Ben xyz Posted February 6 Report Share Posted February 6 Have recently been working with Amaco's velvet underglazes, with clear gloss over some areas of decorative plates and other areas left matte (cone 5). Amaco had previously informed me that they had not done any tests with their velvet underglazes if left matte/velvet and could not vouch for the velvet finish being archival. These are purely decorative plates btw, not used with food. There appears to be only one glaze (out of Australia) that can be used as a matte sealer which does not visually alter the original surface. Unfortunately, it's only sold in large quantities and quite expensive to ship. Thankfully a spray booth has recently been set up at the studio, which will enable me to try out clear matte/velvet glazes, with as few coats as necessary, since they usually become cloudy and lighten the underglaze colors they're applied over. Any success with clear matte glazes (without fogging) at cone 5? Would like them to become archival. Thanks! Attached below: Circle designs have clear gloss glaze over them, with velvet matte surface on the rest. Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 6 Report Share Posted February 6 (edited) Hmm, I don’t not know if I fully understand. Underglazes are not glaze and often consist primarily of clay and stain. Many do not really melt so unglazed they are very matte but more sintered than melted hence durability or longevity would be difficult to guarantee. For a gloss finish it’s common to apply clear gloss glaze over the underglaze. For matte appearance with reasonable durability it’s also common to use matte clear glaze over the top of the underglaze. Any clear matte will cloud to some extent because of the diffraction of light. Thin application definitely better than thick as far as glaze clarity. As far as a glaze that works for you and your clay and the desired finish you will likely need to test. If you look on Glazy.org Marcia’s matte https://glazy.org/recipes/19734. Was created to be very dry ( but easily adjustable) and melt over fairly heavy underglazes. It has great reviews, but it may not work for your clay, desired aesthetic, etc…. Sadly clear glazes often tend to take testing to meet an artists needs. There are many matte glaze recipes though - which one works for you will require testing. Edited February 6 by Bill Kielb Ben xyz 1 Quote Link to comment Share on other sites More sharing options...
Kelly in AK Posted February 6 Report Share Posted February 6 It’s not for food. Liquitex matte medium, a room temperature finish, may fit the bill. It’s UV protectant. Produces a satin finish. Reliable and long lasting. Your fired pieces should be archival without that though. Ben xyz, Callie Beller Diesel and Min 3 Quote Link to comment Share on other sites More sharing options...
Hulk Posted February 6 Report Share Posted February 6 Archival, just checking... From Utrecht Art Supplies document, "Just for Fun: What does 'Archival' Mean?" "When artists say 'archival', usually they really mean 'durable to the standards of permanent art.'" Ben xyz 1 Quote Link to comment Share on other sites More sharing options...
oldlady Posted February 6 Report Share Posted February 6 (edited) during the 1990s, i made some bluebird hanging ornaments for a fair. they were cut with a cookie cutter and the bottom half was done with only red Velvet underglaze. the top half was dipped into a blue glaze. i still have one or two of them and there has been no change in them. they do get dirty and i can wash them but still no color change. Edited February 6 by oldlady add Ben xyz 1 Quote Link to comment Share on other sites More sharing options...
Ben xyz Posted February 7 Author Report Share Posted February 7 Thanks for suggestions! May go in w/ a couple buddies for this product: https://madeofaustralia.com/liquid-quartz/ It is a food safe, permeating sealer designed for use on unglazed ceramic ware, rendering it waterproof, stain resistant, & yet completely unchanged in appearance. Liquid Quartz can be applied to all unglazed, stable, porous surfaces; bisque ware, vitrified ceramic ware (yes it is still porous) & alternatively fired clay bodies (pit, smoke, saggar, barrel, naked raku) to create an invisible, long lasting, protective barrier against moisture, food juices, & other contaminants. Made from SiO2 (or Silicon Dioxide/Silica), a naturally occurring oxide & one of the most abundant minerals found in the Earth’s crust, most commonly in the form of Quartz. It is used extensively in the production of glass, glazes, underglazes, clay body stains as well as terracotta, earthenware, stoneware & porcelain clays. It is highly abrasion resistant (7 on the Mohs scale) & thermal shock absorbing. Quote Link to comment Share on other sites More sharing options...
Min Posted February 7 Report Share Posted February 7 There is a thread link below about Liquid Quartz with another link within that thread with more discussion on it. https://community.ceramicartsdaily.org/topic/30248-liquid-quartz/ What was the definition for archival from Amaco? Seems odd that they market their velvets for use with or without a covering glaze but could not say the velvet finish was archival. Ben xyz 1 Quote Link to comment Share on other sites More sharing options...
Ben xyz Posted February 7 Author Report Share Posted February 7 2 hours ago, Min said: There is a thread link below about Liquid Quartz with another link within that thread with more discussion on it. https://community.ceramicartsdaily.org/topic/30248-liquid-quartz/ What was the definition for archival from Amaco? Seems odd that they market their velvets for use with or without a covering glaze but could not say the velvet finish was archival. Thanks for link. I agree with you, Min - thought it odd as well. Why use the description 'velvet' when it can't really be used in that form? Being the priciest of underglazes, I had hoped they would have better customer support. It's possible that the answer is 'not archival', but they didn't want to say. According to Amaco, they didn't bother testing them out in their velvet form, because they're intended to be only under another glaze, end of story. Quote Link to comment Share on other sites More sharing options...
Min Posted February 7 Report Share Posted February 7 Ben, have you seen the work of Jeffery Nichols? He uses unglazed Velvet underglazes on the outside of his pots. Might be worth trying to contact him and asking if he has any research or further info on the durability of unglazed Velvets. Logically they are similar to a highly pigmented stained slip, just with less clay and more flux. https://ceramicartsnetwork.org/daily/article/The-Twenty-Year-Teapot-A-Potter-Discusses-the-Lengthy-Process-of-Developing-His-Voice-in-Pottery-and-Shares-His-Teapot-Making-Technique-Too Pots by Jeffery Nichols Ben xyz 1 Quote Link to comment Share on other sites More sharing options...
Ben xyz Posted April 22 Author Report Share Posted April 22 Thanks Min for the link. Nichols did say: "After firing, I coat the underglaze surface with a food-safe oil sealant (like Salad Bowl Finish, available from home centers) and wax used by woodworkers. This seals the outside surface and makes it fairly durable, but check the instructions on the containers for care and use of these products." Doesn't seem like it would be a very durable surface for something that holds heat, like a teapot, but it seems to work for him. "Fairly" might be the key word there. I would guess the underglaze color would change/deepen with the application of anything oil-based (which may be desired). A UV blocking spray might be helpful for non-utilitarian objects, if it's permanent. I may still contact Nichols about his ongoing experiences with underglazes, since Amaco does not fully know about their products. Likely having a clear glaze coating would legally leave them off the hook for any food safety issues and possible leaching chemicals. Quote Link to comment Share on other sites More sharing options...
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