.jpeg.e14571b8528e66a7a9c872fd28550125.jpeg)
Min
-
Posts
5,957 -
Joined
-
Last visited
Content Type
Profiles
Events
Forums
Blogs
Gallery
Posts posted by Min
-
-
Quick gelli plate and silkscreen process, with and without paper.
Gelli plates don't contain gelatin but you can make your own gel plate using gelatin, don't know how well / long homemade gel plates last for.
1 - gelli plate dusted with cornstarch (gelli plates come in different sizes, I'ld get one just big enough for what you want to screen)
2 - silkscreen in place (can get custom made ones or stock ones, available from a few makers not just EZscreen, can also buy a blank screen and burn it yourself)
3 - Xiem rib used with thick underglaze. Either let it thicken up on it's own or thicken with Mayco silkscreen medium/powder. I tried the Mayco medium I think it's probably CMC, I prefer to just let it thicken on its own. Needs to be almost peanut butter thick.
If you use a gelli plate it needs to be applied to the pot (or vice versa) quickly while the underglaze is still wet. Either lift up the gelli plate and press it onto the pot or roll the pot across the gelli plate.
With paper instead of gelli-
1 - Rice paper (I buy from Sanbao but other places sell it too) rough side up, no cornstarch
2 - tape the screen down, same underglaze process
Can also screen right onto pots if the screen isn't too large to be awkward. I find the paper is easier to apply to rounded forms.
- Callie Beller Diesel, kswan, Hulk and 1 other
-
4
-
-
This has been an interesting thread but I too feel like some comments can get ones back up a bit and I'm not too sure why.
Perhaps it's because many on this forum have been working in ceramics for decades and have put the time and energy into learning how to work with kilns and materials with the respect and knowledge they warrant. It becomes second nature, but it has taken years to acquire this knowlege / experience.
Perhaps there is a bit of unspoken animosity towards some social media type posts, on whichever platform that might be, that blow off this type of learning, usually by a blatant omission of info.
Perhaps there is also the opposite issue of fear mongering in regards to glaze chemistry folklore that is also seen / heard without substantiation. Fear of litigation has shut down more than one ceramics arts dept in schools.
I find that clearly defining what a question is within a post in conjunction with ascertaining a persons knowledge level / experience (hopefully) helps tailor suitable replies.
- Hulk, Kelly in AK and suetectic
-
3
-
12 hours ago, Kelly in AK said:
I have a 4” angle grinder, with a diamond cutting blade (not a grinding wheel, a cutter) I can slice through regular kiln shelves pretty easily.
+1Working outside with the wind at your back if you cut them dry, it will make a lot of dust. Wear a respirator. If you don't have the gear to do this I would ask a local tile cutter if they could do it for you with a diamond blade wet tile saw. Need to have about 2" clearance around the tc.
- Kelly in AK and Pres
-
2
-
-
-
3 hours ago, High Bridge Pottery said:
Need to add something to speed up drying and keep it melting.
Since you have kaolin why not cut the ball clay with that?
3 hours ago, High Bridge Pottery said:It all depends where I want to put a line in the sand and call good on the vitrification side of things, anywhere under 3% seems OK.
On this side of the pond aiming for under 1 1/2% absorption is pretty common for pots that shouldn't weep.
-
1 hour ago, High Bridge Pottery said:
I tested each ball clay with 5, 10, 13, 16 and 20% frit in the order Alkaline, 3124, 3134 and 3195. The last 4 tests have a 50/50 mix ball clay to kaolin and 20% of each frit. Fired to cone 03 and then boiled for 5 hours to get the absorption values.
The results actually came out better than I expected with Hymod ball clay and 10% alkaline frit getting to 0.5% absorption at £1.41 per kg
Just curious if you considered using a red earthenware and adding frit to that? From Hansen's Zero 3 page he speaks of needing 5% frit added to his earthenware to make it vitreous. Given that the frit is the expensive part of the mix it might be worth testing if you are okay with an earthenware colour. There is an earthenware available here that when fired to cone 04 has porosity at 6.0% but when fired to cone 02 porosity goes down to 1.5%, anything like that where you live?
Nice experiment work!
-
15 minutes ago, Mark C. said:
As a potter one should have an understanding of materials and thier use. In terms of safety and use
In an ideal world then yes for sure. But, seems there are always going to be people who for one reason or another don't take the time to learn this stuff before diving in. Just take a quick look at social media sites, full of people with no glaze chem knowledge making pots.
