Stokes' ProjBlog

Almost there… January 23, 2008

Motor Controller Board toner transfer attempt #3: partial success.

Going back to the magazine pages improved things immensely. The paper adhered tightly, and as can be seen in the image below, the majority of the toner transferred successfully.

Despite this being much better than the previous attempt, however, the board is still unusable.

There are a few spots that didn’t come out, but those aren’t anything that couldn’t be touched up with a etch-resist Sharpie. The fuzziness across all of the toner is just paper fiber stuck to the toner; only the obvious large spots are actually bare copper. However, note the traces for the header, centered on the left edge of the board. The missing traces can be drawn back in with the Sharpie, but the smudged portions are a significant problem.

I’m not sure what, specifically, caused the smudging and bleeding. The paper was secured to the board so it is unlikely that it moved during the ironing. The most probable cause is either ironing for too long or using too much pressure. The various how-to articles on the web differ greatly when it comes to the amount of pressure to use: some advocate crushing force, while others say to use no more than the weight of the iron itself. I went with the first approach, and I probably spent more time than necessary (several minutes total).

The fact that the smudging is primarily on the outer edge is actually encouraging. Since the outer edges were the least transferred in the first attempts, I put extra time and pressure into them. For try #4, using my last fresh piece of copper-clad board, I’ll try a lighter, faster approach.