Jump to content
terraforma

The Holy Grail—A ^10 Clear Gloss Glaze Compatible With Amaco Velvet Underglazes?

Recommended Posts

Yes, I am tilting at windmills...

 

I've been doing tons of trials with Amaco Velvet underglazes to introduce some bright colors to my pieces, and I currently work only in cone 10 reduction. I know what I'm up against, but still I must persist. I apply the underglazes on leatherhard so that they will be bisque-hardened to better withstand cover glazing. Yes, most of the colors will not be true, but I've found many I like—without a clear glaze cover. What I need to find is a clear gloss cover glaze that will not completely alter so many of the colors. Amaco's own house brand has its problems, including the crazy price for enough glaze to dip pieces, (they offered no help "because we sell a clear glaze") and the best choice at my membership studio still transforms most of the colors, some into a completely different spectrum (see image).

 

Does anyone have a clear gloss glaze recipe with a better hope of allowing the underglazes to stay as true as possible in a cone 10 reduction kiln? When you stop laughing, I'd love to hear.

post-1160-0-62413200-1426964291_thumb.jpg

post-1160-0-62413200-1426964291_thumb.jpg

Share this post


Link to post
Share on other sites

Yes I have one that is clear and glossy-I am firing today a cone 10 glaze -I'll look it up and take a photo of its use for you. It is clear and I have used it for years (like 35-40) It best put on as a thin coat. If it bubbles rub them out. It does not crawl.

Good to see someone else  working in cone 10 reduction

I have used this mainly on porcelain bodies over drawings.I did post it once years ago but the folks who work in cone 10 here are few and far between ,but let me go get it from studio.

You will have to test the results over amaco underglazes as that is an unknown.

PS I'm not laughing at all-not if you asked for a clear matt that one is funny

Mark

heres some work  using this glaze covering a few decades-like the 70's and 80's-the clear is on Porc-fired to at least cone cone 9-10 reduction

This glaze is called

 

HT 51cone 9-10

Kingman feldspar(potash for those who do not have this spar)- 27

Ball Clay OM4                                                                              19.5

Whiting                                                                                         19.5

silica 325 mesh                                                                             34                            

post-8914-0-60486200-1426971671_thumb.jpg

post-8914-0-28610100-1426971680_thumb.jpg

post-8914-0-60486200-1426971671_thumb.jpg

post-8914-0-28610100-1426971680_thumb.jpg

Share this post


Link to post
Share on other sites

Yes I have one that is clear and glossy-I am firing today a cone 10 glaze -I'll look it up and take a photo of its use for you. It is clear and I have used it for years (like 35-40) It best put on as a thin coat. If it bubbles rub them out. It does not crawl.

Good to see someone else  working in cone 10 reduction

I have used this mainly on porcelain bodies over drawings.I did post it once years ago but the folks who work in cone 10 here are few and far between ,but let me go get it from studio.

You will have to test the results over amaco underglazes as that is an unknown.

PS I'm not laughing at all-not if you asked for a clear matt that one is funny

Mark

heres some work  using this glaze covering a few decades-like the 70's and 80's-the clear is on Porc-fired to at least cone cone 9-10 reduction

This glaze is called

 

HT 51cone 9-10

Kingman feldspar(potash for those who do not have this spar)- 27

Ball Clay OM4                                                                              19.5

Whiting                                                                                         19.5

silica 325 mesh                                                                             34                            

Thank you, Mark--that does look like a very nice cone 10 clear; there may have been a little confusion in my wording, but I'm hoping that someone has a clear glaze that they've experienced as working well specifically over the Amaco Velvet underglazes. I will keep this recipe to test, though.

Share this post


Link to post
Share on other sites

Great piece Mark. The brushed on work, reminds me of illustrations from old biology books, before photography became commonplace.

I made the pots not the drawings-I want to be clear on this point-they are collaborations.

The shell lidded piece is not mine at all it was made by another potter who long ago gave up clay.

mark

Share this post


Link to post
Share on other sites

I also fire cone 10 reduction and my black and white sgraffito pieces depend on a clear glaze. I sometimes use Amaco velvets for color, too, but my black slip is just Mason stain and my porcelain body. I'll try Mark's glaze recipe to see if I get truer whites and colors. Thanks for the question (and the answer!)

Share this post


Link to post
Share on other sites

It seems a shame to me that many potters have abandoned firing at 10 in reduction.  I did for many years, and only began to explore oxidation out of grim necessity.  The higher range has many benefits.

 

The only useful observation I can make is that in formulating a glaze for your purposes, avoid zinc.

Share this post


Link to post
Share on other sites

Most potters I know who make a full time living at clay all work in cone 10. I only know a few who fire to cooler temps like cone six and they do it in gas reduction kilns.I do know one who is low fire oxidation and has a combination thrown and bought bisque-ware firing in electric.

