From plywood with their own hands. Plywood fastening methods

Adhesives used during plywood production - composition and properties

Sheet plywood has many features according to which classification is made different varieties. The grade is influenced by the material of the veneer used, the thickness of the veneer, the number of sheets glued together, the presence or absence of a top laminate coating, etc. Among the most important characteristics of sheet plywood is its resistance to moisture, and this indicator is greatly influenced by those used during production of adhesives. What grades of plywood exist in terms of moisture resistance?

Plywood with increased moisture resistance (FSF). For its production, different kinds phenol-formaldehyde adhesives.

Waterproof plywood. The veneer is glued with organic albumin-casein adhesives.

As you can already guess what better performance plywood has water resistance, the more difficult it is to call it completely safe for health. You should know that absolutely all formaldehyde resins with various additives emit harmful chemical compounds into the air. The number of these compounds is controlled by special public services and on the basis of their research, they establish a "threshold of harmfulness." This figure is different for different countries and depends not only on the wishes of physicians, but also on manufacturers' lobbyists. So it turns out that in some countries plywood may be banned for use in residential premises, while in other countries the same plywood is proudly called an "environmentally friendly product" by manufacturers. Let's look at each type of adhesive in more detail.

Adhesives based on phenol-formaldehyde resin

Currently, domestic and foreign adhesives based on phenol-formaldehyde resin are used in production, the quality of the resin largely depends on the capabilities of the equipment on which it is produced. Unfortunately, domestic producers resins of world quality standards cannot be produced on domestic equipment; most plywood manufacturers buy it from Americans and Finns. Appearance - transparent homogeneous liquid, the color can be reddish-brown or dark cherry, dry residue is not less than 50%, the amount of free phenol is less than 0.10%, relative density is 1.2 g/cm3. The end time of the gelatinization process is up to 70 minutes at t°=+125°C.

For improvement physical characteristics resins, various additives, combined hardeners and combined fillers are added to it. Toxicity is determined by the chamber method and is regulated by the current state standards. Bonding strength tests are carried out in accordance with the methods and methods in force, separate tests are carried out for this class of plywood physical indicators strength of the adhesive line after boiling the samples. At least three samples are selected for testing, the arithmetic mean of the three measurements is recorded in the final test report.

Adhesives based on urea-formaldehyde resin

Quite toxic resins, banned in some developed countries, industrial production resin causes significant damage to the environment, can provoke the development of cancer in humans, adversely affects the liver, and often becomes an allergen. In European countries, the maximum amount of formaldehyde is two times lower than domestic standards allow. We have already discussed why safety standards vary so much in different countries.

Some reduction in the emission of harmful substances is achieved by adding melamine, but this additive significantly impairs the technological characteristics of the adhesive. In addition, melamine has a rather high cost, which is very disliked by all manufacturers. It is easier and cheaper for them to find "direct contact" with state regulatory services and with their help "to make products absolutely safe and environmentally friendly." Recently, attempts have been made to replace melamine with carbamide - this chemical component has an average strength of glued plywood, the presence of harmful volatile substances and cost. Manufacturers began to produce adhesives from SKMF resin, aerosil, ammonium chloride and wheat flour. The presence of the latter allows unscrupulous companies to focus on the "environmental friendliness" of their products.

The introduction of technical aerosil into the composition increased the number of molecular bonds in the internal structure of the main polymer. Fluorine compounds improved the structure formation of the polymer, which increased the cohesive strength. Aerosil technical speeds up the process of glue curing - its manufacturability during plywood production has improved, the curing time is reduced by approximately 25%.

Albumin-casein adhesives

Only this group of adhesives can be justifiably classified as environmentally friendly and safe for our health. Casein is obtained from dairy waste, albumin is obtained from the blood of animals. These adhesives have been used for hundreds of years but are considered "unfashionable" today. Plywood made using such adhesives is afraid of moisture; in terms of the strength of the connection between veneer sheets, it is much inferior to chemical adhesives. Plywood can be used to create light-loaded and medium-loaded furniture structures. In construction, it is almost never used due to unsatisfactory physical characteristics.

