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Step 2Clean the Copper and Apply the Resist for the Circuit Pattern
There are lots of Instructables about how to apply the circuit pattern onto your copper, including peel and press, photo paper, tape, photo-sensitive emulsions, and even Sharpie pen. I will not touch on that part of the process here, but the method I prefer to use is laser printing onto a piece of Pulsar's dextrin paper and using one of their $70 personal laminators to apply the toner to the board. Then you rinse the paper and PCB under water and the paper slides right off, leaving the toner stuck fast to the board.
The key to any method of applying the resist is to make sure your copper circuit board is absolutely clean. I use a Scotch Brite pad and some dish detergent to scrub the copper clean, as shown in the first photo. Then I blot it with paper towel and let it completely dry. Never touch the cleaned copper, because oil from your fingers will cause the resist to not adhere to the copper, and the resist will come off during the etching process.
If you want to play with this Instructable right now and you don't want to make an actual circuit, just use a Sharpie pen to draw a little squiggle onto your cleaned copper circuit board.
In this case, I laser printed the Instructables robot onto Pulsar paper and applied it to the clean copper board with a laminator. Hey, it came out pretty good!
The key to any method of applying the resist is to make sure your copper circuit board is absolutely clean. I use a Scotch Brite pad and some dish detergent to scrub the copper clean, as shown in the first photo. Then I blot it with paper towel and let it completely dry. Never touch the cleaned copper, because oil from your fingers will cause the resist to not adhere to the copper, and the resist will come off during the etching process.
If you want to play with this Instructable right now and you don't want to make an actual circuit, just use a Sharpie pen to draw a little squiggle onto your cleaned copper circuit board.
In this case, I laser printed the Instructables robot onto Pulsar paper and applied it to the clean copper board with a laminator. Hey, it came out pretty good!
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Hi Asteidl...
That's great! I'm going to need to look for a new printer as I have switched to using Macintosh computers about 2 years ago, but the HP 1100 laser printer I have is parallel port, and although I have a wifi print server for it, there aren;t any drivers for the Mac for that printer that I can get to work.
I went to Staples and used the HP multi-purpose printers to make copies of a circuit board image, and I will try to put these samples through the laminator heat roller press to see how well the toner transfers to a PCB board.
I like this printer because it lays down a very thick coat of toner.
Bad thing about this printer is it is parallel port only, and not many computers have those anymore. So you'll need a wifi or Ethernet print server or a USB adapter of some sort. At home, we use a wifi parallel print server I bought on eBay so we can all print to it and it works perfectly. I'm not sure what the modern version of an HP 1100 is that has a USB port.
There is also a program called "LJConfig" that lets you set the toner density and a bunch of other stuff on most HP laser printers. You can even use it to change the idle display message to something more interesting like "KILL THEM ALL" and then change it back after your coworker sees it and reports it to the boss. Check out this page on PulsarFX's web site for more laser printer information and a link to the "LJConfig" program: http://bit.ly/aQQ8t6
You can use acetone or finger nail polish remover, or Zippo liquid lighter fluid (also known as naphthalene and white camp stove gasoline...not BBQ charcoal lighter liquid). Just pour a little bit on a rag and wipe off the sharpie marks.
I was having tons of trouble with the dextrin paper. If I failed to get a good transfer the first time, the copper was super hard to clean good enough. After some experimenting I found a process that works most of the time.
Clean the PCB with acetone.
Clean the pcb with a soft sponge and class cooktop cleaner.
Rinse well and clean with white vinegar.
Rinse well and clean with dish soap.
Then I replaced the dextrin paper with "Reynolds Brand Genuine Parchment Paper" (kitchen supply stuff)! I used double sticky tape to put it on top of regular paper for the trip through my laserjet. (YMMV with double stick tape in the guts of a printer! You can easily cut it into big enough sheets not to need that if you worry.)
Toner sticks well enough to the parchment paper, but just barely. One pass through the laminator and the traces were fused perfectly and no need for the soaking. Due to the transparency of the parchment paper lining up double sided boards is easy in any light. The biggest problem is that the board doesn't stick to the paper even a little so you need to be careful when feeding it into the laminator that it does not shift. An iron would probably not work if the paper shifted under it at all.
Hi Dustin...
Wow, that's a great idea! I use parchment paper all the time at home for cooking candies and breads, and I never thought of using it for this purpose!
Thanks!
You can certainly try it though! It might be good enough.
The way I did these boards was with the toner transfer method. They way you do this is as follows:
o Design your circuit and print it backwards with a laser printer onto photo ink jet paper or special paper made by PulsarFX (http://www.pulsarprofx.com/pcbfx/main_site/pages/products/transfer_paper/transfer_paper.html)
o Place the printout face down onto super cleaned scrubbed copper clad PC board
o Use a clothes iron or laminator to heat the printout and the board, and the toner will be remelted and will stick to the copper board
o Put the paper and copper board under warm water and allow the paper to soften (if you are using dextrin coated paper, it will slip right off). This step will leave the only toner on your copper board with no paper.
o Now you can etch the board with ferric chloride or peroxide/hydrochloric acid etchant.
I plan to write up this article as an Instructable sometime.
Good luck!