Measure the inside bottom of the spool to the inside top (Image 1). Cut four pieces of 2x4 to fit tightly inside the electrical spool. Stand up the 2x4s near the edge and screw them into place (Image 2).
To create a smooth top surface, place a few pieces of duct tape over all the nuts and screws on the bottom of the spool (Image 1). Place foam on top of the spool, measure and cut to size (we used two half circles). Use hot glue to adhere the foam in place (Image 2).
Lay batting over the top of the spool and wrap it down the sides (Image 1). Cut to size and leave plenty of extra batting to be tucked under bottom of spool. Turn spool over and staple the batting to bottom and sides (the 2x4s). If necessary, use a hammer to make sure staples are in fully recessed. Trim excess batting and glue down the edges if necessary (Image 2).