Chapter XXXVIII: Artificial Wood: How to Make It and What to Make of

IT.

BY THE LATE DR. SCOFFERN.

You will admit, I think, that if instead of fashioning wood by tools it were possible to make the wood grow into the shape desired, it would not only be curious, but under certain circumstances useful. Suppose, for instance, I wished to have a boat; it would not only be curious, but in some cases useful, if I could make the boat grow under my eyes by almost imperceptible additions, instead of fashioning it, as now, from planks. This is just what I am going to show you how to do, and very pretty work you will find it in long evenings.

You must begin by making a fluid called cupro-ammonium (you cannot buy it), which has the singular property of dissolving woody matter just as completely as water dissolves gum. You make this cupro-ammonium thus: Go to a wholesale druggist, or a drysalter, and purchase a Winchester quart bottle full of the very strongest solution of ammonia. This is known commercially as ‘eighty-eighty’ ammonia, by which name you are to inquire for it. Were you to purchase less than the measure of a Winchester quart it would cost you a much higher proportionate price, because, being very irritating to the nose and eyes, the vendor will take good care to charge you for all the sneezes and eye-blinkings he has to encounter in measuring out your required quantity.

Next you will require an _empty_ Winchester quart stoppered bottle, or a bottle of equal capacity. Being thus provided, you will pour just one half of the contents of the full bottle into the empty bottle; the reason for doing which will presently be seen.

Get now some copper wire--it matters not what size--and having got it, cut into such lengths that being thrust into one of your half-full Winchester quart bottles it shall lie partly immersed in the ammonia, and partly exposed to air, like this:--

You will observe that the sketch represents not one length of copper wire, but many, the fact being that the object of using copper at all is that it may be dissolved by the ammonia; and it stands to reason that in proportion as the copper is more so will the necessary strength of solution be arrived at more quickly. Contact of air being necessary to effect the solution affords the reason for your dividing the original ammonia into halves.

So your bundle of copper wire being placed in the half-full bottle as described, there let it remain and steep, but you must take care to remove the stopper of your bottle from time to time--say once a day, at least--shaking the contained fluid well about, so as to promote air contact. An interesting change will be seen to take place. The ammonia solution, originally colourless as water, grows blue and bluer still, until so very blue that you cannot see through it. To this blue solution the name of cupro-ammonia has been applied. It has the remarkable property of dissolving wood, as we shall presently discover in our workings.

Before going further I must point out to you that this cupro-ammonium has a very strong smell; not a disagreeable smell, far from it; the smell of hartshorn, in point of fact. Not an unhealthy smell, but one may easily have too much of it. To be working amidst sneezing and eyes full of water is not agreeable, so I will tell you betimes how, in your small workings, you may avoid this inconvenience. The smell depends on a colourless gas ammonia, which is a light gas and very tractable. If you sit in a draught and on the windward side whilst working, and in the open air, the ammonia is blown away from you and you smell nothing. If you work in a room and before a chimney, up which there is a draught, then again you smell nothing, because all the ammonia evolved goes up the chimney. These points being remembered, no trouble will be experienced in doing such small work as I shall teach you; but before working with cupro-ammonia could be conducted on a large manufacturing scale, as it now is conducted, special means had to be devised for disposing of the ammoniacal atmosphere.

Good, so far! And now about the tools. The hand, with its four fingers and a thumb, is so excellent a tool for an infinity of purposes, that certain thoughtless people would seem to be under the impression that whatever new thing they may have to do can be done without tools altogether. This is a mistake; tools you will want, but they are of the simplest description.

Inasmuch as cupro-ammonium not only stains the skin but irritates it, do not let it touch the skin. There is no danger in the matter, only inconvenience. You do not want the ladies of your family petulantly complaining about those boys having been ‘dabbling with their filthy chemicals.’ Should your fingers get stained, a little vinegar will get out the stain, but not without a certain smarting that may as well be avoided.

The chief tool you will have to employ will be a finger of the right hand. Some operators may prefer the forefinger to others; the second will come most natural. But whichever finger you determine to employ, case it in india-rubber. This is easily done, and as follows: Having procured a sheet of raw or unvulcanised india-rubber, cut a piece off, hold out your finger, and get some friend, after warming the rubber, to stretch it over the finger so:-- squeezing the rubber where it comes round the finger above into a flattened crest. The two surfaces will stick together quite as much as is desirable. Now let the operator, with a pair of sharp scissors, and at one sweep, cut away the crest close up to the finger. You will then have an india-rubber finger-stall.

If you choose to be a little more extravagant, you may provide yourself with an india-rubber glove. Gloves of this material are common enough now, being used for a variety of purposes, more especially by photographers for protecting their hands against the corrosive and poisonous agents employed in the practice of photography. If, however, you do use gloves, see that they are thin, fitting well to the fingers. If thick they will interfere with the delicacy of touch necessary to your working. For my part, I do not recommend gloves, looking upon a finger-stall of india-rubber as superior.

The next tool that you must get is a pair of forceps, such as watchmakers use. It is a very inexpensive instrument, costing only a few pence, and in shape it is like this:--

The next tool--and the last I shall have to indicate--is a pair of sharp and delicately made scissors. Do not calculate on family resources, taking the first pair of scissors that may come to hand: get a pair of your own. See that they are first-rate when you are about it, and you cannot buy scissors of this sort at random at any hardware shop. Go to a surgical instrument shop, where you will be able to get what you want.

And now I leave your cupro-ammonium to brew, and you to get together the few tools indicated. When you are quite ready, we will proceed to see what to do with it.

The first exercise I shall put to you is the manufacture of an artificial wooden bottle. There will be no particular use in the thing when made, but it will be a curiosity, and the making of it is the very best exercise that suggests itself to me after many years’ experience.

