Plywood is one of the most widely recognized multi-purpose engineered wood-based panel products used in wood construction projects and furniture. Plywood panels are fabricated from multiple layers of wood veneer glued together with the grain direction of each layer of veneer perpendicular to that of the adjacent layers. These cross-laminated sheets of wood veneers are fastened together with a resin adhesive and cured under heat and pressure.
Plywood products for both structural and non-structural uses suitable for both wet and dry service conditions, including subflooring, flooring, wall panelling, rooftops,and furniture requirements and even concrete formwork.
Now that we know what plywood is and how versatile it is let us see how do we grade the plywood on the basis of water resistance and waterproofing. They are mainly divided into two categories, namely 303 Plywood and 710 Plywood. These are the grades given by the Beauro of Indian Standard for Plywood
What is 303 Plywood?
As per Indian standards, the 303 plywood or 303 grade plywood specification stands for Moisture Resistant grade of plywood.
The MR (Moisture Resistant) grade 303 plywood is not waterproof plywood but can resist moisture up to a certain level. Resin used to bond the sheets of wood in MR grade plywood is Urea Melamine Formaldehyde. MR grade plywood also known as Interior Grade plywood which means that it is suitable for the interior applications such as cabinets, shelves, bed, kitchen etc which is not prone to get wet.
What is 710 Grade Plywood?
Now that we have walked through the basic knowledge of 303 plywood, its grades and uses let us also look at the 710 grade plywood. The 710 grade plywood or the marine grade plywood is much stronger than MR grade plywood. It has superior waterproof qualities. This can be gauged from the fact that Marine plywood can be submerged in water for 72 hours without any kind of damage. The resin used for bonding the piles of veneer in marine plywood is Phenol Formaldehyde.. It is also known as interior grade plywood because of its high water proofing capacity and ability to withstand extreme weather conditions. Contrary to 303 plywood, the marine grade plywood can be used for both interior and exterior wood work. Due to its superior qualities and premium quality, it is little expensive compared to MR grade plywood.
Now that we have got to know about the 303 plywood and 710 plywood at length, let us put them side by side to draw a much clearer comparison.
- 303 plywoods are water resistant and not waterproof. They are made to withstand a certain amount of humidity and dampness. On the other hand, 710 grade plywoods are marine grade plywood which are totally waterproof and used to make ships and boats and even withstand extreme weather conditions.
- Diluted Urea Formaldehyde resin is used to bond the softwood veneers in 303 plywoods. On the other hand, undiluted Phenol Formaldehyde resin is used to bind the softwood veneers in 710 plywoods. This synthetic plastic resin enhances the waterproofing quality of 710 plywood.
- 710 plywood is a better external grade plywood as compared to the MR grade plywood coming under 303 plywood.
- 710 grade plywood is more expensive than 303 plywood. This is because of the superior quality of resin and wood used in the 710 grade plywood.
In conclusion, we want to bring to your notice that 303 plywood is not the cheaper version of plywood but it is used for a different purpose than the 710 grade plywood. So, if you want to make indoor home or office furniture which is not prone to water you can go for 303 plywood. Wigwam Plywoods are also available in MR grade which make them perfect for making waterproof furniture and wooden requirements that can be used both for indoor and outdoor requirements.