The Klein method of cementing broken china and glass articles employs the use of two different cements. The identification, description, and purpose of each of these cements are as follows:
NO. 200 Cement
This cement is a new European formula, combining cement with hardener that is mixed together at the time of application to form a chemically setting, self-hardening cement that does not depend on air for drying. It produces a tight joint that is alcohol, water, and boil proof. Cemented according to instructions, the joint should never come apart. No. 200 is used for cementing together broken articles such as:
NO. 100 CEMENT
This cement is a chemically setting, self-hardening cement that depends on air for drying. It has remarkable adhesive strength and qualities, where it is not subjected to cold, hot, or boiling water.
Cemented according to instructions, it produces a strong, tight joint that is both heat and water-resistant, but not waterproof. It will hold indefinitely. It is ideal for cementing the many varieties of china ornaments found in the home, like lamp bases, vases, or china and bisque figurines with a finger, hand, head, arm, or leg broken off.
No. 200 cement can be used in place of No. 100, but never use No. 100 when No. 200 has been specified.
With this information there should be no difficulty in choosing the proper cement to repair a damaged article.
One very important thing to remember is: Be sure to save all pieces of a broken article.
Cleaning, assembling and cementing instructions
Cleaning and preparation
Surfaces to be cemented together must be clean and free of any traces of old cement, grease, dirt, oil, stains, etc. Cement will not adhere to any dirty or greasy surfaces. This rule applies to any article of china, glass, or pottery. For a fresh break, when the article has not lain around to collect dust or dirt, cleaning is not necessary. Where the surfaces are dirty and have never been cemented together before, washing with soap and hot water will in most cases clean them for cementing. After washing, air-dry for three hours or heat-dry for one hour at 125 degrees; surfaces must be thoroughly dry before cementing.
To clean surfaces that have been cemented before, place the pieces of the article in a bucket of cold water and slowly bring to a boil. Be sure the pieces are submerged in the water. If a portion is exposed, any salt in the water may cause a line to form at the water level and crystallize. When this happens, the crystallized line can never be removed.
Simmer the pieces for about ten minutes. For perfect results, use No. 30 strong washing powder in the water. (Use this boiling method to take apart a poor cement job. The boiling action will loosen the joint and permit separation of the pieces. This is the only way a cemented joint can be taken apart.) While the china or glass is still warm, use a piece of Turkish towelling to rub the surfaces clean. Any stubborn spots can be scraped off with a razor blade.
Be sure all traces of old cement are removed. Rinse the pieces in fresh water, then place in a warm oven, about 125 degrees, for an hour to dry out moisture, or allow twenty-four hours air drying time. Surfaces must be dry. ( Remember not to heat clear glass at temperatures above 125 as more intense heat may cloud the glass and ruin its appearance. )
A. There is another way to clean surfaces that have been cemented before, and in many instances it is considered better. Instead of submerging the pieces of the article in water and boiling, clean the surfaces with No. 51 thick strong cleaner. This method of cleaning is recommended in all cases for speed cleaning, and should be used for the purposes listed below in B and C as the best method.
B. The pieces of some articles are so large that completely submerging them in water for boiling is impractical. For these large pieces, clean the surfaces with the No. 51 thick strong cleaner.
C. The same cleaner ( No. 51 thick strong) is considered the best for hollow articles like figurines that have small vent holes put in by the potter at the time of manufacture to allow moisture and steam to escape when the article is baked in a high-temperature kiln. If pieces like this were submerged in water and boiled for ten minutes for cleaning, water could enter these vent holes and become trapped in the inside hollow pockets.
Any trapped water would pose two problems; ( 1 ) after the article has been repaired and put to use, trapped water could ooze out of the vent holes and possibly spoil any surface the article rests on. If washing powder was used in the water for cleaning, the solution oozing out could cause serious damage to textiles, paint, or anything else with which it came in contact. ( 2 ) When heating the article in the process of making repairs, any trapped water could create steam vapours and, being locked in, could crack the article.
To avoid these problems, clean the surfaces of hollow articles that have been cemented before with the No. 51 thick strong cleaner. ( To take apart a poorly cemented joint, and separate the pieces of hollow articles, it is necessary to use the boiling method. This is the only way the joint can be separated. To keep water out of the hollow pockets during this process, plug up the vent holes with wooden match sticks. After separating the pieces, clean the surfaces that were cemented together with No. 51 thick strong cleaner.)