Mark

Share this post


Link to post
Share on other sites

I'm with you, Mark.  Steven Hill is firing at 6 now, but he's a god, so he can get away with it.  We mortals need all the help we can get.

 

But I should probably start another thread if I want to rant about this.

 

We have a little cabin up in the North Woods, and I've been thinking about building a kiln up there.  I might be too old for wood, but not for oil.

Share this post


Link to post
Share on other sites

I never want to be a god -but thats another rant.

I'm only aware of a few people doing cone 6 full time as potters (Mea here is one)but thats just in my small world or shows in 4 western states .

I know its it the thing in the hobby market and everyone talks about Steven Hills move to cone 6 but thats not in my world nor what I see on the street at my shows.

Nor is it moved into our local arts center which is cone 10 still. The University is low fire and high fire still as is our Junior collage which also does wood fire. 

I have yet to master much in life except I do have my cone 10 glazes down where disasters are very rare so when I have the dragon sleeping I see no need to wake him up and switch to cone 6 and suffer thru that learning curve. My customers would kill me I'm sure if the dragon did not.I have developed a market for this work over 43 years and when its working I see no good reason to save 20$ -30$ per fire.Cone 6 is just a point to get thru in my fires.I love reduction fire no mater what the process-salt-wood-gas-even raku in times long gone by.

Mark

Share this post


Link to post
Share on other sites

There's probably nothing magic about the high reduction fire... but it has always seemed to me that the mark of the fire is more apparent, and happy accidents more common in that range.  When I was a fulltime working potter, I tended to fire to 11, which might have been getting carried away.

 

Still, I think that if you're a good potter, your work will be good no matter what you fire to.  I'm a great admirer of the English slipware potters, for example. 

 

As I said, I should probably start a new thread.  I apologize to the original poster for the hijack.

Share this post


Link to post
Share on other sites

+1 for cone 10 reduction. Almost every single glaze I touch looks better in gas than electric. Ah, but electric kilns are so beautifully set and forget easy...

 

If I could only stop my come 10 reduction firings always sneaking up to cone 12!

Share this post


Link to post
Share on other sites

I'll be watching this topic because I rely on the Amaco Velvets for some pop on my stoneware. (I'm new here, and the small number firing at cone 10 has surprised me! :)

Share this post


Link to post
Share on other sites

only the opinion of a novice but i think the cone 10 potters are still working, they just don't bother with things like forums where people talk instead of do.

 

signed, the biggest talker of all

Share this post


Link to post
Share on other sites

 

 

Yes I have one that is clear and glossy-I am firing today a cone 10 glaze -I'll look it up and take a photo of its use for you. It is clear and I have used it for years (like 35-40) It best put on as a thin coat. If it bubbles rub them out. It does not crawl.

Good to see someone else working in cone 10 reduction

I have used this mainly on porcelain bodies over drawings.I did post it once years ago but the folks who work in cone 10 here are few and far between ,but let me go get it from studio.

You will have to test the results over amaco underglazes as that is an unknown.

PS I'm not laughing at all-not if you asked for a clear matt that one is funny

Mark

heres some work using this glaze covering a few decades-like the 70's and 80's-the clear is on Porc-fired to at least cone cone 9-10 reduction

This glaze is called

 

HT 51cone 9-10

Kingman feldspar(potash for those who do not have this spar)- 27

Ball Clay OM4 19.5

Whiting 19.5

silica 325 mesh 34

Thank you, Mark--that does look like a very nice cone 10 clear; there may have been a little confusion in my wording, but I'm hoping that someone has a clear glaze that they've experienced as working well specifically over the Amaco Velvet underglazes. I will keep this recipe to test, though.

hi! have you tested this yet? i, too, am searching for a clear for cone 10 reduction that doesn't severely alter my amaco velvet underglazes.

Share this post


Link to post
Share on other sites

Everyone I know IRL that works cone 10 reduction (myself included) doesn't use a clear glaze for any reason. Clears are more easily achieved at lower temperatures, and if you're firing that upper range it's because you're after a certain surface richness from the atmosphere, among other things. I'm positive it's doable, but most of us don't have one in our back pockets. It's not part of the usual visual canon, so to speak.

I do know that if you spend a bunch of time in the digitalfire materials section under stains, they have information about how to formulate a base glaze that won't turn your burgundy stain green. The information mostly applies to come 6, but if you email Tony Hanson, he's very good about helping you troubleshoot and direct your own inquiries.

