One of the wooden blocks with the plaster still attached to it. The plaster failed, not the epoxy glue.
I was trying to avoid buying a new drill, to keep the budget down and I wasn't even sure that the new drill would be able to drill into the concrete. After a bit of research I found that SDS/Rotary hammer drills were recommended for drilling into concrete. I bought a Bosch Rotary hammer drill. It's reasonably priced and also weighs only 2.2KG (compared to 3.5 to 5KG) which would make drilling overhead a bit easier.
After work that same day, I successfully drilled into the concrete ceiling
The drill is very quiet and almost vibration free. It's a bit mind boggling because you cant feel the drill fighting you. When you look up there's a hole in the ceiling and a mess on the floor
That night I unhooked the one side of each frame and got the hooks secured. At last the ceiling is secure.
But there's still a few finishing touches needed:
1. There is a little gap where the two frames butt together. This is caused by the bowed wood used to make the frame.
2. There is also a seam in the black material that runs down the middle of the two frames.
1. Solved by cutting a strip of cardboard (that will run the width of the frame) and wrapped in black material. I then velcro'd the cardboard strip in place to hide the gap.
2. On another visit to the fabric store, browsing every isle for the right fabric, I happened upon a black sequenced organza fabric. I wasn't planning on using it but I had an idea to overlay it down the middle of the ceiling. It would hide the seam and I'd also have a budget star ceiling.
In the pic below, arrows point to the cardboard wrapped strip in the middle. The arrow at the far end shows the wood strips that I painted and then screwed around the border of the frame. If you look closely, you'll notice the side of the wood strips is not painted. I will have to touch up these areas.
The camera flash makes the stars light up
A shot of the back of the room. The projector will be shelf mounted.