I am remaking my road sign using a 3/4 sheet of HDO. (Not MDO) It 5' wide by 3' tall, and double sided. The old one had brackets that bolted through the face but they will not fit with the vinyl sign that's going to be attached. They are also rusted and I can not find more.
Plan B is to pre-drill holes into the top edge and screw in course eye loops. Maybe with some epoxy to really secure them. Would this be able to handle the weight of the sign itself? The only extra weight is the vinyl and paint. and its only about 50% of the full sheet.
Plan C might be making a metal frame that screws into the side edges. I could spread the weight among 3 screws along each edge. I would only want to do this if there was no hope for Plan B.
Any insight into how well ether option might work is greatly appreciated.
Best Answer
A large sign should be hung with a fastener that is passes through a hole that is drilled through the face of the plywood.
Using fasteners into the edges of plywood is almost always to be discouraged because the threads of screws or lag bolt type fasteners just do not hold very well. In the case of a sign the hole in the top edge invites the possibility of moisture intrusion and the separation of layers which can further weaken an edge joint.
There are various types of hanger brackets that can be used for a face drilled fastener in the sign. Here is a picture of one type that could be used: