Lost Art Press

Author: fitz

Woodworker, writer, editor, teacher, ailurophile, Shakespearean. Will write for air-dried walnut.

Laying and Finishing Hardwood Floors

Posted on by fitz

odell_fig_1

The general demand for finely finished floors of hard or soft wood in modern residences has given rise to such a variety of tools and finishes designed for this special purpose that natural confusion arises as to the best tools, finishes or methods to employ in this highly important branch of the trade.

The growing demand for the conveniences of the city residence in the homes of the smaller towns and the rural districts often brings the carpenter and the painter up against this sort of work, demanding methods of treatment with which they are unfamiliar, and many a good job of floor has been spoiled or indifferently treated by otherwise good mechanics, simply because they lacked the knowledge or experience so essential to success.

It has been the fortune of the writer to have a somewhat extended experience in the better grades of modern floor finishing, and it is with the hope of affording some degree of general information to the craft that this discussion of the topic is undertaken. For convenience in treatment the subject will be considered with reference to the following elements:

1. The carpenter.
2. The tools required.
3. The laying of the floor.
4. Preparation of the surface.
5. The painter’s work.
6. Different varieties of finish.
7. Relative cost of floors and finishes.
8. Suggestions as to estimating.
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Water vs. Wood

Posted on by fitz

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Freshly-cut red oak, destined to become Roubo workbench legs

A few days ago, Chris broke one of the cardinal rules of this blog: he began a sentence with, “You should…” He said to me, “You should be writing about this stuff…as a full-on blogger.” I agreed, then explained that the reason I don’t is that I find writing to be painful. So what does he do? He offers to let me write on his blog. I suppose I should be thankful that he didn’t kill me outright, like poor Raney. On the other hand, Raney’s death was quick and presumably fairly painless. Mine will more likely be slow and lingering.

Wood and water. From the woodworker’s point of view, not exactly a match made in heaven. Why is it that thick slabs of wood take so %$#@! long to dry? You may have heard the old air-drying rule of thumb, “one year per inch of thickness.” I remember reading it for the first time many years ago and thinking, That can’t be right. From basic geometry, doubling the thickness of a piece of wood should quadruple, not double, the drying time, and my own experience with drying wood since then has at least approximately confirmed that. There are two factors that cause thicker pieces of wood to dry more slowly: one, there is simply more water to remove through the same amount of surface area, and two, the water has to travel further, on average. Both of these factors are proportional to the wood’s thickness, and they’re multiplicative, so in the simplest approximation the drying time goes as the square of the thickness.

I’ll skip the physics lecture (for now, but there might be an exam later) and show the results of some computer simulations that I ran for water loss in wood, from fully saturated to near equilibrium, using a few assumptions (physicists are all about making simplifying assumptions). The assumptions I made are:

  • the board is wide and very long compared to its thickness, so I only have to worry about water movement through the faces of the board, and not the edges or ends,
  • the temperature is a constant 52°F (the year-round average for southeastern Ohio, where I live), and
  • the equilibrium moisture content is 12% (a typical outdoor value for this climate).

Here are two graphs (click to enlarge), showing the computed change in moisture content over time in red oak, in a 1″-thick board (left) and 6″-thick board (right), subject to the above assumptions and using published data for the various water transport parameters:

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As the graphs show, the 1″-thick board settles down in a couple of years, while the 6″-thick board takes over 70 years to equilibrate to the same degree. Apart from the 36-fold difference in time scales, the graphs are nearly indistinguishable. In other words, there’s no significant qualitative difference between thin and thick boards; they both behave more or less the same, just on very different time scales.

So that’s at least a partial answer to the puzzle. In part 2, we’ll look at the role that end grain plays in drying (there’s good news, and there’s bad news), and examine Chris’s hypothesis about how “being surrounded by so much dry wood keeps the moisture in” (hint: he’s at least partly correct).

–Steve Schafer

Further reading:

Bergman R et al. (2010) Wood Handbook, Wood as an Engineering Material, http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr190.pdf.

Hoadley RB (2000) Understanding Wood, Taunton Press, Newtown CT.

