How To: Use Boiled Linseed Oil (Safely)

By Scott Sidler

Boiled Linseed Oil (BLO) is a common item in my shop and in a lot of woodworker’s shops. It is a great oil treatment for woods, leaving a smooth touch on the surface. It revitalizes old dried wood and gives it a new life.

BLO is often mixed with other finishes and was once one of the main ingredients in most paints. There are still companies that make linseed oil paints like Allback if you’re interested.

Boiled Linseed Oil is not actually “boiled” like the name suggests, rather, it is chemically modified to encourage faster drying. Slow drying oils are a good thing, but regular linseed oil can take weeks or even months to fully cure in cold weather and that’s just too stinking long. Boiled Linseed Oil will dry in only a few days give or take depending on weather.

As awesome as this product is for both wood and metal, it has some dangers (specifically flammability) that need to be addressed in order to use it safely. Let’s talk about safety first.

Boiled Linseed Oil Safety

The hard truth is that Boiled Linseed Oil can spontaneously combust if stored or used improperly.

“Why on earth would you use it then?”

Well, gasoline is a lot more flammable than BLO and I don’t hear anyone calling their cars a death trap (except Corvair owners).

Here’s what happens: BLO cures by a chemical reaction with the surrounding oxygen in the air not by evaporation like water-based finishes. This reaction generates heat like most chemical reactions. The heat generated can be intense in certain circumstances and can lead to spontaneous combustion.

Larger amounts of BLO create greater heat. Smaller quantities generate less heat.

How to Avoid Fires

  • Always store BLO in metal containers. You can pour it into plastic containers for temporary use, but for long term storage it should be in a metal container.
  • Any rags soaked with BLO should be laid flat on a non-flammable surface away from flammable items until they are completely dry or they can be placed in a metal container with water.

The most common source of BLO fires is from a wadded-up rag that has been soaked in BLO. The rag is wadded up and thrown in the trash with wood dust, newspapers or other kindling.

Since it is wadded up, it generates more heat because there is no air to pass over it and cool it. It then heats up to the flash point of the surrounding materials and the fire starts.

Watch this video to see how this happens.

Despite this issue, I still believe BLO is a great option for wood and metal. Read below, and you can learn how to safely use Boiled Linseed Oil.

Boiled Linseed Oil & Wood

BLO is a great protectant for wood both indoors and outdoors. It beautifies any wood and, once cured, protects the wood from sun and water damage. It can really reinvigorate old dried out wood and bring it back to a healthy status.

The powerful thing about an oil finish like BLO is its deep penetrating abilities. After application, the wood fibres draw the oil deep inside which protects not just the surface, but the whole piece of wood like in the image here.

Wipe on a couple coats of BLO on furniture, trim, or any bare wood and let it dry until it is no longer tacky (usually 24-72 hrs). The application is as simple as it gets and the results are more than worth the effort, which is why it has been used for hundreds of years by carpenters and refinishers.

Boiled Linseed Oil & Metal

A lesser-known use for BLO is to protect metal from oxidation. You can apply a thin coat to non-moving parts and once dry it will protect and beautify the surface. Thick coats can get gummy which is another reason you don’t want to use this in moving parts which get stuck together.

I use it mainly for chisels, screwdrivers, heirloom tools, block planes, and more specifically cast-iron tops of my “Big-Boy” tools in the shop like the table saw, mortiser, and band saw.

Sand off the rust and polish the metal with some 0000-steel wool, then wipe on a thin coat of BLO and you’re good to go.

Boiled Linseed Oil has one other thing that can cause concern, especially in humid climates. On exterior surfaces in humid wet climates, it has a tendency to mildew. So, before you go coat all your Adirondack chairs, test an area for a while and see how it does. If you do get mildew, it’s not the end of the world as it can be easily cleaned off, but that’s why in Florida I prefer to use it mainly indoors.

The Filling of Hard and Soft Woods

BY A. Kelly (1911)

The following woods are called “open-grained” woods and require a paste filler to make a good foundation for a varnish finish: Ash, beech, butternut, baywood, black walnut, chestnut, elm, mahogany, oak, and rosewood.

The following woods are called “close-grained” woods, or softwoods, and should be treated with a liquid filler to fit them for varnish finish: Basswood, cedar, California redwood, gumwood, Oregon pine, poplar, spruce, tamarack, white pine, Washington fir, whitewood, and yellow pine.

The following woods are called “close-grained hardwoods,” and are sometimes filled with paste filler, but this is not generally done, it not being absolutely necessary: Birch, cherry, Circassian walnut, and maple. Fill with liquid filler.

The filler must be coloured to match the wood; it is best to make it rather darker than the wood. It is important to get the right colour for a filler, so that it will be as near the colour of the wood as possible, only a trifle deeper in shade. Again, the colour of the finish may be determined by the filler; that is, the filler will be stain and filler both. Some of the finest colour effects with woods are obtained in this manner.

The purpose of paste filling is to make a solid surface for the varnish coats. The paste enters and seals the pores of the wood and all the open parts. This can only be done on wood having an open grain. But while the cellular structure is thus filled, the fibre is left more or less unfilled, and hence it is customary in many cases to apply a coating of liquid over the paste filling, when dry and rubbed down.

For this purpose, we may use shellac varnish, or a light-bodied liquid filler.

Liquid fillers are used where the wood is not open enough to take in a paste. Its purpose is to saturate the fibre of the wood and thus prevent it from taking up the liquid of the varnish coats, thus robbing the varnish of its oil and turpentine, causing it to be too brittle. Shellac varnish is a liquid filler and is often so used.

Application of Fillers

Liquid filler may be made from paste filler by the addition of the proper thinners. Usually liquid thinner is simply a cheap varnish, with the addition of cornstarch, or clay, or another suitable base. Before the advent of commercial liquid fillers, the surfacing or filling of close-grained woods was done with varnish, applied in several successive coats, each coat being rubbed down and into the pores of the wood by means of a piece of soft white pine, made chisel-shape, and upon this foundation the varnish finish was laid.

Various woods and their adaptability to the different fillers, substances in use, formulas for fillers

The use of a liquid containing some pigment or starch makes it possible to filler surface the wood with one coat. This may be sandpapered down, and a coat or two of varnish will give a finish. We call them surfacers because these liquid fillers are not rubbed into the wood, but laid on the surface, the same as varnish.

The filler or surfacer simply saves us the costlier varnish.

Shellac and Other Substances

Shellac is preferred where cost is not taken into account, because it sandpapers easier than varnish filler, but it is less desirable under varnish than even cheap varnish, because of its hard, inelastic nature, causing cracking of the varnish placed on it, particularly when the shellac is placed between two coats of varnish.

Liquid filler does better over paste filling than varnish, as it seals the open pores better. Liquid filler should be applied much the same as varnish, flowing it on even and smooth. It is best not to colour liquid filler if it is made with silica, because the silica, owing to its weight, will sink and allow the colour to float, giving the surface a painted effect.

Such substances as terra alba, talc, whiting, corn starch and barytes have the fault of whitening or fading out in the wood, a serious defect where any colour is used.

Carbonate of magnesia is very good for holding up the filler, and the same may be said of a few others of this class, but all in all nothing equals finely pulverized silica, whether for paste or liquid filling.

Starch makes a transparent filling, but it is impossible to make a dry starch and varnish filler that will keep long before using. Cooked starch makes the transparent filling, but raw starch will show white in the pores, perhaps worse even than whiting, which also is bad. Even silica is not free from the fault, but is less objectionable than any other mineral filler. Silica does not absorb the liquids of the filler, and, being thus non-absorbent, it is not affected by moisture as is corn starch. It unites mechanically with the fluids of the filler, fills the pores of the wood well, and adheres to the surface perfectly so that finishing over it is easily accomplished. It has been well said by an expert finisher that “a good finish cannot be obtained when starch, earth, and similar substances are used in the filling. “Starch is soft and easily applied, and work can be rushed by using it, and that is the most we can say for it as a filler.