Conclusion for reflection

We did not discuss specific brands of adhesives, there is no fundamental difference between them. We consider it important that you understand the main differences between the various components of adhesives, and already draw your own conclusions, do not pay much influence on the manufacturers' advertising brochures. These are the realities today - you have to pay for the quality of life, and you have to maintain your health with the help of a pharmacy.

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Plywood - construction material, active use required by furniture, packaging and even the automotive industry. Wood veneer is used to manufacture this multilayer material. coniferous trees. Result - solid construction, which can be fastened with screws, nails and bolts, but glue is the most convenient option.

Plywood laying methods

How to glue plywood to plywood? The most environmentally friendly is water-based glue. It is completely odorless, it can be diluted with water and used instead of a primer. Such styling requires additional fastening, and the main disadvantage is long drying.

The adhesive, which is based on a solvent, dries a little less - 3-5 days. In this case, it is necessary to pre-impregnate the concrete screed with a special primer. The downside is the strong smell.

How to glue plywood to plywood and save time at the same time? This desire can be maximally satisfied by using it. It dries for about 24 hours and does not need dowel nails.

How to choose glue for plywood

Solving the question of how plywood is better to plywood, depends on the type of connection and further operating conditions. The process can be represented by an independent installation of plywood on a screed or carry an additional function, for example, to strengthen the structure.

If you plan to use uncoated plywood, then you can purchase any glue. The main requirement is a dry and clean surface. To apply the composition on both surfaces to be glued, it is better to use a roller or brush. After that, you can strengthen the plywood connection with nails, screws or clamps. Finally, you need to remove the excess mixture.

How to glue plywood to plywood if solid sheets are to be used? You just need to cover the surfaces with a mixture, and then press them with temporary dowel-nails.

It is not recommended to glue a laminated surface covered with a film, therefore, before applying the epoxy composition, the sheets must be cleaned sandpaper.

How to glue plywood to plywood so as not to disturb the texture of the material and not cause discoloration, but at the same time get a high-strength structure? PVA glue is ideal for interior work, and phenol or

The level of reliability of the connection is affected not only by the applied mixture, but also by strict adherence to the recommendations, since if the latter are violated, the properties of the adhesive may not fully open.

Glue composition

At the heart of almost any glue for gluing plywood are the following components:

main adhesive ingredient;
solvent;
filler, which is usually used as wood dust or flour;
additives, on which the curing rate and maximum adhesion directly depend;
plasticizer;
antiseptic.

The hardener is usually some kind of acid or ammonium chloride, and resistance to wetting is guaranteed by the presence of tannins (formalin, copper salts, etc.).

Adhesive Requirements

Glue for plywood should have the following positive qualities:

reliable fastening of materials;
ease of use at home;
good moisture resistance;
not susceptible to the destructive effects of bacteria and fungi.

It is equally important that the adhesive does not destroy the wood veneer and does not change its color.

Which glue is better: "KS" or "Tarbikol"?

When deciding how to glue plywood to plywood, people most often opt for "KS" or "Tabrikol".

A little more about their properties and features:

Influence of plywood brand on the choice of adhesive composition

The brand of suitable glue for plywood directly depends on the level of strength required and how high the humidity is in the room in which the structure is planned to be used.

What kind of glue to glue plywood to plywood, if ready product will be in a well ventilated area? PVA, protein or synthetic is well suited.

If you plan to make country furniture, which will be both indoors and outdoors, it is better to use one of the synthetic compounds.

After the choice was made in favor of a moisture-resistant material for interior, you need to determine how to glue plywood to plywood. Reviews indicate that the connection is best done with compositions based on the use of unlined sheets makes it possible to glue plywood with any type of glue.

How much glue do you need to lay plywood on a concrete surface?

The amount of consumption depends on the number of irregularities, the presence or absence of porosity and the quality of the screed. It should be based on the recommended consumption of 1.2-1.5 kg / m 2, but do not forget that the plywood must be laid on the base without voids. Only uniform pressing of the plywood to the base can ensure optimal distribution of the adhesive over the entire surface.

Tools and materials necessary for work

Before you start working with plywood, you should stock up on the following tools:

foam roller;
clamps;
hammer.

