High Bridge Pottery

+1 for Ozone removing ALL of the odor (100%). Reasonable precautions of course - it is an irritant. The good news it’s used for water purification, removing smoke smell from fires, cars with years of cigarette smoke etc…. So extremely useful.
More good news, It’s hard to make more than about 3-4% concentration of O3  and it reverts to O2 in a fairly short time. If you set this up outside, then a box or simple plastic garbage bag is ideal. You do not want the generator to recycle its own output so basically a way to blow ozone / fresh air and let it leak out naturally.
Humans can smell extremely low concentrations of Ozone which contributes to its relative safety, sort of like mercaptan in natural gas products, most people can smell it very quickly. So if you do this, do it in a well ventilated area (outdoors) and stay clear while operating. 10-15 minutes exposure is often enough to remove any trace of odor and 30 - minutes post ozone production is often enough for all the ozone to revert to oxygen on its own.  A decent ozone generator ought to have specific warnings so read and follow all precautions for sure. 

Dunno if it would work but you could put them in a box with an ozone generator, just be careful not to breathe the O3.

Dunno if it would work but you could put them in a box with an ozone generator, just be careful not to breathe the O3.

I picked up a little Evenheat test kiln last Fall and finally got around to getting it up and running this week. It was in brand new condition, only fired a handful of times to low fire temps, but it was a cone 8 kiln, not ideal for all the cone 6 firings I'll be doing in it. So I talked with Euclids and had them make me some custom elements that bumped it up from 2000 watts to 2700 watts, a 35% increase in power. It should have great element life now. It was originally set up for 120V service at 17 amps, and with the new elements it's set up for 208V 1P service at 13 amps (wired in series). I gutted the control box, removing the Kiln Sitter and wiring, and installed a terminal block that connects the elements directly to the power cord. I don't need the sitter since I'm using a wall mounted digital controller. The controller has a Genesis Mini controller and a solid state relay- you can see the heat sink on the left side of the control box. I've been using this box for a few years now and it works great. It was originally an Orton Auto-Fire, but I modified it a couple of years ago to work with the SSR. I also put the thermocouple in a protection tube.
I had a successful bisque firing yesterday, and I'm running a cone 6 glaze firing today. I don't expect any problems, but it's still a bit stressful since it's a new setup. Fingers crossed!

That's true you could make them all 1.44 ohms instead on 240v and get 16.6amps and a 4kw kiln instead of 15 amps and 3.6kw. Looks like the controller has a 30amp relay so that shouldn't be a problem on the relay either and give you additional room for wear.
What size is the breaker on the kiln? 16.6amps +25% does just take you over 20 amps but it might be bigger anyway.

You might want to pick an original wattage to match and establish the new resistance to the original design using his current operating voltage. This way he will have the amount of designed heating energy available.
 
When electric kilns wear by about 10% they usually have trouble making top temperature. In this case since this is a very small kiln electrical and load, bumping this to 4000 watts likely has no effect on his current wire and breaker and could provide additional room for future wear.   Just a thought.

Good to know they are all the same besides the hairpin length. It can be tricky to get an exact read on these things.
 
Having them all at 2.2 ohms means the kiln is drawing just over 10 amps on 240v supply  so I am not surprised it wont reach top temperature/get there slowly. I would maybe confirm it with whichever company but the basics should be voltage/amps = resistance so 240/15 = 16 ohms for 10 elements in series and 1.6 ohms for each element.

Thank you for sharing. Doing the maths and either pretending the water doesn't exist in the weight after dipping or assuming the bisque weight it the same as fired clay weight and LOI is 6.5% you are somewhere in between 5-10% dry glaze for the weight of bisque. I always felt it would be 1% or less but never ran any tests to prove that to myself before now. I think for a glaze that could be thinner maybe 3% is the lower limit.
 
 

Thank you for sharing. Doing the maths and either pretending the water doesn't exist in the weight after dipping or assuming the bisque weight it the same as fired clay weight and LOI is 6.5% you are somewhere in between 5-10% dry glaze for the weight of bisque. I always felt it would be 1% or less but never ran any tests to prove that to myself before now. I think for a glaze that could be thinner maybe 3% is the lower limit.
 
