Hi everyone, marie here with another informative video for you.
In this video I'll be answering pottery slip questions for you. I have a list of 21
questions that I've been asked on this YouTube channel and my Pottery Crafters website. I'll
be sharing these questions with you to help you better understand pottery clay slip and all its
uses. Slip is also called slurry. It plays an important part in crafting pottery. Let's learn
more about it. This first question is from several beginner potters What is clay slip used for?
Clay slip is a very versatile material that can be used for a variety of purposes.
The most common use for slip is to join pieces of clay together. The slip acts as an adhesive,
helping to hold the pieces in place. Slip is also used for decorating,
and there are many different ways that you can decorate with slip,
including painting with the brush, dipping your pottery, and slip dripping, slip on your pottery,
splashing slip on your clay to create some cool effects, and slathering it on to create some cool
patterns, just to name a few. Slip can also be used for slip casting, which is a process of
making duplicates of an original object using a plaster mole like this. Whether you're looking to
join pieces of clay together or create a unique decoration, slip is a great material to use.
This is another frequently asked question. How do you make clay slip?
There are several ways you can make clay slip. The first is a simple slip made with clay and
water. Mix together in different ratios to create a slip with different consistencies. A basic slip
has a consistency of yogurt or sour cream. You can create a thinner slip by adding more water to the
mixture. You can also use thicker slips by using less water with the consistency of cake frosting
used for creating more textured surfaces. Another way is to add a deflocculent for slip casting,
which I'll get into slip casting more on question number 19.
Jana asked is underglaze the same as slip? While slip and underglaze are similar,
they're not the same. Slip consists of water clay and stains to add color slip is mainly applied to
green wear because it doesn't contain frit. Underglaze can be used on bisque wear and all
stages of green wear because it does contain frit. Frit is a mixture of silica and flux to
help bond the underglaze onto the pottery but not enough to form a glass-like seal on the pottery.
Micah asked, I'm trying to make slip, but I don't have a blender. Is it okay if my slip
isn't that smooth? If you don't have a blender, you can put your bone dry clay in a container
and let it soak overnight to ensure that the water has absorbed into the clay.
Then you can mix it by hand. You may think that the slip is smooth just from blending the clay and
water together, but it's not. The strainer plays an important part to ensure the slip is smooth.
Try tapping your slip through a strainer first, then push the rest of it through with a spatula.
Matt asked.d I hear people use vinegar when making slip. Why is this done?
Many potters do use vinegar when making slips the vinegar is a flocculant it helps the clay
flock together and make it stickier. Vinegar also has anti-fungal properties
which can help prevent mold from growing on the slip when stored for a long time.
This one is from Katrina, Can you use fresh clay to make slip if you don't have any old dry
clay bits. While older bits of clay and scraps are typically used to make slip, you can still slice
off fresh clay and dry them out, then break them up and make slip. This process is just
fine for those that don't have scraps of clay on hand. CJ asked, can you make slip with wet clay.
I wouldn't recommend making slip with wet clay. It takes a long time. A
really long time because wet clay doesn't absorb water as fast as dry clay does.
When you make slip make sure the clay is bone dry otherwise, you'll be mixing for a long time.
Jan wants to know, How do you make colored slip for decorating pottery? Making colored slip is
fairly easy. Start by adding water to broken up bone dry clay the smaller the pieces the better
then add more or less water to create thinner or thicker slip as needed. Blend it together
and put it through a strainer. Then add mason stain or oxides for color. Blend it all together
and put it through a strainer again. I have a step-by-step video on how to make colored clay.
I left the link for you below in the show notes. It's also at the end of the video, along with
how to make plain slip. I now have a super thanks button right next to the download button where you
can donate to the channel and help with supplies to make these videos. Thanks for your support.
Deborah asked, Could you add mason stain to the water before you add the water to the clay slip?
Yes, both ways will work. I personally like to have the consistency of the slip right before
I add the colorant. If you add the water to the colorant first you may not need all of
the colored water. So it makes sense to get the thickness and the amount of slip right
before you add the colorant. It's important to measure out the slip
and colorant. If you have a project that may need more slip of the same color.
Terry asked, Would it work if I use mica instead of mason stain to my slip?
No. I would not recommend mica instead of mason stains because mica can only withstand
temperatures around 1422 degrees fahrenheit or 772 degrees celsius that would be cone 016
mica has been used in Raku firing because Raku firing is done at a lower temperature,
so if you're interested in experimenting with mica in your raku firing
give it a try. Stacy asks, Do I need a coat of transparent glaze over my slip decoration?
