Slippery Rock Gazette

Bob Murrell 

M3 Technologies

Photos by Bob Murrell

Above: Refinishing dark Corian – starting with diamond-impregnated pads on an orbital sander, and replacing original medium gloss

Above, top to bottom: Dark Corian surface has scratches and the surface has dulled through repeated scrubbing with an abrasive kitchen pad. 2: One of the dull areas, before refinishing. 3: Area with scratches filled with glue, before repolishing. 4 & 5: Scratches and dull area refinished and repolished to a higher gloss.

I know, I know, it’s not stone. However, as restoration professionals, it is in our best interest to be versatile and know how to refinish those occasional projects that involve different hard surface materials than usual.

I’m sure there are readers out there who know much more about working with Corian and similar solid surface products than I.

I do have some limited knowledge of these surfaces and have refinished many of them, some more than others. Therefore, my information in this article will be general in nature as the specifics will need to be gleaned by each contractor through research and testing.

Let’s start with Corian, with which I recently had a battle. I thought to myself, I can restore absolute black granite and this stuff is basically plastic, so how hard can it be to refinish, right?  Wrong! Now to be sure, once I figured out the procedure, refinishing Corian was easier than granite or marble for that matter. It was just Figuring out the procedure that was the issue. 

We have just passed the 50th anniversary of Corian.

It was invented in 1967 by Donald Slocum (no relation to the founder of Braxton-Bragg), who was a DuPont chemist.

It was originally intended as a kitchen and bath material and was available in only one color. Now it is available in more than 100 colors. Today’s Corian is available in deeper, darker colors that are more resistant to scratches and cuts than previous generations.

Corian is composed mainly of an acrylic polymer and alumina trihydrate. It is softer (2-3 on Mohs scale) than marble and therefore softer than granite.

It is, however, a solid, non-porous and homogeneous surface that is hygienic. Because it is non-porous, it will not harbor bacteria or mold. It is also an inert and non-toxic material and emits no gases.

It can be thermoformed in wooden or metal molds in order to create one-piece, solid 2D and 3D objects.

Because of all of the positive traits of Corian, it makes for a great kitchen and bath surface material. Being a somewhat soft material, it will scratch and scuff and will therefore require periodic refinishing. That is where the restoration and maintenance professional comes in.

I recently helped a local contractor who needed assistance with a dark Corian kitchen countertop that had scratches and had been dulled by the homeowner cleaning the surface using a coarse green kitchen scrubbing pad.

Similar to stone, there are several levels of surface sheen or shine associated with Corian: the manufacturer calls the finishes matte, satin, and high gloss. To stone care professionals this would correspond to a low-level hone, medium hone, and polish. 

The countertop in question was originally a satin gloss or medium hone.

But as we all have come to expect, shiny is clean, according to the homeowners.

Shinier also has typically more color, too. So, naturally the homeowners decided they wanted this higher level of sheen or polish.

I mean, why wouldn’t they, right? Of course, this decision came after the submitted test area had been completed and the original finish had been duplicated.

This was easily accomplished using a combination of resin diamonds and diamond impregnated pads from the standard stone toolbox. After looking at the test area for a week and just prior to the scheduled project, the homeowners decided they wanted a high gloss instead. 

So, it was back to the drawing board, as the satin level was actually the highest level that we were able to provide with the equipment available. After some research, and after some new equipment and tooling orders were placed, the confidence level was once again high. As I have said, we are stone restoration professionals; how hard can this be?

Cut to the chase: we ordered an orbital sander, some Velcro-backed aluminum oxide sandpaper, some special Scotch-Brite pads (in different grades), and some 3M Finesse-It polishing compound. As we have covered before, there are significant differences between aluminum oxide and diamond abrasives.

Aluminum oxide is softer and rounds more easily and therefore tends to polish better in some applications, such as this one. Because Corian is a softer material, diamonds may not always be the best choice for honing and certainly pre-polishing.

There are some diamonds that will work such as the old dot-matrix flexible diamonds. I also made good use of the diamond-impregnated pads in the process.

It was, however, the aluminum oxide sandpaper and the Scotch-Brite pads under the orbital sander that did the best prepping (honing) job overall. The final polishing was accomplished using the standard right-angle slow-speed polisher and a white pad with the Finesse-It compound. It tuned out gorgeous!

Maintenance would be performed using the Majestic No-Rinse Neutral Cleaner. I suggested the homeowner use the concentrated version, dilute according to the directions, and keep handy in a quart spray bottle. 

“Clean routinely and as needed with this solution,” were the instructions they were given. Also, “Avoid cutting on the Corian surface, and please use a cutting board (I like the new acrylic versions) instead.”

The moral of the story is to be able to think on your feet, research, test, and test again to confirm both the results and the procedure. 

I am currently working on another material that is more akin to faux marble. It does contain marble dust and therefore etches and scratches like marble.

What I have unfortunately discovered is that it does not polish just like marble.

I am still in the testing phases, but so far, resin diamonds seem to hone OK, but I have not yet been able to get the standard marble polishing products to produce a high polish.

I may have to use a combination of what I learned on the Corian and what I know about marble, but who knows? Stay tuned as I will advise the outcome in a future article.        

As always, I recommend submitting a test area to confirm the results and the procedure prior to starting a stone or hard surface restoration or maintenance project.

Also the best way to help ensure success is by partnering with a good distributor 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.