Rex Johnson Posted August 16, 2018 Report Share Posted August 16, 2018 I'm buying some Laguna ^6 engobe to use over Laguna B-mix and others to use as a white background for the ware. Looking for the white-est I can get, as B-mix is sort of buff-ish when fired even in oxidation. Question is, should I coat the ware before or after a bisque? I also bought some Laguna ^6 whote slip to experiment with as well. I'm also wondering how either will work if spraying as opposed to brushing.... Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 16, 2018 Author Report Share Posted August 16, 2018 Where's all my Pros?... Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted August 16, 2018 Report Share Posted August 16, 2018 Having learned the hard way, when I have multiple options, such as the ones you have mentioned, I plan to test each way and do a careful evaluation of the outcomes to see if the final results are justified by the 'extra' efforts of each pathway. My experience has been that such a protocol provides more information about outcomes; and that 'extra' information will be useful in later situations. That said, I have found that application of commercial coatings such as engobes and underglazes prior to a bisque fire results in better adherence of the coating to the substrate. If I am applying decorative underglaze to bisque ware the ware is bisqued (again ) prior applying glazes. LT Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 16, 2018 Author Report Share Posted August 16, 2018 Hmmm...well basically I'm trying to whiten the body so that I can have at it with undergalzes and glaze pencils and so the final result doesn't show the ugly clay color at the end. I intend to, for instance, spray or coat the insides of vessels with a clear gloss. That glaze over B-mix body is very bland in color. I get the testing part for sure. From what I'm reading in one article engobe is best applied over leather hard clay. Having said that, my stock of thrown pieces are all bone dry now. The CAW article gives me promise saying it can be applied brush or spray at any stage: "...an engobe can be formulated for use at any stage, including over bisque-fired ware. Engobes also often are used without a covering glaze, giving a wider potential for experimentation with the surface. An engobe or underglaze is more like a glaze in structure and may contain very little plastic clay. " Link to comment Share on other sites More sharing options...
Dick White Posted August 16, 2018 Report Share Posted August 16, 2018 Yes, "...an engobe can be formulated for use at any stage..." but the formulation is usually different for the different stages. Engobes formulated for use at one particular stage may or may not work when applied to ware at a different stage. Read the instructions that are provided with that particular commercial product and follow them. Link to comment Share on other sites More sharing options...
preeta Posted August 16, 2018 Report Share Posted August 16, 2018 If you want WHITE then use porcelain casting slip that you can dip into right after trimming. Though if you really want WHITE Use a white underglaze. Nothing in my experience will get you white under clear like underglaze. You are not going to see too much difference with engobe. Under clear it does not retain that white. Neither does Dave’s or Tom’s porcelain under clear. But white underglaze under clear remains white. Why are you getting both? To experiment? So the slip/engobe will act as a canvas right? If you are using underglaze to draw and watercolour then the engobe/slip raw layer is fine. However if you use pencils I am not sure if you will like the quality of marks. I played with hard Oxide hard pastels in spring and I had to have a bisque surface underneath to get the kind of line quality I wanted. Otherwise the slip came off or wouldn’t record a line. I think of engobe sorta as a glaze. Use both on bisque and raw. But slip only on raw. If I use engobe on bisque I like to fire it to 04 before glazing as I have not liked the way raw engobe looks under glaze. Link to comment Share on other sites More sharing options...
Min Posted August 16, 2018 Report Share Posted August 16, 2018 @Rex Johnson, I seem to remember you high fire? If this is correct you could try Daniel Rhodes engobe for dry clay, his high fire version. ^ 6-11 engobe Kaolin 15 (no specific type given but if you want white I would use grolleg or halloysite) Ball clay 15 (cleanest one you have) Calcined Kaolin 20 Feldspar 20 (no specific type given) Silica 20 Borax 5 (I would dissolve this in hot water before adding to the mix) Zircopax 5 (I would bump this to 10) 100 (105) I would just make up what you can use in a short time as the borax is soluble and likely to crystalize over time. If you get hard little bits in the engobe sieve them out and remelt them with a bit of water in the microwave and add back into the engobe. Another option is to use Fish Sauce Slip. It will be cleaner than the above recipe as it doesn't contain ball clay. Recipe below is what I've modified the original one from (it used bentonite which can be dirty) It can be used on bone dry but don't put it on too thickly. I would also suggest wiping your pots down with a damp sponge before applying the engobe or slip. Fish sauce slip altered ^04 - 10 Minspar 27.5 Grolleg 40.7 Pyrophyllite 8.5 Silica 17 Macaloid 6.3 (sometimes called Bentone MA) Zircopax 10 110 If neither are white enough then bump the zircopax to 15. Link to comment Share on other sites More sharing options...
