GreyBird Posted April 5, 2017 Report Share Posted April 5, 2017 Hi, When a recipe's parts add up to 100%, does it matter if you use 1/4 cup scoops or should you always measure out the parts by weight? Thanks, -Mary Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted April 5, 2017 Report Share Posted April 5, 2017 It is safe to assume that glaze recipes are based on parts by weight unless they are explicitly stated as parts by volume. LT Link to comment Share on other sites More sharing options...
GreyBird Posted April 6, 2017 Author Report Share Posted April 6, 2017 Ah, this could be why none of my glazes came out right. UUgggghhhhh. I mixed 4 whole buckets. what a waste. Link to comment Share on other sites More sharing options...
jrgpots Posted April 6, 2017 Report Share Posted April 6, 2017 You could find out what a cup of each of your ingredients weighs, then multiply the # of cups by each individual weight. You would have what is in each glaze by weight. At that point you could add ingredients as needed to get it to the desired recipe. It's work, but the 4 buckets of glaze material could be salvaged. Jed Link to comment Share on other sites More sharing options...
Guest Posted April 6, 2017 Report Share Posted April 6, 2017 Digital scales are cheap, if you want accuracy that's the way to go. Link to comment Share on other sites More sharing options...
GreyBird Posted April 6, 2017 Author Report Share Posted April 6, 2017 Oh, great Idea. Thanks! I will try that. and do test tiles this time instead of ruining a whole kiln load of pieces... I am new at this Link to comment Share on other sites More sharing options...
GreyBird Posted April 6, 2017 Author Report Share Posted April 6, 2017 OK, so I have two digital scales... One I got a long time ago for making glazes and one I got more recently for weighing my parrots. I weighed out the ingredients of the glaze below which I got from the "Mastering Cone 6 glazes" book. The first weighing I noticed the ceramics scale was not zeroing out the same each time so I redid the weights with the parrot scale which seamed to be more consistent. Surprisingly there is no difference in the weights of all of the ingredients except for the rutile. According to my numbers below, since there is 71% more Rutile than there needs to be I just need to add 1.8 x the amounts used of each of the other ingredients to correct the batch. Does this look right to you guys? Waterfall Brown: Ferro Frit 3134: 33.5 1/4 cup = 2.5 oz so 1.8 x 33.5 = 60.3 oz Ferro Frit 3195: 26 1/4 cup = 2.5 oz so 1.8 x 26 = 46.8 oz OM-4 Ball Clay: 17 1/4 cup = 2.5 oz so 1.8 x 17 = 30.6 oz Silica: 23.5 1/4 cup = 2.5 oz so 1.8 x 23.5 = 42.3 oz Red Iron Ox: 12.5 1/4 cup = 2.5 oz so 1.8 x 12.5 = 22.5 oz Rutile: 1 1/4 cup = 3.5 oz ​I'm not very confident with my math, maybe I should just cut my losses and start over Link to comment Share on other sites More sharing options...
Guest Posted April 6, 2017 Report Share Posted April 6, 2017 Stick with grams instead of oz or cups. The more weight conversions you make the more chance of an error. Weigh out each ingredient separately then transfer them into the bucket with the other chemicals one at a time. Link to comment Share on other sites More sharing options...
GreyBird Posted April 6, 2017 Author Report Share Posted April 6, 2017 Will do, thanks Ron. Link to comment Share on other sites More sharing options...
Guest Posted April 6, 2017 Report Share Posted April 6, 2017 You're overthinking this. Keep it simple Ferro Frit 3134: 33.5 grams Ferro Frit 3195: 26 grams OM-4 Ball Clay: 17 grams Silica: 23.5 grams Red Iron Ox: 12.5 grams Rutile: 1 grams Total 100grams times 10 for 1000 grams Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted April 6, 2017 Report Share Posted April 6, 2017 There really should be a difference in weight. I don't think clay should weigh anything like silica or frits by volume. The problem with scoops is they are inaccurate, If the weights were right and you retotaled the oz values into 100 then you could probably in theory work out what you need to add. That guessed recipe might not even match to what you actually scooped in. I worked out from your weights you have double the rutiile in the recipe or 195% Link to comment Share on other sites More sharing options...
GreyBird Posted April 6, 2017 Author Report Share Posted April 6, 2017 Hi Ron, the thing is what I was trying to do was to fix what I already had as Jed had suggested. So since I started with a 1/4 cup scoop as measure I had to start from there but I have decided to keep it simple after all and start over. This way I know they will be correct. Thanks! -Mary You're overthinking this. Keep it simple Ferro Frit 3134: 33.5 grams Ferro Frit 3195: 26 grams OM-4 Ball Clay: 17 grams Silica: 23.5 grams Red Iron Ox: 12.5 grams Rutile: 1 grams Total 100grams times 10 for 1000 grams Link to comment Share on other sites More sharing options...
neilestrick Posted April 7, 2017 Report Share Posted April 7, 2017 Each material has a different weight per unit of volume. A cup of frit is about 300 grams. A cup of silica is slightly more. A cup of EPK is only about 125-150 grams. Plus if you go by volume, the amount of material actually present in a scoop will be different each time due how tightly packed the material is in the scoop. Do everything in grams for the best accuracy. Link to comment Share on other sites More sharing options...
