I need to install a cat flap in my conservatory wall, the base of the conservatory is constructed from moulded concrete panels, 30mm thick. A normal hammer drill was largely ineffective drilling holes though it, it took about 10 minutes and 3 bits to get a single hole through it.
I am mounting the flap in a wooden tunnel which will in turn be fixed into place into the hole (approx 20cm square) I make through the concrete so the edges don't have to be perfect (though the neater the better).
The two ways I can think of to do this are:
1.) Use a 9" angle grinder with a diamond disc to cut the hole. There will have to be a bit of overshoot on each cut though due to the curvature of the cutting disc.
2.) Use an SDS drill to perforate the perimeter then attack with a chisel bit.
Any thoughts on which method will work best? Or maybe there's another option I've not considered?
I am mounting the flap in a wooden tunnel which will in turn be fixed into place into the hole (approx 20cm square) I make through the concrete so the edges don't have to be perfect (though the neater the better).
The two ways I can think of to do this are:
1.) Use a 9" angle grinder with a diamond disc to cut the hole. There will have to be a bit of overshoot on each cut though due to the curvature of the cutting disc.
2.) Use an SDS drill to perforate the perimeter then attack with a chisel bit.
Any thoughts on which method will work best? Or maybe there's another option I've not considered?