These first two are fairly non-technical, but they focus on the what and have little to say about the how and why.

Baronas R et al. (2001) Modelling of Moisture Movement in Wood during Outdoor Storage, Nonlinear Anal. Modell. Control 6:3-14.

Includes an excellent comprehensive overview of the theory of moisture movement in wood; requires a working understanding of partial differential equations.

Simpson WT (1993) Determination and use of moisture diffusion coefficient to characterize drying of northern red oak (Quercus rubra), Wood Sci. Technol. 27:409-420.

Source for the data used in the computer simulations.

Glue and Sand-Paper

Posted on by fitz

glue_sand_paper

The superior processes introduced into industry, in modern times, by the knowledge of chemistry, has led to the establishment of various branches of manufacture, and made them of great importance, though they deal with articles which were formerly either entirely unknown, or disregarded as of no value.

Glue, in the modern industrial world, is a case in point. Like many of the important things in industry, it has heretofore been overlooked; and though the world would suffer, to-day, much less in its comforts and conveniences of living from a loss of all its gold and silver than from that of its glue, yet this fact would be most probably overlooked by the large majority of those whose well being is so intimately dependent upon its abundant and cheap supply.

Yet, in fact, glue is absolutely indispensable to the arts of modern industry, and as yet no substitute has been found to take its place. Without it, turpentine and petroleum would escape from the barrels which now contain them, and be lost. The very paper on which we write would, but for glue, make nothing but a series of blots; and so on through all the series of domestic or household arts.
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The Use of Wood for Furniture: Past and Present

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Industry and Idleness

From the remotest periods of antiquity down to the present time, wood has been largely employed in the manufacture of all the principal articles of furniture. In this particular but little change has taken place within the memory of man, and even the lapse of centuries has effected comparatively few modifications.

In the course of a series of articles on “Gains and Losses in the Use of Wood,” that appear in the Timber Trades Journal, the writer, touching upon the use of wood for furniture, says that glass has been introduced in the panels of certain furniture, to the displacement of wood, and a light and elegant character of design has taken the place of the old heavy-wooded fittings, which, of course, has somewhat interfered with the bulk of wood used in the manufacture of a given quantity of furniture. This is at best but a minor loss, and, had it not been for a solitary loss of some moment, we need not have singled out the detail of furniture for notice.

We here allude to the discontinuance of the use of wood in the important item of bedsteads. This article in the old days of “four-posters,” capped with heavy cornices, and furnished with head-boards, foot-boards, and lathed bottoms, was a host of timber in itself. These gave way to the more elegant half-headed bedsteads, with their circular cornices, a style that existed to the end of the long career of wooden bedsteads. Practically speaking, this style of furniture has been swept away, and its place has been occupied by brass and iron.
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We Must All Do Our Part

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boy-with-saw-jpegThe Basket of Tools; or, We Must All Do Our Part

A Joiner’s boy, going to his work, carried with him a basket of tools; and as he walked rather quick, it occasioned some little commotion among the sharp-edged instruments. The consequent accidental rubs which took place as they encountered each other at length excited an irritation of spirit, and the inconvenience of this unavoidable jostling soon proceeded to raise a voluntary purpose to injure one another, under the pretence of retaliation for the knocks, and scratches, and cuts which were inflicted from the deplorable circumstances in which they were placed.

“Pray, brother, keep your teeth to yourself,” said a Hatchet to a Saw. At the same time bouncing up, he gave him a pretty sharp cut on the handle, which making him strike a File with some violence that lay under him, forced its rough side against the point of a Gimblet; and whilst itself felt the hurt, it drove the handle into the box of a Plane, which it knocked out of its place and stuck fast therein.

“What are you all about?” said the Plane; “do you see what a situation you have put me into? What is to become now of your clumsy operations, if you are without the finishing touch of my ability? What sort of work will you look like, do you think?”

“I think,” said the Saw, ” that we can do perfectly well without your insignificant help. What do you do towards the forming of the things we are employed in? Whatever it be, I am the most important; the length and breadth of all things are determined by my power, and each part made to suit the other.”
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