Jul 31

CHINA AND GLASS
China restoration is always delicate work, requiring care, accuracy and knowledge of technique. How much knowledge depends entirely on how ambitious you arc. Most people, if they Fail in simple efforts to stick china together, take it to a professional restorer if the piece is of any value. It also depends on what is going to happen to a piece after it is mended. If it is to stand peacefully on a shelf, then the repair need not be so strong as it would have to be for domestic use. Some people try to restore a piece to the state where only a very close scrutiny will reveal the mend. It is technically possible to fool even ultra violet light. Others feel that there is no shame in a few cracks in old china. Like so many skills connected with making and mending things, china restoring can develop from the ability simply to stick broken pieces together, to the most complex dowelling and pinning and moulding and modelling and casting and painting. It can start by being a chore and end by being an art, which like any art develops into pride in craftsmanship, and pleasure in achievement. Maybe the kind of painstaking repair I am thinking of comes outside die scope of a book on restoring junk, but I shall include an outline of some of the methods and materials and tools needed just in case you do decide to venture further than a little bit of glucing.
Some technical colleges run classes on china restoration, but they arc few and far between, although this is one of the best ways to gain expert knowledge and experience. The study of books on die subject and plenty of practice should make you reasonably efficient if you are not totally ham-fisted !
There arc so many objects in so many shapes and sizes made of so in-uiy materials; so many ‘pots’ that it is difficult to detail all the techniques, and each job must be treated on its merits. The first and easiest method is to mend by sticking. Sticking things together used to be more difficult than it is now, because die old adhesives were nothing like so easy to use or so heat-and-water-resistant, so free from shrinkage, or attacks by fungus, so clean, so invisible, or so strong. The invention of cellulose glues and epoxy resin adhesives has completely revolutionised sticking, and made it possible to mend things with adhesive alone where riveting, dowelling, or pinning would once have been essential.
As a general rule, a piece of china, be it a plate, a pot, a Statuette, or a vase, can be mended by sticking alone if the two faces come together properly and neatly and if they can be made to stay in position while the adhesive is setting.
If a part such as a curved handle, or the limb of a figurine, is broken, perhaps in more than one place, and there are pieces missing; or if the surfaces to be joined are chipped and do not fit, or there arc whole sections missing; then more ambitious methods will have to be used. Whole sections can be remade by modelling with epoxy resins just as the sculptor models, or by making plaster moulds and taking castings. Large missing parts can be moulded or modelled incorporating wire supporting frameworks fixed to die whole piece.
Broken parts are refixed together and to the whole, provided they are thick enough to carry drilled holes, either by pinning—which means inserting a metal pin into a hole drilled after the pieces have been stuck—or by dowelling, which is the joining of pieces by drilling matching holes in each and cementing in a single dowel. Any or all of these methods might be necessary at the same time in one single object (see Fig. io).
Lastly, broken pieces can be riveted together. The ugliness of this technique, strong though it is, means that it has largely been superseded by other methods since the discovery of die better adhesives, and is really only used for extreme strength and utility rather than for restoration and beauty.
Cleaning. Before any porcelain or pottery may be mended it must be cleaned. Normally all that is needed is a wash in warm soapy water. If die piece is already clean, then wipe it with a piece of silk dipped in methylated spirits. Keep any old pieces of real silk for china restoration work, as silk does not leave little bits of lint or fluff caught on jagged edges.
Remove stains from china with very dilute hydrochloric acid, but test first in case the acid etches the glaze. A cloth dipped in either bicarbonate of soda or common salt will remove coffee stains.
To remove dirt along cracks which are not going to be repaired—cracks which are, and look dirty—make a pad of cotton wool and saturate it in a mild bleaching solution such as hydrogen peroxide and lay it along the crack for some days, renewing the solution as die pads dry out. When the treatment is completed, scrub the piece gently with a soft brush, and even more dirt may conic away. This method is useless on earthenware, but for this and for English porcelain, which is usually so porous that the dirt is well ingrained, soak the piece for up to a week in a solution of domestic bleach. This will remove most stubborn stains and won’t etch the glaze.
