How to start with repairing china and glass

1 The very first thing to do about a broken article is to examine it carefully. Study the damage or damages to find out what needs to be done. The work may be just that of cementing pieces together. A head or hand needs to be cemented to a figurine; an article of dinnerware is broken apart and needs cementing together; a handle needs to be cemented back on; a crack needs cementing together.

Cementing pieces together is the most common of all repairs and the easiest. Because the techniques are different, cementing articles is divided into two classifications:

  • A. Cementing pieces together
  • B. Cementing a crack together

2 Some broken articles cannot be repaired by cementing alone because parts are missing, for instance, a cup handle, the spout of a teapot, the hand of a figurine, a section of a plate chipped in washing. As explained in the preface, the work of replacing missing parts is called restoring. To decide what needs to be done to restore damaged articles, it is important to know the names of the different damages that occur and wherein they differ.

Damages that need restoration are divided into three classifications:

  • A. Where a portion of a surface is broken out ( regardless of size ), without going through to the reverse side, the damage is called a flake chip. A damage of this type usually occurs at the rim of an article, but it could happen at other locations.
  • B. A small missing piece, like a nick, broken out at the rim of a cup, plate, vase, etc. (not exceeding 1/4" in width or depth), is called a chip. Chips up to this size can be filled in without the need of a mould for holding or supporting the liquid ceramic substance while it dries and hardens.
  • C. A large missing piece along a rim or the edge of an article ( over 1/4" size mentioned in classification B) is called a missing part. All other missing parts, like a head, arm, hand, finger, leg, foot; a knob, a handle, etc., are also known as missing parts.

3 From the description and identification of each classification, it should be easy for a person to determine whether a damaged article needs the work described in 1: A. Cementing pieces together; B. Cementing a crack; or restoring as outlined in 2: A. Restoring a flake chip; B. Restoring a chip; C. Restoring a missing part. If an article is severely damaged, it may need a combination of any of the classifications, or even all of them.

4 The next consideration is to find out what work is involved for each classification, and how it should be done. For this information, refer to the techniques and procedures as listed below:

  • A. Cementing pieces together
  • B. Cementing a crack
  • C. Restoring flake chips
  • D. Restoring chips
  • E. Restoring missing parts

5 Read and study the techniques and procedures for the work required thoroughly, carefully, and completely. Do not skip over any portion for all the instructions must be studied and understood in order to know what work is required and how it should be done. The instructions are written as simply as possible. In many instances the reason for a certain technique or procedure is explained to make it more understandable.

Many illustrations are also included for visual explanations. It will be noted that the various techniques and procedures are planned to cover a wide variety of conditions. It is wise for an inexperienced person to consider all the techniques as a sort of check list, so as not to overlook some important condition. As experience grows, one should be able to determine in a short time what is required to repair any damaged article.

6 Sometimes certain articles with missing parts can be repaired by removing or modifying damaged portions instead of restoring with new parts. Projections left by damages can be ground off even with the surface of the article, or reshaped with the grinding wheel. Depressions left by damages can be filled in with a ceramic substance.

An example is the spout of a teapot that has a chip or a missing piece on the lip. Instead of restoring the missing piece, consider grinding the end of the spout below the damage, reshaping the lip in the process. The spout may be a little shorter, but in many cases after the repair has been decorated it will make little or no difference in the appearance of the article. Another example is a footed glass article with a part of one foot broken off and the piece missing.

As the damage cannot be restored with glass, consider making the repair by evening off the break and reshaping the remaining part of the foot with the hand grinder. Then grind off and reshape the other feet to correspond with the damaged one. To restore the sheen to the ground surfaces, first they should be smoothed with the hard carbide rubber wheel in the hand grinder and then given a coat of glaze.

7 Now comes the planning stage. Work can be made easy or hard according to the way one plans and executes a repair job. Read the directions carefully and follow the sequence of the work steps indicated and you will not go wrong. At first it might be best to write down the order of steps in each procedure. Repairs on china and glass must be made, just as a building is erected, in an orderly succession of steps.

Along with each step the paragraph numbers of the instructions on this site are also listed, together with supplies, tools, and equipment needed. This sheet can be used as a check list to determine whether all necessary supplies are on hand before starting the repairs. A similar procedure can be used for any sort of repair work. Double check your plans before starting work. A haphazard plan or guesswork will surely result in difficulty and possible failure.

8 In repairing do not be concerned about how long it will take to do the job. The important point is: How well will the cement hold the pieces together, or how long will the repair stick to the article? A fast job is no good if the repair fails to hold properly, and in time comes apart. The cements or materials making contact with the article must adhere securely for a satisfactory job. In many instances, this means the repair material must be "anchored" in. The different methods of anchoring in are described in the various specific techniques and should be studied carefully.

9 Get all tools and supplies together and have them at your finger tips before starting any repairs.

10 Proceed slowly and carefully to make the repairs. It is vitally important to allow the necessary waiting period between each step. Your failure to do so will result in an unsatisfactory repair. If several pieces are to be cemented together, cement the first piece, then wait until the next day to cement the next, and so on.

