liambesaw

I'm glad you came here to collaborate, this is a great place do it!  As you know, one of the main reasons developers choose to make their software open source is to draw on the knowledge and abilities of a community to make the project better, the same can be said of the hardware in this case.  I'm excited that this has the potential to turn my manual old 75 dollar kiln into something I can control as well as a newer 2500 dollar kiln.  I'll be doing this project eventually and without you coming here, sharing, and being humble and open to criticism, it just wouldn't happen.  So thank you!  And thank you to everyone else who has contributed here!

@High Bridge Pottery Are you deciding if you should turn the relay off or on every 2 seconds?
Yes.  This is a configurable parameter. The code originally made this decision every .5s and that duty cycle was too high for kilns.  I have heard some folks going as high as 10s.  Since it is configurable, you decide the value that works best for your kiln.
How did you come up with the PID values to use?
I read many articles discussing PID tuning.  Some were complex algorithms, some simple.  I tried to find the simplest method that could be done in a few hours.  The process I used is described here... https://github.com/jbruce12000/kiln-controller/blob/master/docs/pid_tuning.md
The tuning it provided the first time around is good for my use.  If you find a simpler, better tact, post a PR and I'll check it out.
Part of our duties...
@Min
@neilestrick @Bill Kielb
If you, Neil, or Bill feel like this has become too big a risk to remain on the site, I totally understand. The last thing I want is for anyone to violate local code or endanger themselves.  I am committed to improving my implementation, but it will take time.  I have a full time job and this is a side project / experiment for me.
I cannot stress enough the value I have found in this forum.  I thought I was pretty good at what I was doing.  Turns out, I made lots of mistakes.  If I made these mistakes, others will too.  I think if folks had a resource where they could learn these things, it could prevent folks going down the same road I have.
Not sure what else to say on this topic.  Assumptions can be dangerous.  Reflect carefully on risks others point out.  Strive to become better.

Please understand that this is just an interesting project / experiment. Please note that I have no intentions of creating a product.  Please understand that this hardware is not finished and is in an alpha state.  I do not want defend improper practices and I am here to learn from others and improve.
I love that I have found a passionate, intelligent, experienced group of people in this forum.  If I had a forum with information like this when I started the project, it would have changed the course of the project.  So now, I'm left to make things right with folks so they don't follow the wrong path.  Please help me do that.
1. Conductors on the input side need to be to code (could I use a replacement 50A dryer cable for this?)
2. Grommets for any conductor that goes into the bud box
3. connect the heatsink directly to the SSR (can I then mount the heatsink to the bud box?)
4. use an Ultra Fast Acting fuse at the rated amperage of the circuit to protect each of the SSRs - 50A
5. use an SSR on each leg, instead of just one
6. use mechanical safety relay to disable all SSRs in the event there is an SSR failure/short.  I'm not at all sure how to implement this.  Can someone post a link to a schematic?
 
Did I leave anything out?

sorry i was not clear.  i do not mean pressing down vertically on the whole clay surface, i mean forcing the sharp indentation into a curve, not a sharp angle.  that means shoving the dowel horizontally along the work surface  into the deep angle to round it.

Ha....this one was made just for me! These are face-pressed. The white one is slip cast, the next is porcelain w/clear and Pallidium glaze, next is stoneware  with granite dust , multiple firings, micro glitter & a bit of gold enamel (mounted in an open frame); the last was angama-fired.   HMS is my Hidden Mask Series--a bit of self-absorption with therapeutic properties.  The mask concept, using my own face, emerged in defiance of the ceramics instructor who told me "Art is not therapy" (no, art is spirituality in drag) and wanted me to quit because I was falling apart a bit at the time and I was arguing that I should be allowed to hand build if I didn't want to throw. Titled in order: Art Is; Two-faced Selfie; Assembling the Surviver, and; Emerging.

That's a handy tip, thanks @neilestrick

Drill bits are less likely to crack the piece, since they remove material as they make the hole. Hole cutters force the clay to expand to make room for the wall thickness of the cutter. If the clay is too firm, or the hole is too close to an edge, it will crack.
The biggest problem with all holes, and one that many, many people do not address, is the sharpness of the edge of the hole. Rubbing out the edge with a sponge or finger takes forever. The simplest solution I've learned is to use a countersink LIKE THIS ONE. Just twist it lightly in the hole once it's just past leather hard, and it will knock off the sharp edge. I use this on all my colanders, and I can do all the holes in a matter of a minute. It puts a nice little bevel that looks rounded once it's glazed.

@shawnhar, if the clay is isn't too dry you can use a straw to cut the holes with. Snip the end of the straw at an angle, the clay you are removing stays in the straw which you can cut off after you've finished punching holes. (milkshake straws are a good size or for bigger holes bubble tea straws)

I use a short piece of dowel or stick to clear the straw when punching multiple times. 
Saving any size plastic straws I come across now....an endangered species ;)

Kind of, I do them while shaping with my steel rib.  I pull the cylinder and then scrape the slip off and shape the base at the same time, then I will fine tune the shape from inside with a small wood rib.  I probably should go back and sharpen them up again after, the line is just the line of slip that the steel rib leaves.  
Should have seen me sitting there in my shed trying to figure out how to do it nicely like the ones I mistakenly left like that last time. I like the way glaze breaks over the horizontal line though, it's really nice.
If you were talking about the fluting, I did that at soft leather before I put on the handles
Also the "electrician" won't be here tomorrow, mainly because I found out he's not an electrician.  

Having an electrician come out tomorrow to install the kiln circuit.  Fingers crossed it turns out well.
I have a bunch of mugs I've been working on this week, trimmed, fluted and handled a few today, pulled more handles and will finish the rest up tomorrow, might even give the electric kiln a run if everything goes well!
 

