Many small fabrication shops struggle with proper laminating of stone surfaces. Often the joint created on an edge is colored improperly and is jagged and very visible. How does one obtain a tight, invisible joint? The way to achieve the perfect joint is in the proper selection of adhesive, proper color matching and the laminating technique itself.
Selecting the Proper Adhesive
In order to choose the proper adhesive and consistency you must identify your purpose and logically select the material. There are four main reasons for using an adhesive in the stone industry: laminating, sticking, filling, and penetrating.
• Laminating: Adhering two or more pieces of stone together usually stacked at the exposed edges.
• Sticking: Adhering two or more pieces of stone together, usually to fix a broken piece and on the same plane.
• Filling: Repairing voids, pits, cracks, or fissures, usually with adhesives or shellac sticks (waxing).
• Penetrating: Strengthening a fragile stone that usually has fissures or cracks, by pouring a very thin adhesive into these weakened areas.
Back in the early 1980s your adhesive selection was normally a polyester resin with benzoyl peroxide hardening paste and either a knife grade or flowing consistency. Today there are many adhesives and consistencies to choose from.
You can select penetrants, super penetrants, precolored, crystal clear epoxies, as well as the old polyesters. Be sure to check the date and shelf life of the adhesive before using it. You also need to check the label or material safety data sheets (MSDS) for hazards and recommended personal protective equipment (PPE). Most adhesives are flammable, which means you should wear a vapor respirator, protective gloves, apron, and face shield.
Polyester vs. Epoxy
Most people use polyester adhesives for marble, and epoxy adhesives for granite. The following are characteristics of polyester and epoxy adhesives: