What Thickness Copper for a Still? Gauge and Ounce Explained

For most home-size copper stills, the best choice is 20 oz copper, which is about 22 gauge or roughly 0.027 inch (0.69 mm) thick. It is strong enough to hold its shape and handle years of heating and cleaning, but still thin enough to heat up fast and be formed and soldered by hand. If you are asking what gauge copper for a still makes sense, 20 oz is the sweet spot.

This guide explains what ounce and gauge mean, which thickness to use for the pot, thumper and worm, how long a copper still lasts, and how to tell if a copper pot is real. Every alchemist should know their metal. Copper is the heart of a still, so it pays to understand it before you buy.

What Gauge Copper for a Still Is Best?

For the pot (the boiler) and the thumper on a home still, 20 oz copper, about 22 gauge, is a strong all-around pick. It resists dents, holds solder seams well, and spreads heat evenly across the bottom so your wash is less likely to scorch.

Thinner copper is cheaper and lighter, which is why many cheap thin imported stills use it. But thin walls dent easily, can warp under direct flame, and wear through sooner after years of cleaning. Much thicker copper (like 32 oz) is very tough, but it costs more, weighs more, takes longer to heat, and is harder to roll and form by hand. For most home sizes, it is more than you need.

Here is a simple rule of thumb:

• Under 16 oz: Too thin for a pot that sits over a flame. Fine for trim or decoration only.
• 16 oz: Workable for very small stills, but dents and wears more easily.
• 20 oz (about 22 gauge): The sweet spot for pots and thumpers on home-size stills.
• 24 oz to 32 oz: Very heavy duty. Used more on large stills, but harder to work and slower to heat.

Ounce vs Gauge: What Do the Numbers Mean?

Copper sheet is sold two ways: by ounce and by gauge. They both describe thickness, just in different ways.

Ounce (oz) means how much one square foot of the copper sheet weighs. So 20 oz copper means one square foot weighs 20 ounces. More ounces means thicker, heavier copper. This is the most common way roofers and coppersmiths talk about copper sheet.

Gauge is a number system where a smaller number means thicker metal. That trips a lot of people up. 18 gauge is thicker than 22 gauge, and 22 gauge is thicker than 24 gauge. Gauge charts for copper are not perfectly standard, so it is best to use gauge as a rough guide and ounce weight (or inches) as the exact measure.

Approximate copper sheet thickness:

• 16 oz copper: about 0.0216 inch (0.55 mm), close to 24 gauge
• 20 oz copper: about 0.027 inch (0.69 mm), close to 22 gauge
• 24 oz copper: about 0.032 inch (0.82 mm), close to 20 to 21 gauge
• 32 oz copper: about 0.043 inch (1.1 mm), close to 18 gauge

What Size Copper for Still Parts: Pot, Thumper and Worm

Not every part of a still needs the same copper. The pot does the hardest work. It sits over the heat, holds the full weight of the wash, and gets scrubbed after every run. That is where thick sheet copper like 20 oz matters most.

The thumper keg gets hot vapor from the pot and redistills it, so it also benefits from the same thick sheet. If you want to learn more about how it works, read our guide: What Is a Thumper Keg?

The worm (the coiled condenser) is different. It is made from copper tubing, not flat sheet. Tubing is measured by its diameter and wall thickness, not by ounce. The worm sits in cool water and turns vapor back into liquid, so it needs good flow and good contact with the cooling water more than heavy walls. Soft copper tubing in common sizes like 3/8 inch or 1/2 inch is typical on home stills, with wider tubing used on bigger stills so vapor can move freely.

Quick guide by part:

• Pot (boiler): thick sheet copper, 20 oz is ideal for home sizes
• Thumper: same thick sheet as the pot
• Cap, column and lyne arm: sheet or pipe, sturdy enough to hold a tight seal
• Worm/condenser: soft copper tubing, sized to the still so vapor flows and cools well
• Joints: lead-free silver solder, never lead solder

Why 20 oz Copper Beats Thin Copper

Copper is used in stills because it moves heat very well and reacts with sulfur compounds in the vapor, which helps clean up off flavors. But those benefits only last if the copper is thick enough to stand up to real use.

Here is what heavier 20 oz copper gives you over thin copper:

• Fewer dents: A bump while moving or cleaning will not crush the wall.
• Even heat: Thicker copper spreads heat across the bottom, which helps prevent hot spots and scorching.
• Stronger seams: Solder joints hold better on thick, stiff metal that does not flex as it heats and cools.
• Longer life: Copper slowly wears with every cleaning. Thicker walls have more metal to give before they wear thin.
• Holds its shape: Thick copper does not warp or bulge under heat the way thin sheet can.

How Long Does a Copper Still Last?

A well-built copper still made from thick copper can last for decades, and many get handed down. How long yours lasts depends on three things: the thickness of the copper, the quality of the solder joints, and how you care for it.

Thin copper and poor solder joints are the usual reasons a still fails early. Leaks most often start at seams, not in the middle of a sheet. Good care matters just as much. Copper can slowly develop pits if it is left wet, stored with leftover wash, or cleaned too hard with harsh chemicals.

To help your still last:

• Rinse and dry it after every run. Do not store it with liquid inside.
• Clean with vinegar or a mild acid, not abrasive steel wool. See How to Clean a Copper Still.
• Never heat an empty pot. Dry firing can damage the copper and melt solder.
• Use steady, moderate heat so you do not scorch the bottom.
• Check seams for leaks before each run.

How to Tell If a Copper Pot Is Real

Some cheap stills look like copper but are actually steel, aluminum or brass with a thin copper coating. Plated metal can flake, wear through, and does not give you the same heat and flavor benefits. Here are simple ways to check:

• Magnet test: Copper is not magnetic. If a magnet sticks firmly, there is steel under the surface.
• Look at the color: Real copper is a warm reddish orange. Brass is more yellow-gold. A very shiny pinkish finish that looks painted on can be plating.
• Check an edge or scratch: On a hidden spot, look at a cut edge or tiny scratch. Solid copper is the same color all the way through. Plating shows silver or gray underneath.
• Feel the weight: Copper is heavy. A big pot that feels very light may be copper-plated aluminum or very thin sheet.
• Watch the patina: Real copper darkens over time and can form a green or blue-green layer when exposed to moisture.
• Ask the seller: A good maker will tell you the ounce weight of the copper and what solder they use. Avoid any still with lead solder.

How Our Stills Are Built: Heavy 20 oz American Copper

At Fort Wilkins in Pittsfield, New Hampshire, every still we sell is hand built from thick 20 oz, 22 gauge American copper. That is much heavier than the thin copper you find on cheap imports. We assemble every joint with lead-free silver solder, and each still is cut, rolled, formed, soldered, tested, adjusted and inspected before it leaves the building.

I built my stills this way because I wanted them to last. Thick copper and good silver solder are the two things that matter most for a long life, and we back our copper stills with a lifetime warranty. — Alchemist G.G. Wilkins

Our complete units come with the pot, thumper and worm included, so you get the full setup in one box. Browse our moonshine still kits complete with thumper, see all copper stills for sale, or if you like working with your hands, try a DIY still kit you solder yourself. Remember: under US federal law you may own a still and use it for water, essential oils and similar uses, but distilling spirits for drinking requires a federal TTB permit. Learn more in Are stills legal to own?