-
I'll pass along your issue to admin, they might take a few days to get back to you as they are taking a few days off at the moment but shouldn't be too long. (unfortunately this isn't something mods can fix) Just double checking that you know your login for ICAN CLAYfliks etc is a different login from this forum?
-
How I'm reading his comments are the recipe won't work without the manganese and copper as they are necessary to flux the glaze. He did state the glaze without the manganese and copper won't work as those two oxides are necessary to flux it. It looks like he's taken a typical Metallic Glaze with high manganese and swapped the redart for custer, kaolin and a bit of talc.
I don't know what Glazy's policy is on posting recipes that aren't suitable for functional ware surfaces with or without a caveat stating so, perhaps that is something to bring up with Derek Au. We do make a point of stating if a glaze isn't suitable for pots coming in contact with food surfaces on this forum and to fire glazes or claybodies, slips and engobes containing manganese in a very well ventilated area. No, I don't think you are an "old codger" telling people you shouldn't use such glazes inappropriately.
-
All these suggestions of what to do with your found clay are great!
Given that you are brand new to working with clay I would think about what your goal is for this clay, what do you want to do with it? How much time, if any, do you want to spend testing modifications of it?
-
I think it's also about the type of material the buckets are made out of. Google search brought up buckets made from polypropylene, polyethylene (low and high density), polycarbonate, polyvinyl chloride, polyetheretherketone, and something called Halar®. "Halar® tops the list for chemical resistance in plastics. It can resist even the harshest chemicals, acids and solvents – including sulphuric acid – without effect on its mechanical properties. The only corrosive chemicals that can affect Halar® are hot amines and ketones."
I had a quick look at the underside of a couple of my buckets that have stood up well, they say HDPE which I think stands for high density polyethylene. (wine makers 6 gallon buckets) If we wanted to actually pay for buckets I'ld get the ones that are more resistant to chemical attack and weathering.
-
1 hour ago, cafedunier said:
You are saying its over fired, but why are the cones not bent all the way over, indicating that its not fired to maturity?
Common Orton cones range from cone 022 (thats zero twenty two) approx 1080F up through cone 14 approx 2530F. Bisque firing is usually done between cone 08 and 04 if the clay is going to have a higher glaze firing. (exceptions in there but generally). Cone 5 might be what your friends clay matures at but it's not what your found clay matures at. Firing clay to it's maturity ensures you will get as strong a clay as possible. Typically potters fire to within 3 ranges, lowfire (approx cone 04 up to cone 01), midrange (around cone 4-7) and highfire (approx cone 9 - 12). Your found clay looks like it will fire to maturity in the lowfire range. What cone is optimum will take firing samples of it in the lowfire range. First link in that thread I posted above will help in testing your found clay.
1 hour ago, cafedunier said:I found it in Northern Quebec
Have a look at some Geological Survey maps of the area in Quebec it is from. Might not be necessary but it could be interesting.
-
There is a lot of leda / quick clay in the Ottawa Valley, a quick Google search brings up quite a few documents and geological surveys done in the area. Does the location of where the clay was dug up match up with locations such as those in this link? Like @Hulk said it looks overfired at cone 5, would probably need to either fire it lower or amend it with other materials to fire at midrange. How plastic is it? Can it be made into a coil and bent around your finger without cracking?
I started a thread on Wild Clay here, might be something in the links in that thread that you find helpful.
-
1 hour ago, Benzine said:
Front loaders are definitely an attractive prospect.
I had a 10 cu ft front loader for a lot of years. Used 20" square shelves, it was easier on the lower back but harder on the upper back when putting the top shelves in. I'm vertically challenged too, when using my top loaders I stand on a little footstool to load the bottom shelf, really helps.
-
1 hour ago, Pir said:
Min, does he free-hand these designs?
Nope, it's a dangerous method involving salt water and electricity.
1 hour ago, Pir said:Small revelation last night: I glazed the inside of a mo-diffusion cup first, and as it dried a yellow stain crept out onto the outer walls.
Just mineral salts, seeping through the walls from either a glaze material or just the water itself. I always liner glaze my mugs the day before glazing the outside, happens every time. Hopper's slip is mostly ball clay, fired colour of the ball clay you are using will be the main influence of the slip colour. If you want a whiter slip try finding a ball clay with lower iron. I haven't tried adding zircopax to the slip but could try that too.
