Architectural hardwood finishing

Front matter

Class

TT ?

Book

Preface

The series of articles which is here republished in book form was printed in the twelve issues of The Painters Magazine for 1905. They were written by a practical mechanic, who has had more than twenty years' experience in all classes of hardwood finishing and who has invented a number of valuable materials and processes. Two articles on kindred subjects, Piano Finishing and Best Methods of Using Water Stains, which also appeared in The Painters Magazine, have been added to make the work more complete. The publishers trust that this book may prove an acceptable addition to the library of the practical painter, the architect and every one interested in architectural hardwood finishing.

New York, January, 1906.

ODERN methods of wood finishing in new buildings will be described in this book, the subject being treated from the standpoint of the practical wood finisher engaged in all grades of work in modern buildings. At the risk of telling something already known to the experienced wood finisher, every branch of the work will be thoroughly described in all its details, in order to make the entire subject of hardwood finishing perfectly plain to even the most inexperienced finisher. We must also remember the necessity of every one connected with the painting business of knowing the proper treatment of hardwood. The wants of even the most experienced finisher will not be forgotten, and many suggestions will be given to practical painters for up-to-date work and all the new methods will be described with which the writer has become acquainted in twenty years' experience in that line.

page seven

CHAPTER I. Woods Used

f . *vHE woods most commonly used V] p^ at present for the trim and

1 1 floors of buildings which re-

^^ quire a natural finish are oak, ash, walnut, mahogany,, birch, cherry, maple, redwood, cypress, sycamore, pine, whitewood, rosewood, and a number of others.

They are divided again into hard and soft woods, — open pored and close grained woods, — and each of them require a different preparation and finish to suit the taste and style and to conform with the nature of the wood. Each kind of wood has its own natural beauty and the main object of the finisher should be not only to make a superb finish and to preserve the wood, but to improve and develop its natural grain and beauty. The most expensive wood will look cheap if not finished properly and a more common wood will look beautiful if rightly treated.

Oak is classified first by the manner in which the boards are sawed into straight and cross-cut, or quartered oak and again into white, red and dark oak.

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Ash is generally of but one grade and is often used for framing oak panels, as it is less expensive than the former, except the Hungarian ash, a beautiful variety.

Walnut has a number of grades and nearly every climatic condition produces its own and peculiar species, some being of very great value. We have the straight American walnut, the French walnut, used for panels and cut from the root of the tree ; also the South Russian or curly walnut, which is a softer kind, but very rare and expensive.

Mahogany is obtained in endless varieties, including prima vera or white mahogany. Much of the wood sold as mahogany is cut in the United States, but the more valuable kinds come from San Domingo, Central and South America.

Birch is divided into straight and curly, and, like cherry, is an American wood.

Maple is known for its whiteness and hardness, and is generally used for floors, with the exception of the bird'seye maple, which is used for paneling and requires great care in finishing.

Redwood, especially that coming from California, is a wood resembling mahogany in many of its characteristics.

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Sycamore is exceptionally hard, and the cross-cut or quartered produces wonderfully beautiful effects.

Cypress is in a class by itself. It is related to the cedar, very tough and durable, and, on account of its long fibers, it is very troublesome for the finisher.

Rosewood has been abandoned on account of its scarcity. Its oily nature has made it difficult for the best finisher using the best material to produce perfectly satisfactory results.

"Whitewood, or poplar, is not often finished in natural, and curly poplar has been very seldom used because its value is overlooked.

Pine has received the greatest attention and is used in endless varieties and for almost all possible and impossible purposes. It is divided into hard and soft, white and yellow, straight and curly pine.

White pine of good quality has become very scarce and is now more expensive than oak, but is largely used for doors.

