bluetsilk wrote:
Have a brick fireplace. Also have your basic slab of exotic wood (7feet
by 18 inches, 2 inches thick) that I would like to place on this
fireplace as a mantle. Not sure how to hang it, but am sure want the
hanging to be invisible. Am thinking of drilling 4-5 half inch holes in
the mortar line, placing a metal rod along with epoxy in those holes,
making sure they are plumb and true. And long enough to stick out 8-10
inches. Then drilling matching holes ( maybe a wee bit larger) in the
wood slab. Then sliding it onto the rods with or without epoxy. That
should allow for a nice invisible installation. Anyone have suggestions
or shoot down commments? Or a better way?

The fireplace has a gas fireplace in it that is used infrequently, but
will be about 2 feet below where I envision the mantle.

thanks.

Use only 3 rods (how much weight?)
1/2" is probably too big a hole for the mortar joints
How will you drill the holes level/straight into the wall?
Do you have drill press to make the holes in the wood straight?

Sounds like it will work but be difficult to execute.

Have a friend with a welder? Clamp a piece of steel to the back of the
wood and drill through the metal and wood together to make sure it is
all lined up. Weld the rods in place on the plate and the screw the
plate to the wall with Tapcon screws. Over engineered for sure but
that's half the fun.

One of the pros at rec.woodworking have probably already solved this
problem, try a post there.