Starch will not hold up the varnish, nor will the application of three or four coats help matters much. Silica can be pushed into the grain of the wood, making a solid foundation on which two coats of varnish will give a splendid finish. Silver-white and pulverized silica look much alike, having much the same atomic or molecular formation. Silver-white is a white siliceous earth found in Indiana. It is much used for making fillers.

One other fault of silica, and it is not a very serious one, consists in the fact that it will settle or not hold up in solutions. Also, it dries out rapidly, but this may be modified by adding a little oil to ‘ it, and in some cases the thinning may be done with oil alone, of which I shall speak presently. However, the fact of its setting so quickly is an evidence that it will be durable.

It should be said here that where large quantities of filler are used, as in the finishing room of a large furniture concern, the barrel of filler should be kept covered, to prevent the evaporation of the liquids, and to keep out dirt and all foreign substances. No one would think of leaving a barrel of varnish with the head out and uncovered, yet filler is composed largely of the same volatile liquids and will oxidize and become hard in like manner.

Referring again to corn starch filler, when it is applied it seems to fill perfectly because it is very absorbent of the liquids and seems to fill the pores of the wood perfectly. In a measure this is true, but in course of time, in the process of drying and hardening, it shrinks and a close examination of the filled wood with a microscope, or even with the naked eye, will disclose a surface full of unfilled pores and this may still be seen after the varnishing has been done. Furthermore, the filler will require much more time for hardening than is ever given it, and the result is seen in the chilling and cracking of the varnish.

Hardwood filler should set in from IS to 20 minutes, and to do this it should not contain an excess of oil, which would retard the drying. Thin, it with turpentine.

Filler Formulae — Liquid Fillers

Shellac varnish is a very satisfactory liquid filler or surfacer, in that it dries quickly and can be sandpapered easily. But it is usually too costly for general practice, besides which it is thought to act more or less badly under oil varnish. When used for surfacing close-grained woods, it should be applied thin. Two coats are better than one. It should be sandpapered down well.

 Imitation shellac may be made. A finisher says he makes one that is not only cheaper than shellac but is better in other ways. He takes equal parts of raw oil.

 Turpentine, brown japan and rubbing varnish, to which he adds enough corn-starch to thicken the mixture, making it rather heavier than ordinary paint, or so it can be applied with a brush. After it has been on the wood long enough to set, he rubs it off with a coarse cloth, rubbing the stuff into the wood at the same time. He applies two coats.

Here is another formula: Take four pounds of either finely pulverized and floated silica or China clay, the former preferred, and stir it into one quart of Japan driers, and beat the mass until perfect admixture takes place. Then add, while stirring the mass, six quarts of the best light hard-oil finish, or other equally good varnish, after which let the mixture stand an hour or so; then strain through a fine sieve. When desired for application, thin up to the proper consistency with turpentine, making it quite thin for liquid filling. It may be used also as a paste filler without thinning.

Oil may be used in place of varnish fora liquid filler for some purposes. Many of the best yachts and steamships have all exposed woodwork filled with an oil-thinned filling, over which is applied a number of coats of elastic varnish, like spar or carriage finishing varnish, with ample time for each coat to dry, and each coat is sandpapered. The process involves time and expense, but it gives a very durable finish when exposed to the weather.

Kaolin, Silica and Other Fillers

Kaolin filler may be made thus: Mix together a gallon of pale body hard-drying carriage varnish, one pint of turpentine, and one pint of pale-drying Japan. Take two and one-half pounds of kaolin and add enough of the mixed liquids to form a paste, which run through closely set hand paint mill, grinding it once, then add the rest of the thinners by brisk stirring, until perfect admixtures secured. Then the filler is fit for use, though it may be further thinned or made stiffer as desired.

Silica paste filler may be thinned down with varnish and turpentine to form a liquid filler. To four pounds of the paste filler add a gallon of coach varnish which may then be thinned with turpentine to a liquid filler consistency.

Liquid filler should be given at least24 hours to dry; 48 hours is better still.

Silver-white filler may be made with equal parts of raw oil, gold size japans and turpentine, with silver-white enough to form a paste, which must be worked smooth. Then it may be thinned with turpentine to the proper consistency.

