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learning to use underglaze

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After ten years being a hobby potter the time has come to expand my glazing knowledge.  I fire at cone six in an electric kiln using Georgies (Portland OR) glazes and Duncan Envision glazes now.  I am pushing the Envision glaze at cone six as they prefer to be fired at lower temps but I started using them because that is what the community art studio had.  

Now I want to learn to use underglaze to enable better control at decorating.  As there are very few (none) classes in my area on glazing available I am struggling to learn how underglaze works and what final glaze to use.  Using Amaco or Duncan is easy due to local availability but I am not schooled enough to know what is best. 

What brands or methods would work best for someone starting on the glazing path?  Can you offer suggestions on websites I can visit to learn how to underglaze?

Thank you for your assistance.

Kim

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Kim,

Have you talked to the folks a t Gerogie's. Talk to Christy, she is the person who makes the glaze formulas for Georgies glazes. She is a wealth of information. Tell her what clay and underglazes you are using. Christy has helped me a lot when I have had glazing problems.

 

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Depends on what you want to do. You can just brush them like paint- 2 coats will usually get you good coverage. They can also be thinned down and used more like watercolors. You can mask areas with paper before applying the underglaze. You can do mishima and sgraffito. Lots of possibilities. Commercial underglazes can be used at any stage of the process before glazing- wet, leather hard, bone dry, or bisque. It just depends on what you're doing as to when they would be applied.

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Hello Howdy,

A lot depends on what type of effects you want. One recommendation: It's easier to paint your underglazes on greenware or bisque ware, then fire and apply clear glaze after the underglaze has set. This helps to avoid bleeding and movement of the underglazes.If you are firing to cone 6 make sure the underglazes you use are rated for that. Some will lose color at higher temps. .

Ceramic Arts Network (here) has lots of freebies on glazing techniques.  I would start by looking up majolica techniques. Linda Arbuckle has some video clips and books out there. Check also online for books and videos on glazing techniques(YouTube is usually helpful). For books and DVDs read the reviews or previews of content to see if there is good info on underglaze use. UG is used a lot for low fire work so don't forget to check the info on low fire glazing as well.  It's pretty straightforward stuff to use. It can be applied heavily for more opaque application or used thinly for a more watercolor-like result...and anything in between.

Happy glazing.

Edited by susieblue

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I'm just gleaning around on old posts and I'm discovering that I know very little also about the only thing I thought to know...: underglazes!

I'm using underglazes by many years but I've always used them pretty thinly (like a watercolor) on bisque and I have always applyed the clear glaze by dipping  before firing a second time.

I find pretty hard to figure out how to obtain a "solid" uniform color coverage with underglazes, like those I see in Linda Arbuckle jobs! Really do all her backgrounds are made with underglazes?

Sounds strange to me also to hear that I could fire underglazes and clear glaze in 2 different times... This because I knew that underglazes have not sufficient fluxes to  fix well to the bisque... Really to fire underglazes and glaze in 2 times not only is poossible but is better?? Problably because I've Always used underglazes like a watercolor but I never faced bleeding problems...

Finally, is there any advantage in applying undeglazes on greenware? Is there some precaution to be taken?

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Take advantage of all the free info on the links in the above header ICAN https://ceramicartsnetwork.org/freebies/free-guides/ceramic-decorating-tool-techniques/ and ceramic Arts Network blogs like Erin Firimsky 

 

I see you found the freebies while I was posting. Lots of good stuff there. here's more

 

https://ceramicartsnetwork.org/freebies/free-guides/ceramic-decorating-tool-techniques/

 

 

Great wealth of info in those free downloads and you tube videos.

Marcia

 

 

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andros, one technique you might be able to use is demonstrated on facebook.  if you look at Davis Vachon Gallery find the instructional videos that show putting glaze on bisque using small plastic squeeze bottles.  the artist covers sections that have been drawn in pencil and when fired there is a solid section of color.  they use glaze but the technique can be used with underglaze as well as slip or any liquid.  i am not able to link directly to the part you want to see.  

