Score! The Ultimate Joining Slip

So my work is quite dependent on scoring and slipping, the method of joining two parts of leather hard clay together. In a workshop I did recently at U of L for the Louisville Clay group, I mentioned how I make the slip that I use to attach the parts. I was surprised how many people had no idea what I was talking about. I am writing this to spread the word about the ultimate, best slip to use for joining.

I basically start with my throwing scraps, the large chunks from my splash pan.

Sometimes I use the thickest parts of my reclaim bucket. Just go for whatever clay you have sitting around that is at a peanut butter consistency. Put a pint of that in a 1 quart container, such as a mix-n-measure from the hardware store.

1. Add 1 ml of Darvan #7

If you use terra cotta, you might want to use Darvan #811. These are deflocculants. They basically work by changing the charge of the clay particles to negative, causing them to repel each other. The result is a liquid with less water in it than would normally take.

2. Mix the slip with a stick blender.

It should come out the consistency of loose pudding. if it is thinner, let it sit out over night and mix it again. I store this and use it for about a month. If it dries out, don’t bother to rehydrate, just toss it. Make sure it does not get into the reclaim bucket. That Darvan is bad stuff to get into a plastic clay body.

When using this, there are several advantages.

  • It has less water, so It will shrink less
  • It is sticky like syrup, allowing fast joining
  • It flows down into the score marks easily
  • It dries very hard, harder than the rest of the clay

I have found this to be the most logical, and most effective method of joining, something I have recently gained an expert level of experience at. Hope this helps you, too.


  1. Mickey says:

    I recently “blogged” and boasted about my hand whirr-whirr. (it’s official Studio name)
    I will try you way.
    Thank you for sharing it.
    Mickey S
    On Vancouver Island

  2. […] apply my joining slip to both halves, using small repetitive stokes in both directions parallel to the direction of the […]

  3. Wanda says:

    That’s the slip I use. Darvan is my homeboy.

  4. Katzeye says:

    We have something even better. We call it Stuck Up Slip. It is an industrial secret, but it is how they attach handles without scoring. I know the method you are documenting, and this is even better!
    Email me and I will send you a bottle and some of our clay to try with it.

All Past Writing