Having an electrician come out tomorrow to install the kiln circuit.  Fingers crossed it turns out well.
I have a bunch of mugs I've been working on this week, trimmed, fluted and handled a few today, pulled more handles and will finish the rest up tomorrow, might even give the electric kiln a run if everything goes well!
 

Having an electrician come out tomorrow to install the kiln circuit.  Fingers crossed it turns out well.
I have a bunch of mugs I've been working on this week, trimmed, fluted and handled a few today, pulled more handles and will finish the rest up tomorrow, might even give the electric kiln a run if everything goes well!
 

I do a mix of drawing and then "sketching" with clay.  I usually have something in mind but will play with the design in clay until I'm happy with it.  Once I have a form I like, I will make more and save a finished piece as a reminder when I go to make more.

I do a mix of drawing and then "sketching" with clay.  I usually have something in mind but will play with the design in clay until I'm happy with it.  Once I have a form I like, I will make more and save a finished piece as a reminder when I go to make more.

Just so you have a point of comparison, I fired my E18T-3 yesterday, a fast bisque firing with a 4 hour preheat, and it averaged about 2,600 relay cycles per kiln section. These are typical mechanical relays. Because SSR's have a longer lifespan, it's okay to have them switch more, plus all that switching can increase element life. When relays switch less, the element has greater variation in temperature. That is, it heats up and cools down every time the relay turns it on and off. The longer the time period switched off, the greater the variation in the temperature of the element. As we know, metal expands and contracts as it heats and cools, and that movement decreases the life span of the element. By switching more often, the element can maintain a more constant temperature, which increases its life. So why don't all the manufacturers use SSR relays? Because they cost more, require an additional safety relay (even more cost), and most people don't care enough to justify the greater cost.

I don't think it's because a movie made pottery iconic, I think it's because there's some kind of sensual overtone to the joke that comes with it.  I don't even tell people I make pottery anymore because of it, even though it's a large part of my daily life.  I get "ooo lah lah, like in ghost?" With winks and rapid eyebrow raises.  I don't know what happens in ghost, but just from people's reactions there must have been something smutty or something.  Makes me feel gross and uncomfortable.
 

I was always exposed to ceramics from kindergarten on through college.  Didn't have money for a wheel, kiln, clay, etc until my mid 30s where I am now.  My recent inspiration was my neighbor who is a metal and woodworking artist, I told him I used to really enjoy ceramics and he said I should just do it.  So I did.

I've never seen ghost but have to hear about it all the time.  Wish there was a newer movie that had pottery in it so I could stop hearing the same wise cracks all the time.  All I'm asking for is a little variety

Picked up a used kiln yesterday.  Crucible 234, inside dimensions 23x18.  It's a cone 10 electric with 3 inch brick.  It needs new elements and two of the grooved bricks have chipped but overall good condition!  The person I bought it from only fired to cone 06, so that's nice. The elements are functional but bulged in the bottom ring, might as well replace them if I'm going to have to pin them anyway, right?
Next step is getting the 50amp outlet installed outside, get a few bisques in, and then try making this raspberry pi controller.  Not a bad kiln for 75 dollars I think.  Anyone know a cheap electrician? Haha
 
I made some divided plates last week and my wife likes them so I'll make some more this week.

Will do, first step is saving up for the electrician.  Luckily there will be less than a foot of wire to run, the kiln is just on the other side of the wall from my circuit breaker.  After all is said and done will be nice not to blow 15 bucks in propane every time I bisque.

Picked up a used kiln yesterday.  Crucible 234, inside dimensions 23x18.  It's a cone 10 electric with 3 inch brick.  It needs new elements and two of the grooved bricks have chipped but overall good condition!  The person I bought it from only fired to cone 06, so that's nice. The elements are functional but bulged in the bottom ring, might as well replace them if I'm going to have to pin them anyway, right?
Next step is getting the 50amp outlet installed outside, get a few bisques in, and then try making this raspberry pi controller.  Not a bad kiln for 75 dollars I think.  Anyone know a cheap electrician? Haha
 
I made some divided plates last week and my wife likes them so I'll make some more this week.

Picked up a used kiln yesterday.  Crucible 234, inside dimensions 23x18.  It's a cone 10 electric with 3 inch brick.  It needs new elements and two of the grooved bricks have chipped but overall good condition!  The person I bought it from only fired to cone 06, so that's nice. The elements are functional but bulged in the bottom ring, might as well replace them if I'm going to have to pin them anyway, right?
Next step is getting the 50amp outlet installed outside, get a few bisques in, and then try making this raspberry pi controller.  Not a bad kiln for 75 dollars I think.  Anyone know a cheap electrician? Haha
 
I made some divided plates last week and my wife likes them so I'll make some more this week.

Picked up a used kiln yesterday.  Crucible 234, inside dimensions 23x18.  It's a cone 10 electric with 3 inch brick.  It needs new elements and two of the grooved bricks have chipped but overall good condition!  The person I bought it from only fired to cone 06, so that's nice. The elements are functional but bulged in the bottom ring, might as well replace them if I'm going to have to pin them anyway, right?
Next step is getting the 50amp outlet installed outside, get a few bisques in, and then try making this raspberry pi controller.  Not a bad kiln for 75 dollars I think.  Anyone know a cheap electrician? Haha
 
I made some divided plates last week and my wife likes them so I'll make some more this week.

Here's that last load that came out last week.This is the kiln load in above post
It was a loose load -what I call a year end clean up fire.
Now its a everyday selling pots  at my pottery booth and dropping pots off at my 9 outlets in this county. Xmas is go time in my world.
The 25th is time to put my feet up. Then its stock up the outlets for the slow winter months.