If china has been previously mended, the edges of the breaks may be very dirty, and sometimes glue remains which is invisible except under a magnifying glass. All edges must be cleaned, and you must be sure they fit together before going ahead with the next stages of the job. First of all soak the pieces in boiling water with pure detergent added. Remember, if there is another part of the object which has been mended and which you do not wish to do again, to keep it out of the water or it may melt apart. Glue, Seccotine, shellac and Durofix will come off in boiling water, and joins made with these adhesives will soften sufficiently to be parted. If this treatment does not tackle the old glue then you will have to get to work with the appropriate solvents (see Solvents). Methylated spirits will shift shellac that has resisted boiling water. Swabbing with cotton wool dipped in amyl acetate removes cellulose adhesives such as Durofix. Acetone removes cements, but may take some time about it. Dissolver is a new solvent which will shift many kinds of glues including Araldite, especially some of those used for glass repairs.
Literally to boil a piece in detergent and water is a last resort to remove stubborn adhesive without abrasion. Finally it may be necessary to pick away at the old adhesive with a scraper or even a needle. Obviously this has to be done with care.
If old rivets have to be removed, cut them in half with a needle file and pick out the bits using acetone to remove the cement if necessary.
The first two methods are done with just a few tools, but the moment you have to drill, more complex tools will be necessary, and this means more expense, and also more time spent on learning to handle the tools. China drilling is not difficult, but it takes a light hand and a steady one, and infinite care and patience.
A power drill, which is normal workshop equipment nowadays, can be used with the rightbits for a lot of drilling work provided it has both vertical and horizontal bench stands and operates at the right r.p.m. The ideal tool for most drilling is a dentist’s drill—in fact an electric motor with a. flexible drive and a hand-held drill at the end. But this is an expensive piece of equipment not justified unless a lot of work is to be done, so its use is not described here. A hand drill and appropriate bits will needed for starting holes, and for the awkward holes. A special twist drill with high gearing can be bought for work on china, and some people prefer this to the other types. It is good for dowelling and for work in substantial pieces, but is a little difficult to control on really delicate work.
Brass wire is used for pins and dowels, and unless you arc doing very complex work only one or two sizes will be needed. Other standard tools such as the hacksaw, and calipers you may already have. Small cramps and a pin vice are useful, and all shapes and sizes of small files and rasps, scalpels, and probes. Various materials will be needed for making moulds, supporting pieces while they dry, binding to aid adhesion etc. These I shall mention as they conic into use.
Sticking. There is some general information on adhesives wider that specific heading. Here I shall discuss the various methods used for mending china with adhesives.
Ordinary domestic two-tube Araldite (AV and HV roo) is suitable for all practical purposes for almost any work. It is best used in a well-warmed room, and pieces should always be warm when joined. Keep the tubes of Araldite warm before mixing. All this helps the adhesive to flow readily, and to grip. A cold unheated workshop is not a suitable place. Work in a heated room with a radiator with a flat top or heat conductive shelf above it so that pieces can be kept warm.
The second important point, already stressed several times, is that pieces must be clean and dry. Pieces that have been washed or boiled to clean them may take quite a long time to dry out, especially the unglazed edges of breaks. Damp, dirty surfaces just will not adhere.
Thirdly it is vital to grasp the basic principle of adhesion, whicl, is to bring the original faces as close together as is physically possible, with the thinnest practicable layer of adhesive between. The edges and surfaces of the break then lock together naturally. It is a misapprehension to suppose that thick layers of adhesive will make more successful joints. All the adhesive that is needed is enough to fill all the tiny gaps and crevises between the faces so that the two present smooth surfaces to each other with no air pockets, and they will adhere.
Lastly, stuck joints need to have some pressure exerted upon then, while the adhesive is setting, either by clamping the pieces together, or by putting a weight on top of a flat piece, or more usually by binding the pieces together with gum strip (not Sellotape) in such a way that pressure is exerted on the join.
