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Member Since 15 Feb 2013
Offline Last Active Yesterday, 09:43 PM

Posts I've Made

In Topic: Trouble With Red

21 July 2016 - 03:38 PM

I wanted to give an update on my glaze testing for those of you following this thread.

I sent off 2 cups to be tested made according to their instructions. It cost me with shipping both ways $66.
$18 testing fee for each cup =$36
And $30 shipping ($15 each way)
I could have saved the return shipping by not having them sent back but I want to keep them in the studio for my records.

I used a combination of Coyote Glazes in:
Buttercup Yellow, Orange, Red Orange and Desert Sage on one cup
And the same glazes with a layer of Amaco Zinc Free Clear over them on the other.

Since I was combining several glazes I wanted to test to make sure the glazes were food safe after firing. The clear I did out of curiosity to see if putting clear over another glaze changes anything. It did not, both tested exactly the same which I find interesting. Locally I have talked with other potters and been told that if you put a clear over a non food safe glaze it automatically makes it safe, in this instance both pieces tested the same the clear on top made no difference.

I had the pieces tests for Cadmium. The regulations state anything under .5mg/l is acceptable. Mine came back testing at Less Than <0.01mg/l. So they are testing way below the required limits. If was a relief to see that as you all know from my previous posts I was really stressing over this. For record keeping I put cones 5, 6 and 7 on each shelf in the kiln when I fired the test cups. I marked the cones and in my log book where the cups were positioned in the kiln. I have placed the used cones and official lab report inside the test cups as well as writing in sharpie on the outside the date and test results on each cup. I hope I never need them but it's nice to know I had them tested.

Things I would do differently next time;
I would send 6 cups with different glazes and skip the clear over the top test since that question has been answered my satisfaction. 6 cups is the most I can fit in the size flat rate priority mail box I used and would cut down on the shipping costs per cup.
Even though all of my glazes state they are lead free I would probably go ahead and test for Cadmium and Lead just so I have it on file.

Things I am planning to change OR have already changed due to discovering Encapsulated Cadmium:
All of my drinking vessels, pitchers, most bowls, and large serving bowls will have either a white or a food safe Temmoku interior. That doesn't mean I won't have color on my pieces, I am just redesigning as much as I can to keep the feel of the piece but removing these glazes from food contact areas where I can. This can be difficult at times since I use a lot of Underglazes in my design work. The way some manufacturers seem to go out of their way to make it difficult to find out what they have in their stuff has me researching and downloading MSDS sheets whenever I can find them. I have already starting mixing and using my own colored slips for background colors rather than using commercial Underglazes. I have ordered additional glaze mixing materials and plan to start making and testing my own glazes. As I get these to the point I can get satisfactory results I will send them off to be tested, I can't even begin to say how much peace of mind doing so has given me.

I hope this helps answer some of the questions some of you might have in this subject. Getting your own stuff tested is the only way to know for sure.


In Topic: Hard Time With Extruder..not Extruding?

21 July 2016 - 02:56 PM

I agree with oldlady and Magnolia, the size of the extruded hole also has something to do with the difficulty in pressing the clay through. When I make custom dies with smaller openings I drill a couple additional holes for clay to press out through. These extrusions I loop up and store in a damp box, depending on the plate I use and it's hole size they make excellent coils for seams or as foot rings. I'm all about making stuff easier, more efficient, as well as lessening waste and doing this does all of that.


In Topic: Hard Time With Extruder..not Extruding?

20 July 2016 - 04:18 PM

Probably not helpful but I will chime in away:

I have a Scott Creek extruder and find misting the inside of the barrel with water helps immensely to get the clay to move through. I use fresh clay right out of the bag so it's really soft but there are still times when I am practically hanging from the plunger to get it started. I have also found smacking the clay around a bit to get it into the right shape seems to wake it up and help as well, my extruder is round so I cut the bag of clay long ways into 4 pieces then bang these against the table to shape them into long round plugs that I can drop down the shaft. Also once it gets moving it seems to get easier but that first pull can be a bear some days.

I hope this helps!


In Topic: Starting Up Electric Kiln Help!

12 July 2016 - 03:56 PM

Also make sure when you have the new larger breaker installed that the correct gauge of wire has also been used. Over time the wire heats up, cools down, heats up, etc and can cause the wire to fail and cause a fire INSIDE the wall of your house. Make sure the correct gauge is used for the size of breaker as well as for the length of run to the kiln and the kiln itself. The kiln will tell you in the manual what size breaker and wire to use for so many feet it's away from the breaker box. I had my electrician run the kiln wires on the outside of the wall inside a metal conduit from the breaker to a manual shut off then on to the kiln. Doing this lets me monitor the amount of heat building up in the conduit and will hopefully give me a heads up if I am developing a problem. I like the manual cut off so I KNOW the kiln is OFF when I need it to be.

Getting a new breaker, conduit, proper gauge wire, manual shut off, and correct plug cost me between $300 on my small kiln and $400 on the larger kiln due to heavier load materials needed. These were installed separately 2 years apart would have been cheaper to get both done at the same time. TOTALLY worth the piece of mind to know I am at least starting off in the best spot I can.


In Topic: Storing Sodium Silicate Long Term

10 July 2016 - 07:51 AM

Oldlady - I know nothing about ss so can't help you there, but your test tiles are pretty I LOVE your colors!