Andrew Thomas looks at using wood finishes
Wood finishing is an important and extremely enjoyable skill to learn which, if accomplished correctly, greatly enhances and enriches the natural beauty of wood and consequently the overall attraction of the finished form. This is, of course, a very personal matter for which we all have our own individual preferences and favourites.
In this article I will outline and demonstrate some of the finishes that are available to purchase, and evaluate their effectiveness for the purpose of application to woodcarvings and sculptures.
There are literally dozens of prepared wood finishes available to purchase that are appropriate for woodcarvings and sculptures. These basically fall into the categories of; oil, wax polish and bleach. These can be traditional or modern formulations, with either a hard durable surface, or a softer less durable one. Each of these products creates a slightly different variation of colour tone and effect on the wood grain, which takes practice and experience to understand and predict.
A selection of finishes
Most species of wood, whether hard or softwoods, can be carved to a greater or lesser degree, but hardwood is generally accepted as the first choice. I have selected some of the more commonly used hardwoods for carving, to demonstrate the colour and effects that are achievable with the various wood finishes featured. These have been sanded to 400 grit and are their natural colour before any finishes have been applied.
The traditional oiled wood finishes are arguably the most effective product for enriching the natural beauty of wood grain, in particular the darker species, such as walnut. It is an absolute joy to use and gives immediate results by penetrating deeply into the wood grain and enhancing the various colour tones.
Use a clean, small lint-free soft cloth, approximately 50 x 50mm, to apply the oil, working in the direction of the grain. Apply the oil fairly liberally but do not let it pool into any corners as it can clog the detail (especially boiled linseed oil, which will dry to a rubbery residue, requiring it to be scraped out). Wipe off any surplus oil with a clean dry cloth after a few minutes. Awkward areas can be reached by using a small brush. Please note that oily cloths are prone to spontaneous combustion and must be disposed of carefully outdoors. Please read the warnings on the product data sheets or labels, and follow these guidelines to the letter each and every time you use it!
Boiled linseed oil
Interior: One coat
Exterior: Two to three coats
Drying time: 16–24 hours
Boiled linseed oil is extremely good value for money and offers a most beautifully rich enhancement to the natural colour of timber. For lighter species of wood, such as lime, it produces a deep golden tone, which is sometimes of value for a specific project, but not often appropriate. For darker timbers such as walnut, tulipwood, pear and cherry, it really adds a superior depth to the natural colour tones of the wood which can be exceptionally exquisite on highly figured timber. Boiled linseed oil is a standalone finish in its own right, but dark wax can be used to great effect on top. This should initially be applied after two weeks, and then again one month later, which produces a wonderful medium to high lustre finish, and dramatically enhances the grain and figure.
Interior only: Three coats
Drying time: Four to six hours
Danish oil is quite different from the boiled linseed oil, as it is a blend of oils (including tung oil), resins and dryers, which produce a harder and more durable low lustre satin finish for interior wood. It is slightly thinner in its viscosity and produces a lighter depth of enrichment to the grain colour, but is still very attractive. This finish suits the spectrum of browns from light to dark, and therefore works nicely for all species of timber. It is also appropriate for carvings that have very delicate, fine and fragile detail, as it has the advantage of producing a durable long lasting finish that only requires re-oiling periodically. This oil is also a standalone finish in its own right, but can be waxed on top for a higher lustre finish. Simply flat
back the third coat when dry with a very high grit cloth (1500–2000) or abrasive paper, and then apply the wax polish for a super medium to high sheen.
Interior: Three coats
Exterior: Three to four coats
Drying time: Minimum of 24 hours
Tung oil has a much thicker viscosity than the other oils and can be used for both interior and exterior work, due to the special properties that make it highly resistant to water, alcohol and food stuffs. It is therefore very appropriate to use for finishing any projects that will come in contact with food, for example, carved bowls or cheeseboards. The colour that it produces is in between the linseed and Danish oil, which lends itself more to the darker wood species.The first two or three coats can be diluted with 50% white spirit, which will assist the penetration into the timber. The final coat can be applied undiluted.
There is a plethora of wax polishes available to purchase and everyone, through trial and error, will eventually find their personal favourites. These waxes can either be purchased coloured with a special pigment, which enhances the natural colour tones of the timber being used, or ‘clear’ for lighter coloured timbers, both of which add a degree of lustre to the surface of the wood and protection against ingraining dust and UV rays. These are also available as either quick or slow drying formulations.