-
On 11/18/2022 at 12:13 PM, Astro Adri said:
Unfortunately i cant get a file small enough to attach here
If you email yourself the picture it should resize it smaller then try posting that one.
On 11/18/2022 at 12:13 PM, Astro Adri said:Think something simlar to obsidian in texture.
How would you get it to glaze or glass mesh size particles?
If you are firing your kiln to glaze temps anyways it would be neat to see what it does in one of your regular glazes, I'ld just swap the silica in a recipe with this silica scale (if you can powder it down safely) and see what it does. A clear maybe? And for sure fire it on the inside of a bowl since we don't know what will happen to the melt.
-
A buddy of my husband burns dendritic patterns into wood. This is some of his work.
-
I'm thinking if the original recipe was Albany 85, Nepheline Syenite 5 and Wollastonite 10 and it fired to cone 6 this would be a slip not a glaze. Would probably be a bit less stiff with Alberta in place of Albany. At ^10 Alberta slip will make a glaze all by itself when fired in reduction, is that how you fire to ^10? If it's in reduction I'm thinking the botched glaze will run like crazy at ^10. Won't be nearly as fluid in oxidation.
-
1 hour ago, oldlady said:
thanks, min for the division lesson! as always, you are top of my list when it comes to glazes. wanna do a glaze workshop together over zoom? our guild has lots of new people stuck on bottles instead of mixing ingredients. you be the puppet master and i will do exactly what you say.
Everyone here has something to contribute, I'm just one of many but thank you for your kind words. Re teaching a zoom glaze workshop, sorry but this isn't something I'm in a position to do, thanks for the thought though!
3 hours ago, NanS said:My glaze is the Glossy Clear Base from the Mastering Cone 6 book, and is zinc free (https://glazy.org/recipes/134907).
The chrome tin stain you are thinking of testing probably won't work with this base, likely to get a washed out blue gray colour. Base glaze needs to have at least 10% but better with closer to 20% calcium for any of the chrome tin stains to work, this includes the pinks, reds and purples.
-
1 hour ago, NanS said:
I think I'm planning to aim for 2% for my first tests.
To save yourself some work I would suggest making up 200 grams of base glaze with no stain as a baseline and dip a small test tile then add 0.60 stain (0.30%), re sieve then dip a second test tile, keep repeating this until you get up to 1.80% (that would be 6 additions of 0.60 grams of stain). Given that the 200 grams will be lower with each dip this isn't super accurate but it will get you in the ball park. 200 grams will get you the baseline plus 6 test of increasing stain. Doesn't have to be increments of 0.30%, if you want to test higher amounts bump it up to 0.50% or whatever you think best.
A method to divide up the stain quickly is to measure out the total you will be testing, say 1.8% which for a 200 gram base will be 3.60 grams for my example above. Take the 3.60 grams and put it onto a flat smooth surface like a piece of glass or smooth countertop. Now use a metal rib and compress the stain into a flat square shape. With the rib now divide it down the middle then cut each half in thirds, makes 6 piles of stain, each 0.60 grams. Sounds confusing when I write this but it's quicker than weighing out each batch of stain and will get you close enough for a first run of tests.
-
Looks like nanoparticle titanium dioxide is being used in self cleaning or hydrophobic glazes for washroom sinks and toilets. From this article, there are quite a few more articles if you search for nanoparticle titanium dioxide in hydrophobic ceramics.
-
The Safety Data Sheet for it is here. Snippet of it below, you can see it contains water, fluoridated acrylic copolymer and a "trade secret" ingredient. To get it lab tested you need to give the lab the names of the ingredients you want it tested for unless you get a broad range test done which would be very expensive.
It isn't made for human consumption. You are a lawyer, I think you know the possible ramifications of using a product for other than it's intended use would be.
Extremely stupid and ignorant to hazards with working with clay
in Studio Operations and Making Work
Posted
@LouiseD, as others have said this is totally unsafe and probably illegal situation to have in a workplace. Looks like you are in England, I believe the link below would either be somewhere you should report the situation too or they should be able to redirect you if not. Take some photos if you can. Even if there wasn't lead in the glaze(s) it is extremely unsafe practice to spray glaze without adequate ventilation and well fitting PPE.
https://www.hse.gov.uk/contact/tell-us-about-a-health-and-safety-issue.htm