Adhesives Buying Guide

Getting Started

Adhesives are a category of liquids and semi-liquids that have a huge list of residential and commercial applications. They range from complex epoxies with multiple components to simple wood glue. They often have the same properties, but some of them are more advanced than others. Some adhesives are more flexible while others are stronger. There are hundreds of types of each on the market, so it's easy to pick the wrong model for the wrong material. It's a mistake to think, for example, that wood adhesive is suitable for driveway cracks.

What to Consider

The word adhesive refers to glue. According to the word, it's glue that should adhere to the material its bonding. There is a wide range of products available that claim they can stick to everything within a minute. The truth is, it's not possible due to different properties of materials. For example, some are impervious to air or water, others are porous. Some are rigid, others are flexible.

All adhesives are different. Some require lengthy drying time, others can dry immediately. Some need pressure for a proper bond. Some dry because of a chemical reaction that happens when several active components are combined (take epoxies, for example) and others dry by evaporation. Application methods are also quite different. Note that even when a manufacturer says the bond is secured in a minute, it's best to wait for at least an hour.

Whatever surface you're sticking, you need to make sure it's clean, not dump or wet and free of dust. If necessary, hold everything together with a tape, temporary nails or clamps until everything is dry. It's worth checking setting times - and keeping in mind that they usually vary in summer and winter due to temperature differences and humidity levels.

When you use an adhesive, make sure to carefully read and follow the instructions, Work in a well-ventilated area since some of them contain solvents that give off fumes. Be cautious with superglues which can easily bond to your skin. It's also should be noticed that a lot of adhesives are flammable.

Types

PVA (Polyvinyl adhesive) - Polyvinyl adhesive, also known as PVAs are general-purpose formulas that also come as wood and building adhesives. Although they often look white when you get them out the tube, they become transparent when they dry. There are also waterproof models, which are perfect for areas that can get damp.

Rubber-based contact adhesives - Rubber-based contact adhesives are specifically designed for rubber based uses. They come in clear or yellow liquids. Use these to glue wood, plaster, man-made boards or synthetic laminates. You should apply it to both surfaces and then press them together with tape, clips or heavier objects.

Epoxy resin adhesives (two-part adhesives) - You can stick ceramics, stone, metal, rigid plastic or glass to materials like glass or wood with epoxy resin adhesives. They are great for joints that should be waterproof as well as for the outdoor use. Note, that those in powder form can be toxic. Always check the product description and the labels, as some of these adhesives don't stick to certain materials.

There is also a second class of epoxy resin adhesives. They are fast curing and can set in several minutes. They are useful when time is important. They can stick to most materials but last less than those which take longer to set.

Hot glue - Hot glue is common for DIY work and crafts. It comes in a gun in which the glue sticks are melted and then applied to the material. It looks like a gel when melted and it solidifies to a solid afterward. Hot glue is very strong and works best if applied on substantial amount.

Flooring adhesives (rubber resin adhesives) - These are latex and synthetic adhesives that can stick floor coverings to floors. And they can withstand water and allow slight flexibility, so you don't need to worry that it will crack when you put furniture or walk on your floor.

Tile/coving adhesives (synthetic latex adhesives) - Tile/coving adhesives fill gaps, which makes them perfect for coving corners or fixing expanded ceiling tiles. You can also use it on floor tiles. Just like the previous type of adhesive, they are more flexible than others and don't crack that easy.

Filler adhesives (polyurethane-foam adhesives) - Filler adhesives are sold in pressurized cans and make perfect gap-filler in masonry, wood, plaster and stone because the foam expands after you spray it. However, you can't just remove them and will have to get a specially formulated solvent.

Super-glues (cyanoacrylates) - Everyone knows super-glues: these fast-working glues can stick to all kind of small objects, including glass, plastic, metal or plastic. But be careful because that can also stick to your skin, hair and clothes. And if you stick two wrong objects together, you'll have to get a superglue remover to tear them apart.

Silicone - Silicone can be used both as an adhesive and as a sealant. It can seal glass in windows but it can also be used to glue glass to metal or glass to wood. It is flexible, durable and waterproof. Silicone is a multipurpose material that is widely used to seal aluminum windows and in many other home improvement projects and construction works. There are many types of silicone, some of the, are designed for high temperatures such as those for car engines. Silicone can join plastic but it works best only if you can put a good amount if it.

Mastic - Mastic is a unique organic adhesive that comes from the resin of the tree. This resin is sticky and used in commercial application, construction, and tile installations as an adhesive. It comes in many forms, such as sticky paste, glue or thin liquid and often packed in a tube or a pail.

Using this natural adhesive has its strong and weak sides. Unlike other adhesives, mastic is premixed and ready to use straight from the tube, making it a time-saver. It's usually sticker and set more quickly than other adhesives, which is very handy for vertical surfaces where you want the tile to stay in place, like a kitchen backlash. While mastic has high bond strength and everyone can use it, it also has drawbacks. Since mastic can re-emulsify and react with water, you can't use it in areas that have any contact with water. If the mastic re-emulsifies, the tile will lose adhesion and fall from the wall. This can be a problem in shower and tub surrounds even if there is no direct contact with water or other liquids. Tile that is not sealed properly or a grout crack can allow moisture to get to the mastic. Besides, since mastic is made of organic components it is more prone to harboring mold if there is water present.

Another important drawback is that it cannot provide much structural support. You absolutely have to make the surface even in order to prevent tile lippage. Mastic can't be applied if the surface has minor imperfections. Thus, a lot of work should often be done before actually using mastic.

Choosing the Right Adhesive

When you're in the market for an adhesive, you need to think what job you're going to use it for. However, there are also several things that are worth taking into consideration.

What Types of Materials Are You Going to Glue Together?

The adhesive you use should be suitable for both materials you're going to glue together. It's especially important if two elements are made of different materials. This can be a bit tricky if you want to glue plastic to something, because there are so many types of plastic out there and it's hard to find out which type you're dealing with.

How Strong Do You Want the Hold to Be?

Let's take wood glue as an example. The bond wood glue creates is usually the same as the strength of the wood. However, metal glue or plastic glue are often weaker. If strength means a lot to your project, you may think whether there is something you can do to reinforce the materials.

What is the Size of the Gap?

In most cases, when you glue two objects together, you need to fill a gap with glue. The size of the gap is another thing to consider as different adhesive work best with different gap sizes. Contact adhesive, for example, works well with medium-sized gaps. Cyanoacrylate, however, works only with very tiny gaps. Epoxy glue works great with wide gaps, but it also suitable for smaller gaps.

Will there be Major Temperature Changes?

Sometimes you can find the word "thermoplastics" on an adhesive, meaning it can melt and lose its properties if the temperature rises. If you know this could happen, you should go for the thermosetting glue instead as it can withstand hot temperatures much better.