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repairing grenware?


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#21 bciskepottery

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Posted 19 October 2015 - 07:48 PM

To make it better, you might have to make it worse.  The crack is very thin and you will likely have a hard time getting the mixture in it.  Use a sharp tool (x-acto knife) to make a vee channel on both sides -- you might have to go almost half way through from each side, then put the mixture in.  Not too big of a channel, but big enough to get the mixture completely in with no trapped air space.  That will make sure it goes into the whole crack, not just the surface.  Unless you get the full crack filled with mixture, it will crack during firing. 



#22 cf66

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Posted 19 October 2015 - 09:21 PM

I was afraid that would be the answer...
Well, I did it.
Let's see how it fires when it does!
Thank you guys so much for all the suggestions!

#23 GreatLoverOfMtns

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Posted 22 October 2015 - 06:51 PM

Are you drying your pots to fast? Like in a low humid area? I bought some heavy plastic and lined two shelves in plastic sheet and duck tape and let my pots dry slowly. My stoneware dries fine. But I an starting to play with porcelain and I hear it needs to dry slowly.

#24 Benzine

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Posted 23 October 2015 - 08:40 AM

Yes. soak in water overnight. Squeeze the water out of it. And start mixing your spooze. You may have to add a little vinegar to stir it up.

 

 

I try to avoid adding any type of water into the mix.  So instead of soaking the tissue in water, I soak it in the vinegar, that will go in the mix anyway.  

 

The vinegar alone softens the paper up quite well, and a quick mix with an immersion blender creates a nice mush.  Then I mix in the dried clay, syrup, and a teaspoon or so of hydrogen peroxide, to keep the bacteria at bay.  I've kept some of the mixture over the summer, in a sealed container, and it didn't smell a bit when I came back.  It did grow a bit of mold, that I just scooped off.  

 

I'm a big fan of this stuff.  It works far better than the "Ceramic Enhancer" I mentioned earlier in this thread.  It's also a whole lot cheaper...


"Anything worth believing, is worth questioning"

#25 laughlin

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Posted 24 October 2015 - 05:56 AM

Does anyone use magic water/magic mud/paper-vinegar-sodium silicate etc. concoctions as a matter of course when joining slabs? I mostly see it suggested for repairs or specific attachments, but any reason (besides hassle and expense) not to just use it for all joining?  Seems like it would be extra insurance even when constructing a simple box with moist clay - why not?



#26 bciskepottery

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Posted 24 October 2015 - 12:51 PM

I use magic water to mix the slip I use for joining slabs. Best of both worlds -- slip from the clay body and magic water.

#27 oldlady

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Posted 24 October 2015 - 02:45 PM

yes, there is a recipe for "score no more" in my glaze book.  will dig it out.  if you use more than one clay, mix each one separately and use the right one for each clay. dry powdered gum arabic from Georgie's supply

 

 

 Score no more               attributed to pat horsley

100 grams dry clay body

2 grams dry gum arabic

2 grams custer feldspar

2 grams bentonite 

 

mix dry ingredients thoroughly.  add HOT water, mix and let it sit for awhile, maybe overnight.  should be like peanut butter consistency, if too wet let evaporate or remove excess water.

 

add 1/4 teaspoon sodium silicate 

pinch of epsom salts


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#28 laughlin

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Posted 24 October 2015 - 06:51 PM

Good ideas you guys, thanks!



#29 carole62

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Posted 06 March 2016 - 11:04 PM

Would this work on a piece that completely broke off?  I was making a bead rack/tree.  I let it dry very slowly, but when I moved it to the kiln room to be bisque fired, I bumped it on the shelf and a small triangle that will hold the wire broke off. I saved it and was going to try to repair it another time. I spritzed the rack with a mist of water, wrapped up inside plastic, spritzed the outside of the bag with water, put another bag on, and then did the same and added a third bag.  I figured that would keep it safe until I could read about what to do.

 

I really like the shape and design on this rack but I am thinking I should just make a new one. But if this would work WOW. I would love it.

Carole



#30 TwinRocks

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Posted 17 March 2016 - 02:35 PM

Georgies is great! Id bet the hot water is to dissolve the gum Arabic, it's the same thing used as binder for watercolor paint and can be bought in liquid form from any well stocked art supply shop but then you don't know the dilution compared to the recipe. Since it is syrupy, I'd assume that's why some other other variations use corn syrup...the kitchen cupboard is easy to raid!

I am glad I saw this thread, I'd thought about trying a commercial greenware mender but since the pieces I have are just rim chips this sounds more practical...usually I just scrap broken pieces, but I have two that I invested 4+ hours each in carving, so I'll see if this works for porcelain since I've got nothing to lose since right now the effort is for naught anyway!

#31 oldlady

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Posted 17 March 2016 - 05:25 PM

please let us know.  the original poster promised but there is nothing here about results.  i would hate to pass on a recipe that does not work.  i know that score no more works because Jan Richardson uses it on her enormous stoneware slab boat sculptures and on her thin paperclay bowls that are almost translucent.


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#32 PRankin

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Posted 17 March 2016 - 08:54 PM

I just repaired a green stoneware pot that I clumsily cracked part of the rim off while moving it. I used the formula that I'm sure was listed here a while ago. One third each of the clay body, vinegar and maple syrup. I first applied vinegar to the broken edges then used the wet clay (more slippy than solid) as part of my mixture which I brushed on in layers, letting it completely dry in between. That fixed it and it was successfully bisque fired.

This mixture was also used to successfully fill in a small crack at the bottom of a bowl.




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