Hulk

Welcome--there is a place here for everyone and the levels of training, experience, output, styles, etc. etc. are quite varied. Members are very helpful with using/learning correct terminology, chemistry/science of clay & glazes, properties of various clay bodies, formulating glazes, using commercial glazes,  different types of kilns & fuels-the forums pretty much cover it all, including the business aspect, studio set-ups etc. etc. For some questions/discussion, it helps to post pics along with questions/details of the issue.

Thank you very much 

Hi Earl and welcome to the forum!
You are more than welcome to ask your newbie questions in any of the forum sections! If one of the mods thinks your question should be moved to a more appropriate  section to get responses then we will move it with a link to where it's moved. There isn't one section specifically for new potters but it's very  helpful to say you are a new potter when asking questions so you get answers in keeping with your experience level.
PS - I am going to slightly edit this thread title.

Thanks Min.  
And thanks Calle and High Bridge

@Callie Beller Diesel You could write it out as:
dry weight = portion weight / total weight x batch weight
 
You could either work it out per bucket of slip or make sure to take the dry weight off the batch weight for next time you work it out. Using Callie's example ~
1500 / 7500 x 5000 = 1000 
if you wanted to keep working it out every time you need to take off the 1000 of dry weight from the batch weight for next time so it would be
1500 / 6000 x 4000 = 1000 (assuming you haven't lost water to evaporation) 
 
If the slip is thin enough to measure the volume accurately you can weigh a volume of slip and then
(volume of slip weight - same volume of water weight) x 5/3 = dry weight
 
If you can measure the specific gravity and know what dry weight you need you can also work out what volume of slip you want with
volume needed = (3 x dry weight) / ((5 x specific gravity) -5)
 

Another option would be to put the full 5kg batch into a pail with a lid that can be sealed on (twist type pail lid) then roll it and flip it around for 15 minutes or so. Leave the pail sit for a day for all the dust inside to settle then scoop it out just like any other dry material. If it sits for a while then roll it around again before using. I do smaller 500 gram test batches of base glazes like this all the time using a large freezer ziplock bag.

If you’re wanting to mix a large master batch that then gets divided out, leave out the dry mixing entirely, but weigh the water. If you know how much water went into the batch you can divide it out evenly. If you keep to metric measurements, this will be easier, because 1 ml of water weighs 1 gram. It doesn’t work like that for all fluids, but it does for water. If you are used to using a measuring cup, check how accurate it is by filling it to a given measurement line and weighing it to make sure it’s close enough for your purposes.
For instance, if you add 2500 g of water to your 5000g batch, the whole thing will weight 7500g, so a quantity of slip that weighs 1500g will contain 1000g of slip base. (Numbers made up off the top of my head for ease. You may have to play with your water additions to get your consistency right. Just record what you did.)
From there, you can add your colourants to portions of your master batch. To mix thoroughly, you will need to use a stick blender that rotates really fast. If you use something slower like a jiffy mixer, you’ll have to let it mix a lot longer to get everything distributed properly. For some colourants that don’t break up easily, you may have to sieve the mix again. 

Hi High Bridge and everyone! I am back with good news! last week I did firing with the new elements we made and my kiln reached cone 6 temperature in 4.5 hr, yay...
I didn't buy 12 g wire, it was too expensive, instead, I bought 14 g, cut enough wire to make 8 ohms for each element, winded it, then stretched it to the length we needed, and installed it. Accidentally, the rod I was winding the wire on had a perfect size and fit perfectly. Later I realized that if the rod was bigger I would not be able to insert the elements in the grooves.
Changing the elements was so much simpler than I feared. I probably was reading  F.Olsen's book too much, lol. But after all the self-doubt I made my kiln work, and thank you for your support!
Elena

