Wizard's Press-N-Peel Guide

The two most efficient ways of making your own PCBs at home are the Toner Transfer Method & 
Photo Resist Method. The method I use is the Toner Transfer Method and I will describe below 
the steps I use in making a PCB. If you would like more information on the Photo Resist 
Method please visit www.dssunderground.com and check out the DSS Hardware Forum. Use the 
search function and you will find information on the subject from people who use that method. 



BLANK PCB MATERIAL 

The cheapest place I have found to purchase blank boards is All Electronics 
(www.allelectronics.com) The materials can be found under the PC Materials category 
or you can put 'copper clad' in the search window. They also sell the Techniks toner transfer 
paper. (please see the info on Techniks below) 

Unfortunately All Electronics does not have the 1/32" material needed for the IRD Interface 
and AVR305 designs. I purchase this from Digikey (www.digikey.com) Again put 'copper clad' 
in the search window. Make sure to get the 1 OZ copper boards. 



TONER TRANSFER PAPER 

The brand I use is from Techniks (www.techniks.com) I have tried a couple other brands and 
did not get very good results. Techniks makes two versions of their Press-N-Peel paper, 
Blue & Wet. Make sure you get the Blue version. To be honest I don't have a clue why 
they even sell the Wet version. If you check out their web site they have links to venders 
that sell their products. Please note that I have not purchased the Techniks paper from 
All Electronics so you need to verify that the version they sell is in fact the Blue version. 



ENCHANT 

There are three types of enchant that I am aware of. 

Ferric Chloride - A brown liquid that is capable of staining air. You can get this at 
Radio Shack by itself or in a starter kit. This works just fine but again the major drawback 
is it will stain anything it comes in contact with. 

Sodium per Sulfate - This usually comes in powder form and is mixed with water. There is also 
a catalyst that is required. 

Ammonium per Sulfate - This also usually comes in powder form and is mixed with water but 
does not require a catalyst. 


The two 'per sulfate' types are the ones that I have used. These are the ones that PCB 
manufacturers use. It has been a long time since I purchased any enchant so I am afraid I 
do not know the best place to purchase them. Just use your favorite search engine and look 
for them. 


All enchants work better when they are warmed to ~ 100 Deg F. I usually run hot water in the 
kitchen sink and put the container with the enchant in that. Another trick is in the summer, 
place the container with the enchant out in the sun for a while before you start. 



PREPARING THE PCB 

The first thing you need to do is cut the board to the size you need. In the case of the 
IRD Interface and AVR305 boards I make them a little big and then trim them to size after 
the board is etched. The reason for doing this is because the pads that come in contact with 
the smart card connector pins must be in the correct spot. By making the board a little big 
it can be trimmed so it fits perfectly in the smart card socket with the pads in the proper 
place. Unless you are lucky and have access to a shear you can use a utility knife to score 
the board until it is thin enough to snap apart. This will leave a rough edge on the board 
so you must either file or sand the board to get rid of these edges. 

Once the board is cut to size you need to clean it. While running water over the board, use 
a Scotchbrite pad to scrub the board until it is completely clean. 

IMPORTANT: From this point on NEVER touch the copper on the boards. Hold the boards by the 
edges or with a paper towel. Finger prints on the board will cause both the toner to not 
stick to the board AND keep the enchant from etching away the copper where it is supposed to. 

Use paper towels to dry the board. Again remember to keep your grubby finger prints off the board. 



APPLYING THE TONER PATTERN TO THE PCB 

Please read the instructions that come with the Techniks toner transfer paper. 
Here is how everything is stacked up so to speak: 

1. Place a piece of particle board on the counter to protect it from getting to hot. 
2. Place a paper towel on top of the particle board. 
3. Place the cleaned, blank PCB on the paper towel. 
4. Place the toner transfer paper with the PCB design on the PCB. 
5. Place another paper towel over everything. Be sure you do not move the toner transfer paper 
while doing this. 
6. Carefully place the iron on the board and follow the directions supplied by Techniks. 
Apply a lot of pressure as this seems to help. 



TOUCHING UP THE PCB 

After the paper has been removed, check the PCB to see if there are any places that the toner 
did not stick properly. If there are any use a Sharpie permanent marker (the big one) to fill 
in the bad spots. Let the ink dry and apply another coat. 



ETCHING THE PCB 

After you are sure that all the bad spots have been touched up, place the board in the enchant. 
Agitate the solution often / continuously until all the copper is removed from the board. 



CLEANING THE ETCHED PCB 

After the board has been etched, use either coarse steel wool or 220 grit sandpaper to remove 
the toner from the traces. Lacquer Thinner will work but it makes quite a mess. Only do this 
step when you are ready to solder the components to the board. It only takes a little while 
for the bare copper to oxidize which will make soldering more difficult and can cause cold 
solder joints. 



COVERING THE BARE COPPER TRACES 

If you are making the IRD Interface or AVR305 boards you must put a layer of solder on the 
pads that will contact the pins in the smart card socket. Put solder on the pads and then 
use solder wick to remove the excess solder. You can do this to the entire board to keep 
the traces from oxidizing. This works best with a flat tip for the soldering iron. A second 
option is to purchase a tin plating solution. When the PCB is placed in this solution a thin 
layer of tin is placed on the copper traces. And a third option is once the components are 
soldered to the board, the bottom can be sprayed with a conformal coating. Make sure to cover 
any areas that should not get covered with tape (ie - the iso pads) 


CONGRATULATIONS!!! 

wizard