An irreplaceable little man in construction - types and use of


The first adhesives were made by boiling the skins, hooves and horns of animals to extract collagen, the base adhesive for hides. Slime is used in making furniture, book binding, repairing pottery and other items. Most adhesives today are made from polymers, which are a group of compounds made up of large molecules with repeating subunits. The molecular structure of polymers gives them strength and elasticity, making polymers (both natural and artificial) ubiquitous in everyday life. Wool, rubber, styrofoam, and epoxy are just a few of the polymers you may already be familiar with.

1. Cyanoacrylate, also known as superglue.

Cyanoacrylates are a group of adhesives that form long, strong polymer chains in the presence of water. If the term is unfamiliar, you may recognize the trademarks for the most popular types of cyanoacrylate adhesives—Super Glue and Crazy Glue. In fact, this type of adhesive is very strong, with a tensile strength of up to 4000 psi (depending on the material it is bonding) and has nothing to do with a two part epoxy system. Given its durability and relative ease of use, you may wonder why its use is limited to minor repairs. Cyanoacrylate proved to be revolutionary in industrial, medical and technical production, but it did not play a big role in the construction of buildings, because it is not a very good structural adhesive.

How does cyanoacrylate work?

The acrylate groups of cyanoacrylates form polymers in the presence of moisture. “Because we have a very moisture-rich atmosphere,” Jordan explained, “when you open the superglue, the moisture gets in very quickly and hardens the entire tube. However, in other cases, you may need to add some moisture. When using cyanoacrylates to bond non-porous materials such as glass or steel, you may need to spray them lightly before applying the adhesive.

When to use cyanoacrylates

The main factor in favor of cyanoacrylate is its ease of use compared to some other adhesives. Super glue is also compatible with most materials, both porous and non-porous. However, there are a few downsides to consider: fast setup times, leaving you little time for positioning and clamping work, and low ductility - brittle joints that don't withstand impact loads well. • When you need something easy to use. Unlike two-component epoxy resins, complex mixing is not required. Just apply a small amount of glue to the surface you want to glue with another glue. • Projects requiring a strong connection. Its tensile strength is comparable to epoxy and polyurethane products. • When you work fast. Usually superglue does not require a clamp.Just let the two objects you are joining for a few minutes and they will set (although it is best to leave them for 24 hours to fully cure). • Small projects. Cyanoacrylate is much more expensive than other adhesives, so use it for small repairs rather than large projects.

2. PVA (polyvinyl acetate), also known as PVA glue or wood glue.

The first glue you will use will most likely be PVA: Elmer's glue. Wood glue is a particularly strong form of PVA. The ingredient that makes PVA effective as an adhesive is polyvinyl acetate, a rubbery polymer that forms strong bonds when it dries. One of its advantages when it comes to wood (and some other porous materials) is that the adhesive penetrates the fibers, creating a stronger bond as it hardens.

Cyanoacrylates use moisture from the atmosphere to cure, while PVA removes moisture to cure. PVAs are a more flexible type of adhesive, which means they are more brittle than cyanoacrylates and take longer to cure. A longer cure time will give you more time to work, but it also means you have to be careful not to disturb it while it cures or the bond will break.

Coming in a variety of colors and grades (wood glue is the common name for a yellowish tint and some are for outdoor use), there is wood glue for just about every woodworking project, including both indoor and outdoor. . As a general rule, you will need to clamp the PVA bond for the first 30 minutes to 1 hour while the adhesive sets as it dries. Complete healing takes 18 to 24 hours.

How strong is wood glue?

Wood adhesive strength ranges from 3600 to 4000 psi, which means they can withstand pressures of 3600 to 4000 psi. The bonds of wood glue and epoxy and polyurethane adhesives (both of which can be used to join wood) are stronger than most woods. This means that the wood is more likely to break down before bonding.

When to use PVA wood glue

PVA Wood Adhesive is widely used in furniture, joinery and finished joinery and is often used in combination with fasteners. Fasteners are typically used to hold tightly together while the adhesive is curing. The final product will hold together with the strength of the adhesive, but the nails hold it in place until the adhesive has reached its final strength.