What defloculant(s) are you using?  If there are other dispersants/rheological-modifiers about there may be interactions.
I've no idea how the various sorts of deflocculants interact, so speculation follows.
> Antiprex 461 is an aqueous solution of low molecular weight polyacrylic acid
> Alcosperse® 149 is a pale amber liquid acrylate-based dispersant
BTW https://digitalfire.com/material/sodium+polyacrylate
Sodium polyacrylate dispersants like Allied Colloids 311 and Darvan #7 are used as an alternative to sodium silicate in casting bodies used in ceramics.
If you are currently using a polyacrylate defloculant it might be worth trying to something else/in-addition  as there are already polyacrylates about.
https://digitalfire.com/article/deflocculants%3A+a+detailed+overview
PS
Just for the record, a back-to-basics "lab-technician" guide to optimising the level of deflocculant in a slip
https://static1.squarespace.com/static/527ac372e4b0d4e47bb0e554/t/527fd7f1e4b0c046bfa9b90d/1384110065234/Dispersant+Addition+Procedures.pdf
... and a longer presentation with  some pictures
https://www.yumpu.com/en/document/read/34584429/slip-casting-alfreds-clay-store

... I've no idea how this sort of clay interaction would react with the more ionic deflocculants
IIRC neither discuss the use of multiple deflocculants (except soda ash + sodium silicate)

Thank you for the links Peter. I'll have a look and get back to you. We found previously that the antiprex helped with the slip solution if we had added too much alcosperse.
Tom, the measurements are mL. Apologies for not stating what alcosperse and antiprex are and their units.

Antiprex, a dispersant, rheology modifier, per worldofchemicals.com
Antiprex 461 is an aqueous solution of low molecular weight polyacrylic acid. It is an effective dispersant and rheology modifier for kaolin, gold processing slurries and other mineral suspensions. It functions as an efficient antiscalant for the prevention of scale deposits including calcium carbonate, calcium sulphate, strontium sulphate and barium sulphate in industrial systems.
Alcospere, a dispersant, per manufacturer's website
Alcosperse® 149 is a pale amber liquid acrylate-based dispersant designed for general use in kaolin, calcium carbonate, paints, paper coatings and a variety of pigment slurry applications.
Just curious.

Hi Alistair,
Welcome to the Forum.
What are the units for those two ingredients?
 

Also, I have considered that it is an issue of the inside bottom is glazed, while the outside bottom is not. In that case, I will need to throw the base thicker, so that I can trim on the bottom to have enough space for glaze on the bottom also

@Jeff Longtin                            Wow, didn't think of making slabs for them.!! 
I have a lot of straight preserving "bottles".
I find beginners, unless taught properly, hmm, have quite a lot of failure re coils not squushed, scored and slipped.
Thickish slabs would give the choice of shaping,or/ and texturing.
Thank you Jeff.

That sounds like fun Babs. Congrats!
I would steer the women towards coil building mostly. That allows them to make a pot, of any size, of their choosing. Any time I tried to pinch a pot I was always limited to making small cup forms. (To make a tall pinch pot you really need to let the clay stiffen for a period of time. Is that something you can do in this limited situation?)
If you choose to offer slabs of clay maybe you could bring coffee cans or plastic bowl forms that they can use to mold the slabs? Maybe cardboard tubes as well?
When I was in my 20's I worked part time at a daycare center down the street from my studio. One day the head teacher, Dawn, asked me to introduce the kids to clay. For each of the kids, 15 in total, I made small slabs of clay and a few coils. Seven of the children decided to make nests with their slab and coils. What was really cute was that each off the kids had a little story to tell about their nest. (Each had also made little ball forms which represented the eggs.)
The whole experience went in a direction I did not expect and was rewarding as a result. I hope you have similar success.

Whoa! Nice catch Neil. It's 10 bricks per ring, a 1027 with a 1227 control box. I don't have any provenance on the kiln, it was at the school when I was hired. I'll double check the electrical service. 

Maybe you've got a Frankenkiln and that control box isn't original to the kiln. How many bricks are in each row of the kiln? A 1227 should have 12 bricks. A 1027 will have 10 bricks. In your photo the angle of the bricks looks more like 10. And if that's the case, you'll need to double check your setup to make sure you actually have 208 volt 3 phase service.

I would get the larger kiln. 8 sided kilns are fairly limiting in what you can fit in them.
You can get a wall mounted digital controller from Skutt or others, which basically turns your kiln into a digital kiln. You'll still have to turn on the Sitter, but the firing will be controlled by the digital system. They're not cheap, but you'll still be saving about $1500 vs the cost of a brand new kiln.
With a used kiln, make sure the bricks are in good condition- only small chips, no large breaks. Also check the lid and floor for cracks that go all the way through. Hairline cracks are normal. Also, if the bricks are very yellow in color then that's a sign that they've been fired a lot and are near the end of their life. White/cream colored bricks are what you want.

