Part 2: how to make a casting slip from your own clay body

This video will teach you how to turn your own personal clay body in to a slip casting clay body.
Part 2 walks you through the entire process on how I turn my clay body into a casting body. I break down the various steps the slip will go through so that you can recognize them why you apply this method to your own clay. At the end of the video, you will see my clay body recipe and an example of my artwork.
Part 1 will break down and demystify basic clay chemistry. It is important to understand this chemistry so that you can apply it to your specific clay body. • Part 1: how to make a ...
Hydrometer Links
My top two recommendations for a hydrometer are either the Laguna one from the Clay Art Center ($33.00) or the Eisco one from Amazon ($15.59). Having some sort of a plastic case is key for me because they are very easy to break, especially in a lab with students.
clayartcenter.... $33.00 comes in a thin-plastic tube
The Laguna hydrometer is the best bet for the price and is very easy to use. It comes in a somewhat flimsy plastic tube, but is much better than the cardboard sleeves that the rest of the hydrometers come in. Although the cardboard sleeves are sturdy, they don’t stand up to water, which is unavoidable.
www.amazon.com... $15.59. from Eisco. Comes in a very sturdy plastic case.
You can’t beat the price for the Eisco hydrometer, plus it comes in an indestructible plastic case that is adjustable. So, when you break your Eisco hydrometer, the case will fit whatever hydrometer you buy to replace it. However, the Eisco hydrometer is somewhat frustrating to use because it is much longer than all of the other ones. The Eisco hydrometer has a much larger measuring range and is best suited for measuring lighter liquids (lighter than water). So, when you drop it into a large bucket or vat, it falls over because it is too long. But if you are just starting out and can’t afford the Laguna hydrometer, it will work well enough. Plus, the glass hydrometer itself is fairly thick and less fragile.
www.baileypott... $32.24 comes in a cardboard sleeve.
www.sheffield-... Comes in a cardboard sleeve $49.00
Below are links to excellent articles on slip casting clay bodies by Tony Hansen, who knows a great deal more than I do in regard to the chemistry. If you really get into slip casting, I highly recommend reading these articles. They are easy to understand, provide excellent tips, along with helpful problem solving solutions.
Deflocculation digitalfire.co...
Stoneware Casting Bodies Recipes digitalfire.co...
Low Fire White Talc Casting Body Recipe digitalfire.co...
Slip Casting digitalfire.co...
Viscosity digitalfire.co...

[@janicewilkens5352]

Fantastic explanation for a beginner like me!! So appreciate this information.

[@rebekahbogard3322]

Glad it was helpful!

[@hoanganpham613]

Thank you so much for all details of the process! I've learnt a lot from you. Really appreciated!

[@marciacunningham5877]

I levigate clay from my property. I tried making slip from it and it works great! I can make cups as thin as 1/8". Michael

[@carolgross9007]

Thanks for these 2 excellent videos. I finally understand what thixotropic means! Your explanation is so clear and straightforward.

[@rebekahbogard3322]

Ahh, that is so great to hear! It is a tricky concept! Glad I could help!

[@gordonspond]

Great information. Having said that, you mention a few times that sodium silicate evaporated with your water. I do not believe that is the case (or even possible), as sodium silicate has a MELTING point of around 1410 °C and a boiling point of 2355 °C. If you dissolve sodium silicate in water and let the water evaporate, the sodium silicate will stay behind.

[@____Ann____]

That was exactly what I wanted to write too. It is like sea water, a salty solution. The water evaporates but the salts stays behind.

[@gonzalolorga]

The sculptures at the end are lovely! And the video is super helpful

[@rebekahbogard3322]

Awww, thanks so much! So nice of you to say!

[@TrudioStudio]

Gosh. This was so helpful!! Been struggling with my slip for a few days but especially your factors and demonstration for perfect slip behavior helped me defeat my seemingly unwilling slip! Thanks so much!

[@rebekahbogard3322]

Alright! I'm so glad it helped! Thanks for letting me know how helpful it was!

[@ridgoro]

thank you for this video. Ifyou have a wheel you can easily set up a jig to keep stirring the clay for 12 hrs on its own.

[@rebekahbogard3322]

Wow! What a great idea! Thanks for sharing!

[@micheledickey4066]

This was soooo helpful!! Thank you so much.

[@rebekahbogard3322]

I'm so glad!

[@juliepeel1794]

Great video. I've made casting slip before but sooooo long ago. This was a great reminder and so well explained. Thank you Rebekah

[@rebekahbogard3322]

I'm so glad to hear your found it helpful!

[@lamardon9723]

Excellent and well articulated, with proper terms and concepts. But that non-Newtonian usage is familiar to me from the hydrocarbon polymers (plastic), which has that kind of flow in the molten state. Sister!