D. The cleaner must be mixed thoroughly
before using. Shake the container repeatedly or remove the cap and mix
with a stick.
Repeat this as often as necessary until the surface is free of all foreign matter. Then wipe with regular No. 51 cleaner and finish the cleaning process by washing with soap and hot water, followed by rinsing with fresh water. Dry thoroughly by heating for about one hour at 125 degrees.
E. If any article is stained, use No. 30 strong bleaching liquid, which removes stains from china, glass, and pottery. Keep the article submerged in the solution until the stains are removed. The solution can be used over and over again.
Special preparation for glass articles
In addition to the cleaning steps, glass articles must be given a special preparation. When glass breaks apart, it leaves the broken edges with a sheen. This sheen must be removed, otherwise the cement will not hold. The sheen is removed by a special compound called No. 25 Glass Oxidizing Cream. It comes in a lead tube like toothpaste. Care should be exercised when using this cream. Keep it away from any cuts on the hand or fingers. Keep the tube upright after removing the cap. Don't lay it on a table as any cream leaking out will ruin the surface of wood, tile, glass, etc. The application of this cream is as follows:
A. Work the tube a little with the fingers to mix the cream before removing the cap. If it hardens at the bottom, put the tube in a glass of hot water for a few minutes. This will soften up the cream for mixing. Keep the cap on during this heating.
B. In squeezing out the cream, don't squeeze from the bottom like toothpaste, squeeze near the top. The cream needs air in the container. In applying, squeeze a little on the tip of a Q-tip, or cotton on a thin stick, and carefully apply to the broken edges only. Be careful not to apply the cream over the edges, or so thick that it might drip over the edges, because in a few minutes it removes sheen from glass wherever it touches.
On visible surfaces, this would spoil the appearance of an article so wipe off any excess cream immediately with a clean cloth. ( If despite all precaution the sheen should be removed accidentally, wait until the cementing is completed then brush on a coat of No. 52 glaze, which will restore it. Sometimes it will require more than one application of glaze to restore the sheen satisfactorily. ) Allow cream to remain on the edges for twenty minutes.
Wash clean in warm water. Sometimes there is flint in the glass, and the first application does not entirely remove the sheen. ( This process can be speeded up by preheating the glass. ) When this occurs, apply a second coat of cream. Remember, the edges on which the cement is to be applied must have a dull, flat appearance. After the sheen has been removed, and the article is thoroughly dried, it is handled the same as china articles in the assembly and cementing with No. 200 cement.
If an article is broken in more than two pieces, plan the assembly and just how you are going to cement each piece. Always work from the middle of an article out. First plan to cement the two pieces having the longest surfaces to be joined together. ( Never cement the shorter pieces in first unless the nature of the break would make it impossible to fit them in later. )
Where an article is broken in more than two pieces, the first two pieces are balanced and cemented together. When the cement has dried ( see drying time for each type of cement), the first two pieces are rebalanced to receive the next piece. Repeat this procedure until the article is completely assembled. In rare instances, due to the design of an article and the nature of the break, it will be found impossible to balance the pieces even in a sandbox.
Under such conditions, first consider the use of Mortite to hold the pieces in alignment while the cement sets. It may be necessary to balance the pieces in the sandbox as well. Where this method is not feasible, the pieces that cannot be aligned by any method can be cemented together ( For highly polished glass, copper luster, or articles with polished gold or silver decorations, use flour in the box so as not to scratch these surfaces. ) In some cases pieces can be balanced without the use of a sandbox.
Cementing with No. 200
This cement comes in two parts, a cement and a hardener, each in its own container. The cement itself will not harden; it must be mixed with the hardener in proportions of two parts cement to one part hardener to be usable. The proportions are not arbitrary as there is about a 15 per cent tolerance. In cold weather the cement may thicken; as it cannot be thinned, it should be warmed by putting the tightly capped jars in hot water, on a radiator, or in an oven.
