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Underglaze Issue


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#21 Pugaboo

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Posted 24 February 2014 - 10:31 PM

Benzine - I found that when I painted the dark blue on bisque it came out almost black looking, very un pretty. But I have been playing around and have found that if I paint 1 coat and no more on greenware then bisque it the blue comes out of the glaze fire lighter and brighter and very pretty. I also put down a base coat of white underglaze then the dark blue over it and it really makes it pop. I have decided that I might just know enough to use it on a large set of tumblers and a carrier. This will be the largest item I have tried it on as I have up until now been trying it out on smaller items and boxes. This will be a big test so keep your fingers crossed!

I only had an issue with the black until I switched to Amacos Zinc Free clear. When I first started I used the clear the group studio made up themselves. I think it was just a incompatibility issue between their clear and the underglaze. Nobody before me had ever really used underglazes so they never had a problem that they knew of. In fact I had no issue as long as I only used it on horizontal surfaces but anything vertical ran something awful. I went ahead and bought my own gallon of the zinc free clear and use the exclusively over my underglaze work and since then no issues vertical or horizontal.

Terry
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#22 Benzine

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Posted 24 February 2014 - 10:43 PM

Honestly, I'd probably stop getting the Dark Blue, but it comes as part of a reduced price set that I get from the supplier. It has a good assortment of colors, for a good price. So I put up with the one that is just OK.
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#23 Babs

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Posted 25 February 2014 - 05:36 PM

Could add a little white clay slip to it, but may have to add also a bit of a frit to allow it to fuse as usual.



#24 Chantay

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Posted 25 February 2014 - 06:55 PM

I spoke to a glaze tech person at Laguna today.  He recommended thinning the clear.  He couldn't comment on whether the clear glaze I was using had zinc in it or not,  but did direct me to another clear that is zinc free.  Hhmm, yea, and I just did two kiln loads testing this glaze with all my other glazes.  Uuuugh, more bangging of the head on the table.


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#25 Idaho Potter

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Posted 25 February 2014 - 07:13 PM

Treat underglazes like you would artist's paints.  Mix them.  If a yellow is too brash, add a little white.  If a blue is too dark, add a lighter blue--not white--and you'll find you still have a dark blue, but it won't look black.  There's a great vibrant blue (Marine Blue) that should work great to brighten rather than lighten the dark blue.

 

 I mix orange with yellow to achieve the interior of an orange, or mix with red to create a beautiful persimmon.  Amaco's colors are so stable, and true to the color on their test tiles, that they can be used in a very painterly way.  The only ones that still give me problems are the greens  and very pastel blues and grays.  If you want a lighter color, white is probably not your best choice.  Want to lighten a red?  Try adding yellow with a tiny touch of white (unless you want pink)  Want to darken a red? try green with a tiny touch of black.

 

Regardless of whether you paint on bone dry (as I do) or bisque, another firing at cone 06 is wise.  I've never had underglazes run if the ware has been fired after application.

 

Shirley



#26 KaMaril

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Posted 09 March 2014 - 06:44 PM

Are underglazes thick enough to be used it a cake decorator or something you could squeeze it out of to make the design on your ware or do you have to use a brush and paint it on?



#27 bciskepottery

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Posted 09 March 2014 - 07:55 PM

Are underglazes thick enough to be used it a cake decorator or something you could squeeze it out of to make the design on your ware or do you have to use a brush and paint it on?


By itself, probably not. But, you could add underglaze (or Mason stains or oxides) to a thicker clay slip and use the icing decorator to apply it to wares. You will need to find a consistency for the slip that is comparable with the stage of your pottery, e.g., soft leatherhard, leatherhard, so that the two dry together and do not crack.

#28 Mark C.

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Posted 10 March 2014 - 01:41 AM

The running at least for me is fine-I know you are not happy but its just another effect and really not bad.

Mark


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#29 Chantay

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Posted 10 March 2014 - 11:25 AM

KaMaril,  I was able to use frosting tips with slips that were colored with Mason stains.  What worked for me was using Darvon and then adding more clay till I was able to achieve a suitable thickness.


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#30 Benzine

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Posted 10 March 2014 - 05:12 PM

Terry, recently I have found the dark blue looks much better, with clear over top. I'm still not a fan of it, sans a transparent clear, but it's not too bad with it.
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#31 Pugaboo

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Posted 10 March 2014 - 09:05 PM

benzine - I just did a drink carrier and cup set using the dark blue to create the design and I am really happy with it. I have a picture of it in my camera that I will try and remember to get it and upload so you can see it tomorrow.

I found that the Amaco Zinc free clear is critical in the dark blue working. It's still extremely touchy and when I use it I fire all the pieces with it on them on the same shelf at the same time in the kiln and allow space between each piece as well. It's a very pretty blue when it works and I have been determined to make it do so.