Follow the same procedure on other types of repairs where a time lapse is necessary for cement or mixtures to set and harden. The results of slow and careful work will be well worth your efforts. When you work on a big job, one that will take time and a lot of patience, do a little at a time. Work an hour or so, then put it aside until the next day.

11 Where the instructions specify that the article or the repair be heated, be sure to follow directions and heat for the length of time and at the temperature given. ( All degrees of temperature shown are Fahrenheit. ) All the supplies used for the Klein method are formulated for heating at temperatures of from 125 to 150 degrees.

Never fire the article or supplies in a high-temperature kiln as the extreme heat will ruin the supplies and possibly crack or break the article, especially if it is antique or fragile. For most repairs, heating is necessary at various steps—to remove moisture or solvents; to dry out and harden mixtures; to dry out and remove solvent thinners and eliminate tackiness from a decorated repair, etc. It is important not to omit any heating recommended.

Otherwise, at the time a decorated repair is being heated to dry out the decorating colour and remove tackiness, any trapped-in moisture or solvent in the repair itself could expand, form steam or air bubbles from the heat, and force its way to the surface of the repair, ruining it by blistering the decorated surface. To avoid this disappointment, heat when and as directed, and for the time and at the temperature specified. Time requirements given represent the minimum to accomplish the necessary drying. On damp or cold days or where the climate is humid, it would be best to increase the heating time by 25 per cent to be on the safe side. Heating beyond the specified time, regardless of how long, will in no way damage the repair or the article.

However, the temperature is very important. For clear glass articles and for cementing, the temperature specified is 125 degrees; for other repairs, 150 degrees. Do not exceed the recommended temperature because this could result in the discoloration and deterioration of the materials used for a repair. If heated in temperature above 200 degrees they would be ruined. A degree or two above the temperature would make no difference, but to be on the safe side heat at or slightly below the temperature specified.

To compensate for lower temperatures, increase the heating time in proportion to get the same drying results. Do not guess at the temperature. An ordinary oven thermometer can be placed beside the article to check temperature during the heating process. Leave the door of the kitchen oven fully open if the first temperature control is 200 or 250 degrees. An electric hot plate, a heat lamp, a radiator, or any other form of dry heat may be used, but the article must be covered and the heat must be controlled to the temperature specified in the directions.

An old refrigerator is ideal for heating purposes. It can be easily equipped with three 150 watt bulbs on extension cords, the shelves can be adjusted to accommodate articles of different sizes, and the door can be left slightly ajar to provide ventilation. If you do not have access to an old refrigerator and it is not feasible to use your oven, any metal container can be turned upside down to cover your article and heating device—a metal garbage can, ashcan, metal file drawer, etc. However, be sure to provide ventilation while heating and to control the temperature.

Do not heat in an airtight chamber as trapped moisture or solvents in the chamber would prevent proper drying of the repair. If a kitchen oven is used, always leave the door open to some extent. With other means of heating, be sure that air can freely circulate in and away from the heating area.

12 Decorating colours must be heated at 150 degrees for at least two hours after they are applied in order to remove the solvent thinner and eliminate tackiness. Depending on humidity, it may take three hours or more. This is most important and necessary in damp or cold climates. The heating process will render the colour surface harder, produce a higher sheen, improve adhesion, and make the surface more water-resistant. Heat boil-proof colours 300 degrees.

13 A certain amount of care must be exercised when putting in or removing an article from an oven or other heating device. Sudden changes in temperature can cause damage to china and glass, especially antique and fragile articles. Cracks can appear, or slight cracks can be made worse, or an article may break apart due to rapid expansion and contraction resulting from a sudden change in temperature. Similar damage can be done to a repair area.

Do not put a cold article into an oven already heated to 125 or 150 degrees. It is best to heat the article and the oven at the same time; this provides a gradual increase in temperature. If preferred, a cold article can be put in some warm place for gradual preheating before being placed in a heated oven. Do not remove an article from a heated oven and put it in a cold place. It is best to turn the oven off and let both oven and article cool at the same time; or the article can be removed from the heated oven and set in a warm location for slow cooling. Observance of this rule can save some grief.

14 The caution on the heating temperature and the danger of discoloration or deterioration of a repair substance, cements, mixtures, sizing liquids, and decorating substances due to overheating applies only for the length of time necessary to remove all moisture and solvents and thoroughly dry out these substances after application. Once they are completely and thoroughly set and dry, subsequent heating, even over 200 degrees, will have no bad effect. It is only during the initial drying time, specified in the instructions, that care must be exercised not to overheat these substances.