3. Polyurethane adhesive, also known as general construction adhesive.

Polyurethane adhesive entered the US market before 1994, when Gorilla Glue began selling polyurethane adhesive. (For many Americans, Gorilla glue is more familiar to polyurethane than its chemical name. Over the past two decades, it has become one of the most common construction adhesives contractors rely on for a variety of jobs. Popular brands include Titebond and Loctite.Similar cyanoacrylate adhesives, polyurethane adhesives for curingIt requires a chemical reaction that is initiated by moisture.If you bond concrete to wood, there is no problem: there is moisture in concrete, there is moisture in wood. materials are not porous, additional moisture is required. Jordan recommends simply using a small watering can to dampen one side of the joint, then apply glue to the other side and seal them tightly.

When to Use Polyurethane Adhesive

While using polyurethane as an adhesive is not particularly difficult (although it can be messier than some other adhesives), you first need to understand its pros and cons compared to wood glue, epoxies, and other options. • Connect dissimilar materials. Polyurethane adhesives are truly versatile products that can be used to bond a wide variety of building materials: wood, glass, concrete, metal, carpet, etc. If you are bonding two non-porous materials (such as metal to metal), be sure to dampen the surfaces before gluing them. • Outdoor projects. Polyurethane adhesive is water resistant, making it a good outdoor adhesive. (although they do not withstand immersion in water for long periods of time.• When you need to paint. While some conventional adhesives may be degraded by painting, polyurethane can be painted after it has cured. • When you work a little faster Although a clamp is recommended, polyurethane usually has a shorter setting time than epoxy.

4. Epoxy

Very versatile, durable and extremely heat resistant, epoxy adhesives can be used in almost any situation where you need to bond two materials, such as gluing subfloors, gluing parts to larger structures, or reinforcing fasteners.

Epoxy adhesives can be used on a variety of materials: wood, metal, plastic, masonry, etc. Epoxy adhesives come in two main types: one-component (or thermoset) and two-component epoxy resins. One-part epoxies cure faster, although they are generally not as strong as two-part epoxies.

• Heat-curing epoxies have a wide range of industrial applications, but are not commonly used in general construction because of the high temperature requirements for their curing - even those that react at the lowest heat levels. Exposure to temperatures of at least 200 degrees Fahrenheit is required. • Two-component epoxy resins consist of two components that must be combined in order for a chemical reaction to occur. When resin (commonly referred to as "steel") is mixed with a hardener, the result changes from a viscous liquid to a putty within 24 hours and eventually to a fully cured and hardened material. Like their thermoset counterparts, two-component epoxy resins areare widely used in the automotive, aerospace and other industries, especially in shipbuilding. They are also used in architectural projects where applications include bonding countertops to substrates, attaching concrete elements to other concrete, stone or metal elements, and securing moldings in place.

When to use epoxy adhesives:

Two-component epoxies are commonly used in architectural projects where joining countertops to substrates, bonding concrete elements to other concrete, stone or metal elements, and fixing decorative moldings in place. • When strength is everything: Epoxy's polymeric structure creates a remarkably strong bond that is water resistant and able to withstand high temperatures. • Bonding dissimilar materials: epoxies can bond a variety of materials, while other common adhesives are of more limited use. Polyvinyl acetate adhesives, for example, require porous surfaces, while epoxies are more flexible.

5. Glue for needlework

There are several different types of glue that are suitable for small jobs around the house. Aerosol glue, fabric glue, pressure sensitive glue (usually packaged in sheets or dots) and hot glue (pumped through a glue gun) are suitable for lightweight substrates such as paper, plastic, foam, felt, etc. Although they may being cousins ​​to the adhesives listed above - fabric adhesive, for example, is usually a type of PVA - they lack the strength of construction adhesives and should therefore be used for crafts rather than construction.

Market prices for different types of glue

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