Monday, August 22, 2016

Reparing Broken Porcelain Tea Cups and Saucers Using BSI Insta-Cure Super Glue

Written by Charlee Smith, BSI Glue Pro and National Sales Manager

Saturday was a warm, very dark night. My wife Sandee had gone downstairs to try to coax our cat Frankie into coming inside for the night so that he’d be safe from prowling coyotes. As Frankie came in the door, she turned off the porch light, which turned the house pitch black. Sandee headed for the light switch at the foot of the stairs, but her arm hit something that created a horrible “bull in a china closet” sound that could only be bad news.
Turning on a light, she discovered to her horror that she had knocked over her precious collection of Russian cups and saucers. The floor was now covered with a layer of jagged, broken porcelain. Her treasures were now history. That darn cat!
Daylight revealed not all was lost. Three of the cups and one saucer had absorbed the fall without a scratch. I felt that the one broken cup and one saucer would be relatively easy to repair. The second saucer had a chance, but the third one, sitting there shattered into 17 pieces, almost went directly into the trash can. But hey, I’m one of the BSI Glue Pros. Our glues can make the impossible, possible.

Years ago a raccoon greeted us as we entered our home after being away for a few days (he got in through the cat door). In trying to coax him out an open door, the raccoon jumped upon Sandee’s teacart, shattering more of her porcelain and ceramic collection. One of these was a tea pot, broken into 8 pieces. Since I was able to repair that, I felt that the 17 piece saucer may have a chance, but I wouldn’t have bet money on it.

The secret to repairing objects such as these is to assemble as many pieces as possible without using any glue, relying on small sections of masking tape to keep the parts together.I started with the tea cup.

In repairs like this, if the pieces are glued together one at a time, the final pieces of the puzzle will rarely fit correctly. Any errors in alignment in the first pieces, however minor, throw off everything else. As the final pieces are added with the no glue method, the sections of tape on the first pieces can be removed, if necessary, for minor adjustments and then put back into place.

What looks like a perfect fit in many cases won’t be. Perfection can only be confirmed by feel, not sight. Running your finger across a seam will detect the slightest misalignment. If your finger senses that the joint is as smooth as the glossy surfaces around it, then it is perfect and can be held in place with tape on its backside. At this point, you must ensure you are working with clean hands. Any trace of dirt or oil on your finger will be transferred to the non-glazed porcelain as you slide it across a misaligned joint. With white porcelain or ceramic, this will make it impossible for the repaired crack to virtually disappear, which is possible when these steps are done correctly.

After all the pieces are perfectly aligned, the glue is then applied. BSI’s Insta-Cure super thin CA (Super Glue) has amazing penetrating properties. When applied to even an almost invisible crack, capillary action will fully coat the interior of a joint and go through to the other side. For this reason you must be careful how you hold the object being repaired, since the CA can appear in unexpected places and glue your fingers to the project. This is the reason I prefer to spray the entire repair project with our Insta-Set accelerator after all the thin CA is applied. While not necessary for a strong finished product, the Insta-Set allows me to immediately go to the next steps without bonding my skin to the porcelain.

The handle of the subject cup was set in place with the cup in an orientation that allowed only gravity to hold the handle in the correct position. One drop of the Insta-Cure was applied to each end and it was done.

For precise application of the Insta-Cure, BSI’s #302 extra fine extender tip or #305 capillary tubing should be used at the end of the nozzle (the #302 can be added to the end of the #304 extender tip if you are using a Pocket CA bottle). The CA is applied to the side opposite of where the tape has been placed. Inevitably, you may find that there are puddles of the thin CA where you don’t want them. The corners of a paper towel should be used to soak up this excess CA. This still leaves a thin coat of the CA on the surfaces, but this is taken care of in the next step.
After the masking tape has been removed, the excess CA on the porcelain can be removed using BSI’s Un-Cure debonder. This step is much easier if done immediately after the repair. Cyanoacrylate becomes much harder to dissolve after it has cured longer than 30 minutes. Small sections of paper towels should be soaked in the Un-Cure and vigorously rubbed on the glue joints. This can take from 30 second to a few minutes for each area, depending on the thickness of the cured CA. Your opposite hand should be used to push against the opposite side of thinner porcelain when the rubbing force is being applied.

Thicker amounts of CA can be sliced or scraped with a single-edge razor blade, with Un-Cure used to remove the thin layer that is left. Sometimes using your fingernail to scrape the surface can speed up the process. Areas where the CA has penetrated the masking tape are the most difficult to remove, so patience is an important factor in this process. Care should be observed by washing your hands at least every five minutes, or by using a latex gloves or their equivalent. The dissolved CA gets soaked into the paper towel so don’t hesitate to use more fresh towels than you may have anticipated.

This process does not affect the CA that is forming the bond in the cracks (the object would have to be soaked in Un-Cure or acetone for several hours for this to happen). Acetone (or fingernail polish remover) can be substituted for the Un-Cure in this process but it has a much higher evaporation rate, which slows down the whole procedure.
This saucer was repaired using the same process. The missing section had become little more than dust when the plate shattered, so this is the one obvious flaw in the repair, like the small chips in the lip of the cup. There is a procedure that can be used to fill these areas in, but that will have to be a subject for another time.
When done correctly, the cracks are nearly invisible.
Now for the “impossible” one. The five major pieces were put together and then glued, using the procedures above. The CA was put on no closer than 1” from the unrepaired areas. The non-glazed areas of the broken parts must not see any glue before they are assembled and taped in place.
All but the last two fragments are now in place. These two required more patience since the tape will not work for holding them perfectly in place (trust me on this one). Like the handle on the cup, you should rely on gravity to hold them in place. It may take a dozen or more tries to get them positioned just right at the same time, but once they are, they get the first drops of the Insta-Cure to hold them in place. Then you apply the CA to all the other joints.
Once the tape is removed and the Un-Cure does the cleanup, the saucer, to most eyes, will look undamaged.
While a significant amount of their monetary value has been lost, the Russian cups and saucers are ready to be displayed once more. Happy days are here again! Like Mighty Mouse, I came to save the day. Women like that.

FYI: The Insta-Cure that I used for the repairs is over two years old. Although this goes against the advise we give consumers, it has been open for over a year in my garage, which has exposed it to many days over 90 degrees F. The bottle of Un-Cure is over five years old. I think this makes a statement about the quality of BSI’s adhesives.

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