Author: fitz

The following post is from our friend Mattias Hallin, who has been using linseed oil paint for a lot longer than have we – his approach is different than ours. (For starters, he’s willing to put in a significant amount of time whereas I, a pushy American, haven’t his patience! And OK…I can’t leave things to dry for as long as necessary in our shop for his approach. But his lovely results are undeniable.)

As regular readers of this blog’s ‘comments’ section may already know, I am a great fan and proponent of linseed oil paint as a furniture finish. (I also adore it as a house paint, both exterior and interior, and as a paint in general, but those applications are well beyond both the scope of this blog post and my personal practical experience.)

I won’t come as a surprise, then, that I have followed Chris’s and Megan’s work with and writing on these paints with great interest, not least as I have gone about painting with them myself in slightly different ways. This blog post follows from discussions I have had with Chris and Megan about those differences, and is a presentation of two particular techniques – glaze and three-coat paint respectively – that I have experimented with and used successfully (at least in the sense of to my own full satisfaction) on projects.

For those who don’t know me, I should perhaps add that I’m Swedish, but live in Belgium; hence the trans-oceanic qualifier to the title.

The Paints & Other Materials

To date, I have only ever worked with linseed oils, linseed oil paints and related products from the small company Ottosson Färgmakeri AB in Genarp, Sweden. This is not because I know or believe its products to be superior to those of its competitors, such as Allbäck, Brouns & Co, Gysinge, Heron or Selder (and I’m sure there are yet other brands that I’m not even aware of). I know no such thing. It is quite simply because I tried Ottosson first, and was happy enough that I never looked further. In other words, while what follows is indeed an endorsement on my part of the Ottosson range of products, this is emphatically not to the detriment of any of the others. They may be better, equal or worse, depending on your values for judging such things. But me? I’ve no idea, because I haven’t tried them. One day I may attempt to find out my true druthers by doing some comparative testing. Should such things matter to you, get some samples and get testing! In the meantime, I’d say the paint you can get is always better than the one you can’t, so if you are linseed oil paint curious, get whichever you can and try it for yourself!

Should you specifically want to get hold of some Ottosson stuff, though, in the U.S. you can find it at Solvent-Free Paint in upstate New York, Earth & Flax in Pennsylvania, and Atlas Preservation in Connecticut. If you are elsewhere, there’s a retailer map available at the Ottosson website.

And just to be totally clear, above-board and all LAP about it, I do of course not have any affiliation with Ottosson Färgmakeri AB (or any other company mentioned for that matter), other than as contented customer, and have paid full retail price for all products I’m about to mention.

For brushes, I have mostly used natural (pig) bristle brushes from another small Swedish company, Gnesta Penseln. Their Allround Brush, No. 5530, is my definite favorite, but I have also been pleased enough with their flat No. 609. For some glaze paint work I have also tried and had good results with a synthetic artist’s varnish brush.

To clean my brushes, I use liquid linseed oil soap and water. After painting, I will first remove as much paint as possible, first on some paper or a piece scrap, then onto a rag of some kind. I will then move to the sink, add a good dollop of soap to the bristles, work it in with the fingers to a good lather then rinse under running cold water. This cycle (dollop of soap/lather/rinse) is repeated until the lather shows no trace of color, and the rinse water runs clear. Depending on the size of the brush and for how long I had been painting, it will take me from a couple up to maybe 10 minutes to get the brush fully clean, but this video should give a better idea of how difficult it is (not):

I have not yet tried the alternative of storing my brushes in raw linseed oil without any cleaning, but am sure that this would work, too. I have simply found the task of cleaning them simple enough that I’m fine with the five minutes or so of extra effort at the end of a session.

Finally, while I’m sure all readers of this blog already know this, let’s stay on the safe side, and mention again that any rags or similar with linseed oil products on them must never, ever be left to dry balled-up or just thrown in the trash, as the oxidation that occurs when the oil or paint dries generates enough heat that they can spontaneously combust!

Rags can be laid out flat to dry, after which they will be safe to dispose of; they can be burned if local regulations permit; or they can be drenched in water. For my part, I will usually do what I show towards the end of the above video: hold them under the tap until they’re soaking wet, then tie them up like that in the nitrile gloves I like to wear when painting (‘cause I’m a certified, genuine, bona fide Fancy Lad™, who wants no paint stains on his dainty wee fingers). This keeps them both wet and deprived of oxygen, in which state they can be safely thrown away.

