AdamFG Posted December 12, 2020 Report Share Posted December 12, 2020 Hi All, Continuing on with my adventure of being "self taught"... I have another question I have some lovely coloured stain powders and I really like how they've gone onto bisqueware. I've just mixed them with water... however when I've glazed the pieces with clear glaze, the items have all suffered with crawling. As I understand it, i'll need to add some grit to the stain to stop this. However, I'm wondering if I apply the stain (just mixed with water) onto bisque ware and fire to 1000.c then apply a clear glaze and fire again will this remove the need to add frit? Stains are being applied to Earthenware which fires to 1080c and Stoneware which fires to 1220-1240c I'll be making an order for some more supplies on Monday so I can get any additives (for want of a better word) suggested, but the delivery times here are nuts due to Covid and Christmas so it may be a couple of weeks I know the answer will be "run a test", which I plan to do but I was wondering if anyone had any anecdotal advice / experience with using stains like this? Thanks again! Adam Link to comment Share on other sites More sharing options...
Sorcery Posted December 12, 2020 Report Share Posted December 12, 2020 2 hours ago, AdamFG said: I've just mixed them with water... however when I've glazed the pieces with clear glaze, the items have all suffered with crawling. As I understand it, i'll need to add some grit to the stain to stop this. However, I'm wondering if I apply the stain (just mixed with water) onto bisque ware and fire to 1000.c then apply a clear glaze and fire again will this remove the need to add frit? Isn't paragraph 2 questioning if paragraph 1 works? Some clears may have enough flux to work. Stains are quite refractory, too much in my Local Clay Glaze and they don't melt properly. Sorce Link to comment Share on other sites More sharing options...
JohnnyK Posted December 12, 2020 Report Share Posted December 12, 2020 I've read before that adding 50% Gerstley Borate to the mix with H2O will help...I've also learned that putting a commercial clear over red iron oxide and firing to ^06 has some interesting results... Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted December 12, 2020 Report Share Posted December 12, 2020 If you want the simplest and easiest homemade underglaze recipe, mix your stain with equal parts of EPK and frit. So that’s a 1:1:1 ratio. Bonus points if the frit you’re using is also one of the fluxes in your glaze, but it will all work. reasons for those ingredients: The frit helps bind the sometimes very refractory stains to the pot, and the clay is an extender. Stains can be expensive, so the clay is just there to extend the recipe and help make it more brushable. Edited to add: You will still get a saturated colour if you keep the clay to this level. I have used gerstley borate to mix stains in. It makes a preferable brushing medium, but it will also alter the colour of some stains, so test a bit first. Link to comment Share on other sites More sharing options...
Min Posted December 12, 2020 Report Share Posted December 12, 2020 It's not going to make any difference if the stain alone is fired onto the pot prior to glazing, stains have been fired in their processing so refiring to bisque temps isn't going to change anything. Another reason it's good to add kaolin to the frit plus stain mix is the clay (kaolin) helps prevent the frit plus stain from dusting off the pot, especially when being handled. BTW I've noticed that in England there are also "underglaze colour stains" available in addition to stains alone. If you by chance have some underglaze stains then all you need to add to them is a brushing medium. Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 12, 2020 Report Share Posted December 12, 2020 All solid advice. Think if it this way, colorants have existed forever and are often oxides. Stains generally contain those oxides or a mix of them to establish a color and are often encapsulated in some fashion to preserve the color from dissolving and / or changing significantly in heat of the firing. Underglazes are often made with stains and contain some clay. When clay is bisque fired it sinters and becomes more sturdy to handle but still remain porous. Adding clay and flux(Fritt) to stains is basically a way to make underglaze which when bisque fired will become sintered and sturdy to handle. Think of the clay addition as a binder that helps keep it stuck to the pot during application .......... and once bisque fired makes it impervious to water and reasonably sturdy on the pot ready for over decoration. Link to comment Share on other sites More sharing options...
Babs Posted December 12, 2020 Report Share Posted December 12, 2020 All of the above and some stains, a blue I have, need more frit to meld with the glaze or it remains rough. Link to comment Share on other sites More sharing options...
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