PCB made out of acrylic ?!?

[Borisw37]

Hello everybody.
Does anybody know how (if at all possible) to make a simple PCB on acrylic. I basically need to somehow apply a layer of copper to a sheet of acrylic, then etch it.<p>Any ideas?<p>Thank you,<p>Boris

[Enzo]

How is that going to hold up to the heat of soldering I wonder?

[Borisw37]

I figured if i solder carefully and heat up just enough for solder to melt, acrylic is not going to be damaged, or very very little at that precise point (under neath the trace)...
Maybe I can find some lo-heat solder.<p>[ April 06, 2005: Message edited by: Borisw37 ]</p>

[jwax]

Copper foil and double-sided carpet tape. Press.

[Chris Smith]

You can super glue the foil to the plastic but two bad things any acrylics brings to the table. <p>One is poor heat quality, the second is static charge.<p>Both can be fatal to your design if its imporatnt?

[haklesup]

Is your aim to use a photo-lithographic process to pattern the board or are you open to other interconnect methods?<p>Perhaps you are not making a PCB? Some kind of artistic thing?<p>For a PCB Forget the foil traces and go with point to point wiring using #30 wire wrap wire adhered to the surface with spray contact adhesive.<p>Copper foil tape with pressure sensitive adhesive is available in rolls of varying width.<p>Aluminium foil should conduct adequately well if the traces are wide. It can be attached with spray adhesive also or rubber cement or contact cement. Heck, given the low temp melting point of acrylic, a little glue shouldn't slow you down. You can pattern it with an exacto knife.<p>What do they use to stick gold leaf (which would also work great if not for the excessive price) Gutta Percha?<p>For photolithography you need to make a thin film so you don't have to etch too long and damage the mask and you need a uniform thickness so you don't overetch one area more than another.<p>You can coat most any material with gold, carbon and presumably most any metal using a sputter coating or vapor deposition system. These basically place the object in a vacuum and either bombard a metal target with electrons or create a plasma to get the metal atoms in a gasious state, they then condensce onto the sample surface. This process is routinely used to put the metal traces onto silicon wafers when making IC chips. It is also used by SEM (electron microscope) operators to put a thin conductive film over samples before microscopy (prevents static buildup on sample which blinds the detector)<p>You can probably find a Job Shop type vendor in your area to "flash" the surface with a layer of copper. Expect to be charged by the lot not the piece. A PCB fab (best bet) house may also be able to put copper onto the substrate for you but also at considerable setup charge plus lot pricing.

[sofaspud]

The question is begged. Why do you *need* to apply the copper onto acrylic?

[bridgen]

"I figured if i solder carefully and heat up just enough for solder to melt, acrylic is not going to be damaged, ... "<p>That may be true.
However, that isn't the way to solder. <p>The joint should be heated sufficiently for it (not the iron itself) to melt the solder. <p>Doing it the way you propose is a recipe for a "cold-soldered" joint. <p>Acrylic is simply not suitable.

[Mike]

That would be a pretty neat idea if it worked, though. In fact, acrillic in electronics is pretty neat for anything. Acrylic is pretty heat resistant. The subwoofer on my stereo that I built out of acrylic (http://www.electronet.dyndns.org/electr ... ctures.htm) and the heatsink gets VERY hot when it's cranked (so always ) and the acrylic has yet to show any signs of melting or discoloring. It also handles a lot of weight and shaking with no problems.<p>There was a product I read about back when Poptronics existed about this product that was a sheet of copper about the thickness of paper that you put in a laser printer and it printed the PCB layout directly onto it, glued it to a PCB and etched it. I don't know if the product still exists and if they still make it, but if they do, you may be able to do that and glue it onto the acrylic. But when you etch it do not use ferric chloride, since it will discolor the acrylic. Instead, use ammonium persulphate.

[Mike]

oh, don't listen to the aluminum foil idea. Solder does NOT stick to aluminum without flux, and even then the connection is very weak and can break easily.<p>If they still make that copper sheet it would be perfect.

[Borisw37]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by haklesup:
Is your aim to use a photo-lithographic process to pattern the board or are you open to other interconnect methods?<p>Perhaps you are not making a PCB? Some kind of artistic thing?
<hr></blockquote><p>I am trying to make a acrylic panel with a grid of surface mount LEDs. I dont think 30gauge wires will look as good as nice thin traces.

[rshayes]

I believe that adhesive backed copper tape is sold for shielding purposes. The tape might be too thick to etch easily.<p>Aluminum tape with adhesive backing is sold in building supply stores. I believe that it was used to seal joints in sheet metal heating and air conditioning ducts. This might be etchable with some other chemical than ferric chloride. Or the thickness might be too great for good results.<p>One way around the heat problem would be to use conductive epoxy to make the connections. This might not work with aluminum since it forms an oxide layer very quickly in air.<p>There are also lower melting point solders available than the normal lead-tin solder. It might be possible to use Wood's metal as a solder. This will melt in hot water so there should be no damage to the acrylic support. A hot air gun might be better for this than a soldering iron.<p>Copper wire is still a possibility. Somewhere around number 36 it gets pretty hard to see without magnification. Getting the insulation off of enameled wire this fine can be a problem. Bare copper wire might work.

[Engineer1138]

Does it HAVE to be acrylic? How about a higher temperature-capable transparent material, e.g., glass?<p>Wonder if you can get clear Teflon?

[haklesup]

It sounds like your choice of Acrylic is more asthetic than functional (as a PCB substrate that is, it is quite functional as a structural element). I might now suggest fake traces backed up with the fine wire for interconnect.<p>For example, you could use copper colored spray paint to put down a pattern then lay your wires directly on top of those opaque copper colored lines. do all soldering off of the substrate and use super glue (tac-pak) to stick everything down. An observer looking through the acrylic would only see the painted traces and the LEDs you mounted.<p>Making a mask could be laborious because I can't think of a resist/etch combination that would work with paint for a photolithographic process. I imagine you would have to cut the pattern in acetate or cardboard and use that as a stencil.<p>The last comment reminded me that silkscreening with conductive ink is another possibility for patterning. If it worked well, making copies would be easier than not. Not sure exactly what ink would work best.<p>Maybe Aluminum isn't very compatible with lead tin solder but it does make a fairly good mechanical connection that can be glued to make permenant (wrap Al around lead and tak in place on substrate). All depends on your requirement for reliability and enviornemental stress.

[peter-f]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Mike:
[QB]That would be a pretty neat idea if it worked, though. In fact, acrillic in electronics is pretty neat for anything. Acrylic is pretty heat resistant. The subwoofer on my stereo that I built out of acrylic (http://www.electronet.dyndns.org/electr ... ctures.htm) and the heatsink gets VERY hot when it's cranked (so always ) and the acrylic has yet to show any signs of melting or discoloring. It also handles a lot of weight and shaking with no problems.<p><hr></blockquote><p>
Are you SURE that's acrylic?<p>There are other plastics that closely resemble it and are much more heat resistant.. also much more pricey.<p>Still, I doubt anything other than industrial manufacturing methods can solder on an acrylic or polycarbonate substrate without scorching.