Adhesives - Sticky Situations

So you thought that glue was glue and that if it’s sticky, it would stick, right? Think again!
 
Selecting the wrong glue for your project or repair job can often lead to it falling apart or, in a worst case scenario, cause irreversible damage to what you were trying to fix in the first place. With a myriad of glues and adhesives available at Mitre 10, the trick is in matching the correct glue to your project. This can be a daunting prospect with so many options to choose from.
No matter what type of glue you need, you must ensure it’s fit for purpose and that the materials you are bonding are prepared in accordance with the instructions.
Check the manufacturer’s details to ensure the adhesive you plan to use is appropriate for the materials you want to work on and the environment you are working in. For example, water-soluble glues and adhesives are not suitable for situations where they are likely to get wet on a regular basis.
 
Preparation of the surface you are working, before applying the adhesive, is extremely important. In most cases, this will mean it needs to be dry and free of dust and dirt. Some surfaces may need to have paint removed or the substrate exposed before applying the glue. Good preparation will help you achieve maximum adhesion.
 
In order to make your job easier, here’s our How To guide to glues.
 

PVA or white glue

One of the staples of any standard workshop, PVA glue is used for a wide range of woodwork projects. Non-toxic and easy to use, most PVA glues come in handy, squeezable bottles and can be stored for fairly long periods of time. As the glue doesn’t adhere well to plastic, it’s fairly simple to clean the nozzle out prior to use, rather than finding it all blocked up and impossible to use.
These glues are water-soluble and can be removed when wet with damp rag, making cleaning up excess glue an easy job. If you are staining or lacquering your project, however, sand the PVA surface thoroughly before applying stain, as the glue will show up as a white blemish under the surface.
A good example of this glue is Selleys Aquadhere Interior glue but there are other options that offer slightly advanced performance. For a stronger bond and water resistance, use Selleys Aquadhere Exterior in the same way as the interior product. Durabond is even more durable, featuring great resistance to acids, chemicals and water (although it is not suited to permanent water immersion).
 

Construction adhesives

Construction adhesives can be broken down into two basic types:
 
Solvent-based adhesives use a solvent within the mixture to make the glue easy to work with. As the solvent evaporates, the glue dries. Examples include Selleys Liquid Nails High Strength, Clear and Press ‘n’ Go and Sika’s Nailbond PB, SB and Premium construction adhesives as well as ADOS Nail-It. In addition to the readily available ‘generic’ products, manufacturers such as GIB® and James Hardie have their own construction adhesives that are specifically designed for their products.
 
Water-based adhesives work on a similar principle but use a water base instead of a solvent base. Selleys and Sika produce water-based adhesives such as Liquid Nails (Liqud Nails Fast) and Nailbond (Nailbond WB and Nailbond FAST). The advantage of water-based glues is that they are easier to clean up and don’t have the odour issues associated with solvent-based adhesives. There is also quite a drive to move towards products that have low VOC (Volatile Organic Compound) levels, such as water-based adhesives over solvent-based adhesives, as they are more environmentally friendly and healthier for those using them.
 
Typically used by tradespeople for construction work such as fixing wall linings or flooring, these adhesives can also be used around the home as they are extremely versatile and offer high durability.
Construction adhesives are supplied in tubes with a nozzle at one end and need to be fitted to a caulking gun for use. The size of the hole in the nozzle dictates the size of the bead of glue. When you have finished with a tube of construction adhesive, it pays to seal or plug the tip of the nozzle to prevent it hardening; try using an appropriately sized nail.
 
Cutting a large hole in the nozzle to create a large bead of glue will often lead to a mess when the glue is being applied. It’s always better to cut a slightly smaller hole in the nozzle and apply more beads of glue.
 

Instant glues

These are terrific for those ‘fix-it-now’ emergencies that crop up around the house from time-to-time.
If you’ve broken a family heirloom, such as an old plate or vase, and the pieces are big enough to put it back together, instant glues such as Superglue or one of the Selleys Quick Fix range will allow you to fix it quick, provided you take a bit of care.
The advantages of these instant glues are that they will stick to almost anything and there are specific glues for particular tasks. They do require a bit of care, as they will also stick your fingers together in an instant.
Because they can dry out quickly, keep the tube or bottles tightly capped and store them out of the reach of children to prevent any accidents.
 

Epoxies

Epoxy glues are designed for very high performance and come in two parts: the resin and the hardener. These need to be mixed together to create a chemical reaction, which will allow the glue to cure to create a very durable, high-strength bond.
Epoxies are available in a number of different packages from separate tubes or tubs, right through to dual-syringe cartridges that dispense resin and hardener in the required quantities. Selleys Araldite range even comes in ‘singles’ packs that only need to be mixed together before use.
Drying times for these glues can range from just a few minutes through to an hour or more. Once the resin and hardener have been mixed, you only have a limited time to use the glue before it starts to cure. To avoid wastage, mix the adhesive in small quantities so you can make the most use of them before they start to cure, rather than mixing a large amount and having it cure before you are finished.
Because they require mixing, they can be a bit messy to use and care must be taken not to inadvertently mix the caps of the two different products or ‘contaminate’ each component with residue from the other.
When cured, epoxy glues provide an extremely rigid bond and can be tooled (drilled, sanded or machined) in the same way as the material it is adhered to.
 

Contact adhesive

These are great for specific tasks, such as gluing large, thin sheets of material together or applying laminates and veneers to backing substrates.
Contact adhesives such as ADOS F2 or Selleys Kwik Grip range, are applied thinly to both surfaces, which are then carefully brought together. It really is essential that this be done with caution because, once the two surfaces meet, the bond is almost instantaneous and they will not be able to be repositioned. However, this does do away with the need to clamp or secure two items together while the glue is drying.
Both Selleys and ADOS offer contact adhesives in a useful spray can option, which is very handy for applying the thin layer of adhesive needed to create an even bond. They are also ideal when working with really thin materials such as paper or fabric. However, it does pay to lay down a suitable backing sheet before spraying to avoid any overspray.
 

Hot glue

Perfect for use in crafts and extremely handy where temporary bonds are needed to hold items together for a short period of time.
The adhesive itself comes in sticks or cylinders that are inserted into an electric gun and then heated until they become liquid and pliable. The glue is then applied by pulling the trigger of the gun. When the glue cools, the two surfaces being bonded are fixed together. Because the thermoplastic glue requires heat to activate it, take caution when using it, as getting it on your skin can be a vey painful experience.
Fullers offer both the gun and additional sticks of glue for sale at Mitre 10.