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Rex Johnson

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  1. Like
    Rex Johnson got a reaction from redbourn in How to Push Gas Kiln through Stall?   
    Yeah,  counter to common sense,  turning the gas down will indeed help the heat rise. But it's all about the air/fuel mixture and the flue draw.
    I have to watch my Olympic bottom burner kiln real close. Bisque will over fire in a few minutes if I'm not on the ball...

  2. Like
    Rex Johnson got a reaction from Pres in Beginning wheel throwing projects   
    My first instructor was well traveled in the orient and a believer in the discipline.
    Our first assignment was to throw ten 10" cylinders of the same diameter.
    If you cannot,  then throw until you can.
  3. Like
    Rex Johnson got a reaction from nancylee in Beginning wheel throwing projects   
    My first instructor was well traveled in the orient and a believer in the discipline.
    Our first assignment was to throw ten 10" cylinders of the same diameter.
    If you cannot,  then throw until you can.
  4. Like
    Rex Johnson got a reaction from Rae Reich in QotW:When, where, what, or who influenced you to begin your journey into pottery? If you care to share: what was it exactly about pottery that drew your interest?   
    In JC I was immediately drawn to the feel of the clay, the tactile 'quality', and the process. I liked how I could manipulate clay into a 3D 'something'.
    The relative immediacy made the effort rewarding in itself. Having endured painting and drawing, clay was actual fun.
    I still feel the same way to this day.
    Having said that, I was later drawn to glassblowing like a moth to...talk about immediacy!
  5. Like
    Rex Johnson got a reaction from Rae Reich in Seeking advice on reduction firing with Gas Kiln   
    With an updraft like you have (and I have), in my experience,  you're going to get flames coming out of the flue hole at some point in the firing to get it to target temp.
    There's always going to be some reduction in the atmosphere. However some flame is okay, it's when fuel is not being burned and you see smoke that it's in heavy reduction.
    You need to monitor that flame to where you're not getting smoke.
    On the stacking 'protection' bricks on top, try instead making a 'chimney' (4 sides) using the same bricks next time. I'll use 3,4,5 hard bricks stacked on their sides or ends. This will help draw the air up through the kiln.
    I'll use a a piece of 1/2" kiln shelf as a flue to adjust the flame and reduction. My kiln is super sensitive to this. Just a 1/4" move i the flue makes a difference.
    You have to be delicate in moving it as there can be brick crumbs that will fall onto your ware through the flue hole though.
     
    One way, bricks standing on end...

  6. Like
    Rex Johnson reacted to hitchmss in Seeking advice on reduction firing with Gas Kiln   
    little kilns are IMO much more difficult to maintain atmospheres than a bigger kiln. The small nuances in primary and secondary air make huge impacts in the atmosphere.  a 1/4" closed on your damper might eqaute a 2" on my bigger 60 cubic foot kiln. An O2 sensor would allow you to visually understand what is happening when you make small tweaks to your setup, but without one you're going to have to rely on learning the flames and what that means to your glazes and desired results. You may end up finding out that reduction is great for some glazes and not for others; when I was a noob I thought if it wasnt reduced then it wasnt worth it (big flames are coooooolll!). Most of my work is now cone 12 ox, except for my cone 10 copper reds.
      If you've never learned/experienced reduction before, reduction is gained by eliminating/reducing the amount of O2 in your kilns atmosphere. This is done via two different methods, or combinations of them; increasing fuel source to air ratio, increasing air source to fuel source. Fuel source is controlled only one way; either add it in, or back it out. Air is controlled by your burner, burner set up, or damper. Primary air comes in through your venturi burner tube; you can adjust this with the rotating dial on the back of your burner. Secondary air is just as important as your primary air; secondary air comes in from any other source (mainly burner ports) of air in your kiln's exterior; secondary air is mainly controlled by the damper. Close the damper down, there is less draw in the kiln, less secondary air getting sucked in, consequently less heat, but also less Oxygen=reduction. Open it up, there is more air coming in, more heat, and less reduction. Your burner tip should be about 1" at least away from the burner port itself; this allows adequate secondary air to enter. You can also increase the amount of secondary air by having your burner ports being a "funnel shape"; on a 4.5" or 9" wall this is done by cutting the bricks around the burner port to have a bevel angling into the kiln. On a 2" brick I would not advise cutting the brick away. If your kiln stalls I would suggest fiddling with the damper before messing with your air/fuel controls. More fuel does not mean more heat. After I enter reduction at cone 012-08 (depending on glazes) I dont mess with my primary air, only fuel amounts and damper settings.
       Finding the right amount of reduction, how long of  a reduction, and what glazes like it will take a while. The small kilns allow you to fire more regularly, but IMO they are harder to learn on because little changes make a big impact, so keep accurate notes and have ways to measure your actions (small notches drawn on your kiln lid to measure damper adjustment, turns of the dials, etc).
    As far as seeing your cones; all the above suggestions are great; a reduced atmosphere is often times even harder to see your cones in. If possible I like to place contrasting objects behind my cones; same principle as in a electric kiln when your cone pack is placed in a line of sight, but in front of an element channel (provides contrasting colors in the heat). In a gas kiln I like to place objects which dont offer a completely same surface behind my cones. I also blow on them sometimes when I cant see them clearly; be careful doing this...many a beards/eyebrows/hair lost to practices like this. A quick puff of air cools the cones down momentarily, but to get close enough to do so is a hot zone. Cones also need to be near the spy hole for this to work. Welding goggles and practice. Good Luck!
     
