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Nerikomi Disaster


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#1 jrgpots

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Posted 01 August 2013 - 12:26 PM

Last night I tried to make a Nerikomi style rose following the link from Youtube: www.yuotube.com/watch?v=ihhFSTGBots .  I used two different clays (Laguna electric brown and Moroacan sand) that I thought had about the same % shrinkage ( 12% and 12.5% plus or minus 2%) with drying.  I made a large rose pattern which ended up being about 7 inches in dia.  It looked great.  I cut the cane into 2 parts and set each over a hump mold, turned the outside of each on the wheel and trimmed them up.  They looked great.  However, 3 hours later they started to crack along the joint lines. This AM they have completely fragmented.

 

Here are my questions:

     1.  How can I tell if both clay bodies are equally hydrated?  (I am assuming they broke apart because of this.)

     2.  Do you use slip to attach/glue the different pieces together?  (I did not, since the demo on youtube did not. Would it have changed anything?)

     3.  Would I be best served to use the same clay body and mason stains instead of different clay bodies? 

     4.  Had I sealed the cane in a plastic bag with a few tsp of water and allowed all the clay to come to an equal hydration point, would it have cracked upon drying?

 

Marcia, I know you do this type of Nerikomi cane art.  Do you have any tips?

 

Jed



#2 mregecko

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Posted 01 August 2013 - 01:14 PM

Honestly, that ombre effect is create by blending the two clays multiple times... I can't imagine that, after all of that mixing, the moisture level or relative shrinkage rates of the clay would cause huge problems.

 

More likely (I'm guessing) the problems comes at the stage where the ombre'd lugs are rolled up to create the rose. I could see the boundaries between those pieces were difficult to compress while she was rolling.

 

I'd say try it again, make sure when you roll the piece up you compress inwardly as much as possible by squeezing with your hands.

 

When you cut your slab and form it, spray it with some water, and let it dry slowly.

 

I'm no nerikomi expert though, so I'll defer to those more knowledgeable if my answer sounds wrong to them ;-)



#3 neilestrick

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Posted 01 August 2013 - 02:18 PM

Did you let them dry on the slump mold? If so, that's likely the cause of your cracking. The clay can't shrink as it dries if it's on a mold, so it has to give somewhere.


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#4 OffCenter

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Posted 01 August 2013 - 02:26 PM

Neil is right. If that is the problem just do a slump mold instead of a hump mold.

 

Jim


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#5 Chris Campbell

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Posted 01 August 2013 - 04:09 PM

Well, I have been doing nerikomi for a long, long time and I can point to several problems.

 

- It is very seldom that you can successfully make and use patterns the same day. Maybe with tiny ones, but not 7" canes. You have to let all the parts settle, connect and match up.

- You can connect the parts with slip or just a slight spritz of water. If the clays are wet enough, you don't have to use anything. The important part is when canes are done, wrap in a damp towel and store overnight ( at least ) in a plastic bag.

- I don't understand how you threw them ... cannot picture it at all. Where did you find a video of throwing canes? Seems like a huge mess but ....??

- Once you do make a piece, you have to cover that with plastic and do a slow controlled drying. Too fast and you get cracks and splits.

- You can use different colored clays and there are many who do just that. But you gotta slow down and give the clays a chance to rest and get bonded.

Basically, you have to slow down each part of the process. Realize the demands you are placing on the clay.

I will be glad to help with any further questions and ... would love to see you in a workshop one day. :D

 

Images are of a rose pattern I am working with right now, and showing how they are all covered in plastic when I use them. These have been made for over a week so they hold together very well.

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#6 jrgpots

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Posted 01 August 2013 - 04:50 PM

Well, I have been doing nerikomi for a long, long time and I can point to several problems.

 

- It is very seldom that you can successfully make and use patterns the same day. Maybe with tiny ones, but not 7" canes. You have to let all the parts settle, connect and match up.

- You can connect the parts with slip or just a slight spritz of water. If the clays are wet enough, you don't have to use anything. The important part is when canes are done, wrap in a damp towel and store overnight ( at least ) in a plastic bag.

- I don't understand how you threw them ... cannot picture it at all. Where did you find a video of throwing canes? Seems like a huge mess but ....??

- Once you do make a piece, you have to cover that with plastic and do a slow controlled drying. Too fast and you get cracks and splits.

- You can use different colored clays and there are many who do just that. But you gotta slow down and give the clays a chance to rest and get bonded.

