You can see it is two pieces of 5/8” plywood that have been sandwiched together- glued and screwed. Each piece supports a different load type and together they can support a few hundy pounds. The top arrow shows how the inner piece is actually butted up against the front of the wall stud so that any downward pressure on the mantel surface is pushed straight into the very strong front face of the 2x4, where it is distributed over the stud. The outer panel screws into the side of the 2x4 to hold the inner piece in place. We had an independent lab test the strength of this combination and …bleh. This is strong.
Moving back to the mantel itself; it is going to be mounted above a fireplace and will receive a moderate amount of heat. Thankfully, our fireplace is magnificently inefficient and the TV will not see temperatures above 75 degrees. Just to cover our bases, we lined the bottom of the mantel with aluminum foil:
But first, we used some cool spackle that starts off pink when wet and turns white when it dries to fill in inconsistencies:
The first step in the aluminum mounting process is to use some spray glue to stick the foil. We use 3M High Strength 90 for all these types of things- very sticky and long lasting(…we shall see). We spray the whole length of the board and wait a minute or so for it to tack. After that we apply common kitchen foil shiny-side-visible. This will bounce a lot of heat back from whence it came- who knows, maybe even up the efficiency by half a percent:
Then smooth it out with your hands or something soft so it won’t rip:
Let that dry in the sun for an hour or two, sand it LIGHTLY with something above 300 grit, use some acetone to get it clean, and then lay on a coat of primer:
We then wired everything up so that we could have a whole slew of doodads and widgets running through. Since what we originally wanted was to have a place to put the TV such that no wires would be visible in the room, we had to have outlets in the mantel itself. So we wired one up on the back/center. This outlet faces the fireplace and is in between the wood and the stones, hidden from sight. The TV will plug into it discreetly:
We built a little box around it so we will have a sealed speaker chamber on the other side, when the time comes. We coiled a little extra wire in here which is a good idea whenever you are installing anything in the wall- it gives you the ability to pull the outlet out of the wall/mantel for fiddling with later. We siliconed all around this to seal it up tightly:
After all the wiring was done, we ran a bead of silicone over the whole thing so that it would be sealed when the lid was put on. We used GE brand- the cheap stuff, they have higher end versions which will withstand the force of a supernova: Then we screwed it all down and let that sit overnight to dry.
This concludes this week's Fireside DIY, stay tuned for next time when all of this should be done.