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repairing joins


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#1 anniec9

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Posted 09 February 2013 - 07:28 PM

Is there any way I can repair joins that have shrunk during the bisque firing. They are not large, but enough to mar the appearance of the pot. Also they are on the inside.

I was planning to clear glaze the pots, so is there a way that I can glaze, fire, then repair the joins?

Thanks,

Annie

#2 bciskepottery

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Posted 09 February 2013 - 09:37 PM

Glaze firing will likely make the problem gap more pronounced, and with clear glaze over it, it would be difficult to repair post-glaze firing. It also will be structurally weaker.

You can spend a lot of time and effort to "fix" the problem with spooz, paperclay and a variety of commercial menders. As the ware is already bisqued, firing some of the same claybody as a powder, then mixing with a binder to fill the gap could be more successful . . . as the claybody in the repair will not shrink. After rebisquing, then try a glaze cover.

But you are better off making a new one that does not have the fault/blemish and you'll save yourself much time and frustration. Plus, everytime you look at the repaired item you will focus on the fault.

#3 Marcia Selsor

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Posted 10 February 2013 - 09:18 AM

If you mix up a paper clay patch , wet the bisque surface befor applying it and work quickly. Smooth out the repair, then re-bisque. It should not be noticable. I am editing this to try and get the proportions adequate. You want to have about 20 % paper to the clay powder.

use toilet paper, a little vinegar, karl syrup, dry powder clay of your clay body,

soak about 5 sheets (reduced fro 12-15) squares of tp and whip in water in a blender, squeeze some water out of it. Put it back in the blender, clay, about 1/2 tsp of karo tsp of vinegar, 2-3 tbsp to a 1/4 cup of powdered clay and blend. get it to a wet past consistency by adding a little water..

apply to WET bisque surface. The bisque will suck out the moisture quickly so work fast. Stuff it into cracks.

Re fire to bisque temperature...VERY IMPORTANT to do this.

Marcia

#4 Benzine

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Posted 10 February 2013 - 09:40 AM

I'm going to have to try the paper clay one of these days. It would really help with some of my students' works.

What is the purpose of the vinegar? I learned about using the syrup in college, which if I'm to understand, gives the clay powder a binder, that won't shrink as it dries.
"Anything worth believing, is worth questioning"

#5 Marcia Selsor

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Posted 10 February 2013 - 10:45 AM

I'm going to have to try the paper clay one of these days. It would really help with some of my students' works.

What is the purpose of the vinegar? I learned about using the syrup in college, which if I'm to understand, gives the clay powder a binder, that won't shrink as it dries.


vinegar will penetrate the clay particles without spreading them apart like water does.

Marcia

#6 Benzine

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Posted 10 February 2013 - 11:40 AM


I'm going to have to try the paper clay one of these days. It would really help with some of my students' works.

What is the purpose of the vinegar? I learned about using the syrup in college, which if I'm to understand, gives the clay powder a binder, that won't shrink as it dries.


vinegar will penetrate the clay particles without spreading them apart like water does.

Marcia


Ah, very good. If I want to "Kick it up a notch", can I use Apple Cider or Balsamic vinegar.....hehe.
"Anything worth believing, is worth questioning"

#7 Marcia Selsor

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Posted 10 February 2013 - 01:11 PM



I'm going to have to try the paper clay one of these days. It would really help with some of my students' works.

What is the purpose of the vinegar? I learned about using the syrup in college, which if I'm to understand, gives the clay powder a binder, that won't shrink as it dries.


vinegar will penetrate the clay particles without spreading them apart like water does.

Marcia


Ah, very good. If I want to "Kick it up a notch", can I use Apple Cider or Balsamic vinegar.....hehe.

you asked! I just use the white vinegar. I have many uses fr it in the studio.
Marcia



#8 Pres

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Posted 10 February 2013 - 02:31 PM




I'm going to have to try the paper clay one of these days. It would really help with some of my students' works.

What is the purpose of the vinegar? I learned about using the syrup in college, which if I'm to understand, gives the clay powder a binder, that won't shrink as it dries.


vinegar will penetrate the clay particles without spreading them apart like water does.

Marcia


Ah, very good. If I want to "Kick it up a notch", can I use Apple Cider or Balsamic vinegar.....hehe.

you asked! I just use the white vinegar. I have many uses fr it in the studio.
Marcia



Before paper clay, I used a repair medium for greenware using vinegar, karo, and clay. Later when I had some problems with student bisque pots, I used the same medium by replaced half of the clay I used with filed bisque dust. This cut the shrinkage dramatically, and if I packed the seam, and sanded lightly, I would get a closed seem on glaze fire. However, I never went straight to glaze fire always re bisqued.

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/





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