HOW TO MAKE A SLAB BUILT MUG

After planning the width and length of the slab you will need, roll out a slab, about 1/4 inch thick. (When using a slab roller, the width of your slab will not increase, only the length.) Use a rib to compress the slab and remove any canvas texture.

Texture your slab, and then cut out a rectangle, approximately 4" x 12". To determine the exact size of the rectangle you will need, determine the height and circumference you want for your finished mug. (Your mug circumference is 3.14 x the diameter.) Then use a clay shrinkage calculator to find the size of the slab you will need. Check the website of your clay manufacturer or distributor to find the shrinkage of your clay. It is usually 10-12%. Standard 240 clay shrinks about 13% at Cone 6. Axner/Laguna B-Mix shrinks approximately 12% at Cone 5.

Bevel one edge of your slab by cutting at a 45 degree angle. It's helpful to use a straight edge to guide your knife. Then flip your slab over horizontally, and cut the second edge in the same way. You should then have two 45 degree edges that are parallel to one another. Beveling the edges creates more surface area for a stronger joint.

Note: If you would like to use a cylindrical form to help in constructing your mug, skip this step, and read on.

Beveling the lip of the slab with a pony roller

Create a softer lip for your mug. You can run your finger across the top edge of your slab, or use a pony roller held at an angle to create a gentle bevel. Flip the slab over and repeat on the opposite edge.

Optional: You can use a form to support your slab when you join the edges together. Wrap a pvc pipe, or any other non-porous material, in newspaper. Do not wrap too tightly, so that you can slide the tube or pipe out later.
If using a form, you can skip the previous step of cutting the seam edges at a bevel. Wrap your slab around the form, overlapping the (unbeveled) edges. Make a vertical cut through both overlapping slab layers, holding your knife at a 45 degree angle to create the beveled edges.

Slab standing up with scored ends ready to be joined.

Score and Slip: Prepare to join the two ends of your slab by scoring them. Then apply slip (i.e., watery clay) or water to the scored areas. Scoring is the process of roughing up the surface of the clay to allow for a better joint. Use a serrated metal rib or other scoring tool to make a crosshatched texture on surfaces that will be joined.
You can create your own slip by drying out small pieces of clay. Add water to the bone dry clay to create your slip.

Overlap the 2 beveled edges so that the inner edge of one bevel aligns with the center of the second bevel. Gently press the edges of the slabs in opposite directions across the joint. Use gentle pressure to preserve the texture of the slab. You may leave evidence of the seam or choose to smooth the seam completely, losing some of the texture.

You can use a pony roller, with gentle pressure, to compress the seam. If not using a form, support the slab cylinder from the inside as you press with the pony roller.
If using a form, remove it by sliding it out of the newspaper liner after securely joining the seam.

Smooth the inside seam, pushing the clay across the joint.

If needed, you can use a clay flower pot as a rest to maintain the circle of your cylinder as it begins to dry, and stiffens.

To make a simple strap handle, roll out a slab about 1/4" to 3/8" thick. You can cut a strip of uniform width (as shown), or taper it.

Bend the strap to establish a general curve for your handle and hold it up, just behind your cylinder, to see how it will fit. Pay close attention to the angle at which the curve meets the side of your mug.

MUG HANDLES

When designing the handle for your mug consider how it will feel in the hand of the user. A handle that extends too far out from the body of the mug will make the grip a bit unwieldy. A handle that is too narrow on a larger mug may feel wimpy.

The upper curve of the handle generally does not rise above the lip of mug. Imagine placing the mug upside down to dry. The lip and the handle should both meet at the surface on which they rest.

Consider how the handle will join to the side of the mug. You'll want a strong joint, so a beveled cut, or attaching the inside of the strap to the (bottom of) the mug, will be good choices.

There are many options for making mug handles. Check out my Pinterest page on Mugs and Handles.

After assessing the placement of your handle on the mug, cut the strap at the appropriate angle.

Let the handle stiffen to a soft leatherhard stage. That is, the handle should still be somewhat pliable, but will hold its shape when attached to the mug.

Now you can attach the base for your mug. Place the cylinder for your mug on a slab of the same thickness. Use a needle tool or other pointed tool to score a line on the slab around the outside and inside edges of the mug's cylinder.

Score between the two lines. Then apply slip.

Score and apply slip to the bottom of the cylinder, and place it on the base. Give the cylinder a little wiggle until it seems to attach. Use a wet paintbrush to clean up any slip that may have oozed out on the inside or outside of your mug.

Holding a knife at a slight angle, trim the base, about 1/16" outside the edge of the mug.

Use a cloth or piece of newspaper to lift the base upward, sealing the joint a bit. (This limits finger marks.) This will also create a bit of a lip, that will serve as a stop or break for glaze. You can clean up the edge by gently using the edge of a soft rib, if desired.

After your handle has stiffened just enough to hold its shape, use a needle tool to mark where it will attach on the side of the mug. The seam is a good place to attach your handle. Score and slip the attachment points. Then score and slip the top of the handle.

Carefully attach the top of the handle, supporting the wall of the mug from the inside. Check to be sure the handle is aligned perpendicular to the mug and vertically aligned on the side.

After insuring the handle is vertical, and checking the length and curve of the handle, attach the base of the handle, supporting the wall of the mug from the inside. You can use your thumb to press the handle to the mug and leave a thumbprint at this bottom attachment point. A stamp or other tool can also be used while you support the wall of the mug from the inside. Be sure to score and slip both parts before attaching. Finally, double check the alignment of the handle.

Check the curve of your handle to be sure it will fit comfortably in the user's hand. Make any necessary adjustments. If the clay of the handle is too soft, and seems to slump or sag, use a lump of clay as a temporary support until the handle is dry enough to hold its shape.

If possible, cover your mug with plastic for a day or two to let the moisture content of the mug and handle equalize. This will help prevent the handle from pulling away from the mug. Because clay shrinks as it dries, the wetter handle may have more shrinking to do than the mug, which has probably dried out more during construction.
Finally, sign or stamp the bottom of your mug. Use a cleanup tool to clear away any crumbly bits of clay around your signature.