Eric Sorensen

Step Three: Toner transfer

You are nearly ready to etch the board. Unfortunately, copper clad comes in a slightly oxidized state so that when you look at it it’ll appear dark and flat, not reflective. Before you attempt to transfer the toner to the board, you’ll have to thoroughly clean it. Clean the copper clad with something slightly abrasive- I use either high grit sandpaper (~1000 grit or more) or preferably a scouring pad from the kitchen. The point is to get the board clean and shiny so that it will accept the toner. Any section of board still oxidized will not adhere properly, so it is imperitive that the board is VERY clean before your proceed.

After cleaning the copper you will transfer the toner from the paper to the copper. This creates a negative mask that prevents certain areas of the board from being etched away. Get some tape, an iron, and an ironing board. Use a small piece of tape to align your cardstock face down over your copper board at one corner. If you need to cut the copper clad to size, (very) heavy shears or a paper cutter work well. Set the iron to the highest temperature possible and turn off any of the steam and moisture settings. Start with the corner opposite of the taped one and slowly work your way across the cardstock. As you apply heat and pressure to the cardstock it should adhere to board. After the majority of the carstock is adhered, you can remove the tape and apply heat and pressure to the final corner. Once you have worked your way accrosss the entire surface of the cardstock with the iron, do it again. Then place the iron over the entire surface of the board and press firmly for thirty seconds. Take the iron off of the board, let it cool down a bit then repeat for thirty more seconds- pressing down HARD. At this point you can’t have too much heat and pressure. I spend about five minutes pressing HARD against the board with my iron to make sure every trace has had a chance to fully adhere.

Now throw the board into some warm water for about five minutes. This gives the paper a chance to soften up so you can easily peel it off. Once the paper has soaked, do not be afraid to rub the paper off the board with your thumb- at this point the toner should be firmly adhered to the copper. Pay special attention to the drill holes on the pads because its easy to miss the bits of paper surrounded by toner.

When you are done the board should look something like this. Take it out of the water and dry it off. If you notice any imperfections you can try to fix them with a sharpie by dabbing it against the surface of the copper. I’ve found this doesn’t work particularly well, so if there are significant traces missing or damaged I suggest starting over with one of the extra copies you made at Kinkos.

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