You don't have to if it's a decorative piece of pottery or if you're using high-fire clay and fire
it to vitrification, making the clay waterproof and food safe. If your clay doesn't vitrify
and you don't want to glaze your slip decoration but you want the vessel to be waterproof you only
need to glaze the inside. If you want to put a glossy shine on your slip and enhance the color,
then applying a coat or two of clear glaze may be the way to go
after you bisque fire it. Karen asked if I burnish my colored slip on leather hard clay,
does it still need a transparent glaze to make it waterproof. Although burnishing does compress
the clay particles and smooths the surface, it does not make the pottery waterproof,
but it will if you're using the right clay and fire it to vitrify it. Otherwise, you'll have to
apply clear glaze on the inside of your pottery to make it waterproof, and just hand wash it.
Rob asked, Can I apply slip to my bone dry clay? While the best time to apply slip to your pottery
is in its plastic workable stage or leather hard stage because the shrinkage rate of the clay
is the closest, you can still apply slip to bone dry clay. You can brush on a thin layer of slip,
let it dry, and apply another thin layer, and let it dry. Some potters spray water on their clay
and even dip a piece in water before applying the slip. If you decide to use slip on bone
dry clay it's always best to test it out because many clay bodies are different and may not work.
Sonya asked, can I use slip on my bisqueware?
Because slip has no melting agents to bond to the bisque wear you would have to add a type of
frit to help the slip bond to the bisque wear so it performs more like an englobe or underglaze.
There are many bisque slip recipes out there to choose from. Keep in mind that thick slip
may be too much for the bisque wear and the slip can crack or peel, but you can always
test fire and see what happens to your piece. Jodie wants to know what is slip trailing? Slip
trailing is a technique where you apply slip with or without colorant onto mainly leather hard clay
using a squeeze bottle that has a pointed tip or an application bulb like this one.
This one works really good. This one is for thicker applications of a slip. You want your slip
to be thick enough so it doesn't run out of the applicator. The consistency of sour cream is good.
Simply squeeze the slip out of the applicator to create decorative shapes with lines or dots. This
is a great way to add some extra design to your work, plus it's fun and easy to do. Joanne asked,
How do you thicken clay slip if you find that your clay slip is a little too runny. You can
do a few things to thicken it up. The first option is to simply wait for the water to evaporate off.
This may take a while.
Another option is to add some bone-dry clay to the slip and blend it well, then
put it through a strainer to remove any lumps. Another way is to add Epsom salt to the slip.
This works as a flocculent flocking the clay particles together to help thicken the slip.
Just dissolve some Epsom Epsom salt.
Just dissolve some salt in a bit of water and add small amounts at a time
until you get the desired thickness. With these simple methods you can easily thicken your slip.
Sophie wants to know what can be done if the slip in the container becomes too thick? If the slip
in your container becomes too thick all you have to do is add some water and blend it really well.
You want to add a little water at a time until you reach the desired consistency. Then run it through
a strainer in case any lumps have formed. Sam asked, What is the best way to store your slip?
When it comes to storing slip you have a few options. For large amounts of slip
you can use a bucket with a tight-fitting lid and add vinegar to prevent mold growth.
Check it from time to time for any mold growing or thickening of the slip. You may
need to add more water or vinegar as needed. You can also add bleach. Keep in mind that the
bleach will evaporate in the kiln and won't hurt the clay. For smaller amounts of slip,
freezer bags work great. Simply pour the slip into the bag and let any air out and seal it tightly.
Some of my slip has been stored in these baggies for over a year with no maintenance. I haven't
had any problems with mold growth, and the consistency is still like sour cream. I just
scoop a little out for my attachments, and I'm ready to join my clay together?
Michelle wants to know if clay slip for decorating is the same as clay slip for slip casting. The
simple answer is no. When I started pottery, I didn't know that you couldn't use decorating and
joining slip for slip casting. While, you can use clay and water for slip decorating, it will not
work at all for slip casting. Sue asks can you use slip casting slip for decorating and attachments.
I would not recommend casting slip for decorating or attachments
since casting slip is made for plaster molds to suspend the particles and slow the drying rate
it doesn't have the same shrinkage or absorption rates as simple slip. Plus it's
pretty runny. Romero wants to know if you can make slip out of several different clay bodies?
That's a good question. Working with multiple clay bodies can be tricky as they often have different
shrinkage rates and iron content, this can cause problems with the final outcome of the piece. As
the different clay bodies may not fire at the same rate or produce the same color the consultant at
Amaco told me it's always best to stick with one clay body whenever possible, and you want the slip
to attach and adhere to the piece properly. Well those are all the slip questions I have for now.
If I missed anything it's because no one asked me if you have any more questions feel free to
ask in the comments section below. Slip is great to work with, from decorating to molding. The more
you understand, the easier it is to work with. Now head on over to my how-to make colored slip video
and my how-to make plain slip video. If you do I get to play with more clay. Let's stay dirty.