The best program I could find for printing gerbers to stencils to use for resist and masks is ViewMate 11.0.71. You can down load it free from http://www.pentalogix.com/. Almost all of the other programs I tried, GerbView, GCPrevue, CAM350, CircuitCam, CooperCam and Gerv either won’t permit moving the gerbers are for printing on one page or they print with the black areas as a hatch which won’t work for our application. (Note: Save is disabled on the free version of ViewMate. But once you print the negatives you need you don’t need to save the job.)

Select an empty layer from the Layers Dialog on the left, then import the Gerber files you need to the work space. Then you can select each layer and /Layers… and Edit/Edit Selection/Edit Move them to the appropriate location. Move each layer until they are all stacked like you want them.

Then print. For different stencils, using Eagle and ViewMate I use the CAM and Print settings below.

ViewMate Commands used

• Import                  File/Import/Gerber
• Select                    Select/Layers… (Enter Layer Number)
• Move                    Edit/Edit Selection/Edit Move (Then select the layer and drag it.)
• Unselect              Selection/Clear Selection
• Zoom Out            Page Up
• Zoom In               Page Down

  Excel File Process Chart

 Notes

I've learned that when mechanically etching it is best to mask off everything you don't need plated.  Just doing the inside of the through holes is enough.  If you plate all the pads and borders, etc -- it increases the thinkness of the PCB inthose areas and causes the milling process to be harder to maintain consistency.