White liquid filler is made after various formulas, and the following one is as good as any: In a gallon of raw linseed oil put two pounds of pale rosin, powdered, and place on the fire, stirring the mass until the rosin is melted. Take from the fire and add a pint of white japan and two quarts of turpentine; stir all together, and when the mass is cold, add eight ounces of cornstarch. After mixing the starch into the liquid, make it very thin with turpentine, and pass it through a paint mill or strainer.

Some woods require a transparent liquid filler, but such a filler should be made to match the wood in colour, which is of course very light. Mix together eight ounces of cornstarch, eight ounces of finest pumice stone powder and a quarter-gill of white shellac varnish and a quarter-pint of boiled oil. Mix thoroughly together, and thin for use.

Disston Saw Vice Restored

This was my saw vice before, it was the only picture I could find of it. I thought I had taken pics of it but it turns out that I haven’t

Here it is now. If I had a sand blaster I would have done a much better job. But it turn out that bad either. A bit of history restored and protected from rust. I’d say it’ll do for another 40-50 years. I don’t know how old this vice this. If someone does can you please let me know.

There’s one for sale at Jimbode tools it’s black but mine was red or burgundy. The colour that I bought wasn’t the ideal colour as it wasn’t really what I wanted but they didn’t have it in that brand and their paint is very good.

Lie Nielsen’s Salesman talks BS

Someone on the Australian woodworking forum that I regularly visit put this video up and called its bluff. I thought this was a new video but as it stands it’s dated back to 2015. The salesperson tries to convince the audience that tapered saws, as in height not tapered in thickness, are better than straight saws. His argument is that it’s impossible to saw over the baseline when you’re cutting dovetails with a tapered saw, but that’s not the part that bothers me. What bothers me is when he said “I don’t want to go over the baseline because that will compromise the whole joint.” Wait for it here is another salesperson’s BS, “That’ll end up racking, changing over time with the wood.” What the hell is he talking about? Sawing past the baseline will NOT result in a sloppy fit nor will it rack. If there was any truth to this, then many of my joinery would’ve failed, many of our ancestors joinery would have failed, especially those who intentionally sawed past the baseline when sawing lap dovetails or as our American friends call it half blind dovetails.

It’s people like that who will say whatever they have to just to make a sale irrespective if it’s false and people like who tarnish the good name of a company that has served us faithfully and truthfully for over 30 years. What is it I love about Lie Nielsen? Above all, besides the quality and second to none customer service is they’re traditionalists. Their tools are beautiful. They don’t take a beautiful design and turn it into some space age Buck Rogers of the 25th century tool. They replicate antique tools and even bring back what was once extinct. Some were cheaper to buy than the antique like the Lie Nielsen bench rabbet plane. I think I’ve said enough so I will leave you to have a read of what what one of our saw makers and forum moderator’s Ian Wilkie said on the topic.


 Your right Lance, it does look a bit like LN’s attempt to outdo Lee Valley on April 1st!

Where do I start? There was no explanation of how the canted (I prefer to call that particular taper a “cant” to distinguish it from a taper of the blade thickness), blade is supposed to help you hit the line on the far side. In fact, if anything it should make it harder. If the tooth line is parallel with the spine, which you can easily watch, then by keeping that horizontal you’ll hit the line back & front simultaneously. Judging whether the tooth line is horizontal from a canted spine is surely less intuitive!

Sawing to the rear line is something I struggled with at first, with any saw. I’d say, provided the saw is reasonably sharp & set, the major aid to accurate sawing is simply practice.

That said, there are a few things you can do to help yourself. The first thing is to place the job in the vise at a height so that when you hold the saw comfortably & ‘naturally’, the toothline is roughly horizontal. For most of us, that will be with your wrist in a ‘neutral’ position, neither rotated up nor down wrt your forearm. That way you’ll saw “level” almost by default. Now precisely what height the job will be depends on the hang-angle of the saw – the more ‘vertical’ the handle, the higher up you need to hold the saw to have the teeth horizontal. The LN saw has a higher hang-angle than I prefer for this job, and our demonstrator put the sawing point low down in the vice, which allowed him to hold the saw ‘naturally’ and have the teeth horizontal.