You also need to prepare the necessary materials:

blanks;
sanding paper;
nails.

Plywood gluing sequence

Before you get started, you should figure out how to glue plywood to plywood. The instructions below explain in as much detail as possible all the subtleties of this process:

First, plywood sheets must be cleaned of dust and various kinds of contaminants. To remove the laminated layer, you will need
Then the plywood should be thoroughly dried.
Distribution of glue to obtain an even layer is recommended to be carried out using a roller.
Now you need to press the plywood parts together with clamps. It is recommended to remove protruding excess with a knife and rags.
If there are large parts, then they will need to be connected with nails.
Finally, when the adhesive mass is completely dry, the product must be released from the clamps.

Coffee table from plywood scraps

Much has been said about how to glue plywood to plywood, but how to make something useful from this material?

After various repair work there are a lot of plywood scraps that just go to the trash can.

But it is these pieces that are ideal, for example, for creating an unusual and beautiful coffee table.

List of materials and tools needed for work:

a whole piece of thick cardboard small size for template;
many plywood pieces of the same thickness, from which the main structure will be made;
moisture resistant glue for wooden surfaces;
jigsaw;
pencil;
vise;
a circular saw;
Sander;

Gluing plywood: a practical example

How to quickly make a plywood table? First you need to make a paper template for cutting the legs of the product. Coffee table will look good on openwork or curved legs.

Have to take big leaf paper and draw legs on it in a scale of 1: 1. When transferring a drawing to cardboard, remember that finished construction should be located on symmetrical legs.

After completing the work with the template, you can proceed to gluing the plywood pieces. The manufacture of the structure must be carried out so that the shape resembles the future legs of the table. The gluing of each 2 parts must be accompanied by the removal of excess mortar and tight compression of the plywood pieces. At the end of the work, the legs should be placed on a flat surface, put a template on top of them and circle its outline with a pencil. To trim the excess structure, you will need a jigsaw. Place a worktop on top of the product and connect the parts together.

The procedure for gluing plywood on your own is as follows:

Processing of joints and the bordering surface of the material in order to degrease and remove dust and dirt residues.
If you want to glue laminated sheets, then the next step is to sand the material in order to get rid of the slippery laminated surface over the entire joint area. Or make it rougher.
Before gluing, take care of the quality drying of the sheets.
Apply glue to the adhesive surface with a roller for greater uniformity of the product.
Apply special clamps to ensure a fixed and tight fit of the parts to be glued. Attention! When gluing large parts, additional connection with self-tapping screws and / or nails is necessary.
Remove excess adhesive with a rag or knife.
After the adhesive has completely dried, remove the clamps.

Ready to get down to business?

Then cook the following materials and tools:

Nails and/or screws;
Sander with appropriate attachment or sanding paper;
clamps;
A hammer;
Rags;
Glue;
roller.

What glue to use?

To correctly answer this question, first decide how large pieces of plywood you want to connect and how to use after gluing.

For gluing construction (rough) plywood, which does not have a front layer, any adhesive composition is suitable. The main thing when connecting is to clean and degrease the glued surfaces of the sheets as efficiently as possible.

When gluing large sheets to each other, after applying the adhesive, the workpieces are pressed with temporary clamps.

If, when gluing plywood, it is important not to disturb the texture and color of the material, but to ensure a reliable connection, we recommend using PVA if the blanks will be used indoors in the future. If we are talking about outdoor use, epoxy or phenol would be ideal.

To ensure a strong and reliable connection of workpieces, it is important not only to choose the right glue, but also to use it correctly. Because violation of the technical regulations is fraught with "non-operation" of all the qualities of the adhesive composition.

Easy to use, suitable for household use;
Provides reliable fastening;
Resistant to moisture;
Inert to the effects of fungus and mold;
Non-violating color and composition.

Which glue is better: based on liquid glass or polyurethane?

The universal composition of the adhesive, which is based on liquid glass, guarantees high moisture resistance of the adhesive joint, as well as inertness to sudden temperature changes. Such a composition is ideal for gluing plywood to the floor, fiberboard or chipboard, as well as tile or glass.

