A brief history of the Resin Treatment of stone
Whoever wants to learn more about the “Resin Treatment of stone” must look backwards from the perspective of the historical period when this process was developed. From the second half of the 1950’s, on the crest of the wave of the economic boom there was a dramatic increase in the demand for all types of stone. As a direct consequence of this, quarries were subject to such an overexploitation that no on-site control of the blocks’ quality could be carried out, and the companies involved in slab and cut-to-size production were often supplied with excessively fragile material. If the large quantities of fractured slabs produced through block cutting could have just been repaired, the huge rise in demand would be met. However, this was not possible and the situation seemed so hopeless that the entrepreneurs had to simply accept to bear losses equal to the profits made or even higher.

The solution came from the progress in the chemical industry, because the latest generation synthetic resins were suitable to repair faulty slabs and to reinforce the delicate ones. The attachment of a sheet of fibreglass mesh with resin to the back of the slabs made it possible to reconstruct the fractured materials and strengthen those which tend to break. The application of a layer of artificial resin was the most effective way to restore the surface of slabs damaged by cracks and holes.

In spite of encouraging results from laboratory testing, the industrialization of the treatment of stone with synthetic resin proved to be far from easy. Indeed, there were a number of practical problems which made it difficult to replicate at an industrial scale the methods developed through experimentation on an industrial scale. For example, it was necessary to pour a good quantity of resin onto absolutely dry and clean slabs, and after resin application the stone had to be exposed to high temperatures so that the liquid chemical products hardened reasonably quickly. Therefore, the requirement for dedicated equipment arose.

Having observed that the machinery manufactures who tried to adapt ovens used in ceramics or timber processing failed badly, S.E.I. took on the project and made a series of “tunnel ovens” for the drying of the stone and hardening of the resin.

Despite their relative simplicity, these tunnel ovens played a pivotal role because with them S.E.I. laid the foundations for its future. In fact, it was through the use of these ovens that the company gained the skills, knowledge and experience it needed to create a proper production line.

In 1991, S.E.I. launched a closed-cycle plant whose method of working involved the slabs transported on conveyor steel trays undergoing a sequence of drying, mesh backing or resin coating and resin hardening at specialized workstations. This revolutionary so-called “Linea di Resinatura” plant allowed its users to mesh back or resin treat ten slabs per hour, an extraordinary achievement for that time attracting such an interest that S.E.I. soon received many orders for similar or even bigger “Resin Lines”.