Glaze Paint Technique

I’m not entirely sure what this technique should properly be called in English. The Swedish word is lasyr, from the German Lasur, and it is etymologically related to words like azure and lapis lazuli. It is in effect to paint with transparent or semi-transparent paint, so that the underlying wood or other surface (such as a previous layer of paint – it is also a traditional fine art technique) still shines through. However, both various dictionaries and several paint makers refer to it as glaze or glaze paint, so that is what I will call it here. [Editor’s note: I think “glaze” is correct.]

As a wood finish, I believe this technique is often used to make one wood look more like another in color, or as part of grain painting. At least I know that Ottosson sell pots of paint in the correct size and intended for mixing with glaze oil that have names such as “walnut”, “teak”, “mahogany”, “oak”, “old wood” and “driftwood.”

For my part, however, I have been more interested in glaze paint as a technique to bring vibrant but transparent color to a project.

My first-ever attempt came about as part of my workbench build. The bench itself, in hard maple, had already been finished with two coats of boiled linseed oil. Having spent upwards of 800 hours on building it mostly by hand, my patience was beginning to wear just a little thin, and I wanted to be done and get woodworking. So instead of dimensioning the lumber for the shelf by hand from rough-sawn maple stock, as I had done for the rest of the build, I ordered a couple of S4S boards from my local lumberyard. They mostly sell construction lumber, and don’t carry hard maple, but do a usually nice enough sideline in ash. What they gave me this time was excellent quality, but to my mind perhaps not the most attractive grain pattern, so I hit upon the idea to liven up the bench with some color. which in turn made me wonder how a glaze paint might look?!

I read up a bit on glaze paint products, and, as we were going to Sweden anyway, decided to look in at Ottosson in Genarp. (They’re located about 12 miles from my old hometown of Lund, although their first production site was actually across the street from where I grew up!) My wife and I ended up spending a good couple of hours there, talking products, options and techniques, and came away with quite a shopping bag.

After a sufficient number of test pieces with which I will not bore you, I settled on a glaze paint mixed 50/50 from Ottosson glaze oil and the company’s Light English Red linseed oil paint. The glaze oil is a ready-made mix of boiled linseed oil, castor oil, lemon oil and odorless mineral spirits and, judging from the Safety Data Sheet, probably also a small amount of cobalt-zirconium driers (this particular product is thus not VOC-free, so not in the buck-nekkid application category).

I first gave the boards a base coat of boiled linseed oil and left that to dry for 24 hours.

(The Ottosson boiled linseed oil, by the way, is a traditional one, that is to say a purified linseed oil that has been pre-polymerised by heating for better drying properties but with no metallic driers added.)

After the base coat had dried, I applied a first coat of the paint-and-glaze oil mix in a thin but even coat and left it to soak into the wood for about half an hour. I then wiped off all the excess with a lint-free rag, a rather depressing procedure as the initial rich and vibrant color almost completely disappeared.

The second coat was applied in the same manner: brush on, wipe off, leave for 12 hours, but after application of the third coat, I gave in to temptation (ooh! pretty!) and just left it as it had been brushed on, with no subsequent wiping. Not my best idea. I did get away with it, but it took close to a week before the boards were dry enough to put in place, and even then, they remained ever so slightly sticky for a couple of months.

At the same time as the shelving boards, I also glaze-painted the bench’s swing-away seat, this time mixing Ottosson glaze oil with an Ottosson artist’s oil paint from a tube, in ultra-marine. I found no significant difference between mixing the oil with linseed oil paint or with linseed oil artist’s paint, except that it was easier to figure out the proportions with the standard paint as it was a liquid rather than a paste. In this instance it didn’t matter, but for multiple batches I think liquid paint will make for easier repeatability.

Once more I was tempted by the initial ooh! pretty! shine to skip the wiping. This time, though, it didn’t work. While I found the rich ultra-marine color absolutely lovely as such, it became impossible to brush out all air bubbles from the surface. Worse yet, it simple refused to cure, staying sticky seemingly forever, and it eventually began to slightly wrinkle and also to look dull.

