A smoker is one of those things people build themselves eagerly and often badly. Welding a box is easy; the trouble starts later — a metallic taste in the food, rust after the second season, smoke escaping everywhere except through the chamber. Here is what decides whether a smoker lasts years or one summer.
Galvanised sheet is not an option
The most common and most dangerous mistake is building the chamber from galvanised sheet because it is cheap and does not rust. Heat breaks the zinc coating down, and what comes off it ends up in the smoke and then in the food. Galvanised steel is acceptable in a cold-smoking flue, where the metal stays cool, but never in the chamber.
The right material is food-grade stainless steel, typically AISI 304. It adds no taste, does not rust from condensation and takes hot-smoking temperatures without scaling. The budget alternative is plain structural steel from 2 mm: it works, but needs burning in before first use and eventually scales from the inside.
Metal thickness
A camping smoker for occasional use is fine at 1 mm. A permanent one that will stand in the yard for years wants 1.5–2 mm stainless: thinner metal distorts under uneven heat, the lid stops sealing and smoke leaks out instead of doing its job.
The floor is a separate case — it takes the whole heat of the fire, so it is made thicker than the walls. 2 mm against 1.5 mm is a sensible ratio. Smokers with thin floors burn through first, usually along a weld.
Chamber dimensions
A working reference for a domestic hot smoker is 500×300×300 mm — enough for 4–6 kg of product, which is a normal family load. 400×300×250 is the compact, portable version; 600×400×400 and up is a permanent unit.
Three levels are needed inside: chips on the floor, a grease tray above them, then grates or hooks for the food. The tray is not optional — without it, fat drips onto the chips, flares up and leaves bitterness and soot. Allow at least 7–10 cm from the tray to the lowest grate and 12–15 cm between grates.
Hot and cold smoking are different builds
Hot smoking runs at 80–120 °C with chips smouldering inside the chamber, and the food is done in 40–90 minutes. The build is simple: box, lid, tray, grates — which is why this is the version most people make.
Cold smoking runs at 20–30 °C for anything from hours to days. The smoke has to cool on the way, so the chamber sits 2–3 metres from the fire and is connected by a flue, or fed by a separate smoke generator. Nothing in a cold chamber gets hot, so thickness matters less than sealing and draught.
The universal build is a two-mode chamber: a removable chip tray inside for hot smoking, plus a side port for a smoke generator. It costs 15–20% more and covers both scenarios.
Water seal and lid
A water seal is a channel around the top of the body that the lid skirt drops into, filled with water. It keeps smoke in and air out, so the smoker can even run indoors with an extractor. It is made from folded strip welded around the perimeter — an operation where folding accuracy matters more than weld quality.
Without a seal the lid has to fit tightly on weight and geometry alone. That works, but only if the body did not distort during welding — another argument for thicker metal and for a folded body rather than one welded from plates.
Smoke generator
The simplest smoke generator is a vertical tube of 80–100 mm with a lid, an ejector and an aquarium compressor. Chips smoulder upwards inside the tube while the compressor creates suction and pulls smoke into the chamber. The tube must be thick-walled — a thin one burns through in a season.
In practice it is three parts: the tube, an ash box at the bottom and an ejector made of two fittings. Accuracy only matters in the ejector, where the ratio of diameters decides whether there is any draught at all.
Common mistakes
- galvanised sheet in the chamber — the worst possible choice;
- no grease tray — bitterness and soot on the food;
- 0.8–1 mm metal in a permanent smoker — distorts after a few fires;
- an oversized chamber for a small load — smoke disperses and the food smokes unevenly;
- a continuous weld all round in one go — the body twists before it is ever used.
What is worth ordering
Stainless is exactly where DIY runs into equipment. AISI 304 can be cut with an angle grinder, but the edge comes out burred and heat-tinted, and thin sheet distorts. Laser cutting gives a clean edge and every hole in one pass, press brake folding produces a body with no corner welds, and TIG welding leaves a seam that does not rust and needs no dressing.
We build smokers to order in your dimensions — from compact portable units to permanent stainless ones with a water seal, along with smoke generators and grate sets. Send us the sizes through the form, or see the other ready-made products we manufacture.