After mixing, the cement will stay usable for only about twenty minutes before it starts to set. The success of this cement depends to a great extent on how it is mixed and applied. If directions are carefully followed, your repair will be permanent.
In using this cement, heating the china or glass until it is warm to the touch before applying the cement will result in a stronger and closer joint. The heat of a piece thins the cement as it is applied, so that it penetrates more readily into the pores of the broken edges. This thinning also permits applying the cement in a thin film for a close, tight joint.
Heat the pieces for at least fifteen minutes, but not over 125 degrees. It is better to balance an article in the sandbox first, then heat both the box and the balanced piece, with the other piece beside it. If the balancing is done after heating, the time consumed to obtain perfect balancing could permit the pieces to cool off too much. Also, have the pieces heated before mixing the cement. Where more than two pieces are to be cemented together, after the first joint has set and dried for twenty-four hours, balance and heat the pieces for the next joint and so on until the cementing is completed.
Mix and apply No. 200 cement as follows:
A. Dip a knife into the cement container and remove the estimated amount for the job. Since a very thin application is advised, the amount may be only a few drops. Place this on a slab or piece of flat glass.
B. Immediately clean the knife of the cement in No. 200 cleaner before inserting it in the hardener. Never put an implement having any traces of cement into the jar of hardener as it will destroy the hardener liquid. The use of separate instruments for each will eliminate the need of the cleaner.
C. Using a knife, as in step A, pick up the proper proportion of hardener ( one half the amount of the cement ). Place this beside the cement on the slab. By this method it is easy to judge whether the proportions are correct. Mix the two together thoroughly and completely with the point of a knife. A thorough mixing is very important. At room temperature the mixed cement has twenty minutes' working time before it starts to set.
D. Use the special stiff brush that comes with the cement to apply a coating as thin as a sheet of cellophane to each joint. In brushing, look for and remove any small bits of china or a bristle from the brush that might hold the edges apart and prevent a close, tight joint.
The edges to be coated should be face up. In this way the cement will have a chance to fill in all the pores. Apply only enough cement to make an even contact joint. ( This is important as too much cement will cause the pieces to slide out of line during the drying process and will make a tight, smooth joint impossible to achieve.)
Where there are only two pieces to be cemented together, apply the cement to the entire edge, from one end to the other. But where there are more than two pieces, always remember this rule: Never apply the cement to the very end of a joint in any location where another piece is to be cemented later.
Leave about 1/8" from the end free of cement. This is to prevent a lump of cement from forming on the end of the joint as any excess is squeezed out when the pieces are pressed together. Any lump in an area where another piece is to be cemented later, no matter how small, will interfere with the fit of the later piece.
If any cement should squeeze out, it should be removed immediately with a cloth that has been dipped in No. 200 cement cleaner. Figures illustrate the right and wrong way to apply cement to a plate broken in four pieces. The heavy lines in Fig. 6 indicate the extent each edge is cemented—on the edges of pieces 1 and 2, starting from the rim and continuing to %" from the end. When this joint has dried, cement is applied to pieces 2 and 3 of joint B in the same manner.
When this has dried, piece 4 of joint C is cemented in, but in this case the cement is applied from the rim the full length to the joining point, since this is the last piece to be fitted in. Any lumps forming at the rim location can be removed with a razor blade after the cement has set and dried. This technique can be used on any article that is broken into more than two pieces in one location. Be sure to clean the stiff brush in No. 200 cleaner immediately after use to keep the bristles in proper condition.
E. Immediately after applying the cement ( even momentary delay may ruin your repair), align and press the pieces together firmly and evenly. Feel the joint with a fingernail for any unevenness. Correct if necessary. Try to align the pieces perfectly the first time. In pressing the pieces together, the idea is to create a vacuum. This has three purposes: ( 1 ) it forces out any air and prevents it from getting back into the joint; ( 2 ) it makes the cement skin-thin by forcing out any excess, thereby making a perfect cohesion; ( 3 ) it locks the pieces together. To insure this vacuum, where possible use the wooden handle of a light hammer to tap the top piece lightly into place.
The weight of the top piece in balance is all that is required for pressure. Do not attempt to remove any excess cement along the joint at this time as this could loosen the joining. This is best done after the cement has dried, using a razor blade to cut it away. Be sure not to remove the cemented piece until after the specified air-drying time.
