CircuitWorks Conductive Pens

A trace drawn with the conductive ink will combine with solder, provided the soldering temperature does not exceed 350°F (177°C) and the solder joint is formed within 5 seconds. If the drawn trace must be soldered to, we recommended that tin/lead solder containing 2% silver be used and that the trace is heat-cured at 150°F (66°C) for five minutes to produce the most durable trace possible.

For optimal adhesion to most surfaces, clean the repair area prior to ink application. That insures the surface is free of oil, greases and handling soils. For precise cleaning just around the rework area, Chemtronics offers CircuitWorks Flux Remover Pens, which contain fast evaporating cleaning solvents. Chempad (#CP400) isopropyl alcohol (IPA) presaturated wipes and Chemswab (#CP25) IPA presaturated swabs are also well suited for surface prep.

If you experience difficulty in producing a smooth flow of conductive ink, this could indicate clogging of the product outflow channel within the tip assembly. As the pen sits in storage, especially if stored tip downward, the suspended silver particles will slowly settle and can clog the channel through which the product flows. To restore the pen to proper operation, it must be shaken vigorously, usually for two to three minutes. Shake the pen until you can hear the internal mixing bearing “clicking” or moving within the pen barrel. Once you have established movement of the mixing bearing, continue to shake the pen for another minute or so to completely re-suspend the silver particles within the polymer matrix, which will produce a smooth, homogenous product. If shaking the pen does not free the mixing bearing (you cannot hear it moving within the pen barrel) or the ink still refuses to flow when the pen tip is retracted, then the clogging within the tip assembly is more serious and will require a more rigorous cleaning to re-establish proper operation. Remove the cap and with the pen tip pointing up, grip the white base of the tip assembly gently but firmly and turn it to the right (clockwise-because the tip assembly is “reverse-threaded”). Remove the tip assembly and drop in into a small container of Flux-Off® Heavy Duty or another suitable solvent.  Let the tip soak for 30 minutes to one hour, with occasional shaking or swirling, to clear the internal spaces within the tip assembly. As dried polymer dissolves you may see a fine dust of silver collect on the bottom of the soaking container. While the tip is soaking you may want to cover the opening in the pen barrel with a piece of tape to minimize exposure of the conductive ink to air and moisture. Once the tip has been cleared of ink, remove it from the solvent and let it drain on a paper towel and stand in the air for 10 minutes to allow the cleaning solvent to evaporate. Check that the tip stopper moves freely and retracts into the assembly easily, then screw the tip assembly back onto the pen barrel. The pen should now perform properly. If not, repeat the soaking procedure until the tip has been cleared. If soaking the tip assembly does not get the pen flowing, then the pen is probably past its usable shelf-life and should be replaced. 

A common method of repairing a broken trace is to solder on a jumper, which is basically a wire bypass around the broken trace. This can be time-consuming and visually unappealing. Chemtronics offers CircuitWorks® Conductive Pens, which contain a highly conductive material like silver or nickel suspended in a liquid polymer. These pens allow you to literally redraw the trace.