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Member Since 04 Oct 2011
Offline Last Active May 27 2016 09:34 PM

#107439 Different Firing Rate/speed When Firing Pottery Vs. Ceramics?

Posted by neilestrick on 24 May 2016 - 01:15 PM

Ceramics= pretty much anything made of clay materials. Technically, anything made from aluminosilicates.


Pottery is ceramic. Little figurines are ceramic. The porcelain parts of spark plugs are ceramic. Knife blades can be ceramic. Toilets and sinks are ceramic. Tiles are ceramic. The slip cast figurine branch of ceramics has taken the term to mean what they do, and call things made with moist clay 'pottery'. People who work in figurine ceramics are the only ones who use the term 'ceramics' they way they do. Everyone else uses the much broader definition of the word. If you read the magazine 'Ceramics Monthly', there are no slip cast figurines in there. It is all potters and sculptors. Some of the work may be slip cast or made in molds, but they create their own molds from scratch.


It can all be fired the same way. There's a lot of mis-information in the figurine ceramics world about what potters do, simply because figurine 'ceramics' folks don't make pottery.

#107225 Lose The Sitter Your Opinion Counts

Posted by neilestrick on 20 May 2016 - 12:03 PM

Go ahead and do zone control. It's not much more money and very worth it. Don't try to put everything in the sitter box. Use a vented external box so everything stays cool. I think the easiest way to do it would be to put a box on the wall and run jumper cords to the box, like an L&L DaVinci. The cords can be hard wired at each end. For the control box connection put in a terminal strip so it's easy to unhook them when you need to do maintenance.


Use SEOOW type cords from McMaster, and put heat resistant sleeving on the wires at the kiln hookup. You can get that at McMaster, too. Get the abrasion resistant stuff or some sort of coated sleeving. All the other stuff frays really badly.


Use cable clamps at all penetrations.


The thermocouple wires can all be external.


Use a 1/2 amp fuse for the control panel.


No need to put a switch between the transformer and controller, but it's nice (and cheap).


Ground everything!

#107109 Newbie And Having Trouble :(

Posted by neilestrick on 17 May 2016 - 10:46 PM

Sounds like maybe the glaze wasn't thick enough. Most commercial glazes need 3 coats, sometimes 4. You can glaze over them again and re-fire them. Fire slowly, as some clay bodies don't like to be re-fired.


I assume your mention of air bubbles has to do with thinking they will cause pieces to blow up? Not true. Think about adding handles or other attachments to pots- we score the clay, which makes tons of little air pockets which don't blow up. Steam is what causes things to blow up in the kiln. Air only expands about 1.5 times when heated up to firing temps. That's not enough to blow apart the clay. However water turning to steam expands 1,700 times. That is enough to blow clay apart. Bone dry pots have some water in them. It's impossible to have 0% moisture in the clay when it's in a room that's 30-80% humidity. So that water must evaporate at the start of the firing before it turns to steam. Pots that are thin have no problem drying completely at the start of a firing. Thick pots take longer to dry, so at typical firing speed a thick piece may not get totally dry before the kiln gets hot enough to turn the remaining water to steam, and BOOM! Kids pots tend to be thick, so they are more likely to blow up if the teacher doesn't slow down the firing or give them a good preheat in the kiln.

#107077 2 Chambered Kiln?

Posted by neilestrick on 17 May 2016 - 01:54 PM


The Minnesota Flat Top design is not any simpler to build than an arch. In fact, I would say it's more complicated and requires more maintenance in making sure everything is staying tight. There's nothing stronger or longer lasting than an arch.


I wasn't going to come right out and say it.  ;)







Wimp. ^_^

#107073 2 Chambered Kiln?

Posted by neilestrick on 17 May 2016 - 11:39 AM

The Minnesota Flat Top design is not any simpler to build than an arch. In fact, I would say it's more complicated and requires more maintenance in making sure everything is staying tight. There's nothing stronger or longer lasting than an arch.

