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Rex Johnson

Member Since 27 Jul 2010
Offline Last Active May 17 2017 12:23 PM

#126075 New Kiln Burners

Posted by Rex Johnson on 02 May 2017 - 09:36 AM

I'm terrible at this math stuff...according to the Ward link my 2' x 3' x 4' downdraft requires...?...I'm never sure.

That said, my kiln is only 4 1/2" softbrick thick with a 1/2" outer layer of fiber blanket sandwiched within sheet steel and a 7" softbrick flat roof and about a 12' chimney.


I have two squirrel cage blowers on with 2" Sticktite burner tips on about 12" length pipes with the appropriate propane sized orifices.

My propane tank is a 250 gallon that has 1" gas pipe running about 22' away from the valves.


It takes a lot of adjusting and monitoring to get this puppy to cone 10 which is why I decided to go with cone 6-7 clay and glazes last year.


Per Ward's formula 2' x 3' x 4' x 30,000 BTUs/cu. ft. = 720,000?


At any rate, I can do a strong cone 7 firing, fairly even in 8-10 hours.



#125738 Show Me Your Handy Dandy Spray Booth

Posted by Rex Johnson on 24 April 2017 - 02:59 PM

Though I work outside, spraying gets pretty messy.

I spray more stuff than I dip these days, platters up to 18", bowls of all sizes etc.

I've used a cardboard box with a squirrel fan but that didn't last long...


Outside of spending a big chunk on a commercial booth just to pull away the fog, I'm seeking an easy-up idea that will hold up to outdoor weather.


PVC and plastic? 2x4's and plastic? A plastic trash barrel?

What's your 'brilliant!' idea?....


#115614 Pulling Walls

Posted by Rex Johnson on 03 November 2016 - 01:41 PM



...yes! I made a few of these just for that reason, as blank canvases for my next saggar....

...here ya go kids,

well you get the idea...








How tall are those and how much clay did you use?



This one is about 14-15", but thin-ish walls and a heavy-ish bottom.

I'm challenged, I admit it. It takes me a good 20 minutes to pull maybe 10-12 pounds of clay which is my limit.

Younger and stronger potters would pull that amount more like 18".

#115300 Pulling Walls

Posted by Rex Johnson on 28 October 2016 - 03:16 PM

...yes! I made a few of these just for that reason, as blank canvases for my next saggar.

The discipline of setting down and throwing cylinders is just that, discipline, especially for me.

I can't keep a beat with either foot...

First assignment in my Pottery 1 class was throw 10 exact cylinders.

So I do it once in a while.


Ofcourse because I can't keep a beat, and evidently have  no discipline, I wander...


same session >>>



#115290 Pulling Walls

Posted by Rex Johnson on 28 October 2016 - 01:18 PM

I'm working on tall cylinders right now using about 1/3rd of a bag, about all I can handle. Running from 11-15" wet.

I never used ribs in my former life as a potter.

Now that I do, pulling straight sidewall cylinders as much more controllable.

I'm finding that even if the piece has a varying wall thickness and/or slightly off center it can be corrected with a rib.

...that said, I am spending alot longer on one piece's symmetry.


#114269 Help! I Can't Center Anymore!

Posted by Rex Johnson on 04 October 2016 - 02:26 PM

...love it Antoinette!

#114268 The Only Absolutely True Rule For Potters. Pay Attention To This

Posted by Rex Johnson on 04 October 2016 - 02:13 PM

...the ugliest piece will have the best glaze...and vice versa... :blink:

#113598 Does Ceramic Fiber Deteriorate?

Posted by Rex Johnson on 22 September 2016 - 02:19 PM

...wondering...my saggar kiln made from a 50 gallon drum seems to take longer to fire after a couple years of use.

Yes, it sits outdoors, but it normally stays covered with a tarp in the winter.

Just seems to fire slower.

Maybe 2 1/2 hours in the past, but at least an hour longer to get to cherry red/orange.


better days...don't have a recent pic on hand but she's getting uglier woth age...




but hey, here's a pic of the studio cat...


#110110 Cobalt For Brushing Decoration - Keeping It Mixed...?

