Stone Restoration and Maintenance Corner:
The Historic Picnic Table Project, Part 2

Bob Murrell 

M3 Technologies

Photos by Bob Murrell

First, I wanted to update everyone with a personal announcement: Bobby Grace is here so, and with great pomp and circumstance, I am now officially a grandfather! I have been given the name Bob O, from everyone else involved. Julie will be called JuJu. Where did these names come from? Well, they call me Bob O at the gym and Julie was called JuJu as a nickname when she was younger.

Bobby Grace came in at 7 pounds., 12 ounces and measured in at over 20 inches long. Her feet are so long I think she could water ski on them. Most importantly, she and her mom are healthy and doing well. I am beaming with both relief and pride.

Now during this same period, my youngest daughter graduated high school. She made me extremely proud and will be attending WKU this coming fall. Of course with Logan, Bobby Grace, and Taylor all residing in Bowling Green, my logistics will be as close to perfect as you can get. I am a blessed man.

So on to the outcome of the historic picnic table made from a couple of Pink Tennessee marble varieties. I am confident these stones were extracted from one of the many quarries that Candoro Marble Company owned, back in the day. The table, bench seats and column style legs were cut, ground, and honed at Candoro’s fabrication facility. If my timeline is correct, and I suspect it is very close, the table is at least 80-plus years old. This means that it was fabricated sometime in the late 1930s, possibly by a steam powered block saw and other equipment. Candoro switched to electricity in the early 1940s when TVA made it more readily available in South Knoxville, and installed a special line for them. 

After much discussion, the homeowner was ultimately convinced the best course of action was to leave the table in a honed condition and seal it. Polishing the table would look great for a while, but would not survive being subjected to environmental forces well, even with a custom cover.  

Per the completed test areas, the table surface was honed using a Makita tool and 5-inch ELF flexible metal-bond diamond. It still took quite a while to cut through all of that tough organic crust. Sodium hypochlorite (bleach) was then used to remove any contaminants left behind in the veins and open pores of the stone. Once all biologic materials were removed, an ELF5 60 grit, ELF5 120 grit, and ELF5 220 grit flexible diamond were run in succession.

As many of you know, metal-bond diamonds are fairly aggressive and can leave a honing pattern on a surface, so a 220 grit DICP5 resin-bond diamond was then used to help clean this up. Even a resin-bonded diamond can leave a honing pattern, so ultimately a 7-inch PLP 200 grit diamond impregnated pad was implemented to smooth out any existing patterns and make the surface consistent.      

Remember, the table surface and edges, bench surfaces and edges, and legs of both, all had to be cleaned, honed, and sealed. Granted, the legs didn’t have quite the quantity of organic material grown into the surface, as the horizontal surfaces. A 3,500 psi pressure washer, in combination with the bleach product, was successfully used to clean the legs. 

The bench seats also had to be honed starting from the flexible metal 60 grit and then finished much the same as the table. One bench seat was broken and jagged, and had to be ground and honed smooth.   

The arisses of all 90 degree corners were both sharp and jagged. They were actually a safety hazard and all had to be eased or beveled using the Makita and the ELF5 flexible metal-bond diamond and / or a 2-¼ inch x 3-¾ inch diamond hand pad of the same grit. This took quite some time as there were plenty of edges – you can do the math!  

Once all surfaces were properly honed to satisfaction, they were sealed using Akemi Color Intensifier. This particular product was chosen because it is a much more refined color enhancer, and because this Tennessee marble was very dense, the Akemi Color Intensifier penetrated better than many other color enhancing products. If this had been a limestone or other porous material, I probably would have recommended a different product.  

Above, left: Among other repairs, the broken end of the bench seat had to be rounded and smoothed. Above, right: All arrisses (sharp 90 degree corners) had to be eased or beveled for safety.

Above, left: Among other repairs, the broken end of the bench seat had to be rounded and smoothed.


Above, right: All arrisses (sharp 90 degree corners) had to be eased or beveled for safety.

As you may notice from the photos, there are two different materials used in the picnic table and benches. The table itself is made from a darker and more colorful Tennessee Cedar while the bench seats and legs are made of a lighter pink variety. The Akemi Color Intensifier deepened the cedar and will protect all surfaces for quite some time. The contractor is recommending that the table be inspected and evaluated every couple of years and re-impregnated as necessary. 

The picnic table is set on a flagged Tennessee marble patio and includes a block retaining wall of the same stone. The house exterior is also constructed of the same material. The inside contains similar and many different marbles as well. It is certainly a historic home worthy of restoration. Julie at Knoxville Marble Polish has been working for this particular client for several years on various projects around the estate. This project turned out great and the client loves the newly restored picnic table she and her family will now enjoy. 

There is also an oven/grill across the patio from the picnic table. It has cracked on both sides and is being re-enforced using an epoxy that is UV and environmentally stable. Of course, that could be used as a future article, so we’ll see…

What a minimalist work of art – simple yet elegant! Notice the tabletop was of the darker cedar material – and most likely was originally honed.

What a minimalist work of art – simple yet elegant! Notice the tabletop was of the darker cedar material – and most likely was originally honed.

As always and before beginning any new project, I recommend submitting a test area to confirm the results and the procedure, prior to starting a stone or hard surface restoration/maintenance project. Also, the best way to help ensure success is by partnering with a good distributor, like BB Industries, that knows the business. They can help with technical support, product purchase decisions, logistics, and other pertinent project information.

 


Bob Murrell has worked in the natural stone industry for over 40 years and is well known for his expertise in natural stone, tile and decorative concrete restoration and maintenance. He helped develop some of the main products and processes which revolutionized the industry, and is currently the Director of Operations for M3 Technologies.