#106766 Installing The Second Kiln... Pointers, Opinions, Suggestions Anyone?

Posted by neilestrick on 12 May 2016 - 11:58 AM

I would have them much closer to the wall and each other :-)


My kiln said a minimum clearance of 12" (18" in California) was needed to combustible surfaces. I have wooden shelves 12.5" inches from it and complete peace of mind.


I wouldn't put wood shelves that close. 16" minimum for my peace of mind.

#106765 Replacing Kiln Power Cords

Posted by neilestrick on 12 May 2016 - 11:53 AM

There's often talk here on the forum about replacing power cords on kilns. This may be because the prongs on the cord don't match the outlet, or a longer cord is needed. It seems like a simple thing, but there are a few things you need to look for:


1. If it's a new kiln, replacing the cord on a new kiln may void the warranty unless it's done by an approved technician or with a cord from the manufacturer. True, it would be tough for them to ever find out, but it could happen if you need a tech in the future, and karma can be a real bugger. Plus it's usually easier to replace the wall outlet than change the cord. Also, changing the power cord to one with a different plug configuration or length length may void the UL listing (if the kiln has one), which may affect how your insurance company feels about the kiln. In all cases, you should check with the manufacturer first before making changes.


2. Make sure the new cord is rated for the same amperage as the old cord. Too small and you'll have a major safety issue on your hands.


3. Make sure it has the same number of prongs. Single phase kilns usually have 3 prongs- two hots and a ground. 3 phase kilns have 4 prongs- 3 hots and a ground. Some single phase kilns also have 4 prongs- 2 hots, a neutral and a ground. You cannot change this! Never snap off a grounding prong! It is very dangerous to fire a kiln that is not grounded.


4. Make sure the cord is rated for 105C/220F. This is the one that everyone overlooks. Most power cords you can get at the hardware store are only rated for 90C, which could overheat.


5. Wire it up properly. That means putting the hots, ground and neutral in the right places, as well as using the proper strain relief to hold the cord tight in the control box. Make sure all the connections are good and tight!


6. Building your own cord is often the best way to go, especially if you need a longer than normal cord. SEOOW type cords are wonderfully flexible and easy to work with. They can be purchased online from McMaster Carr or other sellers. You just have to attach the appropriate plug to the cord, which isn't all that difficult. I have found that plugs from McMaster are pretty pricey, so I usually get the plug from Ace, Lowes, etc. If ring terminals are required for the kiln connection, I recommend using high temp terminals. If the old wires have heat resistant sleeves on them, you can reuse them on the new cord if they're in good condition. Otherwise get new sleeves.


Happy wiring!




#106687 Stain Percentage To Make Colored Slip

Posted by neilestrick on 11 May 2016 - 12:19 PM

With most things in ceramics, percentages are by dry weight.

#106480 Metal And Arcing In An Electric Kiln

Posted by neilestrick on 07 May 2016 - 04:52 PM

I used to heat treat a ton of banjo brass drum rings with zero issues and they where piled fron the bottom of kiln to top.
My friend is the owner of Wildwood Banjos and used to live on my hill.


Those are beautiful banjos! See if you can get me one. They're out of my price range, so I had to build my own.

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#106414 Got A Brand Shimpo Aspire....aaaand It's Clunking. Normal?

Posted by neilestrick on 06 May 2016 - 02:01 PM

If you feel handy, make sure everthing is tight, especially where the bearings attach. There's a chance the screws are loose, but I'm betting it's the belt. Take off the cover so you can see the belt run, and check to see if the clunk is when the seam on the belt hits the small drive wheel at the motor.

#106411 Got A Brand Shimpo Aspire....aaaand It's Clunking. Normal?

Posted by neilestrick on 06 May 2016 - 12:42 PM

Could be the seam in the belt. Call them.

