Limber Done

Take a sanding stick and sand down the top of the brick.  Trim the plastic sheet around the edges of the brick so that it's even all the way around.

Glue another piece of sheet plastic on the top of the brick.  The Evergreen Scale Plastic comes in thinner sheets of plastic that are less expensive than the .040 sheets.  They will also work and would same some money if a lot of them were being built.  I use Plastruct Plastic Weld General Purpose Plastic Solvent Cement.  It works well with Lego and fake bricks.  Legos and similar bricks don't always glue well without specialized adhesives.

Cut a piece of Evergreen Scale Models item number 297 Angle 1/4" size that is the same length as the brick.

Line up the edge of the angle with the top of the limber and glue it onto the front of the limber.

Put the wire into the groove at the bottom of the limber.  The wheels are from Eagle Games American Civil War artillery.  They are large, cheap, and durable.

Drill a hole in the front bottom center of the limber the same diameter as the plastic coated wire.  Insert a length of rod into the hole and glue it with the Plastruct glue.

Drill a second hole in the rear center bottom of the limber.  Insert an eye pin into the hole and glue it into place.  Put a dab of superglue on the eye pin, and a dab of Plastruct glue in the hole.  Make the loop at the end of the eye pin vertical.  Using your wire cutters, clip a bit of the eye so that creates a trailer hitch for the cannon.  Eye pins are sold in the jewelry department of stores like Hobby Lobby and are little wires with a loop at one end.  This makes a very good limber, not too expensive and not too hard to make.  I have several other versions that I make and likely they will appear in another issue of Bunker Talk.