oldlady Posted August 17, 2018 Report Share Posted August 17, 2018 "bone dry" does not mean permanently dry. if you just very quickly dip the piece in a large enough container to allow it to get totally wet and pull it out instantly, it will survive the dunking. the pot can be made damp enough and if you let it sit covered for awhile, you have a perfectly ready piece so it can accept a clay based covering, or slip. i do not understand why potters do not do the simplest test of their clay body, dunking it in water when dry. if you dunk and scrape a little off and repeat this until the test is finally wet enough to disintegrate you will learn a great deal about your particular pots, your thickness, clay density, etc. very basic info that hardly anyone tests to learn. Link to comment Share on other sites More sharing options...
Hulk Posted August 17, 2018 Report Share Posted August 17, 2018 "Lucky" for me, I'm still not up on the electrician's list (60 amp circuit), hence a new round of culls - into the slop bucket w'ya - is required to make space for new makes; I'm coming around to it being a good thing, especially now that the local JC semester has started, hence I'll be able to fire for the next four months. I'm breaking them up before and/or during the slaking, finding more thick spots than thin, that burnished clay resists water much longer, and that my foot trimming approach needed mods. I'm using speedball underglaze at bisque stage, seems to work just fine, dries quickly, nice colours. Also experimenting with slip (blend, then sieve ^6 clay) at leather hard, where I've found that thin slip brushes on ok, but has too much water to dip into or pour in/out. After settling and removing some water, it can be applied thicker-ly... I've added water to dry-ish pots to facilitate burnishing only, will try your tip Lady, thanks! The engobe the JC carries is for leatherhard stage only. Down the line, sure I'll be interested in trying some slip recipes... Also lucky for me to have found this forum, great resource. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted August 18, 2018 Report Share Posted August 18, 2018 If you want to dip pots into slip while they're in the leather hard stage, it's a good idea to deflocculate the slip: all of the fluidity with a quarter of the water. I mix up an ice cream bucket of slip and add a drop or two of Darvan.. Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 20, 2018 Author Report Share Posted August 20, 2018 On 8/16/2018 at 3:34 PM, preeta said: If you want WHITE then use porcelain casting slip that you can dip into right after trimming. Though if you really want WHITE Use a white underglaze. Nothing in my experience will get you white under clear like underglaze. You are not going to see too much difference with engobe. Under clear it does not retain that white. Neither does Dave’s or Tom’s porcelain under clear. But white underglaze under clear remains white. Why are you getting both? To experiment? So the slip/engobe will act as a canvas right? If you are using underglaze to draw and watercolour then the engobe/slip raw layer is fine. However if you use pencils I am not sure if you will like the quality of marks. I played with hard Oxide hard pastels in spring and I had to have a bisque surface underneath to get the kind of line quality I wanted. Otherwise the slip came off or wouldn’t record a line. I think of engobe sorta as a glaze. Use both on bisque and raw. But slip only on raw. If I use engobe on bisque I like to fire it to 04 before glazing as I have not liked the way raw engobe looks under glaze. I'll admit I am shortcutting due to how much time I get in the studio. In a few weeks I;kk have al my making complete and pieces will be absolutely dry and ready for the biscuit. I bought both try and cover my bets on trying to turn buff clay colored pieces into white canvases. I'd prefer to spray rather than dip. Both for consistency and lack of volume required to dip pieces. If I can spray pre-bisuqe slip, great. I'll see howe it takes to the clay, see if it shivers at all. If not good. Otherwise I'll try the engobe on bisque. It appears it's too late to engobe leatherhard pieces that have already dried, but I can try it on the next making session. https://digitalfire.com/4sight/glossary/glossary_engobe.html Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 20, 2018 Author Report Share Posted August 20, 2018 On 8/17/2018 at 8:16 AM, Hulk said: "Lucky" for me, I'm still not up on the electrician's list (60 amp circuit), hence a new round of culls - into the slop bucket w'ya - is required to make space for new makes; I'm coming around to it being a good thing, especially now that the local JC semester has started, hence I'll be able to fire for the next four months. I'm breaking them up before and/or during the slaking, finding more thick spots than thin, that burnished clay resists water much longer, and that my foot trimming approach needed mods. I'm using speedball underglaze at bisque stage, seems to work just fine, dries quickly, nice colours. Also experimenting with slip (blend, then sieve ^6 clay) at leather hard, where I've found that thin slip brushes on ok, but has too much water to dip into or pour in/out. After settling and removing some water, it can be applied thicker-ly... I've added water to dry-ish pots to facilitate burnishing only, will try your tip Lady, thanks! The engobe the JC carries is for leatherhard stage only. Down the line, sure I'll be interested in trying some slip recipes... Also lucky for me to have found this forum, great resource. I have a new set of the Speedball underglazes to play with when everything is bisqued... Link to comment Share on other sites More sharing options...
