Its already been asked, so I won't ask why it wasn't done in HDU for weight purposes, but you are going to need to be able to get at something structural behind that veneer for any method to hold up something that heavy.
What should have been done by the contractor was to have some threaded rod through bolted the studs in strategic places so you could shim and mount a couple lengths of aluminum angle iron to them.
Then you would attach the same size angle to the back of the sign with short enough screws so that you don't go through the front of the sign. The distance between the angles on the back of the sign should be slightly larger than those on the wall and then hang the sign on top of the wall angles, pop a few screws through them top and bottom and you're done. No visible hardware and as long as the angle sticks out further than the rock protruding the most, you should be able to make it nice and level.
We are matching another sign that they had done a few years ago for a different location. Yes we can get to the otherside, but it won't help to mount it, this is the exterior wall with stucco on it.
If you don't hit anything substantial toggles may work, just add an extra bracket or two.
I agree, and maybe just handing them the sign would be the best option. The tv's although lighter are just lagged into the rock with some type of insert. It's a tough one for sure. Thank you for your time. I'll post it when done, however it happens.Well, then I'd say you pretty well up that famous creek without a paddle..... or as many say..... you be f*cked.
If the customer does not want to allow you to use more conducive substrates and you cannot put all-thread in the wall and bracket it off outside, then I'd tell them to take whatever chances they see necessary in hanging it themselves. You're gonna be hanging about 45lbs or so on a decorative wall with no idea if you're hitting any supports or studding. Without taking that wall apart, how will you be sure to hit necessary supporting pieces ??
Was the old sign they are duplicating applied to a stone wall as this ??
That looks like junk. All different kinds of grains, all going different ways and most likely, just a bought blank. Piece of crap, in my opinion. Plus, it doesn't hang flat and doesn't appear to fit the surroundings. No taste or thought was given to that sign, so I'd suggest letting then hang their own sign for sure in this scenario. Otherwise, hang it on decorative chain from the ceiling and get it as close to the wall as possible.
When you cannot solve something, accent the mistake and make it look like it was done on purpose. That's an old trick from real sign people. Put a light or two on it and focus more attention on the stand off than originally anticipated with shadows and highlights. Make it interesting.
Clearly you aren't in touch with the aesthetics of the younger generations. The reclaimed aesthetic is very "cool" right now, Gino.
Personally, I wouldn't hang that sign. That's just me though.