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Calcined zinc--adjustment?

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Babs alerted me that the yellow zinc oxide I received might be "calcined". The vendor said it was and I was going to have to "adjust " recipes to account for it. When I asked what this adjustment would be, no answer was forthcoming. Does anyone know how to "adjust" calcined zinc amounts in a recipe please?

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I think most recipes consider calcined zinc as the default, since the uncalcined stuff is clumpy and hygroscopic, containing varied amounts of water.   I could be wrong but Ive only ever used calcined zinc regardless of what the recipe called for.

You could put it into glaze calc software and adjust

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You don't need to make adjustments, just use it the same as you would un-calcined zinc oxide. It will only be a negligible difference between LOI from absorbed atmospheric moisture content between calcined and raw zinc oxide. Going forward just keep the zinc oxide in a sealed container (with a permanent label ;)) so it doesn't reabsorb moisture from the atmosphere. If it does go clumpy just re-calcine it with a load of bisque.

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Thank you both very much!  Yes, I got some really nice wide mouth plastic jars from ULine to put my materials in to keep them from becoming contaminated. If you have never used ULine...the jars were very reasonable. Thanks also on the tip about how to calcine the old stuff!

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I use the black and yellow bits and bolts containers for colorants and these clear latching bins for bulk stuff like Feldspars and clays.  I need another shelf though, running out of room 

 

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Edited by liambesaw

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Here are the Uline jars.  They come in pint, quart and gallon.  What I like is that I can trim the plastic neck on those bags, put it in the jar upside down, and everything just flows in......no dust.....no touching the substance. I then use a indelible marker and mark the jar on the side.  The pint ones are really nice for small glaze test samples.Yes---I already had to get a new set of racks for bisque ware.....putting them together tomorrow. The materials and clay ate up the ones I bought. I forgot how much "stuff" is involved in this!

 Round Wide-Mouth Plastic Jars - 1 Gallon

 

 

Natural Round Wide-Mouth Plastic Jars - 1 Gallon S-17077

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MFP, congrats on finding something that will keep things organized and visible so you know when to buy more.   just fyi, if you need to change the label you have put on the jar, try some inexpensive hair spray and a cotton ball.   if it is a sharpie, the ink will come off with perhaps a slight shadow.  if so, use more hairspray and wipe it off again.   so much better than a paper or tape label that can come off and leave you with a question of what is inside that jar.

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5 hours ago, oldlady said:

MFP, congrats on finding something that will keep things organized and visible so you know when to buy more.   just fyi, if you need to change the label you have put on the jar, try some inexpensive hair spray and a cotton ball.   if it is a sharpie, the ink will come off with perhaps a slight shadow.  if so, use more hairspray and wipe it off again.   so much better than a paper or tape label that can come off and leave you with a question of what is inside that jar.

I use WD-40 to remove labels.  Spray, let it soak for 10 or so minutes, and remove.  

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One word about non calcined Zinc is a small thrift shop blender works miracles on that material-I mixed some upo yesterday. Toss it in and hit high speed for two or three minutes and it will pass right thru the screen.The chaep shop blender mixer maked fast work of hard clumping materials that get cuaght up  in screens.

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When I made glazes before, if I had access to a drill with a paint mixer on it, I was thrilled.  Blenders? Screens?  The blender is a good idea.....especially for those small glaze test samples. 

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42 minutes ago, MFP said:

Dry or wet? We didn't do this .

Wet screen glazes and slips, 80 mesh is good for most stuff, if it's got cobalt in it and you don't like speckles, go for 100 or 120 mesh or run it through the 80 a few times.

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On 7/25/2019 at 3:32 PM, MFP said:

{snip} The blender is a good idea.....especially for those small glaze test samples. 

For the USA crowd - regarding blenders, the blending pitcher that screws onto the blade base of Oster and Hamilton Beach blenders has the same thread size as a standard "mason" canning jar. Measure your materials into the jar, screw the blade base on, flip it over onto the motor, and whir it until done. Then put a lid on it. I can make a 400g sample in a quart canning jar.The Waring brand blender has a different thread for its pitcher, so doesn't work this way.

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6 minutes ago, MFP said:

Somehow in the past we seemed to be able to survive without doing this and no specks. 

In school we used a ball mill and wall mixer, that was 20 years ago.  But it took forever, hours of mixing and milling.  Wish we had a sieve then

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11 minutes ago, MFP said:

Somehow in the past we seemed to be able to survive without doing this and no specks. 

In glaze class from my Afreds instructors (at Humboldt state ) we always used a 60-80mmesh when making glazes(I worked the glaze lab for a few years)

My guess is they where always screened but one may not have seen the process-back then it was a galvanized hoop with a brass screen and two sticks over a bucket.

Still have 4 hoop screens along with my 3 talisman screens-one for whites one for irons and one as a spare.Bought two many potters out of all thier stuff I guess.

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The thing that annoys me is that when something is for pottery how the price gets jacked up. I found a very nice 12 inch stainless banding wheel. that turns smooth as silk.....for $24....a cake decorating wheel for $24 at WalMart. Then if you get a plastic one....it also comes with three ribs....for $8.  I was particularly irked last night to find the same fine mesh (80) hoop  sieve that CAC wanted $96 for $7.50 at WalMart. 

Yes.....I am the Queen of Cheap.

It's my birthday and I probably am going to be putting my cat down in about an hour. It does not do much to improve my disposition. Sorry

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13 minutes ago, MFP said:

The thing that annoys me is that when something is for pottery how the price gets jacked up. I found a very nice 12 inch stainless banding wheel. that turns smooth as silk.....for $24....a cake decorating wheel for $24 at WalMart. Then if you get a plastic one....it also comes with three ribs....for $8.  I was particularly irked last night to find the same fine mesh (80) hoop  sieve that CAC wanted $96 for $7.50 at WalMart. 

Yes.....I am the Queen of Cheap.

It's my birthday and I probably am going to be putting my cat down in about an hour. It does not do much to improve my disposition. Sorry

http://www.seattlepotterysupply.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=sps_ecat&Product_Code=84203&Category_Code=SH

https://euclids.com/index.php?item_id=OF080

The expensive ones are higher quality, but at 13 bucks for a cheap one it would take a lot of years to make up the difference.  

I don't think what you'd get from Walmart would be 80 mesh.  80 mesh is 180 microns, incredibly small, has no practical home use

 

I use a heavy aluminum cake decorating wheel too.  The difference between the amaco banding wheel and a cake decoration wheel is that the amaco one is weighted so it spins for a long long time.  Not sure it's a 60 dollar difference, but for some I suppose it is.

Edited by liambesaw

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15 minutes ago, MFP said:

You obviously have never dealt with cake flour.  I am sure it is probably more than 80 mesh. It's exactly the same hoop. 

You're right, I haven't made cake flour before haha.  But I also looked on Walmart.com and couldn't find any 80 mesh sieves either. My point was there is deluxe sieves that are expensive and then the ones that are cheaper but maybe not as well advertised haha. 

Also the nice thing about the clay ones is that they fit on a 5 gallon bucket

Edited by liambesaw

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