Yellow pine serves for all purposes and the Georgia variety is largely used for floors. North Carolina pine is of a curly nature and produces very good results in the hands of the experienced finisher.

page ten

CHAPTER II. Sandpapering, Scraping and Preparing the Wood

LTHOUGH the most essential point in producing a good finish, sandpapering, scraping and preparing the wood is generally overlooked, but it is of the utmost importance and cannot be too carefully done. Only a perfectly smooth surface can retain a good lasting efTect and such a surface will lessen the work more than a good many will admit. An uneven surface showing plane marks must be scraped, which can be done with a number of different tools, of which the plain scraper is always the best. It consists of a piece of hardened steel about 2 by 5 inches in size, the long edges of which are evenly ground. Considerable experience is required in sharpening, which is done by pressing a round piece of steel against the edges, slightly bending them over to form a cutting angle. This round piece of steel is drawn along the edge until the proper effect is produced. Resharpening is generally done with a good steel file, but is better done on a flat oil stone. Other scrapers in all different shapes are used to suit the needed require-

page eleven ments. Their quality may be determined by the length of time they will last without resharpening.

Sandpapering.

Common sense, skill and experience will tell the finisher what grade of fineness in sandpaper is required to do the work. Always be careful to rub with gentle pressure lengthwise, or with the grain of the wood. A suitable block, made of cork or wood, should always be used, and in moldings the block must be cut to fit the hollows. The sandpaper is wrapped around the block and when worn off is turned around or exchanged. Sandpaper should never be torn off the sheet, but cut into parts by placing the sandpaper, rough side down, on a table or board and cutting or ripping the inside with a knife, after which it is bent in a sharp angle and pulled apart. To test the quality of sandpaper bend it sharply and see if it parts, that is, if the coarse part of it will separate from the paper. Use will tell you the difference between good and bad sandpaper surely and quickly. Care should be taken in sandpapering not to round the edges in panel work.

Steel Wool.

The use of steel wool and steel shavings for smoothing purposes in this country is somewhat new and for page twelve quickness and accurate work it cannot be classed with sandpaper, although it is in itself more expensive than the latter. Its discovery, as a material for rubbing down, was left to the father of the writer, who, about the year 1882, procured some steel shavings, a waste material at that time, from a tool factory, and used it for rubbing down floors, Since that time it has been manufactured in a number of different grades, from coarse to fine, arranged

Fig. 1 the same as sandpaper and used for the same purpose. It is advisable to protect the hands with leather gloves to prevent splinters of steel wool from entering the hands. Steel wool will prevent the rubbing off and rounding of fine edges and is the only material which can successfully be used in carvings.

The quality of steel wool is shown by its elasticity and brittleness, the more elastic the better, also by its cut. The best grade of steel wool is cut with a triangular section (see Figure 1.) ; the common grade is cut in the segment of a circle (see Figure 2.)

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For rubbing down very stringy, or very hard wood, steel wool cannot be compared with any other material.

Pumice Stone and Soft Sandstone.

Pumice and sandstone are sometimes used for rubbing straight surfaces and in block form are better than sandpaper for that purpose. In powder form they are used with water or oil for rubbing down varnishes.

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ARCHITECTURAIj

CHAPTER III. Stains and Staining Woods

E now come to staining the wood and the materials used for that purpose.

Staining is s>o variable in itself and it is necessary besides to satisfy the tastes of your customer and the sometimes impossible ideas of the architects, that it requires a most skillful and experienced mechanic to make not only a sightly but also a tasteful and harmonious job. Thorough knowledge of both work and material is required from the finisher.

Stains are divided into numerous varieties, as follows: Water, spirit or alcohol, acid and alkali, oil and varnish, and these again into pigment, lake, aniline and vegetable stains. There are also methods of staining or darkening by steaming, fuming, etc., including the darkening of the wood caused by nreproofmg the wood, which is frequently done, and which requires a special treatment which will be described later on.