That’s fine for you young fellas who can still see that far, but chronologically-challenged optics like mine need things up close & personal. I set the cutting point at around elbow height so to hold the saw horizontal I need a more upright handle. My favourite D/T saw does have a canted back, as a matter of fact, but purely because I like the look, not for any perceived ergonomic advantage, it’s the angle of the grip that makes cutting to te rear line easy. I have similar saws with straight backs & slightly different hang angles but provided I place the cutting points appropriately, I’ll take bets that I can saw to the back line spot-on 8 out of 10 times with these too, without watching the exit side.

Nobody of sound mind would stand there pondering all this every time they pick up a saw! It’s just something that comes with practice; you know intuitively where to place things for the best/most comfortable/most accurate sawing, just as you automatically reach for an appropriate size & pitch of saw (if you have a choice) and you unconsciously adjust the stroke to the length of the saw you’re using. I’d been using saws successfully enough for at least 40 yeas before it ever occurred to me to analyze the process in any way.

And that bit of BS about over-cutting causing sloppy joints & wracking?!! Somebody tell ‘im it’s the side cuts that matter, mate! Small over-cuts are neither here nor there structurally, I always advise a newbie (as I was advised) to cut from the show side so that the joint will at least look neat on one side. Anyone who has repaired old drawers will know it was fairly common practice to deliberately over-cut half-lap D/T sockets by miles at the back in order to minimise the amount of uncut area on the sides & speed up waste removal. The tails still fitted firmly, and most I’ve come across were still perfectly sound after many years of being pulled & pushed around. Our woodwork teacher was an old-school cabinetmaker who showed us the method but made it clear to us he thought it was sloppy technique, though I reckon if I’d been banging out drawers all day every day I’d have been sorely tempted to do the same.

Nah, that video has to be an ‘April-firster’…. “


Rules or Rulers

By Joseph A. McGeough

The unit of linear measure in the ancient world, the cubit, was simply the length from the elbow to the extremity of the middle finger. Although the cubit gave an order of magnitude, it was hardly a standard, and it varied widely in different times and places.

One of many royal Egyptian cubits had a length of 52.43 cm (20.64 inches). It was divided into seven palms (measured across the fingers, not the knuckles), making a palm almost three inches. Each palm was, in turn, divided into four digits of about three-quarters of an inch apiece. Thus, 1 cubit = 7 palms = 28 digits. On occasion, digits were subdivided into 10ths, 14ths, or 16ths.

The common rule of Egyptian masons and carpenters was made of wood, had a narrow cross section, and had one bevelled edge, with the two left-hand palms carrying the smaller divisions of digits. Some Egyptian rods were made of stone and used digits divided into 16ths. These may have been ceremonial rods or, perhaps, master gauges for calibration and comparison; their brittleness would make them unsuitable for the rough handling received by mason’s tools.

The Romans introduced folding rules of bronze in 30- and 15-cm (12- and 6-inch) sizes. These were probably “pocket” instruments for officials—too expensive to be used by ordinary craftspersons, who probably used plain strip rules.

Only scanty evidence exists that graduated rules were used in the Middle Ages and the Renaissance; plain straightedges seem to have predominated. In 1683 an English writer described foot rules as having 1/8-inch (0.32-cm) subdivisions. The folding rule, now made of wood, reappeared at the end of the 17th century.

Measurement was long characterized by great national and regional differences. Because every large city in Europe and most towns had a different but locally standard “foot,” rules with four different graduations (one on each face) were made.

Americanax Glassport PA Broad Hatchet 1889-1921

A new welcomed addition to my woodworking family of tools. It’s a broad axe used for hewing timber. The age of the tool is unknown, but it’s predicted to be anywhere between 1889-1921. Irrespective of the age, this is a must-have tool for any serious hand tool woodworker. One side has a bevel, and the other has no bevel meaning it’s flat and that’s the side you hew the timber with. This axe found its way from the US to Oz and once more it will be put in use. I’ve sharpened it to a razor edge and I mean razor. The beauty about hand tools over machinery is that they never breakdown. They’re easy to store and take with you. However, the skill required to use them comes at a hefty price over a lifetime of dedication and hard work.

