I tested the CircuitWriter from Amazon - it does work, but probably not worth the effort. You need at least 3 layers to get any reasonable conductivity, each layer takes hours to cure, it's thin and runny, there isn't really enough space to tape it off. It might be an acceptable option if you can't solder to save your life (like myself) and only have a handful of Gridseeds to modify, but anything beyond that is better done by soldering or paying someone to do it. Having said that, I did manage to modify a couple of Gridseeds with the CircuitWriter and they are happily hashing at 950 MHz (400 KH/s).
Try shaking the hell out of the circuitwriter. I heard the conductive elements congeal and you get left with minimally conductive solvent. You really have to shake them up a ton or they will be runny and have lower conductivity. Maybe this would fix you having to do 3 layers?
Oh believe me I was shaking it like crazy for a couple of minutes
. I think the pen format kind of limits how viscous it can be. It needs to be able to get through that small hole. And it thins out even more as it cures, so then even a tiny scratch will break it. I did some testing on a scrap piece of PCB and was able to get it conductive with one layer, but it would spread out too much to be able to do the same on the Gridseed.Still not a bad result, I didn't think it would work at all.