I have also found that it really pops on a surface when you paint white underglaze on first then the dark blue even though I use little loafers white stoneware it's not as white as it needs to be to really contrast with the dark blue.

That's pretty much it for now my show at the gallery starts Thursday and I dropped off all my pieces yesterday for them to arrange. I am thinking maybe I'll take a couple days off .... Naw but I will just go down to the studio, and yes I will say it....PLAY.

Terry
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#32 bciskepottery

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Posted 10 March 2014 - 09:42 PM

I have also found that it really pops on a surface when you paint white underglaze on first then the dark blue even though I use little loafers white stoneware it's not as white as it needs to be to really contrast with the dark blue.


Save yourself some money . . . apply a white porcelain slip over the Little Loafers and you can get all of your underglazes to look brighter. Less expensive than applying white underglaze as a base.

#33 Pugaboo

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Posted 10 March 2014 - 09:49 PM

Bcisk - I've never used a slip before how does it work?

I've thought about doing it I just haven't gotten around to studying the process. What little I do know is that if your slip and clay are not compatible the slip with flake or crack off. I haven't a clue yet as to how to know if your are doing it right. I'd also like to set a really dark clay and apply white slip over it and then carve into it but again haven't gotten to the point I even know how to begin... Can you recommend a book or video?

Terry
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#34 bciskepottery

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Posted 10 March 2014 - 10:08 PM

For use with Little Loafers, I slaked down a gifted bag of Highwater's Helios porcelain. I apply a thin coat with a hake brush to items while they are still on the wheel or at medium to leatherhard. I've had no problems with flaking or cracking off because the application is thin and the coating is applied when the wares are still damp. Basically, I dip the brush in water, then pick up some slip on the brush, then apply it to the wares. Think thin as in terra sig thickness. Don't confuse with thicker slips used for texture building like Steven Hill. I started doing this when I began working on the Chinese brush painting technique; LL was nice but we wanted something brighter.

For the kohiki slip wares I make (see my icon) I use a slip made from a recipe Akira Satake handed out:

Goldart, 3 lbs. (30%)
Kaolin - EPK, 5 lbs. (50%) [Akira also uses Grolleg or Tile 6 for a whiter slip and Helmar for woodfired items]
Custer Feldspar, 1 lbs. (10%)
Silica, 1 lbs. (10%)

Add about 4 to 4 1/2 quarts of water, stir, sieve, and enjoy. This makes a 2 to 3 gallon bucket full of slip.

I also apply that slip by hake brush to slabs, wares, either while still on the wheel or while soft to medium leatherhard. Let set up and carve away. On the avator, the clay body is Laguna's Dark Brown.

Or, add some oxides or mason stains to the slip, brush on, and carve to show the white clay body.

#35 Pugaboo

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Posted 11 March 2014 - 01:08 AM

Bcisk - Thank you so much! Next time I order some clay I will get a bag of Helios to try. I might even get a bag of a really dark clay to try and carve as well. If I can get the slip to work as you have instructed it could save me money and even offer additional creative methods for decorating my stuff.

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#36 Pugaboo

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Posted 28 March 2014 - 10:31 PM

I wanted to show everyone a drink carrier and tumbler set I made using Amaco Dark Blue. I am very pleased with the way it turned out especially after so many dismal or so so tests that I was not happy with. I painted the entire thing with 2 coats of Amaco LUG White underglaze then did 1 coat with Amaco LUG Dark Blue for the blue flowers and dots. I want to experiment with white slip as several have mentioned its cheaper than underglaze but white underglaze is what I had on hand. You can't see it in the picture but the inside bottom of each section is glazed with Coyotes cobalt blue glaze and it really sets off the blue flowers and dots.

I hope this gives those of you hope for Amacos dark blue LUG as you can see it CAN be a pretty blue.

Terry

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The world is but a canvas to the imagination - Henry David Thoreau

#37 clay lover

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Posted 28 March 2014 - 10:36 PM

Very cool!  was the carton done with stiff slabs?

  great design.



#38 Pugaboo

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Posted 29 March 2014 - 10:38 PM

Yes the carrier was made using slabs that I let set up until stiff. I sometimes roll slabs out and cut box "blanks" a bunch at a time and let them set up a bit then place thin sheets of plastic between them and slip a stack into gallon baggies for later use. I have stored unassembled boxes like this for up to a month before building the actual box. You can see more boxes I have done in my gallery. I think boxes are my favorite things to make right now. The handle is a fat extruded round bar that I rolled slightly to flatten it out a bit.

Terry
The world is but a canvas to the imagination - Henry David Thoreau




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