 

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On 20/12/2017 at 4:49 PM, oldlady said:

andros, one technique you might be able to use is demonstrated on facebook.  if you look at Davis Vachon Gallery find the instructional videos that show putting glaze on bisque using small plastic squeeze bottles.  the artist covers sections that have been drawn in pencil and when fired there is a solid section of color.  they use glaze but the technique can be used with underglaze as well as slip or any liquid.  i am not able to link directly to the part you want to see.  

 

This is a technique similar to "cuerda seca", I've used it in past months but as I told in another post i have some trouble... anyway I'm just in the task to understand if what in Italy is called litterally "undergaze" is exactly the same thing than you mean... This because I have a little suspect that here what we use and call "undergalze" are something most similar to stains... 

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I use a lot of underglaze with my work.  I use it mostly on bisque because the bisque is more sturdy and puts up with my handling.  But I have used it successfully on greenware.  I put my design on the bisqueware, spray clear over and fire to cone 6.  Designer liner by Mayco can be used to put down fine lines, you can draw with a great deal of detail.  Then you can "paint" over the lines you have drawn with underglaze.   I use Amaco and Duncan underglaze, simply because that is what I have available.  I hear that there are other underglazes that are good as well.  At times I have used underglaze pencils.  They perform well also.  It is simply a different look.  You can use underglaze to coat an entire piece or for small designs. or to add a small pop of color.  Underglazes are quite versatile.  They can be blended and mixed to get just the color or effect you want.  Red is rather expensive, but the rest of them aren't too bad considering how long they last and the small amount a person used.  The maroon and pink seem to burn out at cone 6.  Red holds its color nicely.  

Good luck!

Roberta

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andros, to me, a stain is just the colorant.   a dry powdery combination of minerals that produce a particular color when added to a recipe for the medium that gets the color onto the piece you are making.  "underglaze" is the medium, the vehicle to carry the color onto the pot.  there are published recipes for making underglaze.  once the recipe is mixed up, a particular stain is added to get the color you want.

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@oldlady and @Roberta12, , thank you for your help...! Simply in these days I'm getting so confused... I sow so many new techniques (that in US are pretty usual but in italy are not)  that I do not know what to think anymore! As I told I used underglazes for at least a decade but always as a "watercolor" according to italian tradition, duliuted, because... I  was taught this way! Now I see a deeply different way to use that and I wondering if are even another thing... I don't know... maybe italian underglazes has less clay content or more stain content... I saw some underglazes (US) recipes but but in Italy those recipes doesn't exist.  Exists only commercial underglazes so I don't have a comparison. I know that the ingredients are the same as US undergales but I don't know the proportions. Moreover in Italy there is a website that sells pottery materials and it's the almost the only one that sells one american brand (Mayco). I tried some glazes like jungle gems and stroke and coat. Those products was really good and pretty different form italian products. They have also mayco undergalzes but the descrpition of those underglazes is enigmatic and ambiguous (this site wirte "undergazes-engobes"!!)... I want to buy some pieces to try if they are really different but  so near to Christmas I need to wait some days before to get them!  Moreover I want to use my italian underglazes with the US manner... I'm so impatient to do this! But now my tiny studio is so crowded with other stuff that i would combine a disaster! After holiday period I will try and (hoping not to bore you) I will let you know the results!

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I use amaco velvet underglaze two different ways: on leather hard clay for sgraffito, and on bisque to bring out the lines of intaglio.  Both work at Cone 6.  They also fire ok to Cone 10 in salt and wood.  

 

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On ‎24‎/‎12‎/‎2017 at 12:13 AM, andros said:

I want to buy some pieces to try if they are really different but  so near to Christmas I need to wait some days before to get them!  Moreover I want to use my italian underglazes with the US manner...

Some days  ago I noticed to have in my my inventory some Duncan underglazes... I had not used them for so long time that I forgot to have them! I have always used them very diluted as watercolors. With them I made some tests and actually I noticed that they are different from italian underglazes not for the composition of the color itself but just because they (duncan) are problably added with some sort of gum to meke them "brushable" and to form a compact layer.  I tried also some italian liquid underglazes and although they don't form a compact layer like Duncan underglazes, it's still feasible to use them like "US underglazes", the only problem is that they are sold in very very small jars  (less than 1oz) and to use them in the "pure form" make them definitely not cost effective...

