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Member Since 09 Mar 2013
Offline Last Active Yesterday, 11:06 PM

#56501 Cone 6 Body Or Cone 6-10 Body: Much Difference?

Posted by Biglou13 on 11 April 2014 - 03:54 PM

This unfortunately takes LOTS of test firings.  You need a small test kiln that matches the firing type of your "normal" firings (oxidation/ reduction/soda/wood etc.).
To plot the "cone 6 to 10 clay" for Apparent Porority .... you'd likely fire to cone 3, 4, 5, 6, 7, 8, 9, 10,  11, 12, 13 ...and for accuracy... put in the half-cone firings as well.

I don't actually think ill actually do the tests.......
The homework was ...... I spent hours on the Internet studying MOR, and porosity curve....
I will apply the knowledge to emprical results. And guestimations.

Me likes crazed!!!

#56041 Clay Body Or Glaze Fit Problem - Shattering Cups

Posted by Biglou13 on 03 April 2014 - 10:54 PM

Ok the pattern of breakage is similar to crazing, Albeit larger crazing.
My wild guess is mis match in clay to glaze
My WILD guess glaze contracted while cooling faster than clay. Or maybe (not so much) vice a versa.

If I knew what I was talking about I'd say you need to match the COE/ thermal expasion. Of glass to clay.

Please note I'm not a " brain trust" (I have stayed at holiday inn)

#55796 Formulating An Exceptionally Refractory Clay Body.

Posted by Biglou13 on 30 March 2014 - 08:05 PM

Funny I read your post early today.
I just watched +ulfbehr+t documentary and thought ... Ingot......

My " making clay" brain went to work immediately.
I thought epk, and something to hold it together.... My guess wasn't too far off seeing recipes. Epk being cone 35.... (And I consider it a local clay)
Then I thought forced air/ power burner. (Which I have most of parts for, short gas plumbing parts) ( sure beats pumping the bellows)
Simple "kiln". 2 chamber "beehive-like" hard brick kiln. ( the bricks are in my yard), refractory mud. small hardbrick chamber for crucible, followed by space then beehive....
Did I tell you I like sharp objects (knives). (Attended FMA seminar today, by renowned authority)
I then thought ....too bad your not closer 'cause I'd help you and trade you use of all my parts for something sharp. :(
The formula for the crucible refractory mortar....... Has Left me wondering???? Guessing......
What did they use for refractory material in 300 b.c. In Damascus, or 1000 AD for ulfberht. Since Edgar wasn't around yet.???

Ramble off.....

Let's know how this metallurgic and ceramic marriage works out.

#55509 Ash Glaze

Posted by Biglou13 on 27 March 2014 - 07:30 AM

Added 3% GB

Can't tell from bad picture but it glassed up more , from matte ish finish.
There some more green in the throwing marks.

It's not the "ash glaze" look But still attractive and interesting glaze

Unfortunately can't do cone 9 tests.

I think I'll add some frit..... Next test

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#55309 Best Clay To Start Throwing With

Posted by Biglou13 on 24 March 2014 - 02:25 PM

Sometimes it's not the clay formula.
Often clay may have sat too long and gotten dry.
Others must be wedged and need to be woken up.
Some bodies are just plain finicky, like some porcelains.
Sometimes it's the potter not the clay that is the problem.
Some clays are difficult until well aged.
Some clays are too wet.( probably not in your case)

Are you wedging before throwing? How does it feel when wedging?
Try wedging a few 1.5 # balls, place very damp face cloth/towel on it. Place in air tight bag and revisit in a week. Place a few balls with no damp towel in other air tight bag.

In a week or so re wedge and throw from each bag. If clay behaves better. Your clay was dry.
As always in pottery frequent testing is the norm.

Better solution is to have a experienced potter throw your clay and give opinion.

#55161 Another Kiln Issue

Posted by Biglou13 on 21 March 2014 - 09:36 PM

I'm new is it an option to run multiple thermocouples?

I have a Feeling I'm going to burying my nose in skutt and paragon websites this weekend.......

As always in pottery the more I learn the more I realize what I don't know......

#55155 Different Ways To Sign Pots

Posted by Biglou13 on 21 March 2014 - 08:26 PM

Sharpened pencil
After trimming
I've used a stamp in past

For now it feels more personal to actually "sign" with my mark

Sometimes need to be hit with diamond pad to smooth down after bisque

I usually just hold my pots and dip leaving finger marks. Some get covered sometime not.

I ve been doing this x3 on bottom of most pieces

The 5 lines while minimalist are my initials. LEC

While not as bold part of the inspiration came from koie ryoji, where his bold signature sometimes part of the decoration of pot.

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#55056 Casual Workshop Questions

Posted by Biglou13 on 20 March 2014 - 10:59 AM

Have all attending work shop bring a small piece and place in brown bag. Everyone the picks a bag hopefully not their own.

Hawaii is rough, I can offer to be your assistant while your there, I even look like local.

