TRIED & TESTED: 8 Hardwax Oils

Words and photos: David Luckensmeyer

Hardwax oils are a mainstream finishing solution for woodworkers of all stripes. They are often preferred over other options like shellac, varnish and lacquer. Why? Because they are easy to use like oil except more durable. And they look and feel great.

Manufacturers would have us believe their hardwax oils are the best. At face value they share many of the same qualities. But start applying these products and it becomes obvious they do not have the same ingredients.

There is no generally accepted definition of a ‘hardwax oil’. The most that can be said is they have oil and wax in them. Ingredients are usually listed but not the proportions. Application instructions differ wildly from specific steps to wide-ranging options. And let’s not get started on additives, sheen levels or tint selections.

This review includes clear versions in a medium sheen (where applicable) and is intended to inform readers about surface preparation and application options, as well as provide extensive comparisons. I set out to answer questions about smell, ease of use, aesthetics, water permeability, durability and more.

Samples were labelled according to products, species and application methods.

Testing parameters

With $1,000 worth of products and consumables on test, there’s a lot to talk about. Over a period of 60 days I prepared samples and applied hardwax oils, took photos and videos, wrote notes and performed test after test. Here is what I learned.

For once, we need to read the instructions. These may all be hardwax oils but the guidelines differ substantially. I followed the recommendations to the letter (most of the time). I selected three boards each of kauri pine and Australian blackwood for the samples. The intent was to illustrate how hardwax oils behaved in different species.

Cutting the boards into discrete samples would have been a waste. Instead, I labelled 8 x 250mm sections per board. The products were rolled, brushed, and buffed. Eight products and three application methods gave 24 samples, or up to 48 samples in total since they were duplicated in kauri and blackwood.

I made sure to note where I did not follow instructions. Such ‘experimentation’ yielded surprising results in some instances. Plus having numerous samples for each product (up to 6) allowed for a variety of testing opportunities. Unfortunately, I was unable to test tinting options.

Drying conditions were optimal, with air-conditioned air. Some hardwax oils take a long time to cure – up to a month. Final observations from aesthetic assessments to durability testing were completed after 40 days of application. I tested resistance to water, red wine and acetone, as well as surface hardness. Finally, in my search to determine what hardwax oils contain, I conducted a drying test.

These tests were somewhat subjective. But I sought to reduce variables and assess products with fairness.

Take care to use the tips of a brush to lay down a minimum of product.

Surface preparations

Hardwax oils appear to have originated in Germany (Livos, Osmo, Saicos and Whittle Waxes are made there) for the floor finishing industry. All products refer to finishing floors as a primary use.

Common instructions include a requirement for a smooth, even surface, sanded correctly. Timber must be clean, dry and free of dust. Products are to be stirred thoroughly before and during use. There is a universal recommendation to apply thinly. All instructions refer to good ventilation to aid oxidation. ‘Drying time’ refers to the evaporation of solvents while ‘curing time’ refers to a chemical process (table 1).

The recommended sanding grit level is an important differential. Many hardwax oils specify a grit up to 150, including Fiddes, Rubio Monocoat and Saicos. Livos specifies 180 grit online but 240 on the side of the can, while Osmo specifies 240. Feast Watson and Odie’s Oil give no recommendations. Whittle Waxes also lists 150, but includes the phrase ‘or finer’ which is important as we shall see.

The sanding grit level profoundly affected surface quality (look and feel). Running my fingers along the length of eight samples – smooth to rough to smooth again – showed just how much the results were affected. Online forums are awash with questions like: ‘What happens if I sand to a finer grit?’

This question was asked of the suppliers and there were two common themes to the replies. First, there was no hesitation in recommending finer sandpaper to achieve a smoother result. But second, there is a limit to how fine one should go, because burnishing timber to extremes inhibits adhesion. A sanding range of 180–300 is my suggestion (species dependent).

Application options

One of the attractions of hardwax oils is that they can be applied by cloth or pad. This not only takes the pressure out of finishing but a pad often yields superior results. Options include rolling, brushing, floor brush/pad, cloth/pad (buffing) and spraying. I explored all options for furniture except spraying as my shop is not set up for that.

