Home Repair and Paint Guide

There are a lot of different adhesives available from adhesive manufacturers. In fact, there are so many that it can be difficult to know which one to use in a given application. The choice can be made easier by classifying an adhesive by intended use or chemical type.

The strongest adhesives solidify by a chemical reaction. These also tend to generate heat during the process, sometimes getting quite hot. If you have ever performed any type of auto bodywork using plastic filler, you have experienced this type of reaction. Weaker types harden by some type of physical change.

Toughened acrylics are fast curing and used where high strength and resistance to fatigue are needed. They are available in one or two part compounds. In two part systems, adhesive is applied to one substrate and activator to the second. One good example of a two part system is the adhesive that you can purchase at auto parts stores to attach a rear-view mirror to a windshield.

Anaerobic adhesives cure when in contact with metal and air is excluded, such as a bolt driven into threads. They are often known as locking compounds and secure threaded parts.

Cyanoacrylate adhesives cure through reaction with moisture held on the bonded surfaces. They need close fitting joints and solidify in seconds. Cyanoacrylates are used to join small plastic parts and rubber.

Epoxy consists of an epoxy resin and hardener. There are a lot of different resins and hardeners available to cover a wide range of materials. Epoxy adhesive has good strength and low shrinkage. However, epoxies can have low peel strength and some tend to be brittle. Epoxy adhesives are available in one part, two part, and film forms.

Polyurethane adhesives are chemically reactive, fast curing one or two part systems. They provide strong joints which are impact resistant and have good low temperature strength. Polyurethanes are useful for bonding glass fibre reinforced plastics (GRP). The fast cure usually necessitates machine application.

Silicones are not very strong as far as adhesives are concerned. Their main features are flexibility and high temperature resistance. They are available in single or two part forms. Single part silicones are often used as bath and shower sealants, especially around tubs, sinks, and where ceramic tile meets the top of tub surfaces. Their adhesion to surfaces is only fair, but flexibility and durability are excellent. The two part versions require a hardening agent. Two part silicone systems work better in thick sections than single part types.

Phenolics are used for joining metal to metal and metal to wood. They require heat and pressure for the curing process. They have been in-use for a long time and produce strong joints.

Hot melts are based on thermoplastics and used for fast assembly. The parts to be joined should only be lightly loaded. These types of adhesives cannot handle high load or flexing of the joined materials.

Rubber adhesives and rubber sealants are highly flexible materials that are used to join components or fill gaps between seams. Rubber adhesives and sealants are available as aerosols, films, gels, liquids, slurries, solids, pastes, powders, and putties. They are compatible with substrates made from ceramics, glass, concrete, masonry, paper, rubbers, leather, textiles, metal, plastic, wood, porous surfaces, and composite materials. These types of adhesives are used in aerospace, automotive, electrical, electronic, marine, medical, and military applications. They are also used in abrasives, optics, photonics, and semiconductors. 

Pressure sensitive adhesives are suited for use as tapes and labels. This type of adhesive is not suitable for sustained loads.

Cellulose wallpaper paste has very high water content, around 97%. It usually comes in a small box and is packaged as a white powder. It is mixed with cold water used with a variety of lightweight materials such as porous papers, grasscloth and silk. It leaves very little solids behind and is not suitable for many wallcoverings which require greater amounts of initial tack and holding power.

Wheat wallpaper paste is about 90% water, depending on how much water is mixed with the product. It is used under many wallcovering products that can be successfully hung with this adhesive, including blankstock lining paper, porous handprints, grasscloth, strings, and silks.

Premixed vinyl clay adhesive was developed to hang vinyl wallpaper. There is a machine grade designed for use in pasting machines. The color ranges from tan to gray and is packaged in 1 and 5 gallon pails. Clay base premix has the lowest water content (40-50%) of any wallpaper paste and is often used for wallcoverings which require good tack, such as commercial vinyl, foils, and heavily inked handprints.

Premixed vinyl clear adhesive is based on natural or synthetic polymers. Many are designated for use on bare sheetrock and allow future stripping when redecorating. Clears may be used successfully with the widest variety of wallcoverings. Water content is usually in the 60-70% range.