Gluing

This article will cover what and why gluing is important in wood work, what glue to buy, where to buy it, how to apply it, how to clamp your glue up and how to clean up excess glue.

Introduction

Gluing is the step before finishing, where glue is applied to the joints for strength and stability. Timber glue comes in various types: polyvinyl acetate (PVA), polyurethane, cyanoacrylate, animal or hide, and epoxy. The main reason to glue your piece is to ensure that the joints are strong, stable, square and future-proof.

The gluing process involves: selecting and sourcing the appropriate glue, preparing the glue-up, applying the glue, clamping the glued parts, waiting for the glue to dry, and cleaning off the glue.

Before purchasing any glues make sure they are on the approved materials list or send the relevant MSDS to [e-mail] and request a review.

Selecting the glue

PVA wood glue is recommended for the vast majority of wood working projects. Below are 3 PVA glues recommended for interior use projects, water resistant and waterproof interior/ exterior use projects.

PVA recommended	Usage	Assembly time	Drying time	Cost (473ml)
Titebond Original	Interior project e.g. side table	4 - 6 mins	30 mins clamped + 12 hrs no handling	$12.50
Titebond II Premium	Water resistant project e.g. outdoor furniture	3 - 5 mins	30 mins clamped + 12 hrs no handling	$17.00
Titebond III Ultimate	Water proof project e.g. chopping board	8 - 10 mins	30 mins clamped + 12 hrs no handling	$23.00

The tabs below provides more detail on the various types of wood glues you may consider.

PVA wood glue

PVA wood glue (e.g. Titebond, Gorilla) is a strong, non toxic, water-soluble glue, excellent for any wood work projects.

Advantages: Strong (stronger than timber itself), low cost, non-toxic, no required preparation, fast drying time (30mins - 1hr clamped + 12 hrs no handling), easy to clean off wet glue with damp cloth, and is waterproof (if specified).

Disadvantages: Fast assembly time (4 - 10mins). Does not act as a filler, and does not adhere if there are gaps, or existing glue/ finish.

Epoxy

Epoxy (e.g. West System, Solid Solutions) is a 2 part glue with a lengthy assembly time, excellent for any wood work projects that need extra time for glueing, such as for veneer laminations.

Advantages: Lengthy assembly time (10 - 56mins) and fast curing time (6 - 15hrs), depending on hardener used. It can act as a filler, it adheres to existing finishes (except polyurethane) and it is waterproof.

Disadvantages: Very costly, toxic, requires preparation for both the epoxy (mixing part A + part B) and your project (applying packaging tape to non gluing surfaces). Requires chemicals to clean up wet mixed epoxy residue (e.g. lacquer thinner, acetone, or alcohol) and warm soapy water to clean wet hardener residue.

Polyurethane

Polyurethane glue (e.g. Titebond, Selleys, Sikabond) is a strong glue, excellent for projects that combine timber with other materials such as ceramic, metals, glass and some plastics.

Advantages: Adheres to most materials, strong, lengthy assembly time (10 - 20mins or until there is excessive foam development) and fast curing time (45mins - 4hrs clamped or until squeeze out becomes firm), works on existing finish and is waterproof.

Disadvantages: Costly, toxic, does not act as a filler, and does not adhere if there are gaps. Assembly and clamp time are affected by changes in humidity, temperature and moisture content of timber. Requires mineral spirits to clean up wet glue.

Super glue

Super glue/ Cyanoacrylate (e.g. Zap, Starbond) is an excellent glue for wood work projects that requires repairs, fillings, inlays, and temporary clamping pieces (given its poor sheer strength).

Advantages: Fast drying time of 1 - 5 seconds, can be used as a crack/gap filler, easy to clean off by sanding, works on existing finish, and is waterproof.

Disadvantages: Very costly, toxic, and poor sheer strength.

Animal/ Hide

Animal/ Hide glue (e.g. Titebond, Ubeaut) is a strong, non toxic glue, excellent for wood work projects that requires reversibility (given its capabilities to be warmed up to make adjustments).

Advantages: Strong, non toxic, adheres to existing finish and adheres to existing animal/hide glue (when warmed up).

Disadvantages: Costly, strong smell, not waterproof, and preparation time + working time + curing time vary depending on animal/ hide glue brand. Does not act as a filler, and does not adhere if there are gaps.

Buying the glue

Titebond Original is available to all students and staff in the MSD Machine Workshop.

If you require Titebond Original in a larger quantity or looking for a different type of wood glue, below are recommended glues and suppliers.