Polyurethane-based glue is moisture resistant, does not collapse under the influence of ultraviolet radiation, provides excellent sound insulation, and dries quickly. Two-component polyurethane adhesive suitable for bonding laminated or varnished surfaces.

Choose glue by brand of plywood

Here it is important to proceed from the category of joint strength that must be obtained, as well as air humidity at further exploitation designs.

If the product after gluing will be in a well-dry and ventilated area, then synthetic glue, PVA or protein-based glue is perfect.

For plywood products that are going to be used both inside and outside, use synthetic glue.

Moisture-resistant plywood is better connected by compounds based on carbamide resin.

How to properly connect plywood parts with your own hands

The cross-layer arrangement in the plywood structure makes sheet material more resistant to warping compared to conventional wood panels. But these layers make it difficult to work with plywood - fastening parts end-to-end. Let's consider proven ways to connect plywood blanks with your own hands.

Right angles - the main assembly rule

Homemade mounting brackets will help to set right angles.

The use of mounting brackets for connecting plywood parts.

Do-it-yourself from pieces of chipboard several different-sized sets of these simple fixtures and use them when assembling large and small products.

Details of the mounting bracket: 1 - corner; 2 - long bar; 3 - short bar.

Saw diagonally a square blank with dimensions of 290x290 mm.

Production of mounting brackets for connecting plywood parts.

Mark the cutouts for the clamps on the corners and cut out the excess material.

Prepare the side planks and make countersunk holes in them.

Fasten the corner to the workbench by placing pads of suitable thickness under it. Tighten the screws while drilling pilot holes.

Cut a right angle at the junction of the planks so that when assembling it does not interfere with the tight fit of the parts.

Ready-made mounting bracket for joining plywood parts.

You can also make a mounting bracket with your own hands from thick plywood. Side bars are not needed here, the strength of the material is enough to fix it with clamps directly to the end of the fixture.

Drawing of a plywood mounting bracket.

Four ways to fasten plywood parts

Various methods of joining plywood parts at a right angle differ in the complexity of manufacturing and in the reliability of the resulting joint.

Just end to end

Plywood sheets are easiest to fasten end-to-end with glue and screws. The strength of such a connection is sufficient for many furniture blocks, especially if the structure is reinforced with facade strapping or pressed against neighboring modules.

Fastening plywood parts end-to-end.

Groove according to the width of the part

Reliable and easy to manufacture, the connecting unit firmly fixes the parts thanks to three glued planes.

How to glue plywood together: rules and methods of adhesive bonding

Plywood products, fastened with high-quality fitted grooves, serve for decades.

Fastening plywood parts in a groove along the width.

To make a groove recess, a circular saw or a wood milling machine is used. In the corners, such a connection should be reinforced with a wooden frame or self-tapping screws.

Tongue and groove

A strong butt joint consisting of a groove in a vertical panel and a tongue in a horizontal plywood sheet. Ideal for corners, and maximum strength is achieved by placing the comb on the bottom of the shelf.

Fastening plywood parts "comb and groove".

Forming a ridge and cutting a groove is best done with a manual milling cutter.

Two grooves and a rail

The connection of plywood parts with a rail inserted into the grooves will best solution for fastening sheets of non-standard and uneven thickness.

Fastening plywood parts according to the “two grooves and a rail” scheme.

To ensure that the workpieces are firmly fastened, glue both grooves with glue.

How to drill pilot holes for screws

Learn how to prevent plywood from cracking by making correct holes under fastener. Traditional screws with a tapered shank require drilling a mounting recess for the smooth part and a guide channel for the threaded part, plus you still need to deepen the head. Perform these operations in one pass with a combination drill with a tapered tip and an adjustable countersink.

Drilling pattern for traditional screws.

Advice.Screw brass screws into the threads made in the pilot hole with a steel screw of the same size.

Modern screws have a straight shank and a thinner top than the thread, so they don't need a mounting recess. It is convenient to drill pilot holes with the same combined equipment, but with a conventional drill, selected for each screw caliber.

The scheme of drilling holes for modern screws.

