Homebrew PCBs

Gentlemen,
Stefan asked for more information about my Roll Tinning Machine. I expect 
others may be interested.

I have loaded several pictures into the photo section.

To gauge the size of the machine the main roller is 300 mm x 100 mm cored 
steel. ( Steel pipe with a 10 mm wall thickness)

This roller sits in a bath of molten 60/40 solder. The bath is about 50 mm 
deep. A temperature probe is fixed in the bath just below the roller.

A 2000W element is mounted under the solder bath in contact with it. The 
bath is made of 6 mm steel.

There is a 12 mm piece of insulating board beneath the element.

The top roller is made of silicone rubber on a steel shaft.

To use the tinner the bath is heated up to 244 degrees C and the motor 
drive turned on. A fairly corrosive flux (radiator soldering flux) is 
floated on top of the solder on the back side of the roller. Once the 
roller has been rotating for several minutes the solder will flow evenly 
over the roller.

When this happens the rubber roller is screwed down to the surface of the 
solder roller.

The printed circuit boards are cleaned with a tarnish remover and dipped in 
a water soluble flux.

The board is then fed through the roller from the front.

If the board is double sided it is dipped in the flux again and put through 
the rollers again upside down.

This process gives a very clean solder layer over all the tracks.

David