GreyBird Posted May 3, 2017 Author Report Share Posted May 3, 2017 Update: I used a digital scale and measured out my ingredients in grams. I multiplied by 100 and then doubled the recipe for all 7 glazes I mixed. None came out like the photos in the books but I was happy with a few especially when they were combined (Test Tile dipped in one glaze all the way and then half covered in another glaze (See image of test tiles.) Years ago I mixed "Waterfall Brown" from"Mastering Cone 6 Glazes" and it came out beautiful. Just like the photo int he book. This time around It is just brown which breaks to clear over elevated areas. One of the glazes I mixed (Bright Purple from "The complete guide to Mid-Range Glazes" Came out completely wrong to where I thought I must have gotten distracted and done something wrong. It came out a Matt Brown. Beautiful but not "Bright Purple" as pictured in the book. Thankfully I only fired the test tiles so no pieces ruined and I thought I had found some happy accidents to where I could go ahead and make some stuff and glaze it with my new found combinations. I also re-mixed the bright purple and fired a test of that. The "bright purple" came out exactly the same... Matt brown. Very disappointing because now I don't know why. Also all of my pieces were ruined because what looked good on test tiles, failed on actual pieces. The glazes crawled away from the clay on flat surfaces (See image of Mugs) Now I don't know what the issue is. For one thing I found that the feldspars have changed names since the book was written and where the book called for SodaSpar I used Minspar, as recommended by my supplier. besides that I just don't know why the glazes are not coming out right. Link to comment Share on other sites More sharing options...
Mark C. Posted May 3, 2017 Report Share Posted May 3, 2017 Stick with grams instead of oz or cups Yes ,grams always no cups-no ounces Link to comment Share on other sites More sharing options...
Min Posted May 3, 2017 Report Share Posted May 3, 2017 You have some nice test glazes there. Test tiles often look different than glazes on real pots. Small batch has a greater chance of user error with the weighing out of materials, tiny differences with the scales can make a big difference in the glaze. Just to confirm it's the Bright Purple from Britt's Mid Range Glazes Book right that is coming out brown? I had a look at the recipe and the only thing I could see that would do that is if you used manganese instead of magnesium. Is this possible? What colour was the stuff you added for that? Also, the glaze crawling inside the bottom of the mug, I would put that down to too thick a layer of glaze if the pot was not dusty when you glazed it. Re waterfall brown, try it again with test tiles having different thicknesses of glaze (with room for it to run). Minspar is a sodaspar, it's very close to the F4 that had been commonly used prior to becoming unavailable. Don't think using minspar would be an issue. Link to comment Share on other sites More sharing options...
GreyBird Posted May 3, 2017 Author Report Share Posted May 3, 2017 I definitely used the white one, "Magnesium Carbonate". Unless the tops got switched... is the Magnesium Carb supposed to be white? : Link to comment Share on other sites More sharing options...
GreyBird Posted May 3, 2017 Author Report Share Posted May 3, 2017 Another point is that the "Rutile" I have is very old. I got it from a potter a long time ago... like 20 years ago. It's been in an open bucket that whole time and is brown in color (Has always been brown in color) looks like dirt. The Rutile I see for sale from supplier is white. Is that important? Thanks again, best, -Mary Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted May 3, 2017 Report Share Posted May 3, 2017 GreyBird asked: "is the Magnesium Carb supposed to be white?" answer: Yes. My rutile is was purchased ~ 10 years ago and has a tan color closer to brown than white. Pure Titanium dioxide, the major component in rutile, is pure white. Rutile is an ore, containing a measurable amount of iron, from which pure Titanium dioxide is extracted. LT Link to comment Share on other sites More sharing options...
Min Posted May 3, 2017 Report Share Posted May 3, 2017 Just a suggestion but I would label the containers themselves, not the lids. Same with glaze containers, it's super easy to put the wrong lid on a pail etc. I'll be doing a glaze firing in a few days, I can add a test of that glaze if you don't get it sorted by then. Mixing glazes while using a Chinese finger trap???? it's hard enough as it is without using one of those Link to comment Share on other sites More sharing options...
GreyBird Posted May 3, 2017 Author Report Share Posted May 3, 2017 Thank you so much. I most definitely won't have it sorted by then. The finger traps are for the parrots. I stuff them with treats and they are a foraging toy Link to comment Share on other sites More sharing options...
Mark C. Posted May 3, 2017 Report Share Posted May 3, 2017 Another point is that the "Rutile" I have is very old. I got it from a potter a long time ago... like 20 years ago. It's been in an open bucket that whole time and is brown in color (Has always been brown in color) looks like dirt. The Rutile I see for sale from supplier is white. Is that important? Thanks again, best, -Mary No that all does not matter-rutile has changed color many times over my 40 years of using lots of it. I buy it in 50# bags. Link to comment Share on other sites More sharing options...
jrgpots Posted May 3, 2017 Report Share Posted May 3, 2017 In a high alkaline glaze, manganese can give a violet color. In low alkaline glaze, manganese will give a brown color. In a low alumina glaze, manganese can give a violet color. In a high alumina glaze, manganese can give a brown color. My best gues is.... reduce the alumina in the glaze and use a alkaline frit in the glaze to reverse the brown changing it to violet. A great review of this is found on digitalfire glaze color review. https://digitalfire.com/4sight/properties/ceramic_property_glaze_color.html Jed Link to comment Share on other sites More sharing options...
Min Posted May 4, 2017 Report Share Posted May 4, 2017 I squeezed a test of the Bright Purple into last nights test kiln firing. Went to around ^7, 8 hour firing with fast cool. For the sodaspar I used Minspar and for the ball clay I used OM4. Recipe exactly as printed in book. (glaze is not going to be durable enough for food surfaces) Link to comment Share on other sites More sharing options...
GreyBird Posted May 4, 2017 Author Report Share Posted May 4, 2017 WOW, Thank You. The ball clay I have may not be OM4. It's old and from the same source as the Rutile. Do you think firing to cone 7 instead of 6 could make the difference? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.