Aviation Plywood: BS 1-2 Mm And 3 Mm Thick, Other Grades As Per GOST. Where Is Waterproof Plywood Used?

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-18 12:09

Aviation plywood, an advanced performance material, was once developed specifically for aircraft construction . Today it is successfully used in other areas as well - from the manufacture of souvenirs to the production of furniture. It is worth learning in more detail about where the BS waterproof plywood with a thickness of 1-2 and 3 mm, as well as other brands according to GOST, is used.

Description

Aviation plywood is produced according to the GOST 102-75 standard and is a type of multilayer sheet materials made of birch veneer . The number of layers in a structure is always odd. The minimum material thickness is 0.4 mm, the maximum is 12 mm.

Modern manufacturers sometimes refer to birch aviation plywood as delta wood (DSP-10), since it also uses a plasticized wood-layered structure of sheets.

During manufacturing, the material is impregnated in layers with special adhesives based on phenol-formaldehyde, the work is carried out under a pressure of 6 atmospheres and temperatures up to +270 degrees Celsius . Then the prepared veneer is held together with a bakelite compound. In the manufacture of aircraft plywood, the principle of mutual perpendicularity is used to strengthen its structure. In each new layer, the fibers are laid across the previous one, ensuring the formation of a flexible, stress-resistant carcass.

The acceptable size ranges for aircraft plywood are set at the following level: length 1000-1525 mm, width - 800-1525 mm . A deviation from the parameters up or down in the range of 25 mm is allowed. The most popular is the square format of sheets 1525 × 1525 mm, 1270 × 1270 mm.

The normal moisture content of the material is no more than 5-9%. Plywood should have square cut corners, a flat surface without pronounced geometric distortions.

Marking

Aviation plywood is marked according to the characteristics of the adhesive used. Among the current varieties of this material, the following can be distinguished.

1. BS-1 … To connect veneer layers in this type of aircraft plywood, phenol-formaldehyde resins made in accordance with GOST 20907-75 in liquid form (SFZh-3011) are used. The size range of sheet thickness for this brand is from 3 to 12 mm. It is the thickest aircraft plywood that can withstand significant loads.
2. BP-A / BP-V . Plywood of this type differs only in the use of different types of bakelite films for gluing the material. Products have the same standard sizes: 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm. Other thicknesses are not available.
3. BPS-1V . This type of material provides for the use of different adhesives, depending on the thickness of the sheet. Products up to 3 mm inclusive are glued with B-type bakelite film. Thicker sheets in the range of 4-6 mm are fastened with SFZh-3011 resin. The outer part of such sheets is bakelite.

For plywood of any brand, a certain number of veneer sheets are set in the composition. In the range of thickness 1-2 mm, there are 3. In standard sizes from 2, 5 to 6 mm - 5 layers (except for BPS-1V, where there are 7 or 9 of them). The maximum number of interlayers in 12 mm plywood is from 9 to 11.

There is also a division into grades 1 and 2 .… They determine the conformity of the product to the established quality requirements. First-class material on the outer layer should not have partially intergrown, non-intergrown knots, cracks, dark growth, group veins and traces from them. Traces of fungal infection, as well as any processing defects when cutting plywood, should be excluded: traces of pricks, scratches, mechanical damage.

Defective sheets are considered to be sheets with a partial absence of a bakelite film or impregnation, foreign inclusions in the veneer structure.

Areas of use

Aviation waterproof plywood is used today not only in the design and creation of aircraft. Its properties are highly regarded in other fields of activity. The material was most widely used in the following areas.

Production of musical instruments … Here, the strength characteristics and moisture resistance of the material, combined with good acoustic properties, were in great demand.

Shipbuilding … The material is used for the formation of ship bulkheads, used in the elements of the inner skin. The bakelite outer part is not afraid of contact with sea water, almost does not pick up moisture even when used in damp rooms.

Design and construction . When making mock-up projects of buildings, it is very important to create a solid structure with minimal weight, easy to transport and demonstrate. Aviation plywood meets all these requirements, it is convenient to use and easy to purchase.

Interior decoration . In some cases, it is materials that combine the properties of plastics and natural wood that turn out to be the only correct solution.

In aircraft construction, special bakelite plywood has been used since the days of gliding, providing sufficient strength, lightness and durability of the sheathing material. It is used in the outer and inner parts of the aircraft body, giving the necessary shape to parts using special bending equipment.