For years I have been using the toner transfer method for making circuit boards. I have an old Brother printer and a Scotch TL902 laminator that have worked well for this. One of the problems I have found with this method is that the type of toner you use is very important. If I use real Brother toner, I get very good results for most of my boards. I have tried using generic toner cartridges that are about 1/3 the price, but have not been able to get very good results. Another problem is with large ground plane areas, I have had problems with etch through, and pin-holes showing up in these areas.
I recently saw a post on Instructables about using a chemical method instead of heat to transfer the toner to the circuit board material.
Since my Brother toner cartridge was just about out and I would have to order a new one fairly soon, I decided to give it a try.
Looking around all my painting supplies, for solvents I found a can of denatured alcohol. The original article used Acetone , which I did not have, but I had some Xylene I had used for thinning and cleaning up some enamel I had painted.
I printed up several copies of a board I need to etch using the generic toner cartridge. Playing around with different mixtures of denatured alcohol and Xylene. I found that a 5 to one 1 mix of alcohol to Xylene would soften the toner without causing it to smear instantly. I tried the method as shown in the video with fairly good success, and then tried to modify the method a little. Here is what I came up with.
With an eye-dropper I put enough of the mixture on a cleaned board to evenly cover the board. Then place the printed paper on the board and moved it around to position it properly on the board.
After it was positioned on the board, I used the eye-dropper to saturate the paper with more of the mixture. You could see the paper becoming more transparent and clearly see the toner pattern.
I let this set for about 30 seconds, and then covered with a folded over paper towel. I then placed another piece of circuit board material on top of the paper towel and applied pressure for about 2 minutes. After that time I removed the top board, and used the rounded back of a fork to burnish, through the paper towel. After it looked like much of the mixture had dried, I removed the paper towel and burnished the laser paper directly. You could clearly see the toner pattern through the paper. After a couple of minutes of that, I left everything set for a couple of minutes for the last of the mixture to dry.
After it was dry, I soaked the board in water for a couple of minutes, and removed the paper by lightly rubbing with my fingers.
The toner on the board looked nice and crisp, good adhesion all over, and no sign of smearing. After etching the board, I found very nice traces, no problems where traces went between IC pins.
Also found nice smooth ground plane areas, with no etch through, or pin-holes.
Looks like I will be able to save a lot of money on toner, and finally retire the laminator. Probably only used about a half a teaspoon of the mixture, so the remainder of the quart cans of alcohol and Xylene I had around should last a very long time.
Just a couple of pictures of the boards done with this method.
The completed board, and a close up showing the sharpness of the etching , and nice solid ground plane area without pin-holes.
Now to get to doing something with these boards.