First, I have to say that those of you that build your theaters in a few months are machines! I put quite a bit of time in on the theater this weekend and feel like I hardly made any progress. Not only do many of you work fast, you do amazing work.
My lesson learned for the weekend - I can't hear my wife yelling down the stairs to me when I am in a soundproof theater with hearing protection on and a saw running. She thought I was ignoring her - honest, I wasn't
OK, on to the progress. I ended up putting sand in the larger of the front curved stage cavities. I had extra sand and figured it couldn't hurt. It didn't add that much time. For the really small cavities that it was difficult to stuff a plastic liner into, I just filled them with fiberglass insulation. When I was done with the sand, I went back through and leveled it with a wooded board and cleaned up the extra sand.
One strange thing that I found with the sand was the difference in quality from bag to bag. 90% of the sand that I put into the stage was a very fine sand just like play sand. It was a very consistent tiny grain. I didn't think much of it as I went through the bags. As I was getting to the end, the sand in the last few bags was courser. It almost looked more like extremely tiny pebbles mixed with sand. I don't think it will make a difference, but i was surprised by the variation in quality from one group of bags to the next.
I don't know if you can see it in these pictures, but here is the "clean" sand:
Here is the "course" sand:
Once I was done with the sand, I put down a layer of roofing felt as a vapor barrier between the sand and the wood.
Lastly, I cut both layers of OSB to top off the stage. I was a little nervous about cutting the curve in the stage, but it came out pretty good. It is not perfect. In a few spots, if you look closely, it is a bit wavy, but you have to look to see it. I hope the carpet covers up the flaws.
I couldn't decide how large to make the lip - 1 1/2" OR 2", so I split the difference and went with 1 3/4". I did some experimenting with rounding over the corners. When I was at Home Depot today they had a Freud 1/2" round over bit that was regularly $37.99 on clearance for $15.00. I decided to give it a try. What I think I am going to do is round over the bottom side of the bottom sheet of OSB and then round off the top edge of the top sheet. Here is a picture of a small section I did. You really can't tell what it looks like from the picture. I hope it is enough of a radius.
I'm curious what size radius others used. My decking is two layers of 3/4" OSB, so it is pretty thick.
With all of that done, I still need to finish routing the front edge and put down the second layer of wood with Green Glue between the layers. I also need to cut the wood for the step. I plan to use the cut-off piece from the upper portion of the stage since the radius matches exactly. I will just need to mark and cut the front edge. Hopefully I can work on that during the week. Although, I may get a bit distracted. I have a new toy arriving for the game room on Tuesday. It is something I have been trying to find for a very long time.