Problems in Silk Screening.

1. Kissing. This would be easier on a vacuum table.
2. There were multiple places where the screen got clogged. This might have been from hard spots in the asphaltum.

Etching

1. Etchant was intended to be mixed at 45 grams etchant to 100 grams water. For the 30 205x305mm boards I mixed 1.5 pounds of etchant to 1500 ml of water.  This was 47.6 % roughly oops.
2. The intial etch was 20 (10+10) minutes. It seemed over done with some areas under the edges etched away. However, this was also the thinnest print so it is hard to know.
3. The etching was done on my agitator,, a rocker. The container was rotated 180˚ after half the etch because the action of the agitator is not even. Centers etched slower. The fact that the ends of the board finished soonest points to the idea that the first board was not printed thick enough rather than being over etched.
4. When successful etching times increased to 30 minutes I added about 250ml of concentrated muriatic acid to the bath. This would bring the etching time down to 24 minutes. I did this three times.
5. Each morning a few tablespoons of alcohol were added to decrease the amount of etching that was clinging to the asphaltum after the boards were removed to keep from wasting etchant. It seemed to work well.
6. After the first few I started prepping board by lightly brushing etchant onto the slowest parts of the board keeping two boards going through this process as one was being etched.
7. Another board etching failure seems to have resulted from brushing the center of the board. The margins of the asphaltum were eaten under.
8. several boards had areas where either the  printing was incomplete or damaged. These were repaired before etching with Zim Opaque Pen. This came off in the etchant about half way through. 
9. final etching time was about 40 minutes. I decided to let the etchant wear out further so that there would be less to neutralize to recover the iron and copper.

Cleaning

1. A mixture of about 4 -8 parts  Klean Strip 1-Gallon Odorless Mineral Spirit Substitute   was mixed with vegetable oil. This mix was much better for the initial strip than the mineral spirits substitute by itself. It appears that Klean Strip has either removed the word Substitute from the name or stores have stopped selling this product.
2. I also tried some water based paint remover. It was not very good by itself but was functional as a secondary cleaner. It was less than optimal there too. It did seem to leave the copper without much oxidation. But given that I intended to soft scrub the copper before plating this was of little import.
3. A secondary wipe down with the mineral spirit substitute worked better than other things I tried.
4. Most of the boards were cleaned by pouring a Teaspoon onto the board and spreading it around. Then using a saturated rag often quite full of asphaltum, and light scrubbing. After that a wipe down with a cleaner rag and then used paper towel, then newish paper towel.