Porcelain memorial photographs
Today’s market place offer several choices when selecting your memorial cameo. The industry has traditionally offered pure porcelain base cameos and steel based cameos with a porcelain paint applied to the steel prior to firing. These are the 2 styles that we at Glazed Images have decided to target in our study.
Porcelain cameos that are traditionally placed on headstones; whether they are grass flat markers or vertical monuments have the same harsh environmental conditions on them. Hot, cold, dry or wet environmental conditions take a toll on the porcelain finish as well as glue joints. After visiting and collecting data from numerous cemeteries the findings are pretty much the same.
The mind set in the monument community is that pure porcelain cameos should be placed on vertical installations and steel backed cameos should be placed on flat grass markers. The thinking is that pure porcelain cameos may crack when placed on flat markers especially when lawn equipment run over them. Hence the need for steel backed cameos, these are believed to provide a stiffer platform from bending therefore eliminating the cracking problem; if any.
It appears that the thinking in this industry is based purely on hear say and not data. Our findings showed that 87% of all cameos that we studied were indeed steel backed porcelain photos and 13% were pure porcelain. We also only studied flat grass markers to evaluate the worst conditions.
Background information on the steel cameos revealed that the steel of choice in this industry is called vitreous enamel sheet, enameling steel or “refrigerator steel” commonly known as ASTM A424 steel. The low carbon content is crucial for kiln fired finishes. This steel is not a stainless as we were led to believe and is corrosive in wet conditions.
Armed with this fact we now understand why our findings revealed alarming results. We found the following in almost every cemetery we visited: Of the 87% steel backed cameos we looked at, we found 20% have visible signs of corrosion around the edges of the installed photos. The corrosion had early stages as well as some with advanced stages depending on the age of the installation. In several cameos we could not see beyond the corroded surface. The corrosion starts from an exposed edge or a bottom pin hole from the kiln posts or nick from installation at the factory. The porcelain finish is a vitreous enamel (glass-like) and nicks easily with hand tools and impact from handling. Once the surface is disturbed the corrosion process begins rapidly on steel. The environment that all markers are placed in is a natural setting for this to happen with constant watering at most cemeteries.
When we studied the 13% pure porcelain we found no corrosion on any cameo. This is expected due to the properties of pure porcelain, there can be no corrosion. Most of you remember the Titanic that sank in the Atlantic some 50 years ago, after retrieving porcelain plates and dishes that were in a salt water environment for all those years it came up in pristine condition. Accelerated salt spray tests are used almost always in industry today to evaluate a design for its resistance to corrosion.
We were also pleasingly surprised to see that none of the porcelain cameos were cracked from our samples studied as we were led to believe would happen. We also did observe equipment being driven over grave markers as standard cutting practice at the cemeteries. Primarily due to a smaller lot sample perhaps larger samples would reveal some degree of cracking would be present.
To minimize the cracking it would be important that porcelain cameos be mounted on granite with non-compressing types of setting compounds and not rubber silicones or tapes. Simply stated, bathroom ceramic tiles have been long set in wet environments in showers successfully for many years. These tiles take high impact loads on counter tops as well as shower floors without separation and cracking.
The risks involved with steel cameos can and will be apparent in the years to come. Those of us offering a lifetime guarantee for products may want to think this thru before we make false claims of lasting the test of time. If minimal risk and or product warranty for your company is what you are after then perhaps the pure porcelain with improved setting compounds would be the choice to make for all porcelain cameos in both vertical and horizontal mountings.
Author: R. A. Rapozo
Degree’d engineer in the fields of Industrial technology and processes of industry