Self-tapping screws with a drilling tip and countersinking ribs on the head, allowing you to do without pre-drilling in soft wood, when twisting along the layers of plywood, splits often occur. Do not risk and waste time replacing a cracked workpiece - make holes even for screws with a drill at least half the depth and especially near the edges and ends.

Advice.Calculate the tightening force by selecting the appropriate screwdriver mode. It is better to leave the hat a little sticking out above the surface and tighten it with a screwdriver.

It is not necessary to determine the size of the pilot hole with an accuracy of fractions of a millimeter - this can be done “by eye”.

The diameter is suitable if the attached drill covers the body of the screw and not the thread.

When making grooves for the caps near the edge of the plywood sheet, stick masking tape on the drilling site so as not to destroy the top veneer.

When drilling pilot holes, fix the parts, preventing the movement of the workpieces and, as a result, the breakage of the drill.

Any fastening of plywood parts will be accurate and reliable only if the workpieces are precisely fitted. Make strictly perpendicular cuts of blanks. Always start by making a groove, and then adjust the comb under it.

It is very important that the floor in the apartment is warm and comfortable. Therefore, its installation begins with the laying of plywood, which will play the role of a base and will be able to ensure its stability and strength. This material, consisting of several layers of veneer made from coniferous wood, is predisposed to various types of fastening. It can be mounted with screws, nails or bolts.

How to glue plywood sheets together

But if you choose glue for this purpose, then the work will be much simpler and the result will be of high quality.

General issues

To the question of whether plywood can be glued, today there is a definite positive answer. Since various types of glue have been developed, choosing the right ones can glue plywood to any base. It will firmly connect with concrete, wood, as well as plastic and even metal. Bonding is a fairly easy manipulation that anyone with no prior skills can handle. Such a floor will be resistant to moisture and will not undergo aging. Also, this technology can be used in the arrangement of underfloor heating.

Dispersion adhesive

On the modern market There are several types of different adhesives available. In order to figure out which one is suitable in a particular case, you need to consider their characteristics.

When deciding which plywood adhesive to use, you can opt for an environmentally friendly, odorless and fumes-free dispersion adhesive. People call it PVA glue. It consists of a white suspension containing crushed polyvinyl acetate particles and water.

It qualitatively connects plywood with the base. But, despite all the above advantages, it also has a number of disadvantages. These include:

mandatory additional fastening with dowels and self-tapping screws;
curing for at least 1 week.

Before use, it is diluted with water or a special primer is added to it. For gluing 1 sq. m of plywood need a little more than one kilogram.

To the question of whether it can be used in children's institutions, offices, apartments - the answer is definitely positive.

alcohol glue

If you need to do the work quickly, then one-component glue is used for laying, which is also called alcohol. It is based on artificial resins and solvents, so it has a strong pungent odor that requires the use of a respirator during work and long-term ventilation of the room. Before applying it, the concrete screed must be primed. Additional bracing required. But at the same time, this glue has a number of advantages:

under normal conditions, it dries out after three days;
due to its consistency, it fills the cracks and does not leave voids, thereby compacting the rough base;
does not crack during operation, due to its high elasticity in the frozen form.

It has a higher flow rate per square meter than dispersion. You need about one and a half kilograms.

Two-component adhesive

Laying plywood on a two-component adhesive will be quick and hassle-free. Having a higher cost than analogues, it has a number of advantages, including:

plywood does not need to be additionally fixed with self-tapping screws;

the glue hardens in just two days;
has the highest strength.

This adhesive for plywood flooring is sold as two separate components - a resin and a special hardener, which must be mixed, adhering to correct proportions and immediately before use. It is recommended to work with the material using personal protective equipment.

Glue laying plywood technology

To provide proper styling and fixing the material on the screed from the solution, it is necessary to glue it. This ensures the coupling of two various surfaces, which guarantees a good quality of laying the preparatory floor layer (this process is shown in the video).

Installation should be carried out in the following sequence:

An adhesive composition is applied to a previously prepared even surface, about 2 mm.
Next, the wood adhesive material cut into squares, pre-numbered, is laid, each in its place. To eliminate air, you need to pass the roller over the squares, pressing them.
We carry out the final fixing by placing self-tapping screws around the perimeter of each tile, which should be much longer than the thickness of the sheet (see photo).