PVA wood glue

Brands	Titebond
Suppliers	Carbatec Melbourne Carroll's Woodcraft Delta Recycling Euro Wood Coatings Sandpaper Plus Timbecon Urban Salvage Timber Revival

Epoxy

Brands	West System	Techniglue
Suppliers	Carbatec Melbourne Discount Seamart Eco Timber Group Renovators Paradise Timber Revival Renovators Paradise Sandpaper Plus Urban Salvage Wooden Boat Centre	Boating Central Carbatec Melbourne Canoes Plus CH Smith Marine Timbecon

Polyurethane

Brands	Titebond	Selleys, Sikabond
Suppliers	Carbatec Melbourne Carroll's Woodcraft Delta Recycling Euro Wood Coatings Sandpaper Plus Timbecon Urban Salvage Timber Revival	Bunnings

Super glue

Brands	Zap	Starbond	Hot Stuff Glue	Loctite 401
Suppliers	Timbecon	Carroll's Woodcraft	Carbatec Melbourne	Bolts & Industrial Supplies BSC Insdustrial Repco

Animal/ Hide

Brands	Titebond	Ubeaut
Suppliers	Carbatec Melbourne Carroll's Woodcraft Delta Recycling Euro Wood Coatings Sandpaper Plus Timbecon Urban Salvage Timber Revival	Carbatec Melbourne

Preparing to glue

Get your work ready - Ensure all the gluing faces, edges and joints are clean and free from gaps. Consider adding masking tape along the joints that are hard to access (e.g. inside of a box) for glue squeeze out.

Set up your work bench - Clear your work bench, place a plastic sheet on the bench to protect it from glue, select and organise the appropriate clamps, the appropriate glue and application tools (e.g. brush).

Do a dry run - Before applying any glue, clamp up your work to ensure that all the joints are pressed tightly together. Remove the clamps and keep them organised, keeping in mind that you need to glue within the 'working time' of the glue (e.g. Titebond Original has a 4 - 6 minute working time/ assembly time).

Ensure that surfaces being glued are touching. If they are gaps, no matter how much glue is applied, surfaces will not bond.

Applying the glue

Application tool - Use a roller or a brush (available in the MSD Machine Workshop)

Amount to apply - Apply glue evenly to all surfaces being glued. Too little glue will cause a weak joint, and too much glue will result in a mess and will waste the glue.

Clamping

There are various clamps available in the MSD Machine Workshop for gluing.

1 Parallel clamp, 2 Band clamp, 3 Corner clamp, 4 F-clamp, 5 Sash clamp

For more information on the various clamps available in the MSD Machine Workshop, click here.

Below are some tips on how to clamp flat boards, laminated sheets and mitred edges.

Flat boards

When clamping a flat board with glued edges (e.g. a table top), equally space clamps (Parallel or Sash clamps) on the bench and on top of your work piece. The equal spacing and clamping pressure applied on both the top and bottom, will reduce the risk of your workpiece bowing. When using Sash clamps, use timber blocks between the metal vice to avoid damaging your workpiece.

Laminated sheets

When laminating sheets (e.g. a contour site model to CNC), equally space F-clamps around the outside of your workpiece to pressure between the top and the bottom. Keep the sheets aligned using Parallel clamps. Apply equal pressure across the entire top/ bottom surface using the concrete blocks available in the MSD Machine Workshop.

Laminating sheets using clamps can be tricky to achieve. If laminating more than 2 sheets, use the Vacuum Bag available in the MSD Machine Workshop.

Mitred edges

When clamping mitred edges (e.g. a box), use a band clamp around the top and around the bottom of your workpiece. If your workpiece is narrow (e.g. a picture frame), 1 band clamp will suffice. Alternatively, a continuous strip of masking tape can be used in tension around your workpiece acting as a clamping device.

Cleaning the glue

It is inevitable to have glue squeeze out when glueing, and cleaning up the excess glue is a critical part of the part of the process. It will ensure that the finish (e.g. oil) can be absorbed in the timber to protect it.

There are different methods for cleaning up excess glue. Below are 3 suggestions to clean up PVA.

• Recommended Method: Use a damp cloth while glue is wet. Once dry, sand excess glue.

• Wait 24 hours, scrape off glue and sand excess.

• Wait 30 minutes to 1 hour, or until glue is tacky, and peel off glue.

Ensure that all the surfaces and corners are free from glue so that the finish can be absorbed.

What is next?

Double check that all surface is free from any glue. If it is, then it’s time to start finishing!