Share this post


Link to post
Share on other sites

So good to see this topic, @terraforma.  I may be just a half-step ahead of you in the use of Amaco Velvets and clear glazing at Cone 10...and I'll be happy to share my clear, cone 10 recipe.  It is very similar to the one shared previously.  There are a few things that I discovered that are process related rather than being totally glaze dependent:

  • My experience with the Amaco Velvets is that most (except the reds/oranges) fire with a certain amount of sheen...(for a true red, I switch to Speedball brand)...so making them really shiny doesn't require a lot of clear glaze.
  • I stopped using underglaze on greenware and now apply it exclusively to bisque ware...and more often in two coats.  I'm thinking that too much material burns off even at bisque temps to retain color intensity...and that is what I am after as well.
  • If I really want the underglazes to pop, I will apply (i.e. brush/spray) a coat of white slip over areas that will receive underglaze at the early leather-hard stage.  Note: I use stoneware for most of my builds....the white slip is not necessary if you are using a white clay body.
  • MOST IMPORTANTLY...the thinner the coating of clear glaze, the more likely you are to avoid milky areas on top of your underglazes.  For that reason, I ruled out dipping and spray just enough so that the dried/applied clear glaze is still thin enough that I can almost see the underglaze like a shadow beneath the clear coat.

My next steps are to test blending of Amaco Velvets with an airbrush to achieve gradients (and with a clear glaze over it)...I'll know more after a late January reduction firing.

 

Peace,

-Paul

Share this post


Link to post
Share on other sites

Here is my recipe for Cone 10 Clear:
G-200 (Custer)......... 27.5
Whiting..................... 19.5
E.P.K......................... 20.0
Silica......................... 32.9
Bentonite.................... 1.0

 

Paul

Share this post


Link to post
Share on other sites

Hi all,

 

Thank you all for your recent comments. I'd like to find a clear glaze that works over Amaco Velvets because they are not considered food safe unless they are glazed over; and, because they mostly remain very dry matte in finish after firing, I assume that they can't stand up to the abuse that a functional surface might experience—silverware scraping, dishwasher abuse, etc. If I find this "holy grail" clear glaze, I can finally add some new color pop to the functional interiors of my pieces.

 

I tend to love dry matte finishes, especially including unglazed cone 10 stoneware (Black Mountain!!) and porcelain, but I would definitely love to offer more colorful functional pieces for that large segment of people that want them. Of course, I admit it will be fun for me, too, to have that fresh new palette to play with :):)

 

And my two cents about cone 10 reduction? The gorgeous range of glaze complexity and depth; the happy accidents (especially if they outnumber the unhappy accidents that are all too frequent...); the earthiness and complexity of various unglazed stonewares coming out of the fire; the durability and bell-ringing quality of the highly vitrified ceramic. Of course, I fire at cone 10 also because it is what all of my membership studios have used, as well as the colleges where I took my original ceramics classes. The thought of firing a cone 10 gas kiln myself if/when I finally have my own private studio is, quite frankly, more than a little scary—not to mention the prohibitive cost! When I find that studio, I may dabble in some mid-range firing with the electric kiln I will get, but the majority of my work will still be transported to my favorite cone 10 membership studio for firing.

 

coffeecupsandcuriousities: I haven't yet tested any of the glaze recipes mentioned in this post—I've been absorbing the information coming in. In the new year, I will try the two recipes provided and share pics/info about them.

Mark C: Thanks for the formula! I will try soon as I mentioned above.

Elaine, Humboldt Potter: did you try that recipe yourself yet?

Rayaldridge and Chris Campbell: thank you for mentioning some ingredients to avoid.

and Paul, ChenowithArts: thank you for all of your recommendations and for your formula, which (as mentioned above) I will test and share results of as soon as I can manage in this new year!

Share this post


Link to post
Share on other sites

Terraform a

Thank you for the follow up

It's a rare thing for posters to follow up and it's good to know that you read the suggestions.

So many times I never know if the poster even read or tried any of the suggestions

Thanks for the follow through

Share this post


Link to post
Share on other sites

Hi @terraforma, how did you go with the testing? I would love to know as this is exactly the same problem I am experiencing now:) I am using Amaco Underglazes and they often bleed and run, so I am trying to find a clear glaze that will fit properly with it. I fire to cone 9-10

Share this post


Link to post
Share on other sites

I test the stains and colorants I want to use with my clear glazes by dipping a piece halfway down with the clear, painting a stripe of color (I usually mix colorants into the base glaze) on the vertical surface (outside of a flawed bowl or cup), then dipping the remaining half of the piece in the clear, leaving 1/4" of the pot without the any glaze over the colorants. Some colors look better above the glaze. 

Try mixing the velvets with a little of  your clear candidates if the clear doesn't change the color. I use a variant of a basic ^10 clear glaze and find the velvets will try to be matte but will gloss over with a little extra of the clear in it. 

GZ Clear ^10 R

60 - Silica

60 - Custer Spar

40 - Whiting

40 - Ball Clay

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use.