Water stains are commonly mixtures of lakes or vegetable matters and anilines.

page fifteen

Lakes, or vegetable stains, are decoctions of natural colored woods, such as logwood, Brazil wood, sandal wood, Sapan wood, Lima wood, canewood, Campeachy wood, etc., roots, leaves, fruits, skins, bark and numerous other vegetable matter are also used in their manufacture. Water stains are most lasting, if made from vegetable matter. They also give the most natural looking colors, and they should be applied as warm as possibly can be done, but never at a temperature lower than ioo deg. Fahrenheit.

Water stains, mixed with anilines, are very often used on account of their cheapness and quick preparation, but they are not as lasting in color. They fade quickly, especially if exposed to the sunlight and show streaky and botchy if not properly applied.

Spirit Stains.

Spirit or alcohol stains are made the same way as water stains, and are used to obtain a more penetrative stain, also a greater density of color and to allow a quicker job, as alcohol evaporates more quickly, and when shellacking is resorted to afterward they allow an almost immediate application of the same. Otherwise a water stain is just as effective.

To prevent the raising of the fiber of the wood in applying either the wapage sixteen ter or alcohol stain, a good many wood finishers add a small portion of glycerin or castor oil, but the utmost precaution in using those articles is advised, because a too liberal use of the same will prove disastrous to the after finish, as both of them are of an oily, non-drying nature, causing the shellac or varnish to scale or chip off; preventing also the penetration of the stain into the wood and having a good many other disadvantages.

White pine, whitewood, cypress and a few other very spongy woods are debarred from water or alcohol staining, except when a so-called solid color is required, because the application of stain on those woods cannot be evenly done, as their soft and spongy nature will absorb the stain immediately, and the touching of the same place a second time will show a decided mark or lap. A dipping process would be about the only way to partially overcome those disadvantages.

The application of both water and alcohol stain should be done with a brush, the bristles of which are set in cement, a sponge or swab, but no doubt the brush is the proper tool. All stain which is not at once absorbed by the wood should be wiped off with a soft rag. For dipping, a vat or barrel should be used or any other vessel

page seventeen which does not contain any metal parts whatever, but which is entirely made from wood.

All stained wood should be given the proper time to dry, and should receive two coats of stain, the second coat should be applied after the first is properly dried out, or if a quicker and cheaper job is required a coat of shellac or copal varnish should be given before sandpapering, excepting only where the wood is to be filled with wood filler before finishing up. The reason for applying a second coat is simply that after sandpapering, after the first coat, small light dots will appear wherever the stain has not penetrated deep enough into the raised fibers.

Mordants.

By mordants we understand a chemical to fix or set a color to prevent it from changing. For the finisher, alum and ferro-sulphide, known as green copperas, are sufficient. They are used by dissolving a quantity, about one-half pound to a gallon of warm water, and applying a coat over the work before sandpapering or varnishing.

Acid and Alkali Stains.

Staining with acid or alkali stains is done practically the same way as has

page eighteen been described for water and alcohol stains, with the exception that these stains generally do not require a second application. Care must be used in handling these stains, as most of them are very dangerous poisons. The most commonly used materials for these stains are chromate and bichromate of potassium, ferro-sulphide or green copperas, picric and sulphuric acid, iodine, alum, vinegar, soda, caustic snda, potash or pearl ash, ammonia, lime, etc.

Chromate and bichromate of potassium are generally used to produce a so-called golden oak effect on oak, or an antique mahogany effeci on mahogany. Picric acid will always give a yellow effect and is used to lighten up, in fact to entirely change the color, of walnut. Copperas is used to set and deepen the obtained colors, and alum and vinegar to neutralize or kill the after effects of acid and alkali stains. Iodine produces a very beautiful brown stain, but is rather too expensive to be used commonly. Caustic soda and kindred materials produce dark stains, but on account of their after effects are not often used. Lime will produce a similar effect, but not so deep a color as soda or potash, and is used by slaking the same as in a sufficient quantity of water to make lime milk, which is brushed over the sur-

page nineteen face to be stained, and allowed to remain to dry, after which it is brushed off, washed clean and the surface is then coated with vinegar.

