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Min

Member Since 31 Mar 2010
Offline Last Active Today, 02:09 PM
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#122905 Glazing

Posted by Min on Today, 02:06 PM

Came across a glazing demo, covers the basics with quite a few tips. Seems like there are a lot of posts here about basics of throwing but not glazing. This one is kind of a glazing 101 for dipping and pouring. It's a long but might be helpful for anyone just starting out. If anyone else has come across any good demo's of glazing it would be nice to see those too.

https://www.youtube....h?v=r3RSJcOfhw8

 

 




#122824 Resist Over Glaze?

Posted by Min on 23 February 2017 - 05:46 PM

from NCECA a few years ago http://blog.nceca.ne...he-process-room




#122815 Throwing A Double Walled Pot, But Opening It All The Way

Posted by Min on 23 February 2017 - 03:41 PM

Hi and welcome,

 

Throwing a wide based donut up to the point of closing the 2 walls in, then coning in the inner wall to make a dome, making a depression in that then finish off by throwing the base and outer lip? Am I following you right?

 

And the problem you are having is opening up the donut hole wide enough and having enough clay to do the middle depression bowl bit? If so wouldn't it just be a question of leaving enough clay in the middle? Perhaps opening up to the batt then pull the thick ring of clay outwards (don't have your batt too wet or you might land up pulling the ring right off the batt), to the diameter of the inner dip dish bit then split the ring, leaving more clay for the floor/rim outside part, throw that bit first then go back to the inner wall and close it in. Am I anywhere close to what you meant?

 

edit: after thinking about this a bit more I'm wondering if the bowl part will be possible without the seam where the edges meet splitting apart when pressed into a concave depression. I think a slumped slab across the hole and attached to the sidewalls of the central tube would work.




#122782 Resist Over Glaze?

Posted by Min on 22 February 2017 - 09:49 PM

On some glazes that are low in clay, when the glaze completely dries the wax will peel up since the glaze is too powdery to prevent it. I have a couple that do it. When it happens, it peels up the glaze with it and ruin your nice glaze job. To prevent that from happening, after you're all done glazing the pot and before the glaze has totally dried, lightly go over the wax with a torch to melt it into the glaze. Works like a charm. Or put the pot into the kiln and start the firing right away.


The Mobilizer A oil based wax resist, that takes forever to dry, works super well on dusty glazes. Good to know the torch trick, thanks for sharing that.


#122719 Qotw: Are You Throwing Wearing Bling Bling?

Posted by Min on 22 February 2017 - 01:40 PM

Hi Evelyn,

 

I wear my wedding ring. My wife had it welded on.  <_<  :D JK. I don't think about it and for the most part I haven't had any clay rips in awhile. Besides, if I take it off, I know I will forget to put it back on. And that might get me fried. Although I have thought about making it into a nose ring.  :huh: or an ear ring. I don't wear any other bling blings.  :D

Hope you're doing well.

 

Think your wife needs to talk to my husband. He's a judo sensei and can't wear rings when on the mats. His wedding ring was getting tight so in a hurry one day he took a pair of tin snips and cut it right through to get it off. Guess the look on my face was a little much, he took the ring into a jewellers and had it enlarged and repaired. I keep my wedding ring on, would never hear the end of it if now I went and lost it.




#122674 Tell Me Why This Is A Bad Idea 1

Posted by Min on 21 February 2017 - 06:03 PM

 

Chances are the rim will deform and go out of round unless what it is sitting on can shrink at the same rate as the pot. Roll out some of the same clay as the pot is made from, it can be super thin. Cut out a pancake of clay just big enough to rest the rim on (can cut the center of the pancake out to save clay). Dry the pancake between batts or boards or whatever so it stays flat. Bisque it then place your upside pot on it when glaze firing. The pot and pancake will shrink at the same rate so the rim will stay true. If you are using porcelain slap a quick coat of kiln wash on the pancake. 

 

I wouldn't worry about off gassing, casseroles, french butter dishes, boxes, lidded jars etc are all fired as a closed unit.

 

I've been thinking about this

I'll be using stoneware, but won't the pot stick to the pancake when glaze firing?

 

 

Sorry, I just assumed you are not glazing the rim. If you want to glaze it all over then you would have to use stilts on the bottom and grind off the little sharp bits of glaze afterwards, firing it right side up. Stilts work best for small light pieces when firing higher than earthenware temps.




#122656 A Variety Of Ways To Throw Colored Clay

Posted by Min on 21 February 2017 - 12:53 PM

Those are beautiful Chris! 

 

I had the chance to watch Les Manning throw a couple of his landscape coloured clay sculptures. Very precise and deliberate placement of colours. He built up a cone of clay on the wheel, one colour at a time by adding chunks and wodges of clay, no wedging the final mass, then just got the one shot of throwing the piece. Is that how you do it? (couldn't link to your article successfully)




#122654 Tell Me Why This Is A Bad Idea 1

Posted by Min on 21 February 2017 - 12:35 PM

Chances are the rim will deform and go out of round unless what it is sitting on can shrink at the same rate as the pot. Roll out some of the same clay as the pot is made from, it can be super thin. Cut out a pancake of clay just big enough to rest the rim on (can cut the center of the pancake out to save clay). Dry the pancake between batts or boards or whatever so it stays flat. Bisque it then place your upside pot on it when glaze firing. The pot and pancake will shrink at the same rate so the rim will stay true. If you are using porcelain slap a quick coat of kiln wash on the pancake. 