  7. Like
    Rex Johnson got a reaction from VladCruceanu in How to Push Gas Kiln through Stall?   
    Yeah,  counter to common sense,  turning the gas down will indeed help the heat rise. But it's all about the air/fuel mixture and the flue draw.
    I have to watch my Olympic bottom burner kiln real close. Bisque will over fire in a few minutes if I'm not on the ball...

  8. Like
    Rex Johnson got a reaction from Rae Reich in Why make functional ware?   
    I ask myself this all the time. My answer is my wife and her friends want this utilitarian stuff. Fine.
    In the back of my mind I keep telling myself,  'if I had more time all I'd do is make art'...
    Cups and bowls cups and bowls cups and bowls. I have way too many of them so come and get'em ladies!
    I have to think of the making part as the process I enjoy if it's not redundant, but it's also essentially that they are all blank canvasses for me to have some real fun with.
    Still there's not enough time to really cut loose, 'cuz them ladies want certain colors...
     
  9. Like
    Rex Johnson got a reaction from LeeU in What’s on your workbench?   
    First day of the season it looked like this...

  10. Like
    Rex Johnson reacted to liambesaw in What’s on your workbench?   
    Got some jars and lids thrown, I was going to trim the ones I threw over the weekend but with typical Seattle 95% humidity and a light drizzle, nothing has hardened up one iota.  Not even hard enough to alter the forms or decorate.  Hate this time of year, everything gets put on slow mo.  Gonna try to clear out some shelves so I can at least carefully free up some bats.

  11. Like
    Rex Johnson reacted to liambesaw in Why make functional ware?   
    My observation is this:
    My kids get excited to choose the bowl or cup they drink out of.  They have favorite ones for different foods.
    I've never seen them get excited to eat off of an Ikea plate or bowl.
    If a four year old can tell the difference between a mass produced bowl and one made by some dude in his shed, and somehow appreciate that difference, I think it speaks loads on why a potter might choose to make functional ware.
     
    Now speaking for myself, I make functional ware because it makes me feel happy.  Every part of the process from wedging to throwing, to making and modifying my kiln, to firing in my driveway, mixing and making glazes, all the way to sanding the feet.  They all bring me joy.  But the thing that really turns all that joy real, is when someone chooses to eat or drink out of something I made.  
    So in the case of a functional potter vs. a factory... Where's the joy?  It's rather one sided isn't it.  A factory worker doesn't meet the people using the things they made, they aren't emotionally attached to the things they make, there isn't happiness in every step of the process, and I feel that it shows. 
    That said, asking these questions on a forum full of potters is probably going to come with a lot of answers involving people justifying what they do.  So I think almost everyone here is preaching to the choir.  
    What I like to do, is talk to people and say these same things to their face. It's a lot easier for someone, even a skeptic, to understand the feelings and energy you put into an object, when you justify your craft in person.  Making functional ware is super interesting to people, we sometimes forget that as potters because things become 'old hat' or just another kiln firing.  Describing my process generally leads to "wow, all of that work goes into each bowl?"
     