Ammonia is used the same as all other alkali stains, by reducing it with water to the required strength, and is applied with a grass or fiber brush, as it will destroy any hair or bristle brush.

Acid and alkali staining is done only on wood containing tannic acid in a larger or smaller percentage, as those stains will hardly produce any coloring on any dry, pitchy, or sappy wood.

Fuming.

Fuming of wood is a procedure which is not often resorted to for various reasons, but which has a decided advantage over all other methods, because it does not raise the fiber of the wood, leaves it in its original condition, but produces only color which, of course, can be secured in different shadings from light to dark. It is the only method to produce a so-called Flemish oak effect, and should be done in all cases where a wax finish is required, leaving the wood in its normal state. As a rule, oak is the only wood subjected to fuming, but other woods can be done the same way. Fuming is done in a simple way, as follows :

page twenty

Take an air-tight box or room, place several flat porcelain or glass dishes on the floor containing 26 deg. ammonia. After placing the wood to be stained on brackets, close the room or box up tight, and allow the wood to remain twelve hours or more until such a time as the desired effect is obtained, after which give it a good airing to allow the ammonia gases which remain in the wood to* evaporate before finishing up. The result is a perfect, even staining, without the need of sandpapering.

Oil and Varnish Stains.

Oil stains are not often used by the finisher, as they do not always give the proper result. For very soft and spongy woods, as white pine, whitewood, cypress, etc., they are essential, but on very hard woods they refuse to penetrate deep enough into the wood and with very few exceptions all oil stains will darken and quite often they will cause the varnish to shrink if no shellac is used before varnishing. Furthermore, a good many oil stains, especially when made with ordinary colors, will mar and cloud the grain of the wood, on account of their opacity. The materials used for oil stains are linseed oil, japan, benzine, turpentine, asphaltum, Van Dyke brown and all lake and oil colors. The finer the color

page twenty-one the more brilliant will be the effect. Asphaltum and Van Dyke brown are mainly used to obtain the golden oak and antique effects in oak and mahogany, but have otherwise various uses.

For drying purposes in mixing oil stains the borate of manganese is always preferable to japan driers, except when asphaltum is used. Anilines are not soluble in oil and the articles which are sold as oil-soluble anilines are nothing but aniline dissolved in glycerin or other fatty and non-drying ingredients, and are worthless for the wood finisher. This is a fact which the writer, after years of experimenting, has found out to his cost.

Varnish stains are household articles and are not used by the artisan except when on old work a toning up is requested. In applying varnish stains the same care is required as in enameling, as they set quickly and will show laps if repeatedly worked over.

Paraffine and all non-drying and mineral oils should not be used in staining wood or for any other purpose, except rubbing down.

page twenty-two

CHAPTER IV. The Preparation of Stains

REPARING or making stairs O) is an important point in the work of wood-finishing, and also a very interesting item owing to its many variations. This work should usually be left to the manufacturer of finishing materials, but in many cases the finisher is required to compound his own stains to suit the taste and requirements of the customer or architect.

The time, of course, is past where the artisan went out to gather his own raw materials in the shape of barks, leaves, roots, fruits, fruit skins, etc., and the best he can do now is to buy the finished products, or, at least, the materials ready to be dissolved in the respective solvent.

In the following will be given a few of the most commonly used stains and how to prepare them, considering an effective material, easy to use, and which may be cheaply prepared.

Antique Effect for Oak and Other Woods.

I. Boil together I oz. catechu with l]/ 2 pints of water, apply and follow

page twenty-three afterwards with a coat of I oz. bichromate of potassium dissolved in 1^2 pints of water. The result will be a golden oak effect on oak. The same used on mahogany will produce a dark antique.

2. Coffee, ground and roasted very dark, boiled with water, will produce a beautiful dark brown on oak or other light woods.

3. Green walnut peds boiled with water will produce a deep brown, and if applied several times will turn black, especially when followed by a coat of iron filings soaked in vinegar for several days or a coat of ferro-sulphite (green copperas) dissolved in the proportion of about y 2 pound to a gallon of water.