Basically, you have to slow down each part of the process. Realize the demands you are placing on the clay.

I will be glad to help with any further questions and ... would love to see you in a workshop one day. :D

 

Images are of a rose pattern I am working with right now, and showing how they are all covered in plastic when I use them. These have been made for over a week so they hold together very well.

 

Thanks. 

    1. my hump mold was a glass bowl.  After I placed the rose on the glass bowl, I centered the mold and trimmed the outer surface with a trimming tool followed by a rib.  It cleared up any pattern blur that may have developed.

    2.  I thought about letting the roses rest in a plastic.  In fact I placed one additional cane in plastic before i try to cut it into two roses.

    3.  I like the idea of a slum mold instead of a hump mold.  I 'll have to figure out how to put a foot on the bowl.

    4.  Next time a will use a spritzer while I roll and compress the pieces.

 

I was so excited, I got ahead of myself.

Fianlly, Chris do you ever make your way West doing your workshops? I'd love to set in on such a workshop.

 

  My local art coucil, Hurricane Valley Arts Council, frequently brings in artist for its workshops.  Would you be interested in teaching at the mouth of Zion National Park in Southern Utah?  If so I might be able to get something started.

 

BUT,,, YOU WOULD HAVE TO REMEMBER,  I'm still a newbie and have 15 left thumbs.

 

 Thanks Neil and Jim. Your comments are spot on.

 

jed



#7 jrgpots

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Posted 01 August 2013 - 06:27 PM

Honestly, that ombre effect is create by blending the two clays multiple times... I can't imagine that, after all of that mixing, the moisture level or relative shrinkage rates of the clay would cause huge problems.

 

More likely (I'm guessing) the problems comes at the stage where the ombre'd lugs are rolled up to create the rose. I could see the boundaries between those pieces were difficult to compress while she was rolling.

 

I'd say try it again, make sure when you roll the piece up you compress inwardly as much as possible by squeezing with your hands.

 

When you cut your slab and form it, spray it with some water, and let it dry slowly.

 

I'm no nerikomi expert though, so I'll defer to those more knowledgeable if my answer sounds wrong to them ;-)

You are correct.  The cracks occurred at the ombre lug joints.  I will  try better compression techniques.  I'm afraid the biggest adjustment that needs to be made in the NUT that is pushing the clay....me.

 

Thanks, 

Jed



#8 Chris Campbell

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Posted 01 August 2013 - 10:02 PM

What video did you watch? Can you post the link so I can see it and maybe get an idea what you did?

Glass does not make a good hump mold because your clay will stick to it and it does not give at all ...  so your form will crack as it dries.

Why do you need a spritzer while you are rolling and compressing?

I am very confused here.


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#9 Benzine

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Posted 01 August 2013 - 10:41 PM

What video did you watch? Can you post the link so I can see it and maybe get an idea what you did?

Glass does not make a good hump mold because your clay will stick to it and it does not give at all ...  so your form will crack as it dries.

Why do you need a spritzer while you are rolling and compressing?

I am very confused here.

The link was posted in the first post, but the "O" and "U" in "Youtube" need to be switched around.

 

Interesting video.  I have never seen the "rose" technique before. 


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#10 jrgpots

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Posted 01 August 2013 - 10:42 PM

The link is www.youtube.com/watch?v=ihhFSTGBots

 

Hopefully the link will work this time. The glass bowl was the only thing I had handy.  I thought plaster would dry it too quickly.  I failed to take into account that the clay would adhere too well to the glass. 

 

In her technique she rolls clumps of clay is if she were making a large cinnamon roll.  She uses no slip or spritzer to fuse these clumps of clay.  Instead, she compresses them or flattens them out with a roller.  I followed her technique, but my clumps of clay fell apart from one another. So, If I were to use a spritzer or slip to join these clumps together as I rolled them into a cinnamon roll looking cane, then compress the cane; I wondered if they would stick together better and not crack. 

 

Have I confused you enough?  If so watch the video.... When she gets to the point of rolling all the pieces together into one big cane, that is when I thought I might use a spritzer to joint my "rose petals" together.

 

I really like the shape of the glass bowls I used, so I am going to place a piece of Saran Wrap on top of the glass bowl before I set the clay flower on it. this way it should not stick as it dries.  I will dry the bowls very slowly.  Do you think it would work?



