How to polish dull marble by hand using MARBLE RESTORE kit

Using the MARBLE RESTORE kit you can get a perfect polishing of “marbles” with high carbonate content. For marbles with spurious carbonate content, on the other hand, you will achieve a polishing with less gloss. In such cases, in order to obtain the same degree of gloss, it will be necessary to complete the work with a specific wax .

Keep in mind that the “gloss” is the unit of measurement for the brilliance of a material. It varies between 0 and 100% of reflected light and can be measured with a reflectometer or a gloss meter.

How to polish marble by hand

In the MARBLE RESTORE kit you will find three velcro backed diamond plates; they are three abrasive plates made of resin mixed with fine diamond powder. Compared with carborundum abrasive papers, they have the advantage that they never clog, and remain effective until worn out. These diamond plates present grits ranging from 400 to 1500.

Grit is usually identified by a number which in turn is associated with a certain color. The coarser grit included in the kit is the number 200, with a red velcro back.  200 grit is not the coarsest available on the market for this type of abrasive resinoids (grits 60 and 100 are also produced). With a grit 200 plate you are able to eliminate surface roughness that is perceptible to the touch, and even small scratches, if you exercise enough pressure on the pad and if you carry on rubbing for long enough.

Avoid using too rough grits

However, to restore the polishing of a surface, it is not always necessary to start the job with the coarsest grit. On the contrary, it is recommendable to start working with grits as fine as possible in relation to the roughness of the surface to be polished. In principle, you should start with a grit 200 if the roughness of the surface is clearly perceptible to the touch. If, on the other hand, there is a mark that is only visible when looking closely against the light, but is imperceptible to the touch, you can consider sanding with grit 1500, which is the finest of the series and the last one to be used before chemical polishing.

Which abrasive to use?

This following photos will help you decide which grit you should start the sanding work with.

Above slight corrosion imperceptible to the touch (etch mark)

The etch mark above can be eliminated using 400/800 grit abrasive

Heavy corrosions : start using grit 200

Polishing phase

After passing the diamond abrasives on the surface, the final phase of the recovery work involves the use of a special polishing powder. This phase aims to replicate the so-called “varnish” process, but is carried out without using lead, machines, oxalic acid, or other toxic substances. In our case, the polishing is obtained simply by hand rubbing a paste made of polishing powder and water with the help of a cloth on the surface previously sanded with diamond abrasives. The secret for a perfect recovery work is a good sanding work, done with the utmost care. You will need to completely erase the signs of the previous grit at each step. The powder contained in the kit is a mixture of resins and metal oxides which, rubbed on the marble, causes the chemical polishing by filling all the micrometer sized pores with calcium molecules. It is not a glazing powder and does not cause the formation of any glass-like film on the marble surface.

How do you polish dull marble and granite

“To restore” means to bring something back to its original condition. When dealing with small scale marble restoration interventions, it is often necessary to work on a small marble part, leaving the non-damaged part unaltered. If the part to be restored is located on the surface – and is therefore? visible – the reparation work must be performed flawlessly, so that no sign of intervention can be seen. That’s why knowing how to replicate the same degree of finishing as the original surface on the area of intervention is of foremost importance. Such goal can be accomplished by faithfully replicating the process through which the original finishing was produced.

So, first of all we will have to find out how things are carried out at the factory level. We will discover that, at an industrial level, the manufacturing of stones differs depending on their nature and mineralogical composition. In light of such discovery, for our convenience, we will roughly divide the stones into two broad categories: “marble” and “granite”. That does not necessarily entail that all the stones included in the “marble” category are strictly marbles, and that those included in the “granite” category are st?rictly granites. Categories simply help us determine the surface treatment method we will need to use for the recovery.

In the industrial world, the distinction between materials – with the purpose of grinding and polishing them – is intricate and complex. However, for our purpose, the simplified marble/granite dichotomy works well enough.

Agglomerated marble is a carbonate material sensitive to acids

Two different categories for stone work

Rocks with high carbonate content (marble, limestone, limey sandstone, travertine, onyx), i.e. stones mainly composed of calcite and/or dolomite belong to the “marble” category. We will explain the meaning of the term “carbonate” later.

Non-carbonate rocks belong to the “granite” category: stones with low carbonate levels (such as serpentine and green marble), and stones that have a predominant silica SiO₂ content (such as granite, quartzite, siliceous onyx).

Depending on the category, stones undergo a different sanding/polishing process. The process is carried out with solely mechanical means for the “granite” category, and with both mechanical and chemical means for “marbles”.

N.B. For greater accuracy we must point out that, apart from natural marbles, all composite materials with carbonate as main component (agglomerated marble, Venetian-style marble terrace floors etc.) are included in the “marble” category.

Note that artificial materials such as the so-called “quartz”, “okite” (more generically known as quartz resin), “Corian” (or similar materials known as cultured stone in English-speaking countries) are not carbonate materials. They must therefore be included in the “granite” category.

Corrosion marks reveal the carbonatic nature of the stone