4. Fresh slaked lime, called milk of lime, whitewash, applied with a grass or fiber brush and brushed off after drying will give an antique or darkbrown effect on all woods containing tannic acid, such as oak, mahogany, ash, birch, cherry, walnut, etc.

5. A similar effect is obtained by the application of liquid ammonia (hartshorn), on the same kinds of wood, for oak, especially to produce the old English color.

6. For a XVI. century effect on oak, apply sulphuric acid diluted with equal parts of water.

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7. Black asphaltum varnish mixed with Van Dyke brown and thinned with benzine or turpentine will also give a golden oak effect on oak and a nice dark brown color on light woods.

8. Bichromate or permanganate of potassium will produce a similar effect on oak and mahogany to that described in No. 1.

9. One gallon of strong vinegar, or dilute acetic acid mixed with 3^-pound Van Dyke brown, 1 pound of burnt Turkey umber and ^-pound of rose pink, C. P., prepared at least 24 hours before using, will produce a deep rich brown color on any kind of wood.

11. Bismarck brown added to burnt sienna and dissolved in alcohol can be used in preparing stains for birch, cherry, or other light-colored woods for a mahogany color, or can also be used on mahogany itself to enrich the color of it. By adding burnt Turkey umber the color will be proportionately darkened.

12. Anilin colors, of desired shades, can be mixed with alcohol for any kind of wood, and if the raising of the fiber is objectionable the addition of a small quantity of castor oil or glycerin is recommended, if carefully used.

13. Anilin colors, as auove, boiled with water and a small quantity of

page twenty-five soda or potash, are also used for the same purpose, but such color will show different effects than if mixed with alcohol, and, besides, all anilin colors will fade and change within a short time despite protection by varnish. The use of a mordant for those colors is required, and is applied afterward in the form of alum, i pound dissolved in warm water, or green copperas as previously mentioned. In using this mordant the stain has to be thoroughly dried.

13. A green stain on all kinds of woods is made by dissolving verdigris in soft water or vinegar.

14. Chemically pure colors and lakes, selected according to requirements, and boiled with soft water and a small amount of gelatine or isinglass will produce very good results and are very permanent.

15. The same as above, mixed with alcohol and a small quantity of shellac varnish will be nearly as satisfactory.

16. Another process of staining is by using picric acid dissolved in water or vinegar. This will lighten walnut considerably and give a yellow color to other woods, with the exception of mahogany.

17. Bichromate of potassium, dissolved in water, applied on walnut,

page twenty-six will make a good imitation of rosewood.

18. To imitate walnut on pine lumber use a solution of black privet berry in liquid ammonia, about 2 oz. to 1^2 pints.

19. A metallic black stain on any kind of wood may be had by applying a strong solution of nitrate of silver under exposure to light,

20. All direct color, such as ivory or drop black, ochers, umbers, siennas, can be used to make water, alcohol or oil stains, similar to those described in former items.

21. Logwood chips boiled in soft water or logwood extract dissolved in alcohol are used to make dark brown or soft black stains, if followed up with a coat of copperas solution or iron filings in vinegar.

22. Varnish stains for use in touching up old work, otherwise known as household articles, are made by mixing good transparent lake or mineral colors with japan and adding the desired quantity to a good copal varnish gradually, under continuous stirring.

Numerous other methods could be mentioned, but the foregoing will be found the most essential ones in architectural work, and the desired effects have to be ascertained by experimenting on the part of the finisher.

page twenty-seven

HARDV/OOD

CHAPTER V. Wood Fillers

LTHOUGH a necessity in modern wood finishing, the use of wood fillers dates back only some thirty to thirty-five years. Nowadays a good many articles are manufactured and sold under the name of wood fillers which are good for anything else but the purpose they are intended for. Wood fillers are used not only to fill the pores of the wood, but have to serve also for a good many other purposes, in fact the proper filling of open grained wood with proper material is most essential for the high grade finish of the wood.

