Finishing Continued

This article will explore the various options for finishing internal timber works such as furniture, chests and tables.

Types of Finishes

Different types of products offer different degrees of protection, durability, ease of application and appearance.

Wood finishes come in two different types - evaporative and reactive.

Evaporative finishes - Evaporative finishes include lacquer, shellac and many water-based finishes. This is where the finish dries hard as the solvent or carrier evaporates.

Reactive finishes - Reactive finishes include linseed or tung oil, catalysed lacquers and varnishes. These finishes also contain solvents that evaporate but they cure by a chemical reaction, either by air or a chemical placed into the finish.

Product Categories

1. Waxes

2. Oils

3. Varnishes

4. Shellacs

5. Lacquers

Here is a list of various finishing products to protect and maintain timber which highlight the different features of each finish, their usage and common brands.

Wax

• Creates Shine

• Short protection time and needs frequent application

• Safe when solvents in paste wax evaporate

• Easy application

• Requires sanding and buffing after application

• Can be easily removed with solvents

• Not recommended as an appropriate finish in and of itself

• Can use paste wax (carnauba mostly, sometimes beeswax) to polish furniture but only over other finishes, such as lacquer or shellac

• Brands:

  • Gilly’s Clear Cabinet Makers Wax

  • Gilly’s 100g Carnauba Wax flakes

  • Feast Watson Timber wax spray

Tung Oil

• Derived from the nuts of trees that are native to Southern China.

• Available in a pure, unrefined form and in a heat-treated or polymerised form.

• The heat-treating process makes the oil a bit more durable and speeds up the drying time.

• Gives a warm glow and helps bring grain forward.

• Only provides short-term protection but it’s fairly durable, depending on the number of coats.

• Easy to apply with rags the excess wiped off.

• Brands

  • Feast Watson Tung oil

Linseed Oil

• Unrefined, it's called raw linseed oil, which is rarely used on wood because it dries so slowly

• Boiled Linseed oil has been mixed with chemical additives to speed up the drying time

• Gives a warm glow, ‘popping’ the grain, and darkens with age

• It only provides short-term protection but it’s fairly durable, depending on the number of coats.

• Easy to apply with rags the excess wiped off.

• Brands:

  • Diggers Boiled Linseed oil

Varnishes

• Made of tough and durable synthetic resins that have been modified with drying oils

• Transparent in colour - needs quite a few coats

• Can have a matt, satin or glossy sheen.

• Durable after approx. 30 day curing period

• Most durable finish that can be easily applied by the average woodworker with clean paint brushes

• Varnish surpasses most other finishes in its resistance to water, heat, solvents and chemicals

• Brands:

  • Feast Watson Gloss/matt/satin clear varnish

  • Feast Watson Weatherproof Clear varnish

  • Cabot’s water based Gloss/matt/satin varnish

Oil Varnish Blends

• These mixtures, mostly oil with some varnish added, offer some of the best attributes of both ingredients: the easy application of true oils and the protective qualities of varnish.

• Danish oil, teak oil and a number of other finishes fall into this category. Oil and varnish blends will dry a bit harder than true oils, and the finishes will build quicker with fewer applications.

• Brands:

  • Feast Watson Teak oil

  • Feast Watson Scandinavian oil

  • Johnstone’s Teak oil

  • Cabot’s Clear Danish oil

  • Cabot’s Oil Based Gloss/matt/satin varnish

Shellacs

• Natural resin refined into dry flakes, the processed to make the shellac solution that is ready for use.

• Very shiny, some with a yellow or orange tint depending on grade used

• Fair protection against water, good on solvents except alcohol as alcohol completely dissolves shellac.

• Very durable

• Safe when solvent evaporates, used as food and pill coating

• Very difficult technique to master (French polishing)

• Excellent rubbing qualities

• Brands

  • Feast Watson Mastertouch shellac flakes

Lacquers

• Great all round finish, dries fast, gives the timber a great rich colour and is moderately durable with decent protection (depending on type of timber) and rubs out well.

• Transparent colour with good gloss

• Several different type of lacquer that all exhibit different performance characteristics.

• Brands

  • Bailey Pre-Catalyzed Spray Lacquer

Where to Source These Finishes

Most of the brands that have been listed here are available at your local Bunnings or Mitre-10 store but there is also a plethora of other brands as well that can be bought online or at specialist stores.

If you are just working on one project we would recommend buying the smaller tins of finish as you are much less likely to use a large tin.

How to Apply a Finish

All of the finishes listed above require different application processes.

Make sure that you always read the back of the tin of finish for directions. If you have any questions please come to speak to any of the MSD Machine Workshop Technicians.

There are also a plethora of youtube videos all about finishing timber with different products so feel free to do your own research.

Environmental Considerations

Figure 1. Application of highly flammable finishes e.g. lacquer

A solvent-based finish, such as varnish and lacquer, contains a good deal of organic solvents, which are highly flammable and can affect the environment as well as your health. If you are not applying the finishes in a controlled environment, which is easy to clean, and/or these particulars irritate you, use a water-based finish to eliminate the fire hazard and to mitigate the environmental and health impact.

Pure oil is a good alternative to a solvent-based lacquer or varnish: Pure oil contains no solvents and comes from renewable resources. However, oil-soaked rags must be disposed of carefully in the flammable bins provided in the metal works area outside the workshop.

Shellac is also a good alternative, as the solvent for shellac (i.e. methylated spirits) is distilled from corn, and most people don’t find it irritating or the smell too bad. Shellac is much harder to apply and is not recommended without some prior experience.

Figure 2. Bench top. Designer: Thor’s Hammer

All finishes are nontoxic when fully cured as once the solvents have evaporated; any cured film is safe for contact with food. This does not mean that the finish itself is safe to ingest, it simply means that additives such as heavy-metal driers and plasticisers are encapsulated well enough that they do not migrate into your food. E.g. Wax and shellac are what are used to coat apples, medication pills and lollies like skittles.