A ceramic ashtray is one of the most practical small projects in pottery. It is low, wide and simple, so it suits a first slab or a first wheel session, and it gives you a reason to think about proportions, rim details and glaze in one piece. This guide covers which clay to use, how big to make it, how to shape the rests, hand-built and thrown designs, and why a kiln-fired glaze is the right finish for something that holds heat.
It is research-based. We compared clay makers' published data, the Polyform safety data sheet for Sculpey polymer clay and several published ashtray project guides, checked in October 2026. We have not made these pieces ourselves, so the sizes below are calculated starting points, not tested results.
Choose kiln clay, not air-dry or polymer clay
An ashtray that will hold a lit cigarette needs a body and a surface that have both been through a kiln. Most project roundups online use air-dry or polymer clay because they need no kiln, but neither is made for an ember.
| Material | How it hardens | Holds a lit ember? | Good use |
|---|---|---|---|
| Stoneware (cone 5 to 6) | Kiln, about 2,167°F to 2,232°F (1,186°C to 1,222°C) | Yes, once glazed and fired | Dense, strong everyday ashtray |
| Low-fire earthenware (cone 06 to 04) | Kiln, about 1,828°F to 1,945°F (998°C to 1,063°C) | Yes, once glazed inside | Bright glaze colors, small home kilns |
| Air-dry clay | Air at room temperature | No | Ring dish, display piece |
| Polymer clay | Home oven | No | Small trinket dish only |
Stoneware is the safer default if you fire at cone 5 or 6. Laguna lists B-Mix 5 at about 2.3% absorption, so it fires dense. Low-fire clay works well too, but it stays porous: AMACO lists its No. 25 White Art Clay at 13.7% absorption at cone 04, so glaze the inside fully or ash will stain the bare clay.
Air-dry clay never becomes ceramic. Crayola says its air-dry clay is not waterproof even when sealed, and the acrylic paint and varnish that finish it are coatings, not glass. Polymer clay is a plastic: Polyform's safety data sheet for Sculpey says not to heat it above 350°F (175°C), to keep it away from open flame, and that overheating releases hydrogen chloride vapor. A glowing ember is far hotter than that limit.
How big should a ceramic ashtray be?
A wide, low dish with a heavy base is hard to tip over and gives ash room to collect away from the rests. Published projects mostly sit between 4 and 6 inches across with walls 1 to 1.5 inches tall. Clay shrinks as it dries and fires, so make the wet piece larger than the finished size you want.
The wet sizes below are our own calculations: finished size divided by (1 minus the shrinkage). We used 12% (Laguna's figure for B-Mix 5 and AMACO's for No. 46 Buff at cone 5) and 6.3% (AMACO's figure for No. 25 White Art Clay at cone 04). Check your own clay's number on the maker's page.
| Style | Finished size | Make it wet at 12% shrinkage | Make it wet at 6.3% shrinkage |
|---|---|---|---|
| Small cigarette dish | 4 in across, 1 in walls | 4.6 in, 1.1 in walls | 4.3 in, 1.1 in walls |
| Standard round or square | 5.5 in across, 1.25 in walls | 6.25 in, 1.4 in walls | 5.9 in, 1.3 in walls |
| Cigar tray | 7 in across, 1.5 in walls | 8 in, 1.7 in walls | 7.5 in, 1.6 in walls |
| Deep outdoor bowl (windy spots) | 5 in across, 2.5 in walls | 5.7 in, 2.8 in walls | 5.3 in, 2.7 in walls |
Keep walls about 1/4 inch thick and the floor a little thicker, around 3/8 inch, so the piece has weight low down. Very thick floors dry slowly and are more likely to crack, so add weight with width rather than with a solid lump of clay.
Cigarette rests: number, width and depth
The rests are what turn a small dish into an ashtray. Get them right in wet clay, because you cannot widen them after firing.
- How many: two to four, evenly spaced. Two opposite rests suit a small dish; four suit a shared table.
- Width: measure the cigarette or cigar you plan to rest, then make the groove that width plus your clay's shrinkage. An unsharpened pencil is a common tool for a standard cigarette groove; for cigars, use a dowel or marker that matches the cigar you measured, scaled up the same way.
- Depth: about half the width of the groove. Deeper notches weaken the rim and can crack in drying.
- Angle: slope each rest slightly down toward the center so the lit end hangs over the floor of the dish, not over the table edge.
- Edges: soften every edge with a damp sponge or a fingertip. Sharp clay edges chip after firing and catch glaze unevenly.
Press rests when the rim is soft leather hard and support the wall from inside with a finger as you press. On wet clay the rim distorts; on dry clay it cracks.
Hand-built ceramic ashtray designs
Pinch pot ashtray
Start with a ball about the size of an orange, open it with your thumb and pinch outward, keeping the walls low. Tap the base on the table to flatten it so the dish sits level. This is the quickest design and the most forgiving; our pinch pot guide covers wall thickness and cracks.
Slab tray with corner rests
- Roll a slab between 1/4 inch guide sticks and let it firm until it holds its shape.
- Cut a base from a paper or plastic pattern. Our pottery templates guide gives a fold-up tray pattern with darted corners, already scaled for shrinkage.