Posted by Rex Johnson on 14 July 2016 - 09:22 AM

I'm still having a heck of a time trying to get my cobalt oxide and carbonate with water to stay consistent for brushwork.

I don't remember ever having this issue.

It just settles at the bottom of the jar, and very quickly making it hard to get a consistently loaded brush.

I like to use cobalt for alot of accents and drawing but it's always a pain...


Any ideas?



#109764 Correct Camera Lens For Product Photos?

Posted by Rex Johnson on 06 July 2016 - 01:15 PM

Looking at buying an affordable camera for shooting my pieces.

Not sure what the correct lens I should get, Macro? 50mm?


I should know this stuff but my memory fades...

Though my iPhone takes great photos, the wide angle distorts the piece, giving a false impression.

What do you use?



#109139 $700 Pacifica Wheel?

Posted by Rex Johnson on 21 June 2016 - 03:11 PM

Nice layout, big head and work area, but I'd never buy one again.

I bought mine because I was starting and wanted a new wheel, and they were cheap.

I've had nothing but troubles with the foot pedal. Returned twice, now it's acting up again.

Note to buyer, DO NOT get the foot peddle wet.

Design a potter's wheel that can't get wet? Hmmm...not too smart in the engineering dept.

Otherwise it's nice, it's quite, I like it.

Sell you mine for $400...

#102988 Potter's Marks

Posted by Rex Johnson on 02 March 2016 - 03:12 PM

After brushing a sig I got lazy and thrifty and use my fathers metal stamps, quick, clean, and easy.

Bottom mark is the clay type...



#101716 Paper Clay - I'm New To This...

Posted by Rex Johnson on 09 February 2016 - 01:52 PM

Mostly decorative for the saggar pieces I'd be using for.



#96214 Horse Hair Firing

Posted by Rex Johnson on 23 November 2015 - 03:26 PM

...the biggest thing is getting the temperature just right when you pull the pot out.

Too hot and the hair will just vaporize above the surface and leave no mark.

Fire up a few and test at different temps.

#93495 Does The Glaze Fit The Clay Body? Need Input...

Posted by Rex Johnson on 30 September 2015 - 09:46 AM

O.K., I'm still experimenting with a few glazes ^6-^10. (below).


I'm satisfied with the glazes and their outcome for the most part.

Using the Olympic 2728 kiln is finicky as some of you know, fires hot on the bottom by about a full cone from the top.

That being the case, using mostly ^6 and ^6-10 glazes shouldn't be an issue either.



Since Laguna Clay is where I get my clay locally I'm using B-Mix ^5 -^6 WC-401and ( WC-436 ) (w/grog)  from Laguna Clay.

The problem is the ^5-^6 clay evidently can't take the heat.

At ^6 and above it starts to melt, warp, fracture the pots feet, and on the bottom the clay is blistering (bumps) under the glaze.


Maybe I should be using ^10 B-Mix.

You tell me.

One fellow said if I go to cone 10 clay there may be a problem with the glaze fitting the clay body.

But who makes a cone 6-10 clay body :huh: (???)


The glazes I've been using are those from the CA Tried and True PDF.

Also a couple Coyote ^6 glazes


Temmoku Glaze- "A Cone 10 recipe that works equally well at Cone 6; yields yellow “tea dust” crystals in

Malcolm Davis Shino - "cone 6 or 10 or anything in between... and quite possibly even lower. "

Coyote Shino ^6

Coyote Iron Phoenix ^6

Pete's Black Gloss ^5-^10


I have my schedule down, slow fired (7+ hours) with a 1 hour soak at ^6.

These are reduction at 1650 for 30 minutes and a very slow cool down once shut down.


Third time hasn't been a charm but the glazes are really nice.


Top shelf but fractured foot from the clay actually sticking to the shelf. (B-mix 401 w/o grog)



Mid/top Temmoku w/Pete's Black  this one survived without incident (B-Mix 436 w/grog)



Bottom shelf, Malcolm's Shino w/Temmoku (B-Mix 436 w/grog) but warped foot, and you can see the clay body blisters in this pic...