There was nothing for it but to plane away the glaze paint, start over and let the color depth build gradually. After five cycles of brush on/wipe off, a final, very thin and unwiped coat of pure glaze oil went on top for some extra gloss, and I called the job done.

I’ve since learned on subsequent projects (as on the whisky cabinet shown below) that the way to go to build the depth of color is indeed a base coat of boiled linseed oil left to dry for 24 hours followed by as many thin brush coats as needed, each wiped off after about 30 minutes then left to dry for 12 hours. The number of coats will depend on when one is happy with the result. For extra gloss, a final very thin coat of pure glaze oil can be added.

Three-coat Paint

This is a rather more straightforward and much less finicky technique that consists of near enough what it sounds like – does was it says on the tin of paint, as it were. The aim is a fully painted result, with some hints of the wood grain still showing but not all that much. For my part, I also aim for that paint to initially look just as new as it is, with neither a matte nor a glossy sheen. So far, I have not found any need to add anything like wax or otherwise try to modify the final appearance of the paint.

This is of course a pure matter of taste: I prefer patination to happen naturally, and with these linseed oil paint finishes, I rather suspect I may not live long enough to see them at their absolute best. (Not that I necessarily expect any furniture that I build to last beyond my looking after it, but on the off chance that it does, I try to build it well enough that it might, and choose a finish with at least the potential to wear and age with grace and beauty.)

The necessary ingredients for the three-coat paint technique are just linseed oil paint and boiled linseed oil. It could also include turpentine, which is supposed to make the paint easier to apply smoothly and shorten drying times, but so far, I have refrained from adding any. Turpentine may be a natural product, but it is still a solvent that comes with health risks, and to date I have done all of my painting indoors. My workshop is reasonably well-ventilated, but still indoors. Some nice, sunny summer’s day, when I can work outdoors, I intend to do some tests that include turpentine, but until then I prefer not to include it.

If the piece to be painted is from pine or some other resinous wood, and has knots or resinous pockets, these must first be sealed with two coats of shellac. Otherwise, the resin will sooner or later bleed through and cause local discoloration of the paint.

The first coat proper consists of one third linseed oil paint mixed very thoroughly (stirring! yay! Or do like Megan and get friendly with shops that have paint mixers) with two-thirds purified boiled linseed oil (no driers). This is applied as thin as possible with a brush, after which every part is dry-tipped with another, clean brush to level out any brush marks and to remove any small accumulations at the bottom of the vertical surfaces. (If there are substantial pools of paint at the bottom of the vertical surfaces after one has finished painting the piece, that is a sure sign that the paint went on too thick. What I’m talking about tipping off here are mere smidgens of paint brought down by gravity to the bottom of a vertical surface.)

It is also important to know that linseed oil paint has close to zero self-leveling properties. Any errant brush marks in the fresh paint will still be there when it has dried. It is thus key to work on a consistent (direction, evenness, etc.) final set of brush strokes, which is why tipping off comes in so handy. On the other hand, the long open time of the paint helps – there’s plenty of time to be thorough about it.

If this first, thinned-with-oil coat goes on bare wood, it is likely to be dry to the touch within less than 24 hours, and depending on circumstances (temperature, humidity and – not least – ventilation) might be ready for a second coat in 48 hours. Personally, I try to wait for another 24 hours, as I sand very lightly between coats, and for that want the previous coat to be sufficiently cured.

Strictly speaking it is not necessary to sand, but I have found the final surface becomes nicer and smoother to the touch if I remove any minute nibs and any dust that might have settled in the still-wet paint of previous coats. I have a paint stall in the least-dusty part of the workshop, so dust is not a massive issue for me, but the place is not clean to operation theater levels, either.

I usually sand very lightly with a #500-grit Mirka Abranet disk, either wrapped around a block of cork or just held in my hand, but before the first coat is sanded, I will go over the piece and apply some “Rubinol” linseed oil putty to any minor imperfections. After sanding, I carefully remove all loose dust with a vacuum cleaner followed by a damp, clean rag, and the patches where putty was applied are given a very light touch-up with the initial base coat oil/paint mix to get the whole piece back to an even base color. These patches are then left to dry for maybe 12 hours or so, after which the piece is ready for the second coat.