- Either fold up the walls along the darts or cut separate wall strips, then score and slip every joint.
- Smooth the seams inside and out, press the rests into the corners or wall centers, and round the rim.
Square trays are the easiest way to get crisp rests, since each corner can hold one. The slab pottery guide explains joining and why slab pieces warp.
Coil rim and textured dish
Cut a round slab base and build a low rim from one or two coils, blending them on the inside. Texture the base slab before you cut it with a roller, a stamp or lace; our texture roller guide lists options. Texture works best on the outside and rim, while a smooth floor is easier to wipe clean.
Drape dish
Lay a round slab over the back of a small bowl lined with paper or cloth, trim the edge, and lift it off once it is leather hard. Add a coil foot so it sits flat, then cut the rests.
Thrown ceramic ashtray on the wheel
A thrown ashtray is a wide, low bowl with a flat floor. Start with about 1 to 1.5 lb of clay, the same range many beginners use for a small bowl.
- Center the clay low and wide rather than tall.
- Open wide, leaving a floor about 3/8 inch thick, and compress the floor with a rib or your fingers so it does not crack.
- Pull one low wall, then either flare it out or keep it upright for a deeper bowl.
- Flatten and level the floor with a rib, sponge out any water, and wire the piece off.
- At leather hard, trim a shallow foot or simply bevel the base edge, then cut the rests with a loop tool or press them with a dowel.
Throwing three at the same weight gives you a matched set and a chance to compare rim shapes. If any step is new, our wheel throwing for beginners guide walks through centering, opening and pulling.
Drying and bisque firing
Wide, flat pieces crack where the wall meets the floor when the rim dries faster than the base. Cover the ashtray loosely with plastic for the first day or two, and once the rim is firm, flip it onto a board so the base can dry too. Let it reach bone dry before it goes in the kiln.
Bisque fire to the temperature your clay maker states; cone 04, 1,945°F (1,063°C), is a common bisque. Our bisque firing guide covers loading and schedules.
Glaze choice: why fired glaze suits heat
In the glaze firing, glaze melts into a layer of glass fused to the clay at somewhere between cone 06 and cone 6, roughly 1,828°F to 2,232°F (998°C to 1,222°C). A ceramic ashtray's surface has already survived that heat, so the small, local heat of an ember will not melt, blister or burn it. Acrylic paint, varnish and resin are organic coatings that can scorch, soften or discolor.
- Glaze the inside fully. Glass does not absorb ash or odor and wipes clean. Bare clay, especially porous low-fire clay, stains.
- Pick a stable glaze. Gloss and satin glazes clean more easily than dry mattes. Very fluid glazes can pool in the floor or run onto the kiln shelf, and crawling or textured effect glazes leave rough spots that trap ash.
- Match the glaze to the clay. Use a low-fire glaze on low-fire clay (AMACO recommends cone 05 glazes for No. 25) and a cone 5 to 6 glaze on mid-fire stoneware.
- Keep the base bare. Wax the foot and wipe glaze off the bottom so the piece does not fuse to the shelf.
Our how to glaze pottery guide covers dipping, brushing and coat thickness. Underglaze under a clear glaze is a good way to add color or line art, and sgraffito through a colored layer suits the wide floor of a cigar tray. Even thickness all round matters as much as the glaze itself: a well-fired piece of even wall thickness handles a small ember far better than one with a thick lump in the base.
Common mistakes
- Cutting rests to the cigarette's exact width and forgetting the clay will shrink.
- Walls so tall that a resting cigarette tips into the dish.
- A light, narrow base that tips when someone taps ash.
- Leaving the inside unglazed on porous clay.
- Choosing a runny glaze that pools in the floor or glues the piece to the shelf.
- Using air-dry or polymer clay for an ashtray that will hold lit cigarettes.
Safety notes
Clay and glaze dust contain crystalline silica. Clean with a damp sponge or mop, never dry sweep, and wear a NIOSH-approved respirator when mixing dry clay or glaze materials. Read the glaze maker's SDS before you mix or spray. Kilns get hot on the outside and need the clearance and ventilation their maker specifies. In use, set the ashtray on a nonflammable surface and empty it only when the contents are cold.
What you need
A bag of kiln clay that matches your kiln or studio firing, a rolling pin with 1/4 inch guide sticks, a needle tool, a sponge, a loop tool and a stable gloss or satin glaze will cover every design on this page. Our pottery clay guide helps you choose a body, and the pottery tools guide covers starter kits.
Sources: Laguna B-Mix 5 product data (cone 5, 12% shrinkage, 2.3% absorption); AMACO No. 25 White Art Clay product page (cone 04 to 3, 6.3% shrinkage and 13.7% absorption at cone 04, cone 05 glazes); AMACO No. 46 Buff Stoneware product data (12% shrinkage at cone 5); Polyform Sculpey safety data sheet (350°F limit, open flame, overheating vapors); Missouri Poison Center, polymer clay; Crayola air-dry clay FAQ; Orton cone temperature chart; project guides from eHow, MunchMakers and Clayelle reviewed for topic coverage. Specs checked October 2026.