Step 2: Heat Chamber
- Cut some sheet metal into 4 pieces: one at 14” by 39”, 2 pieces at 11” by 25” and one piece at 22” by 25”.
- Bend the 14” by 39” piece as follows. Start at 3”, bend away from you, at 10” bend towards you, at 29” bend towards you, and at 36” bend away from you. You will be creating a U shape with 3” wings. You should now have 2 sides and the floor of the inner box.
- Starting with one of the 11” by 25” pieces, mark along both 25” edges at 3” and 22”. Draw lines between these marks. Along the 11” edges, make the following marks: 1”, 7” and 8”. Draw lines between these marks.
- Using tin snips, cut from the 25” edge on each line until it cross the line at 8”. Now, along the 7” line from the 11” edge, cut until you reach the slice you just cut. Do not discard this scrap piece, we will use it later. You should now have a T shape piece with small tabs. Follow the same procedure for cutting the other 11” by 25” piece of sheet metal.
- With each 11” by 25” piece of sheet metal, bend along the 1” line towards you. Flip the piece over, and bend from the end of each slice towards you. You now have the remaining sides.
- Using the scrap pieces, bend them in half to form a corner piece.
- Take the large U-shaped metal piece and one side piece. Place the side piece with it’s 1” tab under the bottom of the large U. Using self tapping sheet metal screws, attach the two metal pieces together, screwing through the bottom of the large piece into the tab of the side piece. Use 4 screws. Follow this procedure for the remaining side from step 2e. You should now have a basic box.
- Screw the corner pieces on each corner of the box. The corner pieces should be on the outside of the box, and you should screw from the inside out. Be careful to avoid getting nicked by protruding screws. Use 4 screws for each corner piece.
- The inner box should be ready for paint. Apply 2 coats of black paint to the inside of the box only. Do not paint the upper edge of the box.