F. Complete setting of the cement requires one week of air-drying, but it is better and quicker to force-dry by heating. Let the pieces air-dry for twenty-four hours without disturbing, then place in an oven for two hours, and heat at a temperature not over 125 degrees. ( Remember that clear glass may cloud permanently if subjected to more intense heat.)
Never heat the pieces immediately after cementing as this cement requires a full twenty-four hour air-drying time to set firmly. Also, do not disturb the joint after aligning and pressing together, as any shifting or moving the article about may cause vibrations, and shift the pieces out of alignment.
G. After heating, remove any excess cement from the surface of the article with a sharp razor blade. Hold the blade at right angles to the cemented joint and cut away the excess cement even with the surface along the joint line. Holding the blade in line with the joint could result in cutting into or gouging out cement in the joint.
H. Where the crack of a cemented joint is not to be decorated and made invisible, as instructed in 2.30, and there are any nicks or very small chips on the edges or along the joint, they can be filled in with No. 200 cement mixed with No. 200 special German white powder, except on clear or coloured glass articles. First, the cement and hardener are mixed together, then the combination is mixed 75 per cent cement and 25 per cent powder.
This will form a white boil-proof china filler. Where the colour of china articles is other than white, dry colour powders can be added to the No. 200 mixture to match the shade of the article. On clear glass articles, use No. 200 cement plus the hardener, mixed with a touch of hard dark silver lining powder, as a filler. For a filler for coloured glass, use No. 200 cement plus the hardener, mixed with dry colour powders to the shade of the article. Air-dry the filled joint for one week, or air-dry for twenty-four hours, then heat at 125 degrees for two hours. The filler dries to a rich, glossy sheen, and sands easily if necessary. Any sanding of the filler will remove the sheen, but after sanding the sheen can be restored with a brush coat of No. 52 glaze.
Cementing china ornamental articles with No. 100
Mix and apply No. 100 cement as follows:
A. Follow the same cleaning and preparation, and the assembly instructions. Do not heat the pieces before using this cement.
B. Always mix the cement thoroughly with a stick before using as the mixture separates in the bottle. If the cement gets thick, a few drops of warm water will restore it to proper consistency, which should be like syrup. During cold weather, keep the cement at room temperature—about 70 degrees. Cold cement becomes thick. If this should occur, warm it first to room temperature before checking for consistency.
Approximately every three months, remove the lid and add a few drops of warm water, whether the cement has been used or not. To make this easier, keep the lid threads and the lip of the jar free of any cement. Also apply a little Vaseline to the lid threads occasionally. If more than 40 per cent of the water has evaporated, the cement will start to congeal, in which case it will not absorb water and should be discarded.
C. Apply the cement sparingly to each edge of the joint with a stiff brush, and follow all the other instructions. Clean the brush in water immediately after use.
D. Align and press the pieces together.
E. This cement air-dries in three hours, but it can be force-dried in one hour by heating at 125 degrees. However, do not heat joint immediately after cementing. Leave the balanced pieces undisturbed in the sandbox for the three hours or, better still, overnight, then heat. (This is important to prevent the pieces from moving or shifting out of alignment. )
After three hours of air-drying the cement sets and hardens and the repair can be moved at will for heating. In all cases, heating is necessary because the air is blocked out from the joint and the cement needs heat for complete setting.
F. Where the crack of a cemented joint is not to be decorated and made invisible and there are any nicks or very small chips on the edges or along the joint, they can be filled in with No. 53 mixture for white articles. To match the shade of a coloured article, dry colour powders can be added to the No. 53 wet mixture only. Air-dry for one hour, then sand the filler smooth and even with the surrounding surface. For a high gloss finish, apply a brush coat of No. 52 glaze to the filler.
For a satin gloss finish, apply a brush coat of No. 18 clear sizing liquid. For a dull finish ( bisque ), apply a brush coat of dull glaze.
Cementing instructions for professional work
Cementing done professionally and with the proper type of cement, is a whole study in itself. It must be understood that when a china article is made it is fired in a high-temperature kiln. The extreme heat and moisture exaporation cause a certain amount of shrinkage, and change the characteristics from a soft clay to a hard, brittle substance. This change causes strain and when a piece develops a crack, sometimes the crack will open slightly. This is what is called the breaking of the strain. When an article is broken apart, this also breaks the strain.
