Most domestic hardwoods are about 35-40 lbs per cubic ft., so a 2" x 12" x 52" piece would be in the 25-30lb range.
Just as important as the weight of the wood though is the force placed on the bracket due to the width of the shelf. The further your shelf sticks out from the wall, the more leverage is placed on the mount. Theoretically at least, a weight 12" out from the wall will exert twice the force that one 6" out does. So for a 12" shelf, you're going to want to be pretty conservative with the weight ratings of the brackets which may be based on shallower shelves.
As for the prices for live edge walnut, I've seen huge ranges; everything from $5 to $25 a board ft which would be $125-750 for the amount you'd need. I'd expect a place like Windsor Plywood would be on the mid to higher end of that range while a sawmill or a private seller would be lower, but that might be tough to find in Calgary. And of course if all you can find are 6' or 7' long slabs you're going to have to allow for a lot of waste.
|