 

You already got great reponses here so I  have little to add!  Most of my originals are sculpted in oil clay and initially I did all of my plaster molds directly from them.   If you are careful to use oil clays that are sulfur free you can also avoid most issues with rubber conflicts.   As already noted however, if you are pouring large plaster sections the heat can cause your oil clay originals to melt and deform just like with wax originals.
Once you get some practice and confidence, and you move into higher end pieces you invested a lot of time into sculpting, you may also wish to consider casting rubber masters.  If you make a rubber master of your original, and rubber master pieces of your mold parts you planned to use in plaster, then you can simply recast more plaster production molds over and over again from your rubber masters.  Plaster molds, especially those with very fine detail such as my work, are only good for about ten to twenty casts before the molds will begin to show wear.  The more detailed and complicated the mold the faster you will see problems, especially if you do not clean and store your plaster molds properly after each use.  Simple, low detail molds will last a lot longer.
VanTiki posts wonderful Technical Tuesday Youtube videos that may be hugely helpful to you to learn mold making.  There are also some great blog posts out there if you do internet searches.  Here's a great video on rubber master molds for plaster slip casting right here.  He posts a lot of videos on regular plaster mold making so look him up!
 

Here is another VanTiki video, this one only focusing on making a plaster mold.  This one also shows you about how to make your mold walls using wood (usually a simple box you can slide to adjust sizes, this one is more of a chair form.  You can also make your molds using Lego blocks instead of sealed wood which is my choice when I'm making smaller molds to pour.
 
 

Coil spacing varies greatly from kiln to kiln, and yet they all work. There's a lot of leeway in the math. If you're using the same thickness wire and the same size winding mandrel as the original element then you're good to go. Wind it up and stretch it till it fits. Easiest way to do it is to lay out a length of wire on the floor that gives you the correct resistance (measure from ends with a meter) and just wind that up.

Test tile weight results on 2 test tiles about the same thickness as my pots, maybe a tiny bit thicker.
1 - bisque weight 48.51 grams, weight just after dipping 53.39, fired weight 50.86
2 - bisque weight 54.97 grams, weight just after dipping 61.80, fired weight 58.32
sg of glaze 1.50, this glaze needs a heavy application to develop microcrystalline finish. 
Glaze LOI is 6.50
Yup, salty water and CO2.

8  / 0.3388 = 23.613m  Unfortunately, it's feet not meters. If I am wrong I would be happy.  But the inner diameter looks like 5 mm!

Sorry I probably didn't explain it the best. I don't mean paint a layer and let it set and then do the mold.
Once I have the mold box set up and ready to cast in plaster I will weigh out my plaster and cold water in the right ratio. Add the plaster to the water and let it sit for 1-2 min then gently mix with my hand for 2-3 minutes until I feel it slightly thicken. Now that I am ready to pour the plaster into the box I will use a brush dipped into the plaster and paint onto the form to get into all the detail and then pour the plaster into the box to cast the form. I found if I don't brush the plaster onto the form and just pour the plaster into the box I end up with bubbles on the casting surface.
 
I got the idea from this video, he is not using a box to cast the form and lets the plaster thicken up after brushing a lot more than I would to pour the mold but the brushing idea is the same. Later on in the video when he is pouring the plaster head you can see the kind of consistency I would pour the mold at after brushing it onto the form to capture all the detail.
 

16 awg might work if D is 5mm, couldn't find any exact numbers on what the internal diameter is but they look about 5mm. Can you post what the internal diameter is?
 
8  / 0.3388 = 23.613m
23.613 / (0.005 x Pi) = 1503 windings
1503 x 0.001291 = 1.94 meter (6.36 feet) length unstretched which you can stretch to 15 feet and is within the 2-3 stretch ratio
4.57 meter (15 feet) x 5 = 22.85 meter so under the 23.613 length of straight wire.

The existing wire is about 16 gauge, I just compared to wires I have at home. (I have Nichrome 12 ang 16 gauge) Here is the video where the guy make an element coil, he used wire of length 7 times  longer than stretched coil.  It seems Paragon didn't use Kanthal wire, 
 

Yep, that calculator.
You’re right. I was using volume measurement of 10 in the first box, not weight. (Facepalm)
You can neutralize muriatic acid with some bicarb or diluted ammonia, and might be good to keep some handy while working with it. For disposal, you’d have to check with whoever deals with household chemical disposal locally. Where would you drop off things like used paint thinner?

This one? https://pietermostert.github.io/SG_calc/html/brongniart.html it gives me 6.5g as the answer. If it's a sg of 1.4 then 10ml should weigh 14g? and 10ml of water is 10g? I use the post on clay art so (14-10) x 5/3 = 6.667 Unless I am wrong about the glaze weighing 14g.
 
I tested the glazed bisque again this afternoon and got 7.25% of bisque weight for a 2 second dip and 14.75% for the 6 second dip. Some off the loss from my previous value in % of the 6 second may be from touching it and a bit of water as my glaze is a little dusty on the surface and comes off easily.
I would be interested if anybody wants to try out weighing bisque then glazing and drying to see what values they get.
 
