

ZONGONGO wrote:Awesome job. very cleanly done. I'm impressed !


If you waná do Cum´un!!!!! do it!!!!!!!!!!
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