Sample circuit boards
The following are pictures of printed circuit boards showing the effects of tarnish:
This board was made in 1994. Etched, drilled sheared and trimmed and resist removed. Notice no tarnish after sitting in a damp basement for eight years.
The above board was made in 1970! Before I laid out boards with pads and tape. A resist pen was used to draw the desired track. The paint that came out of the large ballpoint "toothpaste type" tube was red and flowed like enamel paint. It dried within minutes and resisted etchant. It was removed with paint thinner after etching. Notice that after 32 years in an outdoor storage building, tarnish is not that bad. Solder will flow right to the copper.
The board above was an early experiment using tape and pads. Probably 1973 vintage. Notice I used a pair of tin snips (metal shears) and nibblers to cut the board. Very little tarnish noted.
These boards are all surplus boards I pulled out of an old box. All were laid out and fabricated by myself. Still bright and shiny. From this angle some reflections in the image shot may look like tarnish but it is not the case.
This board is a functioning board put in service in 1985. It was laid out using a program called SmartWork by Wintek. No tarnish!
A PIC 16F84 demo board with port A I/O, port B I/O or led and
Board was made Jan 2002 and still shines like a new penny
This board is over 10 years old and no tarnish.
A finished audio product! I happen to run into a company that was closing up shop and had a couple hundred brand new chassis and covers that I was able to purchase for about $30.00 for the whole lot. I now have dozens of projects in them and now have a good chassis for PIC circuits too. Note the only "wire" is the chassis ground to the chassis itself.