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repairs

updated fri 14 nov 03

 

Emily Reynolds on sun 24 dec 00


Hi all,
This thread has reminded me of an adhesive that I used to use that seems to be
no longer available: Elmers China/Glass Cement. It was wonderful, clear, thin,
easy to use, durable, dishwasher proof. I still have a 1/16" thick porcelain bowl
I repaired with it years ago, barely visible, and dishwasher tolerant.
I have tried contacting Borden, who makes Elmer's and they refer me to other
cements that are not as satisfactory. Maybe we could all gang up on them to have
them make this magic stuff again. I still hold on to my last empty tube, for
evidence.
Meanwhile, my newest potion is moldable epoxy when the gaps can be larger, or
need filling. Works just like clay.
On to new solutions. Emily

Cindy Strnad wrote:

> Hi, Cindy.
>
> Maybe someone else will have a better idea for you, but I don't really think
> you're going to save that platter by re-firing it. As it has sentimental
> value, I wouldn't want to experiment on it. You might try breaking and
> repairing a less important piece, to see if your plans will work.
>
> The more knowledge you have about the platter, the more likely your
> experiments may succeed. What temperature was it fired to? What glaze was
> used on it? It's possible you will come up with a method to fix this--never
> say something can't be done.
>
> On the other hand, if it were me, I'd use 5-minute epoxy and then mount it
> into a wall hanger. Or maybe even a shadow box. I would disguise the crack
> with some kind of pigment, if necessary.
>
> If this isn't a subtle enough solution, you might look for a professional to
> do the work. There are people who make their living repairing broken china
> pieces. You could check to see if there is such a restoration business in
> your area. Granted, you could learn how, and do the work yourself, but it
> might or might not be the direction you want to take your studies just now.
>
> Cindy Strnad
> Earthen Vessels Pottery
> RR 1, Box 51
> Custer, SD 57730
> USA
> earthenv@gwtc.net
> http://www.earthenvesselssd.com
>
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Bonita Cohn on thu 13 nov 03


--
Much of this was gleaned from Clayart....
Bonita in San Francisco who has archived as folder and text documents
favorite tips gleaned from clayart, and backed it up on zip discs and cds,
and the next media when it shall be invented.

1. Repairing hairline cracks in greenware

- with paperclay. Some clay is more refractory than
Others and your success rate will be less unless you add some flux to the
paperclay. What you want is clay that will melt enough to literally weld
the crack together again. Take some paraffin (lamp oil) and paint it
directly on the crack. This will show you all of the crack so that you do
not miss the far ends of it that is not visible to the eye. Mark it. Take a
very sharp tool and carefully open the whole crack, right through the wall
of the pot. Take some paperclay (you will find recipes in the archives) and
mix it into a stiff paste. If you work with a very refractory clay
(stoneware or porcelain) you can add a teaspoon of any flux, like Ferro
frits, that will melt at a bisque temperature to one cup full of paperclay
paste. Push that through the crack from the one side of the wall. Keep on
doing that till it comes out on the other end and fill all of the crack.
Wipe off the extra clay. Let stand to dry. It might leave a dimple and in
some cases another smaller crack. In the
last case you will have to repeat the process on a smaller scale, till it
totally disappears. A dimple can simply be filled up till it disappears.
After bisque firing it might be necessary to sand it to get a smooth surface
again. This is a time-consuming process, so you will have to judge whether
it is worth it to go through all that trouble and still risk some failure.
Sometimes it is much quicker to simply repeat the pot and avoid the
mistakes made in the first one.

2. Papooze
From Alisa Liskin Clausen

"I was trying to fix a repair plate of someone else's that I accidentally
snapped the edge off of. I used some of Peggy's Spooze and then went over
it with paper slip. Then I thought, if I mix them together, that should
work really well, in one go. It does!

So, here is the recipe for Paper Spooze, or now fondly called Papooze:

1 part Vinegar
2 parts Sugar or honey
3 parts Clay (Ball or your mix)
1 part Paper fibers, saturated and strained for water
mix to a thick consistency.

Mix up and use like repair slip.

3. Vinegar repair
"It has been known for many years that if something gets chipped or
a handle gets knocked of that it can be re-attached or repaired by
dampening the fracture faces freely with Vinegar and pressing the
parts together. Though this has never been explained by those who
publish these instructions I believe there are two things happening.

The first is that once the surfaces are wet then the slurry from
both is deflocculated in the same way that the strong alkalis
deflocculate, but the charge is positive instead of negative.

The second thing is that the Acetic acid in the vinegar does not
dry by evaporation as does water. It will, in fact, solidify below
about 16 deg C and crystallize as water evaporates, so forming a
solid bond between parts which are being joined.
Nothing magic about the process.
Best regards,
Ivor Lewis. Redhill, South Australia'

4. What to throw away -author unknown
"Someone once described it to me this way:

The clay took thousands of years to form.

It's a living thing - you can shape and change it and keep shaping and
changing it, over and over.
But once you fire it, you kill the clay.

Make sure it's worth it before you kill it."