It's Hawaii relax bruddah, You could go without syllabus or planning and have a spectacular workshop, being a production potter you have and have shared a wealth of knowledge here in this forum, I've seen your work and I'm sure da attendees will be equally pleased.

My crystal ball says you prolly will return to this place, and don't forget da flip flops , and maybe read a pidgin book on way out.

#54821 Trimming A Foot For Bowls

Posted by Biglou13 on 16 March 2014 - 07:56 PM

Practice, you must
Numerous the cylinders, must end up cut in half.

There is no fast track secret.
But scour the Internet and you tube. There are measuring systems

You could read the rest below, or stop,here and just re read and practice the first two lines.

I use needle tool to measure bottom and wall thickness,
Then place same measurements by marking clay on side and bottom.
I subtract , approx finished wall thickness an mark on side
This mark is absolute do not trim below this.
Then memorize shape of inside of bowl
Outside should match
With needle tool and bowl spinning mark approx foot size.
Then I first trim down to line at outside diameter. I begin tapping at this point to get a feel for thickness
Then I trim inside of foot to depth and diameter, tap check
Then trim and shape of bowl, tap check
Fine tune transition of bowl to foot, tap check
Clean it all up. Tap check

For now .Throw bottoms a little thick approx 1/2 inch, dry slowly

In actuality I needle check depth and make the marks, trim to depth, from there on its intuitive, and feel, after awhile you will know how thick your throw , how thick you trim. As of late ill needle check thickness then, fly by the seat of my pants and trim on pure blind faith. (Or just faith)

But above all practice, cut many in half, and keep,few to none

There is some saying about a thousand bowls.......
I'd like to add 1000 cylinders before those 1000 bowls....
(Im still working on my cylinders every time I throw, it's become 1medtitation, I will cheat and throw a bowl,every now and again)

Dave , welcome.
Tell us where you are from
Pottery experience
Pottery influences
Post images in gallery
Etc etx

#53397 Searching For Discontinued Glaze - Help? Also Lead Questions

Posted by Biglou13 on 25 February 2014 - 04:35 PM

There is a difference between food safe and sanitary safe.

I'm a fan of glazes that often craze.

the clay underneath is vitrified in the pieces that I make.

The question is can crazed wares be made food safe with proper sanitary procedure, or convenient sanitary procedure in home and or commercial kitchen.
I can't tell you how many times I've been to restaurants and silver/table ware isin't physically clean. While it may have been through sanitizing solution, any physical residue is a fail.
Don't even get me started on cleanliness of glasses in hotel rooms.
A 180 F rinse cycle is acceptable or dilute bleach rinse are acceptable. Both of which I'd take over other chemical solutions.
If you really want to test for crazing write on a light colored piece with a sharpie, pause then wipe away surface before it dries.

I'm looking forward to seeing the results of your study John.

Ps. I drink from crazed pieces daily.

#53200 How Wet When Throwing?

Posted by Biglou13 on 22 February 2014 - 08:19 PM

Slurry guy here...
I call it butter
I haven't given up the splash pans ... Yet.
I threw about 15 pounds o clay the other day and I could still see dry spots on bottom of splash pans

#52674 You Know You're A Real Potter When....

Posted by Biglou13 on 15 February 2014 - 09:59 PM

A. Making 20 or so yunomi, In the process off trimming, ware board falls, then without emotions clean and sweep up and put pieces in recovery bucket. knowing that the next iteration, or life of this clay will be better ( ok that just sounded a bit Buddhist). Realizing The time spent making then recovering was not wasted.

B. Realizing I'm spending most if my days off (from money job) involved with making pottery.

C. Driving an 8 hour round trip drive to get some pieces woodfired. And can't wait to do it again.

D. When some guy (at day job)(and I've never met) callsme the tea cup guy (today) And wants to see my web site (which I don't have) (except for pinterest)

E. When people at pottery studio can distinguish my cups and bowls from everyone else's work without looking at sig.

#52252 Slab Construction Shrinkage Issues

Posted by Biglou13 on 11 February 2014 - 10:58 PM

That's a lot o shrinkage....

#51865 What To Concentrate On...

Posted by Biglou13 on 06 February 2014 - 10:56 PM

Cylinders, cylinders and cylinders.

After a while you may call the handle less mugs, small ones yunomi, really small one guinomi,

The often become test tiles/ cylinders.

Reclaim many keep few. ( I just realized my reclaim bucket is heavier than my clay bucket)

Make your zen practice throwing cylinders.

If I learned really learned, embraced the cylinder earlier, (not just just a few months ago) my work today would be light years ahead

Wait did I say cylinders.....

#51426 Grog in clay for throwing

Posted by Biglou13 on 31 January 2014 - 07:52 AM

Milling your grog isin't that fun or easy.

Grog size also plays some importance. So screening may be necessary.

Sometimes silica sand can be used a grog, cheap and easily available.

I really like the feel, and like to work with groged clay. I will usually just add when wedging.

I've even added what some would consider pebble size. (Chicken grit)

If I were you I'd just buy some med and or fine grit to start with.. And see if groged body agrees with you.