#11 OffCenter

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Posted 02 August 2013 - 08:29 AM

I think you will still have problems. At least wrap the cane up and let it homogenize for a day or two before making it into a bowl. Your best bet is to pay close attention to Chris's advice. Working with colored clay and having Chris here is like working on an atomic bomb and having Robert Oppenheimer's help.

 

Jim


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#12 Claypple

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Posted 02 August 2013 - 09:50 AM

I really like learning by youtube. Much more efficient than taking classes.

Videos, books, help from the forum, common sense, and a basic knowledge of science. This is all you need.



#13 Chris Campbell

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Posted 02 August 2013 - 09:52 AM

I just watched it and what's missing are the parts where she keeps her clay damp throughout the process as she works. I usually keep a damp towel covered with plastic nearby and store everything but the piece I'm working on there. Also, she had to let it rest ... there is no way it would have stayed together otherwise. I don't think she threw that bowl in the image ... It looks like it was hand built in a slump mold. Hump molds are tricky to use for bowls as you have to take them off before shrinkage causes cracks.
Also, the coloring would go a lot faster with the Skinner Blend technique! See clay lessons on my website.
I've gotta write a book or start doing videos! Just do not want to take the time away from actually doing nerikomi yet.

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#14 Chris Campbell

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Posted 02 August 2013 - 09:55 AM

"Your best bet is to pay close attention to Chris's advice. Working with colored clay and having Chris here is like working on an atomic bomb and having Robert Oppenheimer's help."

OK ... Thanks for a great laugh with your comparison .... I do occasionally blow things up, destroy pots by accident and make huge messes everywhere ... So maybe it is apt.

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#15 jrgpots

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Posted 02 August 2013 - 03:20 PM

I just watched it and what's missing are the parts where she keeps her clay damp throughout the process as she works. I usually keep a damp towel covered with plastic nearby and store everything but the piece I'm working on there. Also, she had to let it rest ... there is no way it would have stayed together otherwise. I don't think she threw that bowl in the image ... It looks like it was hand built in a slump mold. Hump molds are tricky to use for bowls as you have to take them off before shrinkage causes cracks.
Also, the coloring would go a lot faster with the Skinner Blend technique! See clay lessons on my website.
I've gotta write a book or start doing videos! Just do not want to take the time away from actually doing nerikomi yet.

Thank you very much.  Your work  has pricked my interest and I want to get at least one good finished project in this area.  It is cool.  I am headed to you website tonight.

 

I appreciate Jim's comments and recommendation to follow Chris's instructions very carfully.  I have one cane resting in a moist plastic bag.  It has been there two days.  I will let you know how if it turns out.  I'll share a pic as well if it works.

 

jed



#16 jrgpots

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Posted 04 August 2013 - 09:25 PM

I've gotta write a book or start doing videos! Just do not want to take the time away from actually doing nerikomi yet.

I made a rose cane. The roses are now resting. Do you think they are OK?

#17 OffCenter

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Posted 05 August 2013 - 07:57 AM

I hope it works this time. I'm anxious to see the results. How do you plan to shape it? Slumping it over a glass bowl didn't work out so well last time. A while back I posted a quick-and-easy way to make great slump molds with quilting hoops. If interested just go to post 23 in http://ceramicartsda...ge-2#entry38274.

 

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#18 Chris Campbell

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Posted 05 August 2013 - 10:47 AM

It's hard to tell from an image ... My only words of wisdom are "slow down". Everything. Every step. Forming, rolling, drying. Let the clay tell you if its ok to go to the next step. If it starts to seperate or crack, you are going to fast.

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#19 jrgpots

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Posted 05 August 2013 - 01:00 PM

I hope it works this time. I'm anxious to see the results. How do you plan to shape it? Slumping it over a glass bowl didn't work out so well last time. A while back I posted a quick-and-easy way to make great slump molds with quilting hoops. If interested just go to post 23 in http://ceramicartsda...ge-2#entry38274.

 

Jim

I made a plaster hump mold.  But I think I will try your quilting hoop idea with the jersey material. 

 

Thanks, 

Jed



#20 jrgpots

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Posted 05 August 2013 - 01:04 PM

It's hard to tell from an image ... My only words of wisdom are "slow down". Everything. Every step. Forming, rolling, drying. Let the clay tell you if its ok to go to the next step. If it starts to seperate or crack, you are going to fast.

  I rested the individual petals for three days after mixing the clays.  I will let the roses rest for 3 days or so.  The next time I have any time will be Wednesday anyway.  Thank you for the heads up with the skinner blending technique.

 

Jed






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