Both the second and third coats are of full-strength, undiluted linseed oil paint, straight out of the can, and applied as thinly as possible but with full coverage. The paint goes a very long way, though, as with no solvents there is no evaporation either: what goes on, stays on. A good natural bristle brush will hold a lot of paint, too, so it shouldn’t be dipped deep at all. A small dollop of paint is taken up at the end of the brush and deposited in a good spot on the surface, from where it is distributed as far as it will go with strong strokes and stipples in varying directions. Before moving on, the freshly painted surface is equalized with the same brush, while at the end of the session everything is tipped off again with a clean brush as already mentioned. What you see is what you get, so it should look as good as you can make it before leaving it to cure

I leave the second coat to dry for 48 to 72 hours, depending on circumstances, and again sand ever so lightly with the #500-grit Abranet.

The third and final coat I will try to leave alone to dry for a full week before moving or touching anything.

If it hasn’t become clear already, the three-coat paint technique is not for those in a hurry to be done. Not that it is inefficient as such – it takes about as long to apply as any paint, and you don’t have to stand there for a whole week actively watching it dry. (You can certainly go away for a coffee at least three times a day with no adverse effects on the final result.) In a production environment, where a piece has to go out the door before any money comes in, these long waiting times could be an issue. For the hobbyist, much less so, unless a slow-drying piece puts the whole workshop in lockdown for reasons of space or suchlike.

While the piece should be dry enough to handle and use after no more than a week on the outside, in my experience it will still be several months before the paint is really cured all the way through. The way I test this is by closing my hand over a part of the piece. If in a short while the paint feels ever so slightly “clammy” under my hand, I know it is still curing. When it no longer feels that way, I consider it well and truly set.

I thus aim for a fully painted effect, with an even, satin sort of sheen. If one wants a glossier surface, a certain amount of sun-oxidised linseed oil can be added to the paint for the final coat. For such a mix, Ottosson recommends a 10- to 15-percent by volume oil-to-paint ratio. For my part, I have yet to give this a try, so I cannot say what difference it might make.

Below follows a series of photos from the various stages of painting two pieces – a stick chair and a bookcase – with the three-coat technique described above.

Mixing the Two

Finally, below are a few photos of a project on which I used both techniques. This is a whisky cabinet, designed by Geoffrey Fowler, that I (mostly) built during a post-pandemic get-together in London, also organized by Geoffrey,  of a bunch of the regulars on Bench.Talk.101 (see Quercus Magazine #10 for more on that event). The wood is ash, while the glaze paint was made up with the same linseed oil paint used for the three-coat part: Ottosson’s Ardbeg Green.

Given the number of coats needed, the glaze-painting was by necessity a slow and somewhat painstaking process. It was made even more so by the fact that the glaze oil is quite thin, so not particularly suited to vertical surfaces. When glaze painting the cabinet, I found the safest way to a good result was to do only horizontal surfaces, so one side at a time. With four coats per side, six sides to the carcase and two to the door plus some edges that had to be glaze-painted before assembly, and with 12 hours between each coat, it did take me the better part of two weeks to get the job done. I was happy enough with the result, though, that to me it was worth the trouble. Your mileage may vary.

In Conclusion

I still have much to learn about linseed oil paints, and am looking forward both to getting better at what I already do and to picking up new techniques and testing other methods.

For example, I am very interested to see what results can be had with a single-coat system based on diluting the paint with boiled linseed oil only. Ottosson recommends a 20/80 mix of oil and paint for single-coat interior woodwork, but it would be fun to experiment with a range of ratios and see what the results look like.

I also want to find out what adding turpentine will do, and if it would be worth the whiff? Ditto the addition of sun-oxidised oil to the final coat – will I like glossier? Not to mention to see what can be done with artists’ paints on smaller pieces, in the footsteps of Jögge Sundqvist (who, by the way and judging from the photos in Slöjd in Wood, seems to get his artist’s paints from Ottosson). And of course, to give some of the other brands a go.

I am well aware that painted furniture is not to everyone’s taste, but that is a simple problem to solve: if you don’t like it, don’t do it! If, however, you find the idea not entirely without merit, I heartily recommend linseed oil paint. As I hope is becoming apparent from recent posts and discussions on this blog, it is nice to work with and has the potential for some very attractive and tactile results, at least to my eyes and hands.