Crooked Lawyer Potter

What are the characteristics of a liner glaze? Does the term simply denote its position and function in the interior or are there certain qualities distinct from regular glazes?

Gonna try the higher bique and see what happens. I'll let you know.

I got the Leach glaze from Vaughn Smith. Its works beautifully for me (other than this issue)

Callie Yes the kiln is vented. I have always bisqued to cone 06 but changed just recently to 08, just to see if it made a difference in the glaze take-up. I think the current problem appears in both instances -- cone 06 and cone 08 but I am going to make sure by further experiment. Thanks for your input.

No differences. Mugs (and other pots) are dipped using tongs. First glaze (ash) is allowed to dry before 2nd dip in David Leach II.

I need help figuring out this glaze defect. I've gotten these mugs just where I want them except for this issue. The defects do not appear anywhere except in the interior of mugs or glasses. So, for instance, it is never a problem with plates or bowls. I'm thinking it must be related to the different conditions that arise in the tight confines of the mugs interior (higher heat, perhaps?). The mugs are dipped first in an ash glaze, allowed to dry, and then second dipped in David Leach II. The ash glaze is 50% ash, 50% red slip. David Leach II is : potash feldspar 45 dolomite 15 frit 3124 5 EPK 15 Silica 10 Talc 10 colorant (iron ochre, or copper carb, or cobalt carb) The clay is Laguna WC436. Its an oxidation firing in an electric kiln at cone 6 with a slow cool. The bisque was to cone 08. Anyone have any ideas as to what is going on here? (The hole looks to me as if it goes all the way to the clay.)

Will take this to heart. I love pottery but it does not match well with my congenital lack of patience.

Curious about this idea. I DO often start up the kilnfiring without letting the glaze get good and dry, but I always start the fire program with a 2 to 5 hour pre-heat that I assumed would take care of the issue. What do you think?

I may have asked this before, but this business of "viscosity v specific gravity v deflocculation" keeps me in a state of confusion. For instance, if I want to "thin" the glaze I could: (1) add water - thereby thinning it and lowering its SG, or (2) deflocculate itthereby thinning it but keeping its SG the same, right? Is there a reason to do one over the other? And, is "thinning" it the same as making it more "viscous"?

So ... lower the viscosity? or lower the SG? Or a quicker dip?

What do you call this glaze defect? Bisqued at 06, electric fired at 6. Long dip of Fat Cream with an ash glaze rim. BMix. It seems to happen randomly.

Listmates I've have some pit-fired cruets that I want to use as olive oil containers. I know that the relatively low firing temp means they are not fully waterproof so I have treated the inside with a stone sealer that is labeled "non-toxic" and "safe for food preparation areas". Any thoughts on whether this is safe for the intended use? And how does one go about getting such a determination? Are there labs that will test it?

A picture is worth a .........

I'm a sucker for a system. I did not like having to carefully fill those skinny beakers to the 100 g line and then weigh, rinse out, etc. I had this 80 g syringe in my studio so I weighed it empty and noted the result (28g). Then I prepared a chart in Excel that worked out all the SG numbers between 1.0 and 1.75 and stuck on the studio wall so that all I had to do to test SG was to draw glaze into the syringe to the 50 g mark and then lay it on the scale. I then looked at the chart to see the corresponding SG. Sounds complicated I know but its really simple once done and very handy. It looks like this: Scale says: Less 28g (syringe) X2 =SG 99 71 142 100 72 144 101 73 146 etc all the way from 100 to 175

Got ya

Again, my bad. Careless response. I just meant that when i weigh the syringe, the scale is tared to zero. In other words, the reading i get is the weight of the syringe and its contents. And since i know (or thought i knew) the weight of the syringe, i subtract the syringe weight to determine the weight of the 50g of terra sig in the syringe.

Yes i tared the scale.

Mystery solved! I weighed the syringe again and found the error. I had recorded its weight as 28g but its actually 23g and a re-weigh of the full syringe was 75g this time not 70 as before. So, 75 less 23 is 52 x 2 is 104. Thanks to you all for your input. I'm going to assume that SG cant be less than 1 after all.

Yes. I'm not doubling 70. I take the reading of 70 and subtract the weight of the syringe. I then double that number. (42x2=84)

Will do.

Correct. My error.

I draw 50 ml of the terra sig into my syringe and weigh it. It weighs 70 mg. I subtract the weight of the syringe (28mg) and then double the number, as in: (70 - 28 = 42) x 2 = 84

Min Good point. But consider -- this is just the smallest (and presumably lightest) elements of the ball clay.

You would think that a lawyer could communicate better than i have here. I meant to express that my musings about “tiny platelets” was just the uninformed ramblings of a non expert and should not be taken as authoritative. Instead, i just came off sounding like an ungrateful ########. My apologies to those who were offended by my careless language.

I may be misreading your answer, but wouldnt that result in a solution that is 140 grams, of which only 40 grams are ferric chloride? Is that a 40% solution or a 35% solution? (140/40=35). Perhaps this as simple as Chilly suggests above -- 40 grams of FC and 60 grams of water.