 

I wouldn't worry about off gassing, casseroles, french butter dishes, boxes, lidded jars etc are all fired as a closed unit.




#122575 Stoneware Clay Properties

Posted by Min on 20 February 2017 - 02:29 PM

If all suppliers provided the info and quality clays that Plainsman Clays does I'ld be a happy camper.

 

If you haven't had a look at the info they provide have a read through of the Overview then click on any of the bodies listed on the left of that page. I use a fair bit of M370 and find what it is described as is pretty much what you get. If anything it is a little overboard on the care needed while drying and firing.




#122510 Newbie Needing Advice For Handbuilding

Posted by Min on 19 February 2017 - 12:27 PM

Lots of variables to determine if a glaze is food safe or not. Short of lab testing every glaze there are some common sense approaches to take to rule out some.

 

Simple things to do and look at would include using a liner glaze with no questionable materials. Fire the glazes to maturity. Under fired glazes are far more likely to leach than mature ones. For food surfaces using a (mature) gloss glaze is going to be less likely to leach than matte. 

 

From the chemistry side you don’t have to go into extreme analysis to get an idea if the glaze is likely to okay. Make sure the alumina and silica levels are high enough, limit charts with glaze calc software give you this info, if either is too low then chances are there is too much flux in the recipe and the glaze won’t be durable. If there are materials in the over fluxed glaze that are unsafe then its more likely they will leach out.

 

Look at the metal colorants in the glaze, are they in reasonable amounts or over the top high. Example would be cobalt carb, under 2% (in a balanced glaze) is fairly common, if you see 4 or 5% then alarm bells start going off as to the safety of that glaze. Avoid ingredients like cadmium stains unless you are willing to get the work lab tested. Encapsulated cadmium is turning up in all sorts of commercial underglazes and glazes now, it’s not just the bright reds and yellows anymore. 

 

Do home leaching tests, both acid and alkali ones, if these show deterioration of the glaze surface then fix the glaze or don’t use it. If they look fine after home testing but contain dubious colorants (or fluxes), or levels of them, then consider getting glazes lab tested. I believe Pugaboo had some done recently and the cost was minimal.

 

 

One of the huge advantages of using glaze calc software is you know what is in your glaze and don’t just have the next to useless MSDS from the commercial manufacturer. For commercial glazes I would take a guess that the clears and whites are probably safe, the razzle dazzle runny heavily saturated colours are not and the rest somewhere in between. If you are selling work then legally you are responsible, not relying on what it says on glaze jars.




#122401 Throwing Challenge

Posted by Min on 16 February 2017 - 12:39 PM

Only thing I could think of is using a wheel with a 12" wheel head rather than a larger one. Maybe removing the splash pan and rigging up a large carwash sponge to catch the water/slip.  Or even just using the back half of a 2 piece splash pan would help. If you do go for throwing while standing I had a friend who used an ATV lift to raise the wheel, you would be able to change the height of the wheel fairly quickly with the wheel on one of those. 




#122334 Celadon - Application?

Posted by Min on 14 February 2017 - 10:37 PM

<rolls eyes> Thanks Neil - I'll get this straight sooner or later... *sigh*!

 

I was told of an easy way to remember this, just think of a flock of birds. Birds fly together in a "floc" (and get thicker looking) and they fly apart in a "de-floc". So, if you want to gel / thicken up a glaze without decreasing the amount of water in it you add a floc(culant) and if you want to thin it down without adding water you add a defloc(culant). 




#122282 How Much Do You Charge For A Mug?

Posted by Min on 14 February 2017 - 11:52 AM

 

The going rate in my area for a good mug is $30. Prices can range $5 more or less than that for a standard coffee mug, and I charge $15 for an espresso (I only sell these direct to customer, never wholesale), and $40 for a stein.


It takes just as much time to make an espresso mug as it takes to make a large mug so you are basically charging $15 less to make up for maybe .30 cents worth of clay. Charge around the same price.

 

 

I think size does matter with pricing. A platter is going to sell for more than a charger, a serving bowl higher than a rice bowl etc. Vases seem to go for more than pitchers and yet they can be very similar in design but more work for the pitcher. What the customer perceives as a fair price also comes into it.




#122281 Kiln Venting Not Enough - Need Help

Posted by Min on 14 February 2017 - 11:34 AM

"I have been experiencing shortness of breath and coughing (especially when running) for a few years now but just assumed it was from previous years of bad studio practices. I thought that the vent and good cleaning schedule would take care of any issues I have, but it is not."

 

Have you seen your gp and requested a referral to a respirologist? Gotta look after yourself. 




#122109 Ceramic Wall Panel Heaters

Posted by Min on 11 February 2017 - 12:49 PM

I use a parabolic heater, heats with infrared with a little convection. Warms me up instead of the room, I’m not trying to heat the whole room therefore more economical. Wouldn’t work in a classroom setting but is brilliant in my situation. Lots of variables here, area to heat, drafts/insulation, outside temp, electric rates etc. 

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