#106371 Stock Solutions For Glaze Testing

Posted by neilestrick on 05 May 2016 - 08:53 PM

Ha! I just mean using super concentrated solutions of the individual ingredients for a glaze. So if you want to make a glaze with 1% colorant, you make a solution with 10% colorant and use 1/10th of this solution. We did this in the lab all the time--just means you can combine the stock solutions to make a final result much faster. It also means less error because means you don't weigh out very small quantities for a 100ml glaze test.

It seems like the same principle *should* apply, but surprised no one does it, so I figure there must be a reason!


Thank you for the explanation. The problem is that most glaze colorants, being metallic oxides, don't stay suspended very well at all. You could, I suppose, mix them up in a gum solution, but that just adds more steps and probably negates the benefits.


When doing line blends, you can do them as liquid volume measurements rather than weighing out each little portion. You just have to mix each end of the blend to the same volume and go from there. I think that would be similar to what you're describing.

#106286 Bartlett Genesis Review

Posted by neilestrick on 04 May 2016 - 11:45 AM

It's here! I got my new Bartlett Genesis kiln controller today. I still haven't had a chance to go through all the diagnostics info yet, but I did install it and set it up for a glaze firing with a cooling cycle, which it is firing right now.


Out of the box I was disappointed with how small the screen is. I thought it would be bigger. However, after using it for a few minutes it didn't bother me at all. It's plenty big and the 'buttons' are easy to use. The screen and entire panel has some sort of protective overlay that protects it. It feels a little odd since I'm so used to the feel of a phone touch screen, but I get that it needs to be very durable in a studio environment. The screen is very responsive.


The system for setting up a firing is a little different than the controllers we've used in the past, but it's still very simple and intuitive. From the home screen you press 'Load' and select which type of firing you want to do, either glaze, bisque, glass or custom. Then from home home screen you push edit to make changes to the program. You have the usual choices of cones and speeds, as well as a cooling cycle. The cooling cycle is full drop to 1900F, then 150 per hour to 1500F. At this point that cooling cycle cannot be changed, but I spoke with Bartlett and they're open to changing that or adding in a piggyback system where one of the 12 custom programs becomes the cooling cycle. They have actually been very receptive to feedback about programming improvements. So for now if you want a custom cooling cycle, you'll have to do it as part of a full custom ramp program.


For my firing today I just recreated the fast glaze program to cone 6 in a custom user program, with my own cooling segment added to it. Filling out a custom program is incredibly simple because it shows all of the segments on the screen all at once. You can add and delete steps as needed. Very nice. You can store 12 user programs with up to 32 segments each, so those of you that do super fancy firings (glazenerd, I'm talking to you) can do anything you can dream up. You can also put in a name for each program, so you don't have to keep a list hanging on the wall.


During the firing, the screen shows all 3 thermocouple readings as well as the current set point for the ramp. I really like this since before you would have to scroll through each reading separately.


Over all, I think it's a really great first version of a touch screen controller, especially for custom programs. Is it worth $329 to replace an old controller? That's for you to decide. Is it worth $125 to upgrade on a new kiln? Absolutely, especially since more features will be added in the future. It's Wi-Fi enabled, so software upgrades can be done easily. Bartlett said there's also talk of a phone app that will communicate with the controller, but there's a lot of liability issues related to that feature that must be dealt with before it become a reality. Currently, if you want external control then you can invest in Bartlett's KISS software.


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#106202 Relay Life

Posted by neilestrick on 03 May 2016 - 10:53 AM

Whenever I put new relays in a kiln I always write the date on them with a silver sharpie. That way if one fries out I can tell if it was an anomaly, like it happened after only a few months, or if they're old and all 3 should be replaced. While putting the new controller on my L&L E18T-3 this morning I saw the install date on my relays was 4-29-14. I do 150+ firings per year, so they've currently got 300+ firings on them. Not bad!

#106198 What Would Work Best?

Posted by neilestrick on 03 May 2016 - 10:10 AM

I know folks who fire directly on Advancers with no kiln wash, however I have heard that porcelain bodies can pluck if you don't use wash.