Microfibre rollers are effective and generic brands work just as well as proprietary versions. The 4mm nap gives a more even surface and is worth the price. Load said rollers with a minimum of product and you’re good to go. Brushing takes more practice. Where rollers are adept at laying down an even surface, brushed surfaces can be patchy. But brushes can reach areas that a roller cannot.

Consumables used included microfibre rollers, brushes, lint-free cotton cloths, polishing pads and terry towelling.

As for the cloth or pad, I had not previously used a polishing pad with hardwax oils. Such pads are thick and stiff and I thought they would perform poorly. I was surprised by how well they distributed hardwax oil, surprised by how smooth the surface felt after the first coat, and surprised that the pad removed imperfections so easily before a second coat (where applicable).

Feast Watson Timber Floor Wax

Has the strongest smell but nothing too concerning (as it complies with volatile organic compound or VOC regulations). Rolled, brushed and buffed beautifully. After 90 minutes all surfaces looked even and smooth but still tacky. At three hours, buffed surfaces were touch dry (and the smoothest); all surfaces dry by five. Equal lightest in colour along with Fiddes, Odie’s Oil and Osmo, but not quite ‘water white’. Lovely satin sheen across all application methods with even coverage (sanded to 240). This oil was the most forgiving.

Fiddes Hard Wax Oil

Pleasant odour but most viscous, except for Odie’s Oil which also smells nicer. Rolled and brushed well. Buffing (against instructions) gave uneven results. Best to follow instructions, but not the 120–150 sanding preparation. The surface quality suffered, but no more than other products sanded to 150 (Saicos, Whittle Waxes; see Rubio Monocoat). Sanding scratches prominent. Touch dry inside two hours! Light in colour, and dried evenly in both species, with slightly more sheen. Fiddes is a standout, but sand to 240 grit next time.

Livos Kunos No. 243

Smell is more than acceptable. Any application option allowed, but must have a ‘wet oil film’ for 15–20 minutes (I waited 15) before buffing. Product soaked in especially for blackwood. Rolled and brushed samples without buffing (against instructions) were uneven. Soak and buff instructions were superior. Sanding preparation (to 180) was good but sanding to 240 grit would be better. Somewhat darker result for both kauri and blackwood with only Rubio Monocoat darker again. Buffed surfaces felt and looked great.

Odie’s Oil Universal Finish

The small jar, viscosity and amazing smell were points of difference. Worked product into surfaces using a pad, let sit for up to 60 minutes (I waited 50), then hard buffed with a cotton terry towel. Any sanding grit level permitted (I used 240). Consistency of spun honey, good for exterior use, good coverage and required only one coat (same as Rubio Monocoat). Blackwood was patchy initially but samples looked excellent after 24 hours. Equal lightest in colour, and ranked first for surface look and feel. But it’s hard work.

Osmo Polyx-Oil No. 3032

Odour is fine. Rolling was better than brushing, especially with a dry roller to even out surfaces. It is applied too thick if the coat feels plasticky or you can dig your thumb nail into it after 24 hours. The first coat dried evenly, although the blackwood absorbed more. I reworked it several times (permitted up to 15 minutes). Buffing (against instructions) gave stellar results (sanded to 240). Buffed surfaces were immediately touch dry, while rolled and brushed took three (kauri) and five hours (blackwood). Equal lightest in colour.

Rubio Monocoat Plus 2C

Very low odour. This is the only two-part system here, but easy to mix. Applied by pad, let sit for up to 30 minutes (I waited 20), then removed with a white polishing pad. The pad buffed surfaces touch dry. Rolling (against instructions) gave uneven results. Properly buffed, this finish was exceptional in both species. Absolutely does not require a second coat. Samples were the darkest in colour, rich but a very matt look. Seemed smoother than Fiddes, Saicos and Whittle Waxes. Sand to 240 grit next time.