The general make up of a filler should be of a hard transparent base, to prevent clouding the grain of the wood. Furthermore, it should consist of a good binder in the form of a drier, a varnish and oil and also of a thinner.

Competition has brought the price of wood fillers to such a low level that even the large consumers, who are using wood fillers by the ton lots, do not attempt to make them themselves, but buy the ready-made article, therefore it does not pay the smaller user or finisher to make wood filler in small quantities ; first, on account of the lack of proper material and lack of ma-

page twenty-eight chinery to produce a uniform mixture. Clays, chalk, terra alba, whiting, barytes, talcum, asbestine, marble dust, corn starch and all opaque materials or those of a soft or easy decaying nature must be left out entirely in the making of a good filler, and only materials of a certain hardness and transparency should be used. In buying wood filler it would be of advantage lo use the following test.

Test for Wood Fillers.

Take a piece of light colored cardboard or heavy paper, or still better, a piece of raw, unfinished wood; then

W$] Figure 3.

take a small quantity of the pigment or sediment in the filler and place the same on the board. Take a clean steel knife, and by gently rubbing the same over the filler in the same manner as if polishing the knife (see Figure 3), the filler should turn black, which will prove the presence of a hard crystal. page twenty-nine

The sooner the filler turns black the better the quality will be. In comparing two or more different grades of fillers, you will probably find the difference. Should no change in color appear, that is, should the filler fail to turn black, you may safely reject it as an unfit material for hardwood finishing.

Properties of Fillers.

Ground glass or the well known silex or silica are best known, the former being seldom used because the latter is sold at such a low figure that it can be used with advantage in the cheapest grades of fillers, besides it appears so abundantly that there is no fear of its becoming exhausted; in fact one-third of our planet is composed of silex or quartz. It even enters into vegetable matter in the form of coatings, such as cane. Silex is found in several forms: one is the natural deposit of fine silex, which is lacking the hardness and the crystalline form and is valueless in the manufacture of filler; another form is crystal quartz, which is used for a good many purposes, especially in the manufacture of glass, polishing materials and scouring soaps ; and, last but not least, in the manufacture of wood fillers. In its natural state quart2 appears in the form of large rocks, either in a

page thirty milkish white or slightly colored hue of all colors of the rainbow or in a dirty brownish black called smoky quartz. It is chipped, broken into small pieces by heating the same in a kiln and suddenly cooling it by drenching the same with cold water, by which process it also becomes harder. Then it is assorted according to color, reduced to still smaller pieces and finally ground into a very fine powder which is of such fineness that the aid of a magnifying glass of 3,000 strength will be necessary to detect the single parts, every one of which will show the form of splinter or small needle. The hardness of quartz or silex is 7, which is only three removed from the diamond, which is 10. Silex in powdered form looks perfectly white and becomes transparent by mixing the same with oily substances. Silex is non-absorbent, which is another beneficial feature for its usefulness in the manufacture of wood filler. The hardness and sharpness of the single parts of silex guarantee the perfect filling of the pores of the wood, and at the same time act as a cleaner or polisher of harder grains, bringing out the beauty of the wood not only in its natural clearness, but also developing and improving its general appearance. Wood not filled with pure silex filler will always show a cloudy effect and can be easily detected from the former.

page thirty-one

Colored Wood Fillers.

Wood filler is generally colored or should be so if used on the darker kinds of wood or where a certain effect is required on lio^lit colored woods or when a filler is used on stained wood. In the latter case it is only required to match the color of the stain, while in the first case a colored filler is used to produce a colored or stained effect on the wood.

When colored fillers are used on open pored and hard grained, so-called quartered or cross-cut woods, mainly on oak, ash, curly yellow pine, etc., it produces beautiful effects, and the perfect wood finisher can show his ability in producing effects of peculiar results, entirely different from the artificial stained wood.