The same conditions apply to articles made of glass. In most cases the pieces of a broken article will not fit exactly, due to twisting or other distortions, the result of the breaking of the strain. In some cases, C-clamps can be used on both ends or in other places along the joint to align pieces evenly. There are bound to be some areas where one side of the joint is slightly higher than the other. This means that the pieces to be cemented together cannot always be pressed close at all points. However, most of such misalignments are so slight that they can be detected only by running a fingernail over the joint so they can be left unless the joint is to be decorated to make it invisible. There may be one or more slightly open spaces in the joint. In these cases, press the pieces together as closely as possible, air-dry, and heat the cemented joint.
Then, if it has been cemented with No. 200 cement, while it is still warm apply some mixed No. 200 to any open space by pressing in on both sides with the index finger. Then heat the joint again. If it has been cemented with No. 100 cement, let it cool first, then apply No. 100 cement and press it with the index finger in any open space. Then heat the joint again.
Always study the article carefully before doing any cementing to determine beforehand whether there is any grinding to be done. Grinding may be necessary to provide anchor grooves for a chip or missing part along the line of the joint, or for rivet grooves to support the joint.
Since grinding causes a certain amount of vibration which may loosen or weaken a cemented joint, be sure all necessary grinding is done before cementing the pieces together. Not only is it easier to do this in advance, but in some cases it will be impossible to manoeuvre the wheel into the necessary position later. Heat glass articles at a temperature not exceeding 125 degrees before doing any grinding; this will prevent the glass from chipping or cracking.
Grind grooves about 1/8" deep into the edge of each piece where a missing section is to be inserted. The number of grooves will depend on the size of the missing piece. A good rule to follow is to provide anchor grooves spaced about 1/4" apart.
On china up to 1/16" thick, use a No. 2 thin wheel; over 1/16" and up to 1/8" in thickness, use two No. 2 wheels mounted together. For articles over 1/8" in thickness and up to 3/16" or over, use three wheels together, but space the grooves about 5/16" apart. If there is more than one groove on each side, it is a good idea to grind each on a slightly different angle. The grooves are for the purpose of "anchoring in" the repair substance. ( As mentioned above, all glass articles must be preheated.)
In cementing, there are times when exceedingly small pieces cannot be made to fit properly. Instead of spoiling your cement job by trying to make use of these tiny pieces, it is often best to discard them and fill in the area as a missing part. Experience will dictate when such bits should be sacrificed; and anchor grooves should be provided for the repair mixture.
Give special attention to the porosity of an article ( coarse or fine grain ). China ( porcelain) articles are fine-grained, but pottery articles have a grain that is more or less coarse, depending on their clay material. China is semitransparent, and one way to determine whether an article is of china or pottery is to hold it in front of a strong light and pass your hand between the article and the light. If it is china, the shadow of your hand will be seen through it. If the shadow cannot be seen, the article is made of some type of pottery.
Another indication to look for is any crackling of the glaze of an article. The glaze on china does not develop crackles, but on pottery it usually does. For coarse-grained articles, capillary attraction, that is the ability to absorb or suck up liquids, must be considered when applying cement to the broken edges.
The coarser the grain, the more porous the edges will be and the more capillary attraction it will have. This means that the more capillary attraction a surface has, the more cement it will absorb, and the more must be applied. Because of this variable capillary attraction, pottery is the hardest type of ceramic to cement, and No. 200 cement should be used. The following rules must be observed to insure a good cement restoration for pottery.
A. Clean the surfaces to be cemented together, plan assembly and balance of the pieces, heat the pieces, and mix No. 200 cement.
B. Apply a coat of No. 200 mixed cement to each edge of the joint. This coat will be absorbed quickly. Immediately put on a second coat.
C. Inspect to see if the second application of cement has also been absorbed. If it has not, the cement will be visible on the edge as a thin film, and additional cement is not needed. However, if it has been absorbed, apply a third coat of cement and inspect. Repeat if necessary until a thin film of cement is visible on the edge. Do not apply more coats than necessary, as the surfaces should have only a very thin layer of cement.
