|Forum topic by JocknJill||posted 12-05-2015 05:31 AM||1612 views||0 times favorited||16 replies|
12-05-2015 05:31 AM
I’m looking for a way to attach a floating mantle with corbels (essentially a floating shelf, pictured below) to portions of a hollow plaster wall just above the brick fireplace surround (also pictured below). I want it to be super solid to be able to display large rock fossils on it (I love rocks).
I thought I would put toggle bolts through each corbel into the wall and at a few places along the mantel shelf either on the top or bottom (pocket hole style), but messing with a few test pieces in my shop (pictured below) showed that if I countersink the head of each bolt and the bolt head slips into the countersunk hole with the “butterfly” toggle behind the wall already, I could be pretty screwed. The toggle bolt would spin but gain no traction, and I’d be stuck with a mantle hanging off my wall. (...Although maybe I could use that downward cantilever force to make the toggle grip the back of the wall. I just tried this on a test piece, and it seems to work. But I’d have to insert all the toggle bolts at once, and tighten each bolt a tiny bit at a time so that none of them lose traction.)
Another problem is that the toggle bolts require 3 different drill hole sizes—1/8” for the bolt shank, 3/8” to sink the bolt head to later be puttied, and 1/2” to push the toggle through the wall. I couldn’t mount the bolts one at a time since I’d have to tighten down one first to be able to mark and drill the holes for each next bolt placement, so it would be impossible to drill the 1/2” hole in the wall behind the 1/8” hole for the bolt shank. (Maybe i should make a template from a scrap board for the drill holes?) Another problem would be the fact that the toggle would have to be placed behind the corbel after the bolt shank is pushed through the hole, which would be impossible if the mantle were already snugly fit against the wall by 1 or 2 bolts already.
I’ve considered adding a backing board to the piece, in which case I would screw the corbels and mantle shelf to the 3/4”x7.5’ pine board and easily mount the backing board to the wall with toggle bolts. I may still have problems with the bolt spinning and not gripping the toggle against the wall, unless, like I said above, I pulled the board away from the wall to get the toggles to grip behind the wall.
This whole plan just seems unnecessarily complex. Any other ideas out there that would put me out of my misery? My girlfriend would be happy, too, because then she’d be able to hang the stockings before Christmas. Thanks for your help in advance!