How to mount bronze plaques on a boulder (rock).
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The most common methods used to mount a bronze plaque on a boulder are "machine screws with expansion bolts" and "boss & stud" (see below). Regardless of the type of back with which the plaque was manufactured (solid or recessed), mounting on a solid surface is essentially the same.
There is a bit of complexity when mounting a bronze plaque on a boulder - more so than on a block or cement wall. While walls are generally flat, boulders typically are not flat. You may wish to chip away some material from the boulder or have it sandblasted.
You will need a cement bit for your drill and use a drill that has a 'hammer drill' function.
This image shows a "solid back" plaque. This type of back is usually encountered on smaller plaques (less than 24 by 24).
This image shows a "recessed back" plaque. This type of back is usually encountered on larger plaques (larger than 24 by 24) to reduce weight.
No matter what type of back is on the plaque, you mount it in generally the same manner.
SELECTION OF MOUNTING METHODS
Machine screws with Expansion Sleeves and Rosettes
Can be removed from the mounting surface easily.
No additional materials are needed to mount.
Once rosettes are installed, mounting is done.
Anchor must fit SNUGGLY into hole
Boss & Stud
Not easy to remove from mounting surface.
Customer must purchase adhesive to mount.
Need to wait for adhesive to dry or cure.
Both methods require the drilling of 2 or more holes in the mounting surface.
(*) see drill steps below.
In walls that have a mortar joint such as brick or stone, we do not recommend drilling into the mortar joint. It is weaker than the wall.
Expansion anchors, if placed in mortar joints may crack the joints.
Expansion anchors expand in the hole as a result of screwing in the screw - you can not see this if the anchor is NOT in the hole.
BOSS & STUD INSTALLATION
A plaque with Boss & Stud mounting may be delivered with more hardware than needed. Hardware is sometimes provided for mounting on a surface where access to the back of the mounting surface is available Since we are addressing mounting to a SOLID surface, we will discard the hardware used for back mounting.
- The square plates (if provided) are not used – they are used only when the holes are drilled through.
- The nuts (if provided) are also not needed for the same reason.
- Normally, a tube of ‘liquid nails’ or an epoxy adhesive is used – you can get this at a local home supply store.
- Screw the studs into the back of the plaque.
Make sure the studs go all the way into the holes in the mounting surface.
In other words, dry fit the plaque to the mounting surface.
- Fill the holes in the mounting surface with the adhesive. Try to get adhesive all the way into the holes.
You can even put adhesive on the studs – especially closest to the plaque.
- Place a bead of adhesive around the outer edge of the PLAQUE – along the outer rim (if a recessed back) or on the back (if a flat back).
- Push the plaque with the studs into the holes in the mounting surface.
Some adhesive will ooze out of the holes.
The adhesive on the edge of the plaque should contact the headstone ALL AROUND.
- THE PLAQUE MUST BE HELD IN POSITION UNTIL THE ADHESIVE IS DRY. Depending upon how high the plaque is on the mounting surface, you may use a 2X4 to hold the plaque in
place until the adhesive dries.
The 2x4 would be on an angle to the ground. One end on the ground, the other end, covered in thick
cloth, against the plaque to protect the plaque.
You use the 2x4 to wedge the plaque TIGHTLY against the mounting surface. Careful not to damage or dislodge the mounting surface.
- While the adhesive is setting, look at the outer edge of the plaque where it meets the mounting surface. If
needed, use some adhesive to seal the edge against the mounting surface.
Use a dry cloth to clean up any excess adhesive.
Machine screws with Expansion Sleeves and Rosettes INSTALLATION
- The plaque has holes pre-drilled. Either hold up the plaque against the mounting surface or use cardboard to create a template. Place a sharp pencil through the holes in the plaque and mark the mounting surface.
- Drill holes to accommodate the expansion anchors. We use different size expansion anchors depending upon the size of the plaque so it is impossible to specify in this document, the drill size. The expansion anchor should fit snuggly. Remember, the machine screws will screw into the expansion anchor so if the holes are too large, the anchors will rotate. If too small, the holes will deform the anchors.
- Insert the expansion anchors into the holes drilled into the mounting surface in the above step.
- Position the plaque and insert the machine screws through the hole in the plaque and screw into the expansion anchors. CAUTION - the machine screws are center drilled to accept the small screws in the rosettes. This weakens the machine screw but they are strong enough if the machine screws are not forced into the expansion anchors.
- Once all machine screws are tightened to the desired torque, thread the small screws through the rosettes and into the head of the machine screws. The rosettes will be flat against the background of the plaque. For added security, you may wish to use a thread locking material on the rosette screws.
DISCLAIMER: The information presented on these pages is general in nature. It is up to the individual using this information to determine if it is applicable for their specific use. There are numerous variables affecting the applicability of this information for a specific use. We are not responsible for any damages, actual or consequential that arise from the use of this information.
The use of tools may be dangerous. It is up to the individual reading this guidance to determine if they have the ability to accomplish the tasks. Protective gear MUST always be worn and bystanders must not be allowed near the installation site. Drilling cement or other type of walls, chipping boulders or anything else is inherently dangerous.