D. The pieces can then be aligned and pressed together, dried and finished.
There are exceptions to the rule to cement the two longest edges together first. For example, a bird with a wing broken off, and the wing broken in several pieces. To make the repair work easy, plan the procedure so that the small pieces of the wing can be progressively cemented together, leaving only two main pieces—the body of the bird and the wing. If found more practicable, parts of the wing could be cemented to the bird's body. In any case the final cementing should be between only two pieces, the body and the wing.
This will permit balancing the bird in the sandbox for final assembly. Another example is a figurine with the head broken off, and the head broken in two or more pieces. In most instances, it would be more practical and easier to cement the pieces of the head together first, and then cement the completed head to the article. Cementing each piece separately to the largest piece would make much unnecessary work of balancing and rebalancing the article for each piece. Sometimes this balancing might be awkward, difficult, or even impossible. The additional handling could also cause damage, especially on articles with lace adornment.
The pressure created by excessive moving around in a sandbox could snap off pieces of delicate lace or other fragile components. On large articles the sandbox required would be so big and heavy that it would be out of the question to lift or move it about. This technique of preassembly can be used for many multiple breaks of components of an article, like handles, large knobs, arms, legs, and other protruding parts.
Cementing broken pieces together causes the item to increase in bulk, due to the cement between the joints. The greater the number of cemented pieces, the greater the expansion. For example, a lid that fitted snugly may not fit after cementing together. Also, where a plate is broken in several pieces, the increased mass may interfere with the perfect alignment along the rim when the last piece is cemented in. It may jut out slightly. To hold expansion to a minimum, use the cement sparingly, just enough to cover the surface with a very thin layer, and press the pieces tight together. At times it may be necessary to grind the last piece to make it fit.
Where several pieces are to be cemented together, it may be advisable to insert a non-cemented piece to hold the cemented piece securely in place while the cement dries. This will also insure that the uncemented piece will fit when it is cemented in.
In balancing an item in a sandbox, there are times when some sort of prop is needed to hold it in proper position and angle. Small bags filled with sand or other grained material are very practicable for this purpose. Also consider using Mortite as a prop for balancing pieces, whether in a sandbox or not.
Some broken china articles cannot be balanced in a sandbox or otherwise, because the pieces are too cumbersome or are top-heavy. For broken articles that are to be cemented together with No. 200 cement, or ornamental articles that are to be cemented together with No. 100 cement, one or more rivets will be needed to hold the pieces together. The techniques of cementing together these articles that cannot be balanced are as follows:
A. Decide the number and location for the necessary rivet grooves. On small articles one rivet may be all that is necessary. On large articles, two or more rivets may be required. There can be no set rule as to the number of rivets. It will depend on the size and shape of the article and the nature of the break. It will be up to the repairer to decide how many rivets are necessary to hold the broken pieces securely in place. When the number of rivets has been decided, mark their location with a china-marking pencil.
B. Grind in the rivet grooves where marked, first in one of the two pieces and then in the other. To prevent chipping or cracking glass articles, be careful to hold the temperature at 125 when heating them preparatory to the grinding.
C. Fill each rivet groove with pewter.
D. Use a hard carbide rubber wheel in the hand grinder to grind off the excess pewter, leaving the edges to be cemented together smooth and even. The reason for this is that if any pewter extends above the edge surfaces, it will hold the two pieces apart and prevent a close and tightly cemented joint. Test the evenness of the edge surfaces by placing the pieces together and examining the entire length to be cemented to be sure there will be no impediment to a perfect fit.
E. When the two pieces fit smoothly, apply a coat of the kind of cement to be used to each surface. Align and press the two pieces together.
F. Immediately after aligning and pressing the two pieces together, take two or more strands of Mortite, and apply across the break, to hold the pieces in alignment while the rivets are joined together. Where possible apply the Mortite alternately to the front and back surface of the article, at intervals of about 3". Then hold the article tight against the body with one hand, making sure the two pieces are still in perfect alignment, and with a rivet facing up.
