Finir-finir to glue plywood to be able to use a wide range of adhesives, for example:
a) Based on the origin of the material, divided into:
o Adhesive vegetable, such as soybeans, peanuts, cassava (tapioca)
o Adhesives animal, eg casein (milk), fibrin, a protein, bone Ø Adhesives synthesis, for example, urea formaldehyde, phenol formaldehyde, melamine formaldehyde, resorcinol formaldehyde
b) Based on the resistance to water and weather influences outside differentiated by:
o Adhesives WBP, the adhesive is resistant to outdoor weather, water, and air humidity around. These types of adhesives for example fenoll formaldehyde, and plywood produced with this adhesive called exterior plywood (type 1). If highly resistant to humidity around the adhesive force of 5-15 kg / cm2.
o Adhesives MR, the adhesive does not withstand the humidity in the room. Examples of these types of adhesives for example, urea formaldehyde, and plywood which produces so-called interior plywood (type II). When tested strength of less than 5 kg / cm2.
c) By way of hardening:
o The glue that hardens in the heat, for example blood adhesives, fibrin (animal), adhesive synthesis.
o The glue that hardens in the cold, for example, bone adhesives, plant. > The glue that hardens due to a chemical reaction eg casein (milk), adhesive synthesis.
o The glue that hardens due to evaporation of the solvent: adhesives are insoluble in water.
d) Based on the recovery capabilities:
o Perekatthermoplastic, can be restored and rebuilt
o thermosetting adhesive, it can not be restored
When will be used to glue in the manufacture of plywood finir the types of adhesive should be added again with some other materials, among others:
Hardener (hardener), for example NH4Cl (about 1%)
Extender (developer), for example, wood flour, coconut shell flour, starch kaolin (about 6%)
Water (as a viscosity regulator, to taste)
Each mix adhesive with a viscosity (poise) has a lifetime of certain specified that need to be considered in the preparation and use. The amount of adhesive dilaburkan (GPU) per unit area of sheet plywood panels made is determined by the formula:
GPU = Gram Pick Up (kg / m2 / cm2)
S = $ MSGL / $ MDGL usually 20-50
A = area of the panel (m2, cm2)
An explanation of S can be given as follows.
$ MSGL = million square glue line, namely resurfacing adhesive system with one line of adhesive.
$ MDGL = million square double glue line, the adhesive resurfacing system with two lines of adhesive
Adhesives which dilaburkan (GPU) $ MDGL = $ MSGL + 10%
o If the plywood is composed of 3 layers finir, then resurfacing is done with the system $ MSGL on both surfaces of the core finir
o If the plywood layer 5, the adhesive is given a second surface of each cross-band (there are two cross-band). Cross band is finir number 2 of the top-bottom directly below the face and back veneer.
o If the 7-layer plywood is given a second adhesive surface of the 2 CB and the two surfaces of the center core of its veneer. Center finir the core is located at the middle of the middle of the inside of the plywood composition.