Equipment Required:
Table saw
Miter saw
Clamps (straight and band)
Planer
Instructions:
Use a recycled 2x4 about 8 feet long that has been confirmed to not to contain nails or other non-wood materials.
Step 1:
Choose a heating register that is what you want to use (I avoid painted ones to avoid potential lead paint).
Check the back of the register to confirm that around the outside edge there is at least an inch between the inside lip edge and the outside lip.
Make sure material 7/8 inch in thickness will fit easily in this space. This gives space for the box you are going to build.
Step 2:
Remove the damper from the register.
Cut the 2x4 in half in the 4 inch direction on either a table saw to give 2 pieces that are approximately 11/16 inch by 3-1/2 inches.
This also gives another opportunity to inspect for nails or other foreign materials. Safety first!
Step 3:
Trim about 1/8 of an inch both sides of the 3-1/2 inch boards. This should give 2 boards that are about 3-1/4 inch wide boards.
These can now be planed to about 9/16 of an inch thick (both boards the same thickness).
These are going to be glued with waterproof glue to give a board that is about 6-1/2 inch wide and this thickness you have made. These can now be sanded smooth.
Measure the length of the inner edges of the heat register and add 1/4 of an inch to these dimensions. Miter cut the boards.
Step 4:
Now it is needed to make the bottom of the box. Using the excess from the boards that were glued together earlier you will need to likely glue two of the boards together to make a board larger than the bottom of the box.
There should now be 4 pieces that will form a rectangular box. Using a band clamp these can be put together as a dry fit to make sure that the box will fit under the register to test the fit.
Adjustments can be made at this point if needed to make the box fit to the register.
Step 5:
Dry fit the box and use this to mark the bottom piece. After marking the bottom it can be trimmed to fit tightly in the bottom of the box.
Step 6:
Now the box is ready to assemble. I used 4 stacks of two quarter dollars under plastic wrap near the corners of the bottom to raise the bottom of the box and help avoid getting moisture trapped under the box.
Put the waterproof glue around the edge of the bottom piece. The edge pieces can now be added after placing an even layer of glue on the mitered edges and then held in place with the band clamp.
After the glue cures the box can be sanded and filled.
If you have left any holes from removed nails or other holes that go through the wood these need to be patched either from the outside or inside of the box.
I also ran a bead of caulk around the inside bottom of the box to seal up any gaps between the bottom and sides of the box. This step is necessary to keep fiberglass resin from the next step passing through the holes or gaps that might be in the box.
Step 7:
The inside of the box can now be fiberglassed following the package instructions. It is very important to completely seal the inside of the box with fiberglass.
After sanding I finished the box with polyurethane.
The final item added to my boxes were 4 small clear stick-on pads to help protect the surface that the box will be place upon.
Submitted by:
Dave Hanson, in Longview, WA