Put a half pellet of pewter on the rivet and join the two halves together with a hot soldering iron. ( Use no flux.) It is just a matter of fusing the pewter in the rivet in one half of the article to that in the other half. However, this fusing will melt and loosen the pewter in the rivet grooves, and it will be necessary to press the molten pewter tight into the grooves, using a thick pad of facial tissue to protect the fingers. Repeat this procedure for the number of rivets in the article.
After joining the rivets, remove the Mortite as it has served its purpose. ( Mortite can often be used to hold unbalanced pieces in alignment for cementing. Sometimes this is the best or only method, especially for small fingers where the china is too thin to permit grinding anchor grooves. )
G. When the cement is dry, any excess pewter is removed by grinding it smooth and even with the surface of the article, using the hard carbide rubber wheel in the hand grinder. Wash the rivets with soap and hot water, and air-dry for at least one hour. Then give them a coat of No. 100 cement. Air-dry for three hours, or force-dry one hour at 125 degrees.
For some unbalanced china ornamental articles, where the cemented joint will not be subjected to stress or strain, and only when No. 100 cement is used, follow this procedure: Insert the larger piece in a sandbox, and set in as close a balanced position as possible. Then heat both the box and the piece at 125 degrees.
Do not heat the other piece. Apply cement to the cold piece only, then align and press firmly to the heated piece and hold in place for a few minutes. The purpose of heating one piece is that heat quickly activates and sets the No. 100 cement, and in a few minutes the two pieces should be secure enough to stay in position for the balance of the drying time.
Broken-off handles can be cemented on with No. 200 cement, without the need for rivets, provided the handle can be balanced in position. But first the broken edges must be cleaned. There are many other instances where the use of this cement will eliminate the need to reinforce a joint with rivets. Study each problem on its own merits, and determine whether rivets are needed in addition to the cement. Just keep in mind that parts carrying extreme weight or subject to much stress and strain should be reinforced with rivets.
Sometimes, when using No. 200 cement, the weight of the top piece will cause a slight shifting out of alignment as the cement air-dries. To prevent this, use two or more strands of Mortite applied across the break after the joint has been cemented together. Where possible, apply the Mortite alternately to the front and back surface of the article at intervals of about 3".
This method should hold the pieces securely in alignment during the twenty-four hour air-drying period. But it is advisable to inspect at intervals during this time to see if any shifting has occurred. If any misalignment is noted, the pieces can be pressed back in alignment without taking the joint apart. If misalignment has occurred and the cement has set to the point where the pieces cannot be pressed back into alignment, the joint can be taken apart without difficulty and recemented.
Where a joint is taken apart for recementing, be sure to remove the old cement from the edges with No. 200 remover before recementing. Apply a coat of remover and leave it on a few minutes. Then brush the edges vigorously with a stiff brush. Repeat if necessary. Be sure all traces of cement are removed, and that the alignment of the pieces is satisfactory before heating the joint. Once a joint that is out of alignment has been heated, nothing can be done. It is cemented to stay.
It is impossible to make a cemented joint invisible by just cementing the pieces together. No matter how skilfully the cementing is done, there will be a visible crack line where the pieces are joined. The appearance of this crack line, good or bad, will depend on several factors, such as the nature of the crack; whether it was a clean break or tiny chips were broken away from the edges when the damage occurred; distortion, due to the breaking of the strain; skilful or poor workmanship. It will be up to the person making the repair to decide whether to leave the joint as it turned out or go into the very exacting procedures of decorating necessary to make it invisible.
These procedures apply to china or coloured glass articles only. Cemented joints of clear glass articles cannot be made invisible. If it is decided to make the cemented joint of a china or coloured glass article invisible, follow these directions:
A. Feel all along the joint with a fingernail for any unevenness of the two edges, open cracks in the joint, or any unevenness where rivets, chips, or missing pieces were inserted. Do not depend on your eyes; the sense of touch is more sensitive than that of sight for this purpose. Even if the edges of the joint are perfectly even, slight grinding will be necessary.
