Hey there, cpirius, sounds like you managed to source the PEG and you've got something up and running, congrats!
Thanks! I'm using the 3350 laxative powder and it seems to be working, though I don't really have a basis for comparison...
See the comments section of the constant current source article. Andrew Frazer has shared a schematic that looks pretty promising for reverse plating. Although, others (namely Null Space Labs in this thread) have had fairly good success without reverse plating. They were using a brightener (Janus Green B). Other things that I've heard help are anode bags (a very fine filter material around the anode bank).
I have a similar plan for a micro-controller based reverse current setup. I'm going to make a test board with different size holes and run a few of them with different power timings and see what the differences are. At least, I will when I have the time to build the constant current load with current reversing...
What kind of graphite are you using, is it mixed really well, did you follow the ratio outlined in the article? The graphite should be extremely fine. If you have the right kind fo graphite and it is mixed in the proper proportions to the ink, you shouldn't have problems with clogging at all (it sounds like your graphite/ink ratio may be too high).
I'm using 5 micron graphite, mixed in the ratio from the article, or even a little less graphite. I shake it well before using, but it still seems kind of gritty. However, yesterday when I made some more boards I noticed that wiping the ink off the board might be the real problem. After vacuuming I could see light through the holes, but then after wiping it with a paper towel, it pushed material into the whole and some where clogged, and they would no longer vacuum out. Further investigation required.
I've done down to .015" vias without problems using this method (vacuuming out with a shop vac - a really strong vacuum)
I've ordered some more drill bits to try different sizes as right now I have nothing between 12mil and 26mil.
Someone left a comment [url=twilightrobotics.com/prototyping/electroplating1]here[/url] with a link to a purely chemical approach as well as a short explanation. It doesn't sound like they personally tried it and neither have I. Please post back with your experience if you decide to try it.
This sounds awesome! I'm working on sourcing the chemicals needed. Thanks for the info. For some reason the comments section is not showing up for me in chrome, so I missed this. Will let you know how it goes.
You also need to be mindful off the current you're plating with (this is a function of board surface area, described here) and plating time.
I've been plating at 9-10 A per sqft. Haven't tried other currents yet.