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There seems to exist two different procedures to finish wood with vegetal penetrating oils (raw linseed oil, boiled linseed oil, or pure tung oil). One method consists in letting the oil penetrate into the wood passively using only the power of passing time and a clean cloth, referred to as "oil finishing", and the other consists in rubbing/burnishing the oil into the piece ad nauseam, referred to as "oil polishing".

I can't find much information on oil polishing in newer/popular texts -- it seems to be more of a historical method. I may not have the nomenclature completely right, as I can't find a new or old text that covers both methods.

Are these two approaches complementary, or should they be perceived as alternatives to one another? What does the extra labour buy you?

A. Oil finishing

This is coat-wait-wipe dry-and-repeat approach:

  1. cover the work in a generous layer of oil using a soft cloth
  2. wait some amount of time between 10-30m for oil to penetrate
  3. wipe all excess oil with a clean cloth
  4. wait between 24h and 48h depending on environment
  5. repeat (optionally de-nibbing with fine sandpaper or steel wool between coats)

Quoting the label at the back of my bottle of BrandX linseed oil:

Apply on well sanded wood, concrete or stone that is free of lint, wax or debris. Apply sparingly with a soft cloth or brush. Do NOT apply with a sponge. For more even penetration, dilute with equal parts of BrandX turpentine or BrandX paint thinner. Always wipe off any oil that has not penetrated the surface after half an hour. Wait until the first coat is dry before applying a second coat...

Similar instructions are given for pure tung oil:

... The first coat should be a liberal one, and you can rub it over the wood with your hand, a soft rag, or #000 steel wool (#0000 deteriorates badly). Allow this application to sit for 5 to 10 minutes so the oil can soak in, then remove any excess with a clean, soft rag or steel wool. Check after about a half-hour for any seeping, and rub this off as well. Let dry completely (24 to 48 hours) between coats. For woods with very open pores, allow an extra 24 hours drying time.

Source: LeeValley tung oil PDF

This approach also seems to be in line with popular practice (at least of the few who choose oil as a finish). E.g., it is what some spoonmakers recommend.

B. Oil Polishing

Some texts describe a much more laborious process, described as Oil Polishing or Oil-Polishing. It would appear that rubbing (and burnishing) is done with a padded heavy object (like a brick), and continues until the oil has completely penetrated into the wood.

Central to oil polishing is linseed oil, and it should be used in its raw form [...] The oil is heated by placing it in a container and standing it in a bowl of hot water which can be frequently renewed. Warm oil will flow much more easily. Assuming that the wood is smooth and clean, a generous film of oil is applied, using a broad brush. The rubbing is done with a soft felt wrapped round a brick, and working from area to area. The first coat will rapidly soak into the wood. [...]

The end of each phase is marked by the disappearance of the oil. The first coat will not provide a mere hint of polish, but if the operation is repeated some results can be expected.

Depending on the condition of the wood the results will definitely appear after the fourth coat, and it will be marked by sweat points as saturation point is reached. These sweat marks should be removed with a rag soaked in methylated spirit, the use of which will not impair the final finish because it rapidly evaporates.

Chap 9, The complete manual of wood finishing, 1st edition, Frederick Oughton, ISBN 0-8128-2890-9, 1983

I can find a similar process described in Staining and Polishing - Including Varnishing & Other Methods of Finishing Wood, with Appendix of Recipes by JCS Brough

Oil-polishing is most useful for table tops, bar tables, counters and spirit cabinets. A dining-room table with an oil-polished top, and the sides and legs French polished, will make a most satisfactory job. [...]

For a table-top or other surface which is large and level, rub some of the oil well into it, and then polish with a rubber made by rubbing a quantity of felt or flannel round a brick or other suitable block. [...] In applying the oil, do not saturate or flood it, but scrub it in, and afterwards rub long and hard. Of course the wood will absorb the oil, even after several applications. It will need much patience to bring it up to a good glow; in fact it might be said that the work is never finished.

2

Superficially these refer to the same thing, and there are many overlaps, but in practice these days they can tend to describe fundamentally different finishes, giving very different end results as a consequence.

I can't find much information on oil polishing in newer/popular texts -- it seems to be more of a historical method.

"Polishing" is one of the old terms for finishing, so it refers to the job generally. The word makes quite a bit of sense in the historical context as they did in fact polish the wood, i.e. add gloss, to one degree or another — I think it's accurate that no show surfaces were finished and left truly matt, although there were matter surfaces on some things (ebony was often thought to look too brash with a glossy surface to it and ebonised wood was often dulled slightly using fine abrasives). It wasn't until the modern era that full-matt surfaces became a desirable outcome.

Of course here it also refers to the process, since there is a lot of 'polishing' of the surface due to all the rubbing. And the rubbing is key to the difference between the historical practice (see quotes at bottom) and what's too-often done these days.

A. Oil finishing
This is coat-wait-wipe dry-and-repeat approach:

This is a terrible way to apply an oil finish (to be clear, I mean an oil-only finish since these days there are many so-called oil finishes which are blends somewhat like "Danish oil").

The reason is that it's doesn't do anything but saturate the surface fibres with oil, which isn't what oil finishing should be about. Couple this with the duller wood surfaces often produced today when final smoothing is done via sanding and it's easy to see why so many modern oiled pieces appear dull and lifeless compared to historical work (and modern pieces done by pros, and dedicated amateurs, working more in a traditional manner).

Some relevant quotes from previous Answers:

Using linseed oil you should start to get a decent sheen at about the third or fourth coat (if you don't you're not doing it right)...

...after the initial buildup within the wood oil finishing is nearly entirely about burnishing of the surface, not "building up the finish" in the sense that most people would understand it (particularly if they're more familiar with varnish or an oil/vanish product like "Danish oil").

The full traditional oiling regimen could take an entire year from the point the woodworking was finished: one coat per day for a week, a coat per week for a month and then one coat per month for the rest of the year.
Yes, that is 21 applications of oil.
...
All guides to oiling will say that you have to wipe off the excess oil from the surface but these days, with the emphasis on how easy an oil finish is to do, very often they say you're done at that point. And that's responsible for the lacklustre surface on much modern oiled furniture. Traditionally, after the excess oil was wiped away you then rubbed down the piece, hard, and for a long time. There was no danger of leaving excess oil on the wood in the old days after buffing the surface for half an hour!

  • As I refer to elsewhere, one tradition states that you were supposed to oil once per year forever to maintain the finish.... any wonder why varnish was embraced as a significant step forward when it became widely and inexpensively available?! – Graphus Jan 20 '18 at 8:03
  • Beatifully written answer. Very interesting. All key points covered. Thank you! I am trying the oil-polishing on my table. Is one hour a long time? It's the time it takes until I stop seeing a difference in the oil absorbtion. Fingers crossed I won't gouge my tabletop with the corner of the brick on the 21st coat. – ww_init_js Mar 5 '18 at 18:06
  • Yes one hour sounds like a very long time. When I do it I fail to see any improvement after approximately a few minutes with softwoods or close-grained hardwoods, somewhat longer with open-grained hardwoods. Maybe you put on more on than was really necessary to begin with? Another possibility is you're not switching out your wiping cloths enough, so at certain points during the process you're just moving oil around rather than taking it off. – Graphus Mar 6 '18 at 13:09

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