Not an installer here, but just curious. Where do you use the silicone? Do you put it parallel to the VHB and use it as an additional adhesive, or do you seal around the mounting bracket not allowing the elements to come in contact with the edge of the tape?
The tape can hold up to the elements without issue, so that's not something I worry about when applying it.
If I were to use 1" angle on each side of the 2" post as the OP mentioned, I would put four 2" lengths of VHB tape down each of the lengths of aluminum angle. I would do the same down the center of the 2" post. This leaves all kinds of rooms for dollops of silicone which aren't even needed - it's just an added reassurance.
With the above method, that would give 8 square inches of tape on each length of angle and 8 square inches on the post, which would be 24 square inches total. One square inch of tape can withstand 70 pounds per square inch of dynamic shear. If you do the math, you can see why much larger sign structures (and skyscrapers and jet planes and UFO's) are built using VHB when mechanical fasteners aren't an option.
Similar to what Moze said, I have installers put tape around the
perimeter of the angle, then fill the void with Lords Adhesive.
I'm not a big fan of applying it to the actual post. Most of the signs
I work with occasionally need to be serviced... usually graffiti or reprints
from fading digital prints. Though I might be able to pull the sign off
with the silicone, it may make it difficult to service.
Depending on the property, design and budget, I prefer tamper proof
sex bolts when it's time to attach the face/angles to the post. If you are
going through all the trouble of adding angles, tape and adhesive, what's
a few more seconds by adding a clean bolt attachment
I didn't see where the OP mentions the angle size, I would use 2" angle,
giving you 48 square inches of adhesion.
If this was round tubing, say 2", I mechanically attach a 1 1/2" U-channel
to the post, then attach 1 1/2" angles to the panel, slide the angles over
the channel and bolt it down.
Now I wasn't going to respond to Gino, and my post was not a response
to his BUT... a through bolt attachment with washers is the strongest.
Note: I did not say wood screws, metal screws, tapcons... any of those
on a post and you run the risk the screws easing out a little causing the sign
to rattle in moderate to heavy winds and bending out over time. I just
went to a jobsite where the installer ran tapcons though every panel on a
round post... that was a brilliant idea... maybe the little blue dots added
to the quaintness of the design.
But as a designer of some experience myself, I know that VHB and Lords on
a well finished panel and angle will outperform the sign panel, give it a clean
look and have another choices when it comes to designing sign systems with
post and panel.
