Last night at the Hackerspace I tried a new way (to me) of doing PCBs on the Cricut. So far it looks like the most promising yet.
This time instead of trying to scratch off an etch resist, I'm directly drawing it on using a plain old mini Sharpie pen like a plotter would. I understand the Stadtler Lumicolor pen is also recommended.
I just now discovered this link that shows exactly what I need to try next as far as the pen goes: PCB Plotting
-Then, in Eagle, run File->CAM Processor.
-Select Output Device EPS
-Click File and select your output file path.
-Don't worry about the offset and page size.
-Select the "Pads", "Bottom" or "Top", and "Vias" (it will complain if "Vias" is not selected).
-Click "Mirror" if you are doing the bottom layer.
-Click "Process Job," this will write the output file.
-Install a copy of Ghostscript & GSView, and run "ps2pdf [options] input.[e]ps output.pdf" to convert the EPS file from Eagle to a vector PDF.
-Fire up Make-the-Cut, and do "File->Import->Vector PDF File", leave "Import Strokes and Fills" selected, select your PDF file and click "Open".
-Select the imported image and click "Ctrl-B" to Break the circuit up into its pieces.
-Deselect all, then click on each of the four border lines and delete.
-Select all, and click "Ctrl-J' to Join the circuit back up into a single piece.
-Position the circuit on the cutting pad as needed.
-Load up your Sharpie in the tool holder and print a test piece on paper to verify positioning.
-Load up your copper in the machine. If you're running anything thicker than 0.01 you may need to raise the pen in the holder. I use double-stick tape or at least a fresh spritz of spray-tack.
-Print your design. I don't know how many coats are necessary, but I am doing two coats, one after the other. Don't use Multicut for this!!! It does each line multiple times immediately instead of doing the whole pattern completely and repeating it: This causes the pen to dissolve the previous coat and move it around a little.
-(optional) Put the board into the toaster oven just briefly to make sure the ink is fully dry.