The methods of applying this binding
g differ slightly
with every mend. Always use gummed strip, and buy a big roll at least il” wide. Cut this down if necessary. Strips are stuck as nearly as possible at right angles across joins such as simple breaks in a plate or vase. When thc join is rather more difficult, such as a broken vase handle or lid, the strip is stuck on so that it will exert pressure at right angles to the join. The wet gummed strip is easy to put into position, and as it dries it shrinks, holds fast to the china and so exerts pressure on the join. When you reach the stage of placing the prepared pieces together, wet the cut strips of paper thoroughly but remove any surplus drips of water with a swab. They should be damp right through but not dripping wet, as moisture will prevent pieces from adhering if any gets on to the broken edges. Sometimes it is best to pre-stick the strip on to one piece of the work (after you have warmed the piece for glucing, or the gunimed strip will dry out completely) and then put the two edges together. Draw tile loose piece of strip down smoothly and tightly across the join. A little bit of practice at binding diffi llcult shapes will teach you how best these paper bandages can be applied. Remember always that as the strip dries and tightens it must pull across at right angles to the join, so bringing the pieces together and holding them there. Use very long strips if necessary. Make a cross of strips, stand a pot in the middle and bring the ends right up over the top to hold it together. Small
small
pieces of strip may be needed across very joins to exert pressure (see Fig. 7). A binding applied like a puttee round and round an object is almost useless except to keep things in place. The same binding techniques will be used when mending by dowelling and pinning, as described later, and a little thought and study will help you to work out the details for each job. Very occasionally it is not possible to bind, to clamp, or to weight pieces together because of a peculiar shape or a break in an odd place. Make supports out of plasticise or wire to push pieces together, or at any rate to hold them in position while the adhesive sets. No tension is applied to the joint so this way isn’t that satisfactory, but it is better than nothing. Don’t let plasticise come into direct contact with Araldite or any epoxy resin, as the two will react together.
Having cleaned your porcelain or china ready for mending, next check whether or not all the pieces arc there, whether or not they fit together perfectly, and then decide upon your method of restoration. Pieces made of thin China ai-c almost impossible to dowel or pill as there is no thickness to take drilled holes. Hollow figures may need to be dowelled in the hollow sections, or by pinning. But if there are sufficient clean, close fitting edges which will contact nicely, sticking alone may be all that is needed. Details of dowelling and pinning follow, but here I deal with sticking on its own. A piece which has been broken into several pieces should be very carefully checked for fit before applying adhesive. If necessary make tip a kind of jig-saw puzzle, using Sellotape and fit the whole thing together. Be careful not to work yourself into an impossible corner by putting the pieces together iii such a way that i lie last piece cannot be got into place. This can happen, for instance, in a bowl where the break consists of two or more pieces which arc wider at the lower end than they are at the rim end. If a piece is in several fragments it is sometimes easier to stick two or three pieces together to make one large piece, and then join this to the main piece. So do take a bit of thought, and be sure that you have solved the puzzle before taking any irrevocable steps (see Fig. io).
If, as well as being in several pieces, the pot has a Chunk missing, it will be necessary to mould a new piece, but first of all any sticking must be done mid finished, and the Moulding is later carried out as a separate operation.
Having cleaned the pieces, dried them and checked for fit, warm them thoroughly. Prepare a small amount of adhesive, no more than you need, and apply it with a knife to one edge of the two pieces to be joined. Usually it is best and easiest to apply the adhesive to the piece rather than to the whole. Put adhesive on both edges only if the fit is not perfect, or if the material of which the pot is made is very heavy thick porous earthenware, which will absorb a lot of adhesive.
Then bring the two edges together as firmly as you possibly can. Obviously you don’t want to break the china again, but exert as much pressure as you dare on the join so that the adhesive comes squeezing out. If you want to remove adhesive in order to get a clear look at the join through a magnifying glass to make sure it is properly aligned, moisten a water colour brush in a little methylated spirit and take off a little adhesive with that. Do not take it right down to the join as this will weaken it. Surplus adhesive should not be removed along the join until after it has all set. Any adhesive which has escaped on to other as yet unmende8 broken edges, or on to gilt or lustre glaze on the pot, must be removed at once with the paint brush. On the broken edges it will prevent proper matching if it dries into a little lump, and it will lift gilt or lustre when it is finally removed.
