ABC Resin Treatment
Over the course of the years the “S.E.I. Resin Lines” have been continuously updated, eventually becoming high-technology plants available in more than 90 models which differ in terms of layout configuration, overall dimensions, equipment, level of automation and productive capacity.

The best method to explain the workings of any Resin Line is to introduce its workstations one by one, following chronological order of the various operations which make up the processes of restoring, strengthening and enhancing of the stone.

The right approach to the study of Resin Treatment is to learn the distinction between two groups of materials: those which need to be treated on both sides that is to say mesh backed and resin coated and those which only need to be treated on the surface. However, this differentiation is not necessarily a rigid one because the definition between the two groups is not always clear cut. Indeed, the only practical criteria to distinguish is on inspection of the blocks. When a block is fragile and presents numerous cracks it will be cut into slabs which will need to be mesh reinforced and resin treated, while if the block is sound it will produce fairly strong slabs which will only need to be resin coated.

The processing of materials in the first group follows this scheme:

  • Loading of the slabs to be mesh backed and resin coated. – The raw slabs are loaded on the Resin Line.
  • Drying of the slabs. – The slabs are stored in a drying chamber before a mesh backing is carried out.
  • Fibreglass mesh attaching. – A sheet of fibreglass mesh is stuck to back of the slabs through the application of some resin.
  • Hardening or “polymerization” of the resin. – The slabs are stored in an oven aimed at accelerating the hardening of the resin which has just been applied to attach the fibreglass.
  • Unloading of the mesh backed slabs or turning over and immediate repositioning. The mesh backed slabs can be either unloaded or overturned and repositioned on the Resin Line, to be resin coated without breaks.
  • Reloading of the mesh backed slabs (if not repositioned automatically).
  • Drying of the slabs (if necessary).
  • Surface cleaning. – The stone surface must be cleaned of dust and dirt before resin application.
  • Resin application. – A layer of resin is applied to the surface of the slabs.
  • Impregnation under-vacuum. – To increase the resin penetration into porosity and fissures the slabs can be impregnated under-vacuum.
  • Finishing touches (application of a second layer of resin or even a third layer in the case of badly cracked material). – The repair of seriously cracked slabs involves a repeated number of retouches.
  • Hardening of the resin. – The slabs are stored in an oven for resin polymerization.
  • Unloading. – The treatment is completed and the slabs are unloaded from the Resin Line.

The treatment of materials in the second group consists of eight steps:

  • Loading of the slabs.
  • Drying of the slabs.
  • Surface cleaning.
  • Resin application.
  • Impregnation under-vacuum.
  • Finishing touches.
  • Hardening of the resin.
  • Unloading.

Becoming a Resin Treatment expert
“How many types of stone are there in the market?” Nobody can answer this question. Indeed, there are thousands of types of marble, granite, breccia, travertine and onyx, extracted from four corners of the globe and launched into the market in the form of slabs and tiles. The differences among the various materials are so deep that it is unrealistic to expect stone processors to find a method of processing which would be appropriate for all cases. This must be taken into consideration in all stages of the production process (block cutting, slab polishing, slab cutting-to-size) and especially when it comes to the Resin Treatment, where results depend on so many variable factors of production.

Approaching the study of Resin Treatment with an open and flexible mind, without ever assuming to hold the ultimate truth, is an indispensable condition for stone processors to do well in the restoration, reinforcement and enhancement of their material.

At S.E.I. we believe that the best attitude towards learning how to improve the quality of stone is to bear in mind the golden rule: different materials must be processed in different ways.

When we travel around the world to meet companies inviting us to see whether their stone can be turned into highest quality slabs and if so how to, we strive to teach their staff to have a winning mentality.

To reassure and encourage our hosts, we suggest them to stick to the old adage “for every problem there’s always a solution”. Passion, perseverance and patience can solve almost any problem.

Having spent nearly 25 years in the field of stone mesh backing and resin treating, we have gained a vast amount of expertise which so often enables us to immediately understand how to treat a certain material through analogical reasoning. Other cases are much more difficult and require a new approach. To solve them, we need to rethink existing methods, unleash our creativity and carry out a number of resin trials.