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neilestrick

Member Since 04 Oct 2011
Offline Last Active Yesterday, 05:09 PM
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#65113 Irregular Bowls

Posted by neilestrick on 26 August 2014 - 12:02 PM

You've just made a very important realization. My students often make the remark "I could make that" when they see a piece in a magazine that is loosely thrown. But there is definitely a difference between poorly made and loosely made. Beginning students don't usually have the experience to tell the difference.

 

It's kind of difficult to explain, but I think the biggest difference is that loose pots look deliberate. Loose doesn't mean a lack of control during the making process. In fact, I'd say there's more control required to be able to handle the clay when it's not spinning perfect and even. It's easy to spot mistakes in throwing, because we've all made them before, so be very deliberate about your movements and do everything with intent.




#64957 Using A Kiln For Other Than Firing Pottery

Posted by neilestrick on 23 August 2014 - 12:39 PM

Anyone ever baked bread in a kiln?  Any toxicity concerns?

 

Is not a good idea to cook food in your kiln. A certain amount of the stuff that burns out of the clay and glazes is absorbed by or is on the surface of the kiln's bricks. It's a tiny amount, but you don't want that getting into your food.




#64945 New Kiln Questions

Posted by neilestrick on 23 August 2014 - 08:44 AM

Firing Cost

 

In your manual, in the 'Operation' section, are directions for the first firing in your kiln. You will be doing a Slow Bisque to cone 5 with a 3 hour preheat. This long, slow firing will season your elements and bricks, and set the mortar in the lid and floor. No need to put any furniture in the kiln- just leave it empty. After that you're set to fire some pots!




#64903 Do You Donate Your Work For A Worthy Cause?

Posted by neilestrick on 22 August 2014 - 11:02 AM

I only donate if it's a local cause that I have a connection to via a student or my kids, etc. I sometimes donate pots, but I often donate a class since that gets them in the door. Although I sometimes have regular students buy the class at the charity auction to get out of paying full price for that session. That bugs me a lot. The whole reason for donating was to get some new folks in the door. But that's a different rant.




#64902 My New Kiln Lid

Posted by neilestrick on 22 August 2014 - 10:43 AM

A year or two ago I posted some photos of a new experimental kiln lid for my large DaVinci kiln. Instead of being mortared together like the original lid, it used a compression frame to hold it together, similar to a Minnesota Flat Top design. That lid held up very well for a fair amount of time, but the bricks eventually started to crack. Seems they do not like being compressed along their narrow side. I had though this might be a problem from the beginning, and it eventually was. So this time I rebuilt the lid with the bricks being compressed from the large side, spreading the pressure out over a much larger surface area. I also mortared the bricks together so give it even more strength. The lid is made in two sections, held together by the compression frame. Making it in one big slab would be too large and cause a lot of cracking.

 

Attached File  New-Lid.jpg   245.05KB   1 downloads

 

The best thing about this lid is that it's now 4-1/2" thick instead of the usual 3". The added insulation should help with the efficiency of the kiln quite a bit. The lid weighs 250+ pounds, more than the original lid springs could handle, so I attached an electric hoist to raise and lower it. The hoist hangs on a piece of 1-1/4" pipe, which allows the hoist to swivel as it works, and line up in the direction it's pulling.

 

So far it all seems to be working well. I did my first bisque with the lid last night, and nothing fell apart. The first cone 6 firing will be in a couple of days.




#64854 Setting Up A Kiln

Posted by neilestrick on 21 August 2014 - 01:00 PM

The air coming out the vent will be 150F or less, about like your clothes dryer. As long as it's not venting right onto a sidewalk or deck where people will be you should be fine.




#64844 Kaolin Substitutions

Posted by neilestrick on 21 August 2014 - 10:39 AM

In most glazes you won't see any effect. EPK is slightly higher in Titanium, so that can have a small effect, but for the vast majority of glazes it won't matter.