    Anyway, I'm just rambling now, but this was an interesting read to me.  I've thought about these things before, but I've never written them down and made them real.  Wonderful place we have here.
  12. Like
    Rex Johnson reacted to yappystudent in Why make functional ware?   
    Let's face it, I do it for the attention from other potters. 
  13. Like
    Rex Johnson got a reaction from Rae Reich in Potters wheel comparisons   
    The ladies enjoy the view at the annual sale

  14. Like
    Rex Johnson got a reaction from Rae Reich in Potters wheel comparisons   
    Well, I sold my old Brent and Pacifica wheels last fall to eager students, but I still haven't got a new wheel...
    I didn't want to buy equipment and leave it out all winter in the weather, at least until I got a roof on the joint.
    That's finally done!
    I missed a few good deals on wheels I saw on Craigslist due to my day job taking up all my free time.
    Thought about the Soldner but the shipping is a deal breaker, so if I don't find a good used wheel, I'm about ready to order a TS Legend without the SSX drive.
    Free shipping but now I find out they are 3-4 weeks on backorder from the factory! Who'da thunk pottery wheels are so in demand...
    The new lid...it's like I own my own gas station >>>

  15. Like
    Rex Johnson reacted to neilestrick in How to Push Gas Kiln through Stall?   
    @kraythe The thing to remember with a gas kiln is that you're not just trying pump heat into the kiln. Rather, you're moving heat through the kiln. The heat comes in, is transferred to the ware, and moves out, to be replaced by new heat. It's a flow, and your kiln can only manage a certain volume of flow. Pump too much gas or air into it, and the flow bogs down.
  16. Like
    Rex Johnson got a reaction from Rae Reich in How to Push Gas Kiln through Stall?   
    Yeah,  counter to common sense,  turning the gas down will indeed help the heat rise. But it's all about the air/fuel mixture and the flue draw.
    I have to watch my Olympic bottom burner kiln real close. Bisque will over fire in a few minutes if I'm not on the ball...

  17. Like
    Rex Johnson reacted to Mark C. in Gas kiln stalled . Why?   
    So far I'm in 100% agreement on fixes.My guess is also the burners are starved for air(open the inlets)and to much gas added.
    Never close the damper all the way except when done firing.
    My air inlets are almost always set on full open and I just ass more gas . I have not adjusted them in decades once they are set right. The burners will roar later in firing.-noise is ok.
    Just loaded two glaze fires myself and am firing in am.
     
  18. Like
    Rex Johnson reacted to neilestrick in Gas kiln stalled . Why?   
    You should not have to adjust the air inlets on the burners durning the firing once you get them set correctly. You should be able to adjust reduction using the gas and damper only. For now, get as much air as you can without them roaring too much. Adjust the gas until the temp rises at the desired rate. Adjust the damper until you have back pressure out both spies. You'll have a lot out of one, a touch out of the other. It'll take going back and forth with the gas and damper until everything is working in sync. It is possible to use too much gas, so go easy at first, like just open a little bit. You should be gradually increasing the gas, and probably opening the damper as the temp climbs. Up till about 1600 degrees you can do just about anything and it'll get hotter, but start working on dialing things in starting at about 1000.
  19. Like
    Rex Johnson reacted to yedrow in Potters wheel comparisons   
    I do not recommend a Pacifica, we have one that is just a few months old and already we've had to replace the pedal and it feels like the bearings are going out. I don't like Brent for production use, but I think it would be a great studio wheel, and I like their kick/electrics. I know two production potters who love their VL Whispers, I personally don't like the RKs. I know one master potter who is pleased with his Bailey. I like the Soldner type of wheel, but they're a bit pricey for the average potter. Creative Industries makes cheap wheels, nuff said.
     
    I strongly recommend trying the pedal first. Lots of people talk about power, but if you have a weak pedal you are much more limited than if you can't throw a 50# block of clay. I know a 110# woman who can center a 6# chunk of clay as well as I can, and I'm a stout guy. Precision trumps power IMO. However, if you are planning on centering 15 or 20 pounds, you may want to go for a stronger wheel. If on the other hand you are planning on turning out coffee mugs and pie plates, a responsive pedal is top of the list. I can throw on anything, but a touchy pedal, well, it just makes pottery not fun.
  20. Like
    Rex Johnson got a reaction from D.M.Ernst in Potters wheel comparisons   
    The ladies enjoy the view at the annual sale

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