Saicos Premium Hardwax-Oil

Strong odour just behind Feast Watson. Rolling and brushing yielded acceptable results. There was a ‘slippery’ characteristic that flowed off the brush. The coarse preparation (150 grit) was disappointing like the others. First coat dried unevenly, especially on blackwood. Surprisingly, the buffed surfaces (against instructions) were excellent, rivalling Rubio Monocoat (also sanded to 150). At two hours, rolled surfaces were mostly dry; by 3.5 hours all surfaces were dry. Marginally darker (same as Whittle Waxes).

Whittle Waxes Evolution Hardwax Oil

Low odour and pleasant. Can be rolled, brushed or buffed. Rolling and brushing results were good except for the 150 grit preparation (the ‘or finer’ is obviously important). Buffing yielded even better results, but it took some effort to work oil into surfaces. Samples dried evenly across kauri and blackwood, even after one coat (better than Saicos). Drying times were good (all samples were touch dry by three hours). Very light in colour, only slightly darker than the lightest here, and easily one of the better performers tested.

To avoid cross contamination, I used new tray liners, rollers, brushes, cloths and pads.

Aesthetics

Every one of these hardwax oils is capable of producing beautifully finished surfaces. However, the various application methods influenced the results. Buffed surfaces were more attractive than rolled and brushed counterparts, with a more even sheen and a smoother feel. But keep in mind that buffed surfaces sometimes fared less well in the durability tests (see below). So there are trade-offs to consider.

All products tested changed the colour of kauri and blackwood. They are not as ‘water white’ as some other options. If a light colour is important, go for Feast Watson, Fiddes, Odie’s Oil and Osmo. For a richer, more ‘oiled’ look, Livos and Rubio Monocoat are better choices.

Some samples looked and felt better than others, although there was an inconsistency that made it difficult to draw meaningful conclusions. This might have been due to the vagaries of timber grain, or even application errors on my part. Between you and me, I think some of these finishes needed a third coat. Nevertheless, Saicos did not provide an even result across all permitted application methods, whereas Feast Watson and Whittle Waxes were perfectly uniform. Fiddes was nearly as good and offered slightly more sheen.

The dexterity of 100mm rollers is preferred for all but the largest projects.

Durability tests

Durability testing included resistance to water, red wine, solvent (acetone) and abrasion (scratch test).

Water resistance is of relative importance since dining tables need more protection than jewellery boxes. I applied a small puddle of water on each sample, waited 24 hours, thoroughly dried the surfaces and visually examined the results. All samples beaded beautifully. However, I was surprised by the general susceptibility to water damage.

Only Rubio Monocoat was completely unaffected, in both kauri and blackwood. There were no traces of surface markings and no blushing (water haze in the finish). While attractive for other reasons, Feast Watson did not have good water resistance and all samples performed poorly. Livos and Saicos samples did not fare well either.

Rolled and brushed samples were more water resistant than buffed across all products, with the noticeable exceptions of Odie’s Oil and Rubio Monocoat (both buffed). They were the best performers overall, along with Fiddes.

Red wine resistance testing followed a similar pattern. I subjected samples to a small amount of red wine, and waited 24 hours. The results were boring as virtually all rolled and brushed samples were unaffected. There was some variability in the buffed surfaces with minor discoloration especially for Feast Watson and Livos in blackwood samples. Intriguingly, the red wine yellowed all buffed kauri samples except Odie’s Oil.

Water damage ranged from surface markings that could not be removed to blushing and discolouration. Most of the buffed kauri samples suffered a yellowing effect from the red wine.

Solvent resistance testing was with acetone (a strong solvent). It evaporated quickly so I maintained a small puddle on each sample for 15 minutes. After 24 hours (the acetone had evaporated long since), I cleaned the samples and examined the results. Feast Watson, Fiddes, Odie’s Oil and Rubio Monocoat were unaffected across all samples while Saicos and Whittle Waxes barely exhibited any markings. However, acetone ruined all Livos and Osmo samples. The test areas were quite sticky with Livos performing marginally better.