In grinding, hold the grinder with the wheel at right angles to the cemented joint and centred with the crack. Just run the wheel lightly up and down the crack. Do not grind deep—just beneath the surface gloss. ( This grinding must be controlled with the utmost care lest the fragile glass be broken beyond repair. In addition, as previously mentioned, glass articles should be heated at a temperature not over 125 degrees to prevent chipping or cracking the glass due to the heat generated by the grinding action. )
B. If one side of the joint is even slightly higher than the other in any spot, the high side must be ground down even with the low side. In grinding, hold the grinder as in step A, but centre the wheel over the high side to be ground down. Finish by grinding along the centre of the crack as in step A. In some cases the high side may be so far out of line that a second grinding alongside the first is necessary to taper the surface toward the crack.
Run the grinder lightly, carefully, and quickly up and down the joint until the surfaces are even. This grinding of joints or cracks is a very tedious operation, and takes skill and experience to do properly. If not done correctly, the grinding can cause more damage that must be repaired or it can ruin the article. Practice on old pieces of china until you get the knack of it before grinding on a good article.
C. To fill the rough surface after grinding on articles that have been cemented together with No. 200 cement, like dinnerware, coloured glass, or articles that hold water, apply a thin coat of No. 200 mixture and dry. To fill the rough surface after grinding on decorative articles that have been cemented together with No. 100 cement, first give the rough surface a brush coat of No. 100 cement and air-dry for one hour. When the cement is dry, apply a thin coat of No. 53 mixture over the dry cement, and air-dry the mixture for about an hour.
After either type of mixture is dry, sand the joint smooth and even with the surrounding surface, using fine sandpaper about size 2/0. Apply a second coat of the mixture to any hollow spots, dry, and sand smooth. Be sure the ground and filled joint, including any installed rivet, chip, or missing piece, is absolutely smooth and even with the surrounding surfaces, using the sense of touch and the fingernail test.
D. Where No. 53 mixture has been used to fill the ground joint, apply a coat of No. 53 neutralizer over the sanded mixture. This will prevent any colour bleaching from the chemicals in the mixture when it is decorated. Air-dry for one hour, but on damp days apply a little heat, not over 125 degrees. ( Clean brush immediately after using in No. 51 cleaner or the brush will be ruined. )
E. Apply two coats of No. 18 white sizing liquid to the joint, including any installed rivet, chip, or missing piece, overlapping onto the unrepaired surfaces about 1/8" on each side of the repair. Heat between coats for one hour at 125 degrees.
This heating is important. White sizing liquid is both a sizer and a filler for any very tiny holes in the filler mixture. Where a joint passes through a decorated area, that is, where the article has original decorations of flowers, designs, etc., fill any very tiny holes with five or six or more coats of No. 18 clear sizing liquid until the holes are filled. ( Heat at 125 degrees for one hour between coats. ) The purpose of using clear liquid in decorated areas in place of white is that the clear is a sizer only and is perfectly transparent. It needs little sanding.
The white liquid leaves a whitish film on the surface, and in sanding this film away from original decorations you could damage or even remove these decorations. This, of course, only makes more repairs to be decorated. ( Clean brush used for either type of liquid immediately after using in No. 51 cleaner. ) For joints on dinnerware, size with boil-proof glaze.
F. Lightly sand the last coat of either type of sizing liquid even with the surrounding surfaces with very fine sandpaper, size 4/0 or 6/0. Here again, the surfaces must be absolutely smooth and even to the touch. As mentioned in step E for clear liquid, sand very lightly in decorated areas.
G. The repair is then ready for decorating.
It will take practice to acquire skill in preparing a cemented joint for decorating. Extreme care must be exercised when grinding so as not to create more damages or even ruin the article. Practice grinding on old pieces of china until the knack is acquired. Also practice the technique of filling in and smoothing off the areas that have been ground down. When you are confident that you have the required skill, then tackle a good article.
NOTE. In addition to china, No. 100 cement is ideal for use on sea shell work, jewellery, bone, fibres, cork, cloth, wood, and many varieties of nonferrous metals.
The Klein firm are adhesive specialists and supply many kinds of cements for other purposes, such as for alabaster and marble; ivory, metal, wood, and so forth. There are special instructions to cover the application of these cements, and with each type furnished, the instructions are also included.
Procedure in cementing broken china and glass with NO. 200 cement *
Procedures for cementing broken china with NO. 100 cement
* Numbers marked with an asterisk may or may not be necessary in the procedure, depending on the nature of the repair or of the article.