suction cups

I'd try a local hobby place first, or even a big-box home goods store...I know Big Al's has suction cups for powerheads and heaters, not sure if they'd be big enough to a large chunk of wood.
 
The first thing to know about suction cups is the same as the first thing to know about one-way valves: They do fail. If failure would be any issue at all, use other techniques.

All IME & JMHO, YMMV.
 
well what would work better? i thought about getting a piece of slate and drilling a hole in it, but what kind of a drill bit can go through stone?
 
You will need a masonry bit. They work great for going through slate. You will then need to get stainless steel screws. If you look on my website, the aquarium pictures, you will see 2 large pieces of driftwood. Both pieces are attached to slate using stainlees steel screws. :)
 
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