Scratch resistance testing was a measure of relative surface hardness. First, I mounted 120 grit sandpaper to my random orbital sander, attached a string, and dragged it along one board. I did not turn on the sander. The results were surprising: not a single scratch.

So I took a 10kg cast-iron weight, attached 60 grit sandpaper and used string to drag it along. I declogged the sandpaper as necessary and went over the boards twice. The surface damage was extensive.

There was no appreciable difference between kauri (softer) and blackwood (harder), demonstrating that substrate hardness was not in play. It was enlightening to sight down a single board and see how scratches changed from sample to sample. Livos and Osmo provided the least resistance while Rubio Monocoat performed the best. That said, Fiddes was close behind Rubio Monocoat, followed by Whittle Waxes and Saicos.

My scratch test demonstrated the relative hardness of cured surfaces.

Ingredients

Most (but not all) manufacturers provide little information about the ingredients and their proportions. Understandably, ‘natural’ contents are emphasised the most. Hardwax oils are well-known for being food and toy safe. Plus, they are low in volatile organic compounds (VOCs), which are harmful for both user and environment.

It is useful to remember that hardwax oils contain significant levels of solvents. Indeed, solvents feature prominently in the safety data sheets (SDS). Most of these are VOC-exempt and therefore not subject to the regulations so often...

referenced. This is because they are de-aromatised and generally safer. However, they are still strong solvents. All but two of the hardwax oils included here contain 30–60% solvents by weight! For sure, heed the safety warnings and use gloves at a minimum and also a respirator if not in a well-ventilated area.

The exceptions are Odie’s Oil (<2%) and Rubio Monocoat (0%). Odie’s Oil does not require any personal protective equipment (PPE), but Rubio Monocoat requires the most care because of isocyanates in component B. Isocyanates are particularly dangerous and wearing appropriate PPE is necessary.

Drying test

In my quest to understand the behaviour of hardwax oils, and why they are all so different despite containing a ‘blend of oils and waxes’, I turned to Understanding Wood Finishing by Bob Flexner (3rd edition 2021).

The conundrum involves understanding how these finishes cure quickly. The presence of solvents is a clue. Unmodified oils and waxes do not need solvents to be workable because they dry slowly. But ‘polymerised’ oils (modified oils) and ‘varnishes’ (oil/resin blend) dry very quickly and therefore need solvents. Livos says it contains both and is the only product here to share this.

A drying test helped determine whether these hardwax oils contained polymerised oil or resin (or both). In my week-long test, five hardwax oils dried smooth and hard (or relatively hard) within 48 hours, which means they don’t have much unmodified oil in them (if any) and must contain polymerised oil or resin or both (Feast Watson, Fiddes, Osmo, Saicos and Whittle Waxes). If they contained only unmodified oils and waxes, they would have dried more slowly and wrinkly.

Livos and Rubio Monocoat did dry wrinkly so they contain some unmodified oil. But while Livos contains solvents, Rubio Monocoat does not. And yet both are darker in colour which indicates the presence of resins. Whether Rubio Monocoat contains polymerised oil or resin (or both) is hard to know for sure.

Odie’s Oil did not dry/cure at all. Even after seven days the ‘puddle’ was still sticky. Clearly it contains no polymerised oil or resin, which squares with its low solvent content.

For durability testing, I used a large plastic syringe to apply 3mL each of water, red wine and acetone to all samples.

Summary

There is no one ‘best’ hardwax oil. Each product has strengths and weaknesses. A selection of one over another might be due to price, ease of application, aesthetic qualities, or perhaps a standout result in one of the durability tests. It is hard to compare relative value and coverage, partly because pack sizes differ and partly because some of these finishes go a long way. Applying a second coat (where applicable) is easy. So are making spot-repairs or renewing a finish down the track.

Hardwax oil is the finish of choice for nearly everything I make. I hope this review helps you choose which one you might use for your next project.

First published in Australian Wood Review, issue 124, September 2024

Odies Oil and Rubio Monocoat samples provided by Hammer Roo in Brisbane.

David Luckensmeyer @luckensmeyer is a Brisbane-based designer maker, see www.luckensmeyer.com.au