H.M.G. adhesive can be used in conjunction with Araldite to make a fairly quick setting join, by putting H.M.G. on one surface of the join and Araldite on the other. The quicker drying H.M.G. binds with the Araldite and helps to hold the two pieces together while setting takes place.
Then the joins are bound with gummed strip as described above. The piece is put down and left to set. Epoxy resins, especially when the join has been properly strapped, will hold almost immediately, and the pieces will not move in relation to each other unless the joins are imperfect or unless the balance and weight of die pieces are such that gravity pulls them out of place. Plasticine supports, bowls of fine clean sand, bits of wood and wire, will all make supports and cradles. If the piece to be joined is some kind of figurine and not a plate or a bowl with flat or curved surfaces, parts sometimes have to be stuck on entirely by balance. The heads of small figures frequently get broken off, and ifyou intend to stick a head back without dowelling, the fit along the break will have to be perfect, and the figure itself must be held in a firm grip so that the head will balance in place while the adhesive sets. Bury the figure in a bowl of sand, with the broken edge set horizontally just above the level of the sand, and then balance the part on it. Move the buried section about until the broken-off piece balances perfectly upon it. Make sure all loose sand is brushed away from both edges, and then, using very fluid adhesive, anoint the broken edges. Carefully put the piece back into place, and allow it a few moments to adhere before delicately, and without moving the buried base, setting it perfectly into position.
It really is a matter of trial and error, and with a bit of ingenuity you can find a solution to every problem of sticking and binding and balancing.
The final process of sticking when using epoxy resin glues, is to harden the joins by baking. If an entire piece has to be moulded in, after some sticking has been done, it is still best to bake the first work for a short while before doing the moulding, just to make certain that the work which has been done is really firm. Baking can be omitted entirely if the piece can be left alone for a good long time to set.
Up to a point the heating of Araldite softens it, and if you leave a job for some hours before baking and a piece has slipped a little out of place, warm the join with boiling water swabs to soften the Araldite enough to move the piece back into position. Leave joins made with Araldite for a few hours before baking and then place the piece in the oven of an electric cooker or of a solid fuel cooker. Put an asbestos mat on the middle shelf and place the china carefully on that, and keep the oven at a temperature of Zoo deg. for about an hour. Over 3oo deg. the Araldite will darken and in any case the china may not stand it. If your oven has no thermometer, buy a small one. If it is impossible to keep the temperature of the oven steady,heat the oven, put in the piece, and switch the oven right off, leaving the piece there until the oven is cold.
Mending Cracks ivith Adhesive. So often articles crack without breaking. The cracks get dirty, and the piece when touched vibrates a little and does not ring true. It may, one feels, collapse into pieces at any moment. Cracks can be repaired quite effectively without completely breaking the pieces apart. Most forms of pottery and porcelain are to a small extent flexible, so carefully insert the edge of a razor blade and part the crack a little. Clean the crack as described above and make sure that the whole piece is thoroughly dry by standing it on a radiator until it is pretty warm. Heat the separate tubes of Aralditc to get them runny and make up a mix, with a little white colouring in it if there are any chips along the crack which need to be filled. Mix the Araldite on a warm surface and keep it warm while working. My own nightstore type electric radiators which have flat tops, are absolutely ideal for this work and I work directly on top of one. This is not recommended by the makers of nightstore radiators but who cares about that !
Prise the crack apart with the razor blade as far as is possible without breaking the piece completely. If the crack runs right to the rim or edge of the piece, slide the edges of the crack apart a little, one up and one down to expose some of the broken edge. Run the adhesive right into the crack, work it in with a finger if necessary, then move away from the radiator and press the edges tightly together. Wipe off any surplus adhesive with methylated spirits, but not that exactly along the crack. Put several pieces of gummed strip across the crack at right-angles on both sides of the piece, and leave the whole thing to dry (bake after an hour if you wish to) for half a day on the top of the radiator. This should set the adhesive perfectly.

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