Homebrew PCBs

Yes, the thing is, this is easy to over-do.
If you apply too much, say propylenglycol, you'll get ink running all over  
the place.
BTW diluted ink (from a failed print not 100% cleaned) has the same  
wetting effect.

I don't see puddling as the primary problem. The primary problem for me is  
i need vast amounts of ink to form a working resist, while Volkan somehow  
seems to get by with much less. So he can do amazingly fine structures  
while i can only do wider spacing. If i could use less ink the puddling  
would go away by itself.

I don't have the time at the moment to work on this, today i made three  
boards with inkjet which i needed, but i still don't get the fine lines  
Volkan has.

ST

On Mon, 02 Oct 2006 17:49:37 +0200, mycroft2152 <mycroft2152y@...>  
wrote:

> Jam5411's recent EUREKA moment with using the Simple Green wipes on a
> inkjet printed pcb got me to thinking. There has been a lot of
> discussion on the best method to clean pcb's. But in fact, we were
> really discussing the correct method to "prepare" pcb's. A 'totally
> clean' pcb just may not be best.
> The Simple Green wipes left a slight film that affected the surface
> tension of the ink/copper interface and resulted in better inkjet
> printing. My guess is that the "brake fluid" and the TARNEX have the
> same mechanism of leaving a slight invisible film on the copper. There
> are probably many other compunds that would work.
> I looked for some Simple Green wipes locally, but could not find any.
> But based on the MSDS sheets, the wipes used some standard cleaning
> solvent. These solvents or similar are used in most 'spray cleaners'.
> So checking under the sink, I had both Windex window cleaner and an
> Orange Fresh" spray cleaners. (On a side note, the Orange juice
> industry found a way to make money off the waste pulp and rinds of the
> orange. They steam distill off the "bitterness" of the rind which is
> used as an evironmentally friendly solvent.)
> One lab test to measure surface tension is to place a drop of liquid
> on the surface and measure either the angle of contact or diameter of
> the droplet. The test can give quick and dirty comparisons of the
> relative surface tensions. I decided to give it a try.
> My first step was to thoroughly clean the copper. I used a green
> scouring pad with an abrasive sink cleaner (COMET), rinsed it very
> well in water, then follwed by a double rinse in 70% isopropyl
> (rubbing) alcohol and a final rinse with 91% isopropanol.
> I then cleaned one strip with the Orange cleaner and a second area
> with Windex and wiped them dry. The third strip was the control.
> I then carfully applied very small drops of MIS Yellow ink using a
> fine wire. Being carefull to keeep the drop size and application force
> constant.
> It was amazing, the strips with the cleaners had drop diameters at
> least twice that of the control area. The chemicals left by the
> cleaners significantly changed the surface tension. The results with
> both cleaners was similar.
> This means that we can control the wetting out properties and reduce
> the puddling without adding anything to the ink itself.
> As I'm writing this, the thought crossed my mind that this may be
> applicable to Toner Transfer also. The toner is in a liquid state and
> must properly wet out the copper. I'll probably give a try on my next
> run of pcbs.
> Myc