In my inventory I have also many jars full of powder undergalzes. I tried to use them to make solid layers but is unuseful to say that is not possible because once dried they return to be powdery and is not possibile to make multiple layers.

Does anybody know what I can add to powder underglazes in order to make them brushable and to form a compact layer? Maybe some CMC or other? Of some colors I have some lbs  (a lifetime supply if used as watercolors!) and I think it's worth trying to use them like "US underglazes".

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The recipe below was developed by Ron Mason, Mason Color is a stain manufacturer.
 
EPK Kaolin 10 parts
Feldspar.     25 parts (I use Custer)
Flint.            25 parts
Stain.           40 parts
Mix well with water, add 1 part VeeGum T that has been FULLY broken down in water, screen through 100 or finer screen, bring to your painting consistency by addition of more water if needed. Don't skip this ingredient, even though it's just a tiny amount you need it in the recipe.
 
When using very strong stains such as cobalt blues or chrome greens you may need to reduce the amount of stain if the fired colour is too strong for your requirements. If green stains are used and they turn out too dry and crusty when fired then they likely contain chrome which is very refractory, adding approx 15 parts calcium carb will help it flux.
 
This can be used to decorate on clay or bisque. 
 

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35 minutes ago, Min said:

1 part VeeGum T

I think that this is what I'm looking for!

Actually I don't know the exact composition of my commercial powder underglazes but I think that it doesn't differ a lot from an US underglaze...

Unfortuatelly I'm not able to find it in my region... VeeGum-T appears to be a commercial name for smectite clay, that is a very generic name that comprises many different clays... Could bentonite act at the same way?

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@andros,If your supplier carries Bentone MA, also called macaloid then I would use that, if not then I would try the whitest bentonite you can get. You will need about twice as much bentonite as you would if using Veegum T or macaloid.

@RonSa, the word gum in Veegum is misleading, it's not a gum but a super refined mineral called smectite whereas gum arabic is a gum and will rot in the glaze bucket. They both will harden the surface of a glaze and help bind it. I have a fair amount of macaloid and use that for all my glazes that hardpan, it's great stuff though it is more expensive than bentonite. I keep a yogurt container of premixed macaloid mixed with enough water to make a pudding thick gel and add a small amount of this concentrate to glazes that settle too quickly. I whiz it into a cup of the glaze with an immersion blender first, then add it to the bucket or else it just floats on the surface of the glaze in blobs. For recipes I know will hardpan or dust excessively I add 1% to my dry glaze ingredients then mix the glaze up like usual. It does change the "thickness" of the glaze in the bucket so it can be misleading, if you try it I would suggest measuring the specific gravity of the glaze to make sure you aren't watering it down too much.

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Thanks for the info Min. The reason I asked is I have about 1-1/2 gallon of gum arabic hanging around looking for a use.

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1 hour ago, RonSa said:

Thanks for the info Min. The reason I asked is I have about 1-1/2 gallon of gum arabic hanging around looking for a use.

Haven't used it so don't have first hand experience. Thinking that if you added a tiny amount, like 1/4% of copper carb it could keep it from rotting like you do with CMC. Veegum CER (veegum cer has cmc in it). If you try it it would be interesting to hear your results. 

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VeeGum-T is used to make this glaze brushable, and to help keep it suspended since it's not all that high in clay. Bentonites will keep it suspended well, but won't help brushability as much. You can use any gum to make a glaze brushable instead. The problem is that gums are organic, and will get eaten up by bacteria in a matter of days. To preserve the gum, and 1/4 to 1/2 of 1% copper carbonate to your underglaze. It will preserve the gum and won't be enough to affect the color.

I usually use CMC gum. Mix 2 tablespoons CMC and 1/2 teaspoon of copper carbonate to a gallon of hot water and let it sit overnight, then mix it with a blender. It'll make a gel. Substitute 1/3 to 1/2 of the water in the glaze with the CMC mix. It'll keep it suspended and make it brushable.

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@andros, think we have some confusion going on here and need some clarification of what you have that you are trying to make work like underglazes do. If it's stains then a base like the recipe I posted will work, if you are just trying to improve brushability and reduce dusting to an existing product then a gum will work. Or a combination of the two like Veegum CER. Could you post a link from a supplier of what you are working with? 

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