[@mightymel4028]

Thank you for sharing 🤘😝🤘

[@thomasashworth7292]

Thank you for this lesson.

[@rebekahbogard3322]

My pleasure!

[@jonnymccracken2528]

Wonderfully spoken. I sure hope such fluently spoken instructions does not come this naturally to you.. hahaha

[@alirezakhz]

very good explanation . thank you

[@rebekahbogard3322]

Glad it was helpful!

[@jillwazstudio]

Wow! So much great information! Thanks!!!

[@rebekahbogard3322]

Glad it was helpful!

[@Atliermia]

Very 👍 👍 well done.

[@rebekahbogard3322]

Many thanks!

[@lilyolk299]

Thru this process I found it hard to major using my majoring cup but I trust my majorment as my deflocculant allows the viscosity of my majorments to align

[@rebekahbogard3322]

Fixed size measuring cups (volume measuring) are not as accurate as weighing. That's why pastry chefs weigh their ingredients rather than use measuring cups. I find when making casting slip, accuracy is important. But you might find that you do not need to be this accurate when calibrating your casting slip. However, when I make plaster molds, I find this amount of accuracy is unnecessary, which is why I use the volume method for that process.

[@pashaveres4629]

How about using a fixed-size measuring device of a known weight? Scrape the top with a fettling knife after filling and wipe the outside. You'll get repeatable amounts of slip. Tare the scale or just subtract the known weight. Very accurate results. Thanks for your good work. Aloha

[@rebekahbogard3322]

That is not a bad idea. But fixed size measuring cups (volume measuring) are not as accurate as weighing. Especially since the same amount of volume will vary in weight depending on the specific gravity of the slip. I find when making casting slip, accuracy is important. But you might find that your technique works just fine. And it probably would work if you have measured the specific gravity first so that you know that you are getting stable and reliable results. It is important to know what works for you and to stick with it. Thanks for your thought!

[@AnLe-yg9ln]

Thank you very much

[@rebekahbogard3322]

You're welcome!

[@lori3032]

Thank you for your excellent instruction!

[@hashinka4053]

Your videos are so informative and helpful. Thank you! Would b-mix with grog work as a clay body for a casting slip?

[@rebekahbogard3322]

I think so. You may want to sieve some of the grog out. But I have had some pretty good success with transforming clay bodies containing grog into casting slip. Maybe you can leave the grog in and just mix it well before casting. Let me know how it works for you.

[@24-Card]

A vibrating platform is necessary to measure specific gravity in a thixotropic fluid. Liquefaction is necessary to allow buoyancy over drag.

[@tompots2]

It is scary (and comforting) to see you touching sodium silicate slip... it's MDS makes me nervous. I got some reclaim slip to 1.6 ( added too much water) and it is taking for ever to dry but it worked, Matt at Hobby Ceramicraft recommends 1.8 to 1.85.

[@rebekahbogard3322]

Awesome, I'm glad to hear it is working for you. 1.8/1.85 is still in range for slip casting. It all depends on the clay. The specific gravity will vary from clay body to clay body. So you just have to experiment, which is fun! Sometimes when I am impatient and want to get rid of water, I will boil the slip. It is really a pain in the but and because I hate doing it, I just wait for evaporation. But sometimes when mixing terra sigillata, I boil off the excess water.

[@Premises225]

I have my viscosity perfect but after 5 minutes it’s hard again so if I’m correct I need to keep adding deflocculant until it stays runny for 30/60 minutes?

[@Premises225]

I have sodium dispex as it’s common in the UK I couldn’t find any Darvan 7 from a uk seller

[@DesignEcologies]

Thank you

[@rebekahbogard3322]

You're welcome!

[@c50ge]

I am very new to this. When weighing slip would it help to use a palm sander with no paper on it to vibrate the slip in your measuring cup? We vibrate concrete to remove air bubbles in the forms which also levels the concrete in the forms(the main reason we vibrate is to make the concrete look better without voids and bubbles that would need to be filled after removing the forms) I haven’t tested this idea yet, just thinking out loud. Thank you for the education.

[@rebekahbogard3322]

That certainly would be worth a try for measuring the volume of slip, which is what I think you meant to say! But when weighting, that step would not be necessary as this does not effect the weight. Thanks for thinking out loud!

[@annika.ceramics]

I always struggle with airbubbles, even when mixing slooowly the slip… is it possible it comes from water we use?

[@rebekahbogard3322]

I really don't think the water has anything to do with it. It is probably due to the shape of the mold. Some molds trap air towards the top, so I sometimes add "vents."