You will perhaps here call to mind what I have told you about the pungent smell of our working fluid, cupro-ammonium, if one chances to get a sniff at it, and how that inconvenience may be avoided by a little management. In addition to that memory, please now bear in mind that the intensity of the smell of odorous things is in proportion to the surface exposed. Presently, in order to use your cupro-ammonium fluid, some must be poured out into a vessel into which you can dip little pieces of paper. Now it is evident that the smell of a pint of cupro-ammonium, or of any other smelling fluid, will be less intense if the vessel be a comparatively narrow-mouthed jug than if it be a basin; but supposing a basin to be desirable for collateral reasons, then much smell may be avoided by providing yourself with a temporary cover, say a glass pane, which may be laid over the surface, resting on the basin rim at the intervals when the dipping of your pieces of paper must be interrupted.

Next as to the paper you are to use in making this bottle of artificial wood. The best for your purpose will be what is known as printing demy. Writing-paper, having a glazed surface, is not favourable. The glaze is produced by animal size, a material that does not go well with cupro-ammonium. It matters little, practically nothing at all, whether the printer’s demy be new or whether it be printed upon. I have made excellent artificial wood out of, I believe, _all_ the London daily morning papers; so choose your paper, and let us fall to work. Theoretically and scientifically it matters not what shape you cut your paper into, but practically, and present purpose regarded, there can be no doubt but that discs of a circular shape, and scored with cuts all round the circumference, are most convenient. The discs may conveniently run about the accompanying size.

The basis or model of our bottle about to be, or rather flask, shall be a common oil-flask. Provide yourself, then, with one of these, and cleanse it thoroughly from all oil, the least touch of which would be fatal to the success of our workings. Having done this, provide some sort of stand, into which the neck of the flask being stuck, the whole may be turned round and round in the progress of working. It matters nothing what this movable stand is. A candlestick does very well, if you can find a candlestick with candle-socket big enough to admit the neck of the flask. A marmalade pot holding sand can always be got, and into the sand the mouth and neck of the flask being stuck, every necessary purpose will have been answered.

Preliminaries being thus seen to, you pour out some of the cupro-ammonium in, let us say, a basin. Do not be sparing as to the quantity you pour out, for a reason to be explained presently. Take now one of your paper circular discs, and, with your forceps nipping it quite at the edge, dip it into the cupro-ammonium bath. For how long? Ah! that is a question to be solved. Assuming your stock of cupro-ammonium to be in good working order--assuming it to have been brewing with the copper wire for not less than a month, air having been furnished to it day by day, as already enjoined--then about three seconds will be long enough for each immersion. Nothing but practice will settle the point, and after only a little practice the operator cannot be mistaken. Immerse, then, for trial a paper disc, and, withdrawing it after about three or four seconds, lay it upon the crown of your flask and spread it out regularly by means of your forceps and rubber-protected finger. If it feels slippery like an eel the fluid has come to condition; but otherwise, if the disc instead of feeling slippery give the impression of harshness, then the conditions are not all that one would desire them to be. The main question is this: will the next disc, when steeped in the bath, removed, and pressed down, stick satisfactorily to the preceding disc?

This we shall now see. I have shown you here how the discs must overlap each other like the scales of a fish. You need not be particular in aiming at the mathematical symmetry of the scale lying on a fish’s skin; it would be folly to attempt such a result except your discs had been mathematically cut to pattern, and extremely difficult of execution in any case. Supposing the adhesion to be satisfactory, you can go on covering the entire surface of the oil-flask, and I should think common sense would suggest that when you have come down a certain distance in your working it will be more convenient if you take the flask out of its support and reverse it on a tumbler thus:--

When one course of overlap disc-layering has been finished in the way described, I would advise you, this being your first experience, to lay your work aside and let it dry. It will be easy now to see whether the overlap adhesion by all that was desired, and what the process is capable of. You are to remember, please, that we aim at no mere sticking together comparable to the result of gumming or pasting, but to an actual incorporation of material, so that junction being once effected, the layers can never more be separated by any known means. Were it otherwise, a thick material resulting from aggregated sheets of paper would have no claim to the designation ‘artificial wood.’ It would be simply _papier-maché_, reducible to paper pulp by mere steeping in water; whereas the material you and I are now engaged upon may be not only steeped in water, but actually boiled, and will never come to pieces. It will behave under those circumstances exactly like natural wood--that is to say, will soften a little to a certain depth, no more.

Cupro-ammonium is a very funny thing to work with, and has many curious ways. One curious point is this: Capable of effecting such complete adhesion--nay, more, incorporation, actual, bodily, as we have seen it to be--yet that quality ceases after only a few minutes’ removal from the bath. If you ask me the why and wherefore, frankly, I am unable to tell you, not myself knowing, though I have worked at this material for more than twenty years. So whatever work has to be done with cupro-ammonium has to be quickly done.

Another point of very highest importance is the following: Do you remember my telling you not to be sparing in the quantity of cupro-ammonium poured from the ‘brewing bottle,’ as we will call it, into the dipping basin? The fact is that every bit of paper you immerse and withdraw weakens the original solvent power of the bath, so in proportion as the bath liquor is smaller in quantity, by so much more speedily will its working power be lessened. For a long time that working power can be, and in practice is, restored by additional copper steepage, but it cannot be restored indefinitely.

Now pour back your bath-liquor; put away your tools, hereafter to renew your bottle building. Go on adding layer to layer until your bottle is as thick as you wish it to be, then giving the thing a sharp crack with the hammer, the glass flask will crumble almost to sand, which, when shook out, your own flask of cuproxylene, or artificial wood, will remain without support, but quite able to take care of itself.