The Manufacture of bronze plaques
This section will help you understand THE BASICS how bronze plaques are manufactured and what to expect in terms of the physical plaque.
Firstly, all of our cast plaques, be they bronze plaques or aluminum plaques are manufactured using the sand casting process. In the sand casting process, a pattern is made of the text and graphics. The pattern can be made from any substance but typically, wood, foam core, plastic and polymer are used.
Once the pattern is made, a fine sand/epoxy mixture is poured around and over the pattern, packed down and then the pattern is removed leaving the image of the pattern in the sand.
Then, paths are formed in the sand (this is typically part of the pattern process) that channel the molten bronze into the pattern.
The molten bronze is then poured into the form, let cool and then the rough plaque is removed from the sand.
Lastly, the rough plaque is tooled and finished.
This of course is a VERY abbreviated description of quite a complicated process. The process of manufacturing a cast bronze or cast aluminum plaque consists of many many more steps.
THE PLAQUE ITSELF
bronze plaques are quite heavy. A quick estimate of weight is to take the height times the width and divide by 10. So, the weight of a 10 by 10 cast bronze plaque is roughly 10 times 10 divided by 10 or 100 divided by 10 which equals 10 pounds.
As you can imagine, a larger cast bronze plaque can be almost unmanageable in terms of weight. For instance a 36 inch by 36 inch plaque would weigh 36 times 36 divided by 10 which equals 129 pounds. This would equal over 150 pounds in the shipping crate.
Due to this dramatic increase in weight, bronze plaques, as they get larger, are manufactured with a 'hollowed out back' to lighten the overall weight.
(*) Plaques under about 250 square inches are typically cast solid with a 3/8" to 1/2" thickness with a flat back . Because the plaque is only 3/8" thick, a boss and stud mount has only about 2-3 threads for the stud to screw into the back of the plaque. The 'boss' in this case, is nothing more than a shallow hole tapped to take the threaded stud.
(*) Plaques over 250 square inches, are typically cast with a hollowed out back with a apparent thickness as seen from the side, of about 3/4". In this case, and due to the increased weight of these larger plaques actual 'bosses' which are raised places on the rear of the plaque, are cast into the back of the plaque. It is impossible to cast this type of 'boss' on a smaller plaque due to the fact that the smaller plaques are also thinner.
The decision as to the type of back to be cast is at the discretion of the production department and is NOT a customer option.
(*) The number of boss and stud mounting points is variable, some plaques have 2, some have 4 and some very large plaques may have 6 or 8. This decision is at the discretion of the production department and is NOT a customer option.
(*) All of these dimensions and numbers are approximate and at the discretion of the production department and are not a customer option.
The customer can and should specify the type of mount to be used such as through screws, bolts or the hidden boss and stud mounting. Each has its place.