TYPES OF PLYWOOD

Structural plywood – Structural grades its application plywood is suitable. For use in all permanent applications. Its manufactures from hardwood timber species. Because uses for a range of applications including formworks. Flooring, bracing and manufacture beams.

Interior plywood – These are plywood uses in interior applications. Therefore generally not subject to high load. But where an aesthetic finish is a priority. Its applications include furniture construction. Besides as cabinets, tables, shelves. And the internal wall paneling furniture. Ceiling linings, and interior door skins. Interior Grade of plywood generally refers to as MR Grade or Commercial Grade in the Indian Market Space. It meets the rules of IS – 303.

Exterior plywood – Exterior grades its application of plywood for use in exterior applications subject to the elements. Where a high-quality aesthetic finish is also required.  Therefore Exterior Grade plywood in India generally refers to Marine Ply. Applications include outdoor furniture, flooring and similarly exterior door skins, hoarding, signs and non-structural cladding.

Marine plywood – Marine Ply is a subset of Exterior grade plywood. It’s structural plywood for hulls of boats and yachts. And other furniture applications such as in washrooms, kitchens similarly outside furniture meant to withstand the elements water. It is also used in craft construction. Therefore marine plywood manufactures reduce water penetration.  Thus uses a Phenolic bonded formaldehyde adhesive bond.

ADHESIVES USED IN MAKING PLYWOOD

Plywood is manufacture using two types of glue lines :
1) Grade A – Phenol Formaldehyde Resin
2) Grade B – Melamine – Urea Formaldehyde Resin
3) Type A Bond –  The Phenol-Formaldehyde bond is a permanent bond required for all structural and marine plywoods. The Phenolic bonded resin is recognizable by its black color. Therefore is made to not deteriorate under wet conditions, heat or cold.
Type B Bond – Recognisable by its light glue line color. Melamine Fortified Urea Formaldehyde is appropriate for interior applications. Especially in tropical areas marked by high humidity-free from wet or damp conditions.

TREATMENTS OF PLYWOOD

Plywood grades its application by a range of preservatives depending on the application. The most used preservatives include CCA (copper chrome arsenate). LOSPs (light organic solvent preservatives) and veneers, Reply and ACQ (Alkaline Copper Quaternary Compounds).

For residential or commercial construction purposes. The most suitable treatments are Copper Chromium Arsenate (CCA) and Light Organic Solvent Preservative (LOSP).