None that belong to me.
Robins nesting under the worktops on top of the cupboard. 
Found a long-tail til dead on the floor yesterday.  Probably came in through the open window/door and couldn't find it's way out.  Suspect it had flown at the closed (glass) door and knocked itself out.
Lots of bees and butterflies come in through the open window and either get rescued by me or expire in the summer heat..

I have physical projects and virtual projects.
I can have anything between 1 and 10 physical pieces of clay on the go at any time.
Virtual projects live in the privacy of my own head, and I don't know how to count them, but there are lots.  Most are totally unachievable with my skillset, but I love to look at something, and think I could make that with a differnt shape here, or a different colour there or ....

Often Questions of the Week can be confusing, as some will look at the surface of the question and easily answer it like eating a strawberry, others will look at it and see an onion with so many layers to be peeled off before the discussion is over. My play on the QotW is that it invites all sorts of response. I knew this one would be a good one for the onions and strawberries.
 
 
best,
Pres

After Pres and Mark’s responses I realize it’s a little more complex to answer this than I expected. Making work really is a flow, I’m certainly “working on” more than what’s become bone dry. Each kind of piece demands a different kind of attention at different stages. As Mark said, it’s kiln loads, not pieces.
 I make pots after my day job is done. I’ve found somewhere between three and eight wet pots at a time, depending what they are, is manageable.
Controlling how much I produce has a big effect on how well things come out. Two or three at a time is too little, but if I throw twenty mugs and a third of them get too dry to put handles on that’s no good either. Managing to do the right thing at the right time is the best. 

Interesting piece on Slave pottery in the post-I can gift this I hope  to the forum as its behind a paywall. Lets see if it works
https://wapo.st/3nEd56J

Workflow for me is a few kiln loads so its hundreds,many hundreds . Long ago (70s) I stopped counting pieces in kiln loads. Say how many in a glaze fire etc. I think more in cubic feet every glaze fire these past years is a 12 cubic updraft and and a 35cubic downdraft fires at same time.Most loads have over a hundrerd stuffers-from salt cellars to spoonrests to sponge holders.
I really dislike to fire glaze fires without the stuffers as the space is wasted.
This year is a huge transition year  as I'm working less now ,we (my assiasatant) are working two months on then two off or thereabouts
Just delivered a huge wholesale (my largest ever) to a Gallery a few days ago and am working on backstock to supply  local outlets during my break.
On a daly basis I throw in series -My list on the wheel now says salt cellars, garlic roasters and candle trays-I'll make them in dozens -say two dozen candle trays and a dozen garlic roasters and 2 dozen salt cellars. I just dropped off 80 salt cellars and need a small break from them.
When working on larger orders I step up to making larger runs on any given day.
The slow winter time is still here outlet demand wise so now its stocking up backstock so I can play this summer
 

This week there is a new topic suggested in the QotW pool! @Kelly in AK posted. . .   Hey Pres, I got a good one from my wonderful partner: How many pieces do you work on at a time during your normal workflow?
Interesting question concerning workflow. I believe it depends on the pieces made, the skills of the potter, and the techniques used to make the pieces. If I am making chalices, I usually limit the pieces to 10, as there are actually 20 pieces in all, cup and stem. At the same time if doing this in the two piece method, the timing is important as you do not want to join when too dry or too wet. The cups have to be trimmed last, after the stems are trimmed. If reversed the cups usually get to dry before joining, The stems should be slightly pliable in order to join without breaking-cheese hard. I cut a groove in the bowl base for the stem top to set in, then use magic water and the spinning wheel to join the two together and keep them centered top to bottom. Then I finish joining with a rounded wooden spoon rib and trim the bowl a little more at the end to make the piece unified in form.  Plates usually 6-8 for a kiln load. Teapots usually 4-6 for mix and match with spouts and lids. Everything seems to take more time these days, but then it is a labor of love and so seductive!
Once again. . . 
QotW:How many pieces do you work on at a time during your normal workflow?
best,
Pres

Thank you so much! I appreciate you taking the time to post all the links. I will report back for posterity in case anyone else is looking for info.