preeta Posted August 21, 2018 Report Share Posted August 21, 2018 Rex I was once playing with a cracked surface. So I know even thin layer of slip will crack (if not fall off) on bone dry clay. Depending on the formulation as earlier pointed out engobe might not crack on bone dry. I have not tried engobe so I am not sure about it. Also check your underglazes. Will they allow on leather hard? I like most of my work done in the leatherhard stage. As bisque I like the option of another layer, some touch up. But my dark colours I prefer greenware so they don’t bleed into the clear or white (black can show blue) I’m excited for you. I love experimenting and getting to know my materials. Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 30, 2018 Author Report Share Posted August 30, 2018 I'm wondering, maybe I should bisque and then spray my engobe and re-bisque for a hard surface to draw/paint on... On those Speedball underglazes, do the mix color-wise like paint. I have white, black, blue, yellow, red, orange. Can I mix blue/yellow and get green? Even my painter wife wants to know... Link to comment Share on other sites More sharing options...
neilestrick Posted August 30, 2018 Report Share Posted August 30, 2018 3 minutes ago, Rex Johnson said: I'm wondering, maybe I should bisque and then spray my engobe and re-bisque for a hard surface to draw/paint on... On those Speedball underglazes, do the mix color-wise like paint. I have white, black, blue, yellow, red, orange. Can I mix blue/yellow and get green? Even my painter wife wants to know... You can mix colors to tint them but true color theory like blue+yellow=green doesn't always apply, since many colors are much stronger than others. Blue and black, for instance, tend to overpower other colors. Also, sometimes the color mixed color changes when you fire them due to the chemistry of the colors and how they behave together. Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 30, 2018 Author Report Share Posted August 30, 2018 That's what I thought but hoping they might be formulated to respond. As far as a clear overglaze, it looks like Speedball recommends their own S2000 high fire clear. Only drawback there is, it's only sold in pints...hobbyist size. I'd need a gallon. or just go with what I have, a John's Clear or a copper clear I have on hand which I used last year as a general gloss... Link to comment Share on other sites More sharing options...
neilestrick Posted August 30, 2018 Report Share Posted August 30, 2018 @Rex Johnson I'd test your clears before investing in pints. I've used several different clear glazes over Speedball underglazes and they all worked fine. Link to comment Share on other sites More sharing options...
Rex Johnson Posted August 31, 2018 Author Report Share Posted August 31, 2018 Reading around more on this and trying to mitigate a complete disaster, there is stuff about compatability (COE?). These are the three materials I'll be working with. I jope I am close... B-MIX ^10 shows: Avg. Shrinkage 2±% 13.0% Avg. Water Absorption 1±% 1.2% COE x 10-6: 5.2 S3128G ^5-^8 Glacier White casting slip: Avg. Shrinkage 2±% 14.5% Avg. Water Absorption 1±% >0.25% COE x 10-6: 6.04 MS-200 ^5 Dune White ENGOBE (no calcs) Link to comment Share on other sites More sharing options...
Rex Johnson Posted September 4, 2018 Author Report Share Posted September 4, 2018 Well I tried spraying and brushing the S312G slip on various Laguna bodies both on bone dry and leather hard pieces and they all seem to have taken it together well. Biscuit firing in a couple weeks. I'll keep you posted... Link to comment Share on other sites More sharing options...
Rex Johnson Posted October 2, 2018 Author Report Share Posted October 2, 2018 Spraying this Laguna porcelain white slip has been a cinch. Only flaked a bit on a few pieces where it went on too thick. I've bisqued all my pieces. I'm going to do a test fire (1) to check the Speedball underglazes and ceramic pencil with/without a clear cone 6 glaze over. That said, other than Laguna John's Clear which I'm not crazy about, I'm still looking for a really glossy clear cone 6. As usual, I'm in a rush.... Link to comment Share on other sites More sharing options...
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