Finally got some HCl to try dissolving these crystals, just got to work out how to dry and weigh again after sitting in HCl as I am assuming it wont all dissolve. Need to read about safety and disposal, guess I should neutralise it before disposal and figure out a way to catch the crystals again. I don't want to ruin the mesh in my sieve so maybe coffee filter paper.

Firing to cone 10 is really the worst thing you can do to your kiln in terms of longevity. Elements in the US are currently about $350 a set (6 elements, sale price) so you could save $3-4 per firing on element costs. Relays will last longer since they'll cycle less and be exposed to a lot less heat. The bricks will definitely last longer since you won't be firing them past their actual temp rating (2300F).

There are other cost savings with firing to lower temps besides just the cost of electricity, big time if you're firing to cone 10 in the electric kiln.
- Extended element life. Firing just 04 will give you 2-3x the element life versus glazing at 5/6, double that vs cone 10.
- Longer kiln life
- Longer kiln furniture life
- Less energy removing excess heat from the studio (if you're running AC or fans)
Plus you can increase output with shorter firing schedules, and it's better for the planet.

10 - 20% of the weight of a pot is glaze seems really high to me too. I have a glaze firing starting later today, I will weigh a test tile or two and then glaze and reweigh it after firing. Rest of the pots are already glazed or else I would do some of those.

First cylinder of the day (yesterday)

From the top

Cut in half

Bottom was left thick on purpose - I like to trim foot rings.  But the walls were thicker than I was aiming for.  Also it flopped open like that when I cut it - they pretty much all did.  It wasn't flared like that before I cut it.
Second cylinder after cutting:

I intentionally aimed for a thinner bottom but that was thinner than I meant it to be, plus the island humping up in the middle is not my idea of perfection either LOL!  It is a lot taller than the first one, YAY. Walls are too thick especially towards the bottom so I tried again with cylinder 3:

I feel like I made progress getting the wall even and the bottom a little thinner than I usually like to throw but probably not thick enough to trim for the taller foot rings I prefer.  I like to be able to hold on to 'em while I'm a dippin' of the cup.  It's a couple inches shorter than #2 (I'm guessing that was around 6" tall) but the base is broader than it was on #2.
Given that up until a few days ago all my cylinders flared out at the top like upside down volcanos (Cylinder? We LAUGH at your cylinder!  We are BOWLS!) I think I've made a big improvement. If you bigify the picture you can sorta see one of my lopsided off-center vases in the background from last week.  Told ya they look funny when they get off center LOL!
Obviously there is room for more improvement but hope lives yet in my heart.
I'm working on trying to get the base smaller, but I think I have to use less clay to start with.  The instructor's advice is to use 3 lbs, and cut the top off.  But if I throw with that much clay I end up with a wide base, or else I have a tall blob to turn into a donut.  That doesn't seem to work out so well.  
@Hulk I'm not really right handed for "most things".  Just the most common things like writing and using a knife. And hand sewing, come to think of it. Pretty much had those drilled into me by other people. But most anything I've been left to my own devices, especially darts which I took up in my late 20s, I use my left hand by preference. I still, after all this time, occasionally pick up a pencil with my left hand and start writing.  I switch because the left hand doesn't write as well as the right (given I've had 55 years more of right handed practice LOL!)
And now here is a picture of something that I feel turned out fairly well other than lack of planning.  I should have etched the lines in BEFORE I chattered, like Hsin Chuen Lin - I want to grow up to be like him! The thick line was supposed to be 2 thin lines but the 2nd line got caught on the chattering and jumped the tracks so I had to hand carve it into one big line.  You can see where the top line also jumped the tracks.  I left it.  But I think my chattering is coming along!  See the nice little line  around the foot rim?  For catchin' drippy glaze, I hope.

So, I undertook an 800c biscuit fire and the only difference I noted was the fired ware  was not quite as white as usual for my 1040 fire temperature. No difference in strength, just a shade darker, which must mean something.  I then fired a glaze kiln to 1040c,( EW) with some of the glazed 800c biscuit ware and the normal white shade reappeared, no pinholes or any visible crazing. (. I usually mix biscuit and glaze firing at 1040 for efficiency if I don’t have a load full of each.)  One other question… I hear the “biscuit high and glaze low “ quote often,  but what is the consensus on the temperatures for each of those…. low and high ? 

I would say in general colouring the clay and glazing with a transparent gloss is going to be the safer option for the end user but there's so many variables in pottery that there's no one size fits all answer. 
 
https://digitalfire.com/picture/L9hivqD172
On this page Tony says "Stains are inherently much safer to use than raw metal oxide colorants because they are sintered as colorant/stabilizer blends. And much less is needed." So it is possible to make a black/coloured glaze that's food safe but it requires testing.