 

EPK bodies can still be translucent, but for most people that's not an issue anyway. As Biglou said, there will be a slight color difference, but in cone 6 oxidation it won't be nearly as noticeable as in reduction. If your recipes only call for 25%, the other clays in the bodies will already be affecting the color anyway. HERE is an interesting thread from Clayart in which Ron Roy discusses kaolins with some other tech guys. According to Ron, EPK is the whitest of the 4 kaolins they use at Tucker's, including grolleg. Grolleg, however, vitrifies at a lower temperature so you can get more of it into a translucent body than with EPK, which improves workability. Interesting stuff!




#64753 Another Sales Technique ... Maybe?

Posted by neilestrick on 19 August 2014 - 09:12 PM

My trick is to tell them to take it out into the sun outside my booth. It gets the pot into their hands, and the glaze (which they were already like) really pops in the sun and seals the deal.




#64725 How To Get Started With Old Stains, Etc

Posted by neilestrick on 19 August 2014 - 11:35 AM

Stains can be added to glazes to color them. i would run small batch (100g) tests with 2, 4, 6, 8, 10% stain added to a glaze, by dry weight. Stains can also be used to color slip, but higher percentages are generally needed. You can also use them to stain texture on pots or as underglazes, but they will generally need to be cut with a little frit first.

 

I would also run small batch tests of all your glazes before mixing large batches. Start making test tiles!

 

Large batches of glaze should be sieved through an 80 mesh screen. Test batches can be mixed with a stick/immersion blender.




#64717 Interesting Dilemma

Posted by neilestrick on 19 August 2014 - 08:43 AM

 

One is underfired or one is overfired, or both.  With the exception of the silica, it's close to being within limits for both temperatures. The silica is quite low in both cases, though.

 

Personally, I tend to avoid glazes that rely so heavily on one ingredient.

Why is this Neil?

 

 

If something goes wrong with that ingredient, your glaze is ruined.  When you have more ingredients in smaller amounts, an issue with one ingredient will have a smaller effect. I also find that glazes with more ingredients are easier to tweak, and offer more possibilities for substitutions should the need arise.




#64716 Kiln Amps Labeling Conflict

Posted by neilestrick on 19 August 2014 - 08:39 AM

You've got a Frankenkiln. Someone added a third ring but never changed out the serial plate to reflect the change.

 

The amperage rating on the sitter has nothing to do with the actual draw of the kiln. It's just a switch that power goes through, and it can handle up to 45 amps. The actual draw is determined by the service voltage and the resistance of the elements.

 

It's odd that a kiln of that size with 3 rings is pulling 45-50 amps. It should be around 35 amps. Someone's definitely been tinkering with it. I'd get new elements in it that are properly sized for that kiln.




#64713 Base Of Pots 'chipped Edge' After Glaze Firing - Why?

Posted by neilestrick on 19 August 2014 - 08:23 AM

You need a fresh coat of kiln wash on the shelves.


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#64552 Interesting Dilemma

Posted by neilestrick on 16 August 2014 - 08:44 AM

One is underfired or one is overfired, or both.  With the exception of the silica, it's close to being within limits for both temperatures. The silica is quite low in both cases, though.

 

Personally, I tend to avoid glazes that rely so heavily on one ingredient.




#64459 Rust Red Glaze Recipe

Posted by neilestrick on 14 August 2014 - 07:05 PM

Harris Red (Revised)

Neph Sye  18.60

Gillespie Borate  9.20

Dolomite  9.20

Talc  9.20

Bone Ash  7.40

EPK  18.60

Flint  27.80

Total 100.00

 

Add:

Red Iron Oxide  11.00

 

Tends to be more red on stoneware bodies, lighter red on porcelain. Can be really bright brick red on brown stoneware like Standard 112. Looks great with the specks. I usually do a slow cool, 175F/hr to 1550F.




#64444 Pinch Pots

Posted by neilestrick on 14 August 2014 - 02:06 PM

When i do pinch pots with kids, they inevitably pinch with their index finger bent. This is a very aggressive way to pinch, and causes the clay to get too thin and lumpy. So I tell them to use 'crab hands'. Pretend you're making a crab claw motion with your hand- thumb and fingers straight out. This makes a nice soft pinch that gives more control and a smoother surface.