Use a clean, soft lint-free cloth to apply a very small amount of wax polish at a time, working it deeply in the direction of the grain. Keep moving the cloth
to a fresh clean section each time you load it. When the wax has dried sufficiently, use a different clean soft lint free cloth to buff the surface. Two coats are usually necessary on bare wood. Awkward areas of detail can be polished with two soft clean brushes; one to apply the wax, and the other to buff it off. Quick drying waxes must be applied over small areas of between 100–150mm at a time, and then buffed straight off. Slower drying waxes can be applied over the complete carving then buffed off at leisure.
Briwax original – walnut pigment
Drying time: Quick drying
Interior only : Two coats
Briwax original walnut lends itself perfectly for use on any of the darker species of timber. On application it penetrates deeply into the wood, beautifully enriching the natural colour of the grain and figure, and produces a wonderful medium to high lustre finish. The wax is, however, prone to water marks which can ‘bloom’ if not wiped off quickly. It also dulls slightly when handled due to the moisture from the skin.
Briwax was also formulated to be worked when liquefied, which is a very effective way to apply the polish deeply into the surface of the wood. During the colder months of the year, you can melt the wax easily by placing it on either a warm radiator or a hot water bottle, but do not place it near any naked flames as it is highly flammable.
Briwax original – clear
Drying time: Quick drying
Interior only: Two coats
Briwax original clear is the same formulation as the walnut but without any pigment added for colour, and is equally effective. It is therefore appropriate for lighter coloured species of timber such as lime and beech. The tonal variation from the natural colour of the timber is minimal, and the enhancement of the natural rays are deep and beautiful.
Antiquax original – natural
Drying time: Slow drying
Interior: Two coats
Exterior: Three coats
Antiquax original is a traditional wax polish which can be purchased in either a tin or silicone free spray. The polish has been specially formulated to resist fingerprints, which is definitely of high value to the user. The ‘natural’ colour of the wax finishes with a deeper tone to the Briwax, but less so than the oils, which works very well on both ends of the brown spectrum. It produces a fabulous finish which really enhances the depth of the grain.
Drying time: Slow drying
Interior: Two coats
Exterior: Three coats
Renaissance wax polish is marketed as the ‘perfect polish’, specified by museums, art galleries and conservators around the world as the finest cleaner/polish wax available, which is also reflected in its price. It is quite different to the other waxes as the formulation is a chemically neutral, semi-synthetic microcrystalline wax, entirely free of any damaging acids. This polish has a dual purpose of restoring/revitalising, and polishing/protecting many different materials including wood. For the purpose of wood finishing, it’s a very durable wax that strongly resists the effects of humidity and moisture, which is a real plus. The depth of tone that the finish produces is very light indeed, almost identical to that of the Briwax clear, and therefore perfect for the light coloured timbers. The Briwax does, however, produce a slightly better enhancement of the natural rays.
There are occasions when the subject being carved would greatly benefit from being lighter in colour than any natural timber’s colour tones could offer, for example; a swan, polar bear, or a subject that would be enhanced by shadow.
Rustin’s wood bleach offers quite a good solution to this problem, as the lighter tone can be greatly increased, but also controlled to some extent by the number of applications made to the timber. It creates an almost porcelain effect which still allows the grain to persist through to the surface, which
can be remarkably effective.
One to four coats, depending on the brightness of the tone required, two coats of clear wax on top.
The instructions for the handling and use of the bleach are both important and extensive, so please download the excellent data sheets from www.rustins.co.uk for an in-depth breakdown of them. Briefly however, ensure that protective gloves are worn and a synthetic light coloured brush is used. Part A, the alkaline solution, is applied to the bare wood first and left for up to 20 minutes to react, which surprisingly deepens the tone of the grain. Part B, the Hydrogen Peroxide, is then brushed over the surface and left for three to four hours. If a lighter tone is required, then the process of parts A and B can be repeated after just two hours. When the wood tone has reached the correct level for the subject, wash the surface with clean water and allow to dry. The surface then requires neutralising, which is simply a capful of white vinegar diluted in a cup of water, applied liberally over the surface and left to dry.
Wood finish colour tone comparisons