First up, I had to make some tools.  I knew I would be imprinting an image into Green Stuff putty (Kneadatite), to make the pads as identical as possible. 

The first tool I made from a length of brass rod that was the diameter of the symbol's round surface.  As the edge was a bit too thick, I used a drill bit and my power drill to drill into the hollow end of the tube, scraping away from the inside to make the "business end's" edge a bit thinner.  I used an emery pad to smooth out any burrs.  The second tool is from inside an old mechanical pencil with a fairly large lead size.  If I had to imprint any straight lines, I would have used an old X-Acto blade, carefully snapping the point off with a pair of needle-nosed pliers at the desired width. 

The final "tool" I made was what I refer to as the "Mellon Baller."  It's just an offcut of thick (1/4") plastic card, into which I drilled a shallow hole with a drill bit.  This would allow me to have just the right amount of putty for each pad.

After the tools were ready to go, it was time to prepare the pads.  To the left, you see the regular old Tau pad.  Using an X-Acto knife with a fresh blade, I trimmed away the injection marks and mold lines, and then sliced off the symbol, leaving me with the pad you see on the right.

With that completed on all 12 pads, it was time to mix up some equal amounts of blue and yellow to produce some Green Stuff.

Now it's time to break out the Mellon Baller.  I first used a thin film of petroleum jelly to make sure the GS wouldn't stick inside the mold.  Then I squished a tiny amount of GS into the divot, and scraped away the excess so it was flush.  I added a tiny drop of superglue right to the center of the smoothed-off GS blob in the mold, and carefully centered the pad onto it.  It bonds instantly to the plastic, and the GS lifts right out of the mold, and is now hopefully right where you want it.

You'll see in the left picture, it's quite pointy... a bit like Madonna, isn't it?  Using the GW sculpting tool, I smooth it down into a flattened dome shape, which you see in the blurry photo on the right.

On to the imprinting!  First I made sure my tools had a thin film of petroleum jelly covering them, so they wouldn't stick to the GS and pull it out of shape by accident.  First, in the upper-right corner of my GS dome, I used the mechanical pencil tool to make a small circle near the edge (Left side picture).  Then I used my brass tubing tool to carefully place the large curve in the lower left, very nearly touching the first circle.

Using a sculpting tool, I then smoothed out any bumps or ridge created by the pressure of imprinting into the GS.  This also helped to close the trenches I made a bit, tightening up the overall appearance.  The whole process (after my tools were sorted out) took less than 5 minutes per pad, as the 12 below were done in under an hour.  Now the client will have some highly personalized fire warriors representing his chosen Sept World, with a minimum amount of work.  As Tau iconography is made up of circles and straight lines, imprinting any of the sept icons should be a breeze!