Flat one side for hewing

Ain’t she a beauty.

My new Roubo Frame saw

As you all know, I had to modify the frame to make it easier on me to saw with it. After shortening the one arm and bringing the stretchers closer together, I didn’t know what to expect to be honest. I just didn’t know whether this would work. I impatiently started putting it together and because I was rushing, I couldn’t set it correctly. So, I left it and just started working on the finish. I applied a beautiful rosewood mahogany stain with several coats of 1 pound cut shellac and left it to dry overnight.

This morning I said to myself it’s only a saw so get a grip on yourself. I started putting it together and everything fit snugly. Pretty amazing stuff when you’re not overly excited.

Checking for twist

After putting the frame saw together, I made sure the saw blade is dead centred between the two stretchers by measuring from both sides on both ends of the saw between the saw blade and the stretchers. This is important to help you saw in a straight line. Then I tightened the saw blade by hand pressure only by turning the eye bolt. There is a high probability once you tighten the saw blade that it will place the frame in twist and therefore the saw will also be in twist. This is why you need to check for twist before you use the saw. If you use a screwdriver to lever the tightening of the saw blade, you risk snapping the frame or really putting a lot of twist in it. I found the saw works perfectly fine with the saw being tightened by hand pressure only. You don’t need to hear that ping like you would on a scroll saw blade.

If the blade is in twist, I can only parrot from what I have seen on video the people at the Hay’s cabinet shop did to take their frame saw out of twist. They tapped on the blade with a hammer. That’s what appeared to me but I cannot say for sure and I will send them an email and ask them if they can make a demonstration. The way I fixed the previous saw out of twist was by twisting the frame in the opposite direction. It worked but it wasn’t perfect. On this frame it is absolutely spot on which makes me less inclined to build another frame.

I gave it a test drive finally, and I immediately felt the difference. It was lighter and a lot easier to use. What surprised me the most was that the lightness didn’t make a difference in the cut’s speed. There you have it, folks. I think this saw is kick arse and more pleasure to use than a bandsaw.

Here is something else a little off the topic that I found interesting. I flattened my bench today, and I found that the side closest to me was out of flat as this is the side I use. Whilst the other side that isn’t used was dead flat. Go figure I can’t explain it. Maybe someone can explain it to me.

Looks good.

Roubo Frame for saw for Sale

I’ve made a new frame for my saw and am now selling the old one.

This is why I’ve made it first out of pine, because I wanted to test it out for a while before I commit to a design and make it out of more expensive wood like Qld walnut that I’m eventually going to do. There’s nothing wrong with using pine as it’s a straight grained timber. It’s perfectly suited for this saw and will last you a lifetime.

For me this frame is too heavy to use as a one man saw. I know Shannon Rogers uses it successfully without appearing to break a sweat. As for me, it’s a bloody hard workout that isn’t necessary so, I modified the frame and it seems to suit me much better. I brought the stretches in much closer to where I can resaw 4″ thick wood and I made one arm smaller. This brought the weight down significantly and much to my surprise it didn’t affect the speed of the cut.

Before I commit to the new design, I want to use it for a while and see if this is what I want. No use in wasting good wood that’s very hard and very expensive to get anymore.

The stretchers are not glued to the frame as it’s meant to be taken apart at will for easy storage or transportation, much like a bow saw. The frame is finished with shellac and then rubbed down and waxed.

There really isn’t any point in me keeping it since I will never resaw such thick timber. Maybe this frame will suit someone else better than me, so I want to sell it for a very low price of AU$50.00

If anyone is interested please shoot me an email

Chalk line Origin

“Snapping a line,” a technique familiar in ancient Egypt, is employed in modern building construction. The procedure uses a taut chalk-covered cord that is stretched between two points: the cord deposits a straight line of chalk when it is plucked and snapped onto the surface. After 5,000 years the only change in this technique is that, whereas the Egyptians used wet red or yellow ochre, the modern craftsperson follows the method of Greek masons who employed white and red chalks in addition to wet ochre.