Delicate and antique articles cannot be overheated safely. Clear glass should never be heated over 125 degrees ( see H following ). In most cases modern articles of dinnerware can be safely heated above 200 degrees after the initial drying time of the repair substances. But in all cases good judgment must be exercised by the repairer as to when a dried-out repair or an article can be safely heated over 200 degrees, and then only when so instructed for a specific reason, or to accomplish a specific purpose. If a substance has been heated above the recommended temperature during the initial drying time, the following methods may be useful for salvage:

  • A. No. 20 MIXTURE. This should not be heated over 150 degrees. However, heating above this temperature, but not over 200 degrees has little or no effect on the colour or characteristics of the hardened mixture. As long as the mixture can be sanded smooth without crumbling, it can be finished and decorated as if it had not been overheated.
  • B. No. 53 MIXTURE. Do not heat over 150 degrees. Heating above this temperature causes the hardened mixture to turn first brown, then pink, and finally black. At the first sign of discoloration from white, the heat should be shut off, the temperature checked and readjusted. This will prevent further discoloration. However, if the mixture has turned brown, pink, or even black, but has not been heated over 200 degrees, it has not deteriorated to the point that it must be removed. As long as the mixture can be sanded smooth without crumbling, the repair can be finished and decorated as if it had not been discoloured from overheating.
  • C. No. 100 CEMENT. It is preferable to heat this at 125 degrees, but it can be safely heated up to 150 degrees. Heating above 150 degrees causes both the cement and the china at the joint to turn first brown, then pink, and finally black. ( Once the china at the joint becomes discoloured from overheated cement, it remains discoloured. The colour is burned into the china and cannot be removed. Even if , recemented, the joint would be discoloured. ) At the first sign of colour change from white or clear, the heat should be shut off and the temperature checked and readjusted. This will prevent further discoloration. However, if the joint has turned brown, pink, or black, but has not been heated over 200 degrees, it will retain its strength. The only objectionable feature would be the appearance of the discoloured joint, especially if the article is white or of a light shade. Where a joint is to be decorated to make it invisible, the process of grinding, filling, neutralizing, sizing, and colour decoration will cover the discoloration and it will not show, provided the heating necessary in this process is not done above the 150 degree temperature. Where a joint is not to be decorated to make it invisible, the discoloured joint can be given two coats of No. 18 white sizing liquid, heating each coat for one hour not over 150 degrees. Lightly sand the last coat of sizing. Then mix decorating colour to the shade of the article and brush on a coat along the joint, using fast-drying gloss colours for porcelain articles, or fast-drying dull colours for bisque articles. This hand-brush decoration of cemented joints will not make the joint invisible, but it will cover the discoloured joint and make it much less noticeable, provided the heating in this process is held to 150 degrees.
  • D. No. 200 CEMENT. Preferable to heat at 125 degrees but, except for clear glass articles, it can be safely heated up to 150 degrees. Heating above 150 degrees causes the cement to turn dark brown. At the first sign of discoloration of the joint from clear, the heat should be turned off and the temperature checked and readjusted. This will prevent further discoloration. However, if the joint has turned dark brown but has not been heated over 200 degrees, it will retain its strength and it will be boil proof; only its appearance will be affected. Since a joint cemented together with No. 200 cement and heat-dried is nearly impossible to take apart, the only thing that can be done is either to decorate the joint to make it invisible or hand-decorate it to make it less noticeable, as explained in C.
  • E. No. 200 MIXTURE. Heat at 150 degrees. Higher temperature causes the hardened mixture to turn dark brown. At the first sign of discoloration from white, the heat should be shut off and the temperature checked and readjusted to prevent further discoloration. However, if the mixture has turned dark brown even though it has not been heated over 200 degrees, as explained above, it has not deteriorated to the point that it must be removed. As long as the mixture can be sanded smooth without crumbling, the repair can be finished and decorated as if it had not been discoloured.
  • F. No. 18 SIZING LIQUIDS. These should not be heated over 150 degrees. Heating white or clear sizing liquids above this temperature can cause a darkening of the dried substance. If the sizing is to be covered with decorating colour, any darkening should make little or no difference. But if the clear liquid is used for a final decorating coat, any darkening may show. In this case, remove the sizing with No. 51 cleaner, and apply another coat of clear liquid, but be sure not to heat over 150 degrees.
  • G. Decorating colours, glaze, gold decorations should not be heated over 150 degrees. Heating these decorating mediums over that temperature can cause a darkening of the dried colour. If this darkening is objectionable, the decorations can be removed with No. 51 cleaner and the decorating done over, but be sure not to heat over 150 degrees. Boil-proof colours must be heated to 300 degrees.
  • H. Articles of clear glass should not be heated over 125 degrees. Heating above this temperature may cloud the glass and ruin its appearance. Once the glass has been clouded from overheating, nothing can be done; the clouded appearance will always remain.

15 Delicate and antique articles are also extremely sensitive to heat. They may crack or break if subjected to repeated heating above 125 degrees, and cooling, for the various repair steps. For such articles, a good rule to follow is: Heat gradually to about 125 degrees. For less fragile articles in this category, heat between 125 and 150 degrees.

Where instructions call for 150 degrees to dry out cements, mixtures, decorating colours, and so forth, increase the heating time by about 100 per cent to compensate for the necessity of holding the temperature to 125 degrees. This increased drying time will give the same results as heating at higher temperatures. For example, where instructed to heat at 150 degrees for one hour, heat for two hours at about 125 degrees; one and a half hours at about 135 degrees, or one and a quarter hours at about 145 degrees.

16 There is a real satisfaction in planning and carrying out a good repair job. If things do not turn out right the first time, do not be discouraged. Be persistent. In many instances, a little more patience and effort will result in success.

Restoring china