[@parthpalsay2871]

Thank you for sharing your process. I have been trying to deflocculate a clay body composed from scratch and can’t seem to get past the thixotropic stage. It’s nice and flowy with webbing action but it’s gets rather thick about 15 mins later. Do I just keep adding more sodium silicate?

[@rebekahbogard3322]

It sounds like that is the problem; it needs more sodium silicate. I would all a little at a time and give it a days rest before reaching any conclusions. If you try to add what feels like enough sodium silicate in one day, you will likely over deflocculate it. For my slip, I was adding 1/2 teaspoon of sodium silicate (to a gall of of slip) a day, checking back in on it the next day to see if it was enough. It took me about three days of this before getting it just right. It sounds like you are very close to getting it dialed in. Let me know how it goes!

[@charlesfield9286]

Seems like it would be easier to weigh the dry clay and add 0.8 grams of clay per 100mg of water.

[@rebekahbogard3322]

Yep. That would be easier. I don't mix my own casting slip very often. And I am never this scientific about it. I usually just feel my way through it using my intuition. Thanks for your insight!

[@erikadean5164]

Great job putting all this information together. Very useful. PS: Please delete the below inappropriate spamming comment ⬇️.

[@rebekahbogard3322]

Thank you!

[@YWmakeup]

Do you mix your clay body from powder? I'm trying to see if it's possible to take a ready made clay body like the kind they sell at ceramic studios, and then convert it to a slip?

[@rebekahbogard3322]

Both ways work. If the clay is already mixed, I find it easiest to roll it out into slabs (or separate it into chunks), let it dry out, then add the water to slake for a day.

[@applejeanb.magtuba2632]

The sodium Silicate you add in your slip was a diluted one or a pure sodium silicate?

[@rebekahbogard3322]

Pure. Here is a link to buy some: seattlepotterysupply.com/products/sodium-silicate?variant=34391518544011&currency=USD&gclid=Cj0KCQiA2-2eBhClARIsAGLQ2RkO16cMgx56SG_Zz5MnSf4B95ewZBMWbT2PHK_21Y6D3Dqq0dourwUaAkdSEALw_wcB

[@kgkikichick595]

Is tap water ok or should i use distilled water?

[@rebekahbogard3322]

I always use tap water

[@johnking4226]

Is there a variance in gravity with different forms of slip? The reason for my asking is due to knowledge of how to make various Stone Slip such as Marble and other sorts of stone. I'm currently seeking collaboration with those capable of your given talents. Your response would be much appreciated.

[@rebekahbogard3322]

There is definitely variance in specific gravity with different slips. Some slips work best on the heavy side and some work best on the light side. You just have to experiment. Unfortunately your question about marble and stone are outside of my area of expertise. Good luck!

[@johnking4226]

@@rebekahbogard3322 Thanks for responding.

[@notsure246]

Do you make and sell custom pieces?

[@rebekahbogard3322]

I make individual works of art and nearly everything I make is for sale. Thanks for your interest!

[@24-Card]

Epsom salt to thicken. Sodium silicate to thin.

[@Faisal-ds1kb]

Sodium silicate is not available in my country. Is there any way i can make slip of clay without using it?

[@rebekahbogard3322]

Use Darvan #7. Here is a link about Darvan. digitalfire.com/material/darvan

[@Faisal-ds1kb]

@@rebekahbogard3322 Thank you.

[@tukorn5863]

We should to add sodiumcarbonate to reduce the thixotropic?

[@rebekahbogard3322]

If it turns thixotropic too quickly, add sodium silicate. Add only a small amount of sodium silicate at a time and be sure to give the slip time to adjust after adding (about a day). Otherwise, if you add too much sodium silicate, your slip will become very thick and it is difficult and time consuming to remedy. If your slip becomes thixotropic after about a half hour or hour, that is pretty good.

[@tukorn5863]

@@rebekahbogard3322 Thank you!!

[@regularguy8592]

well I just mixed up my first batch

[@rebekahbogard3322]

Wooohoooo!!!! Let me know how it went!

[@patriciakoenig3966]

I have a question I have had a bag of slip stored for quite some time it's a fifty Lb bag and I lost my directions on how much chemical to mix it with can you help? I think there was 3 ingredients.

[@rebekahbogard3322]

Yep. I'm sure it was Barium Carb, Sodium Silicate, and Soda Ash. When Ceramic Warehouses sell casting slip, they always send instructions. I would just go to one of those websites (such as Aardvark, Bailey, Laguna, etc.) and look it up. They always have PDF files on the instructions. Even if you don't know what kind of slip you have, I would just blindly follow the instructions as a starting point. It will get you in the ballpark and then you could simply adjust it accordingly.