After processing the rough surface with a grinder, we glue the tiles on the plywood, having previously cleaned it of debris, primed it, smeared it with adhesive and prepared the tiles directly for laying. We glue the parquet in the same way.

The characteristic features of the cross veneer structure make plywood a more economical material that is less prone to buckling than conventional wood panels, especially when scaling up. But because of these layers, butt joints of parts are not very strong. Here are three ways to increase the strength of plywood structures.

1. Wide groove or tongue

Strong, reliable and easy to manufacture connections. A wide groove (across the fibers) or a tongue (along the fibers) tightly covers the counterpart and fixes it, having three bonding surfaces. As a rule, the groove is made half the thickness of the plywood. Cabinet furniture made using well-fitted tongues and grooves will last for decades. You can choose grooves and tongues on a saw machine or with a router. We prefer the slotted blade saw because it makes it easier to make multiple identical pieces and the job is faster. After choosing the right combination of outer discs, chippers and spacers to match the thickness of the plywood, install the slot disc on the spindle of your saw. Make a few trial passes on the scraps to achieve the desired tightness of the connection - the part should be inserted into the groove or tongue and removed with little effort, but not fall out when the assembly is turned over. Add or reduce the number of shim washers as needed.

Assemble a stack of slot disc from outer discs, chippers, and spacers next to a piece of plywood. Exact thickness matching can be found with a finger.

By adjusting the thickness of the grooving disk, you can cut all the grooves and tongues for parts of the same thickness. Using the longitudinal (parallel) stop, you will be sure that all the grooves on the same type of parts will match exactly.

When selecting grooves and tongues, it is safe to use the longitudinal (parallel) and transverse (angular) stops at the same time, since in these cases the cut will not be through.

IN corner connections such a selection becomes false. Since one of the bonding surfaces is lost in this case, it is better to reinforce the seam joints with additional means, such as screws or a solid wood facade frame covering the edges of the plywood.

Make a simple guide from the scraps - a T-shaped T-square and use it for milling grooves. Align the notch in the side stop of the T-square with the marks on the part to make the notch exactly where you want it.

To keep the comb length uniform, use a rebate cutter. Replacing the bearing allows you to change the width of the fold (and the length of the ridge). The density of the connection is regulated by the depth of milling.

For maximum strength position the comb on the underside of the part to be inserted. This connection broke when a heavy object was placed on the shelf.

2. Groove and tongue

Such a connection consists of a narrow groove and a ridge formed by a fold on the inserted part. It is excellent for corner applications as it has more bonding surfaces, greater strength and stiffness than a simple seam joint.

For the manufacture of such a connection, processing of both parts is required. First select the slots with a slotting disc or router with a straight or helical cutter. Then form those on the second fly a comb that fits snugly into the groove of the first. Make a few trial connections on the scraps to achieve the required assembly density.

3. Rail connection

This connection method avoids problems associated with non-standard or uneven plywood thickness. Since you define all the elements of the connection yourself, the thickness of the plywood does not matter. To ensure that both grooves match perfectly in width, make them with a router with the same straight or helical cutter. Make a simple router fixture from scraps, shown in figure, which should correspond to the thickness of your plywood parts (the dimensions of the fixture can be changed, but its side stops should tightly cover the plywood without preventing smooth movement). It is also possible to cut grooves quickly and easily on a saw machine with a slotting disc, but making a neat groove in the edge of a plywood piece is not easy, especially if the piece is long, as it has to be placed on the edge and becomes unstable. Therefore, we prefer the milling cutter. For maximum strength, the grooves in both pieces should be approximately one third the width of the plywood and the depth half the thickness. After choosing the grooves, cut the hardwood lath so that it fits snugly into both grooves, sawing it in width and length. Lubricate the bottom and walls of both grooves with glue to make the connection strong.

Such a device allows you to accurately mill grooves in the center of the edges of 19 mm plywood. Then a precisely fitted rail is glued into the grooves.

The cross-layering of the plywood structure makes the sheet material more resistant to buckling than conventional wood panels. But these layers make it difficult to work with plywood - fastening parts end-to-end.