Measure the length and width of your art piece, using a tape measure. Use a saw and cut the four 1-inch thick wood pieces to fit the above measurements. Use two pieces for the length and the other two for the width.
Cut a notch on each piece of wood. Place the wood on a table, measure ¼ inch from one edge and cut out the piece, flip the wood and cut again to create a groove.
Take one piece of wood, cut it at 45 degrees on both ends leaving the groove on the inside. Repeat this process for all the pieces.
Attach the wood pieces together with wood glue. Apply glue on each edge, fix the adjacent piece, and leave it to dry.
Fill any gaps left with impasto gel or wood filler.
Sand down your frame. Rub the wood with sandpaper in one direction for a smooth clear finish
Varnish the frame; then, paint it; be careful to ensure that the paint settles smoothly. Apply the paint in one direction; let each layer dry before coating it with another layer of paint. Attach your art piece with glue on the inside of the board.