What Sheet Steel to Use for a Fire Pit or Grill
For a fire pit people usually choose thick mild steel (guides and shops point to about 3-6 mm), for grill parts that touch food stainless steel, and galvanised steel is not used anywhere there is fire. We laser cut flat parts in mild steel 1.5–5 mm and stainless steel 3 and 4 mm; you or a metalworker do the bending and welding.
Already have a flat pattern or a file? We will price it in the sheet you choose: Upload a file and see the price.
Which sheet to choose
| Sheet | For a fire pit | For a grill | With us |
|---|---|---|---|
| Mild steel: DC01 (1.5 mm), S235 (2–5 mm) | Yes. It rusts, so it needs protection against corrosion after cutting. | For structural parts, not for the surface the food lies on. | We cut: 1.5–5 mm |
| Stainless steel 1.4301 (AISI 304) | Yes. It does not rust, costs more, and changes colour when heated. | It does not rust, so it can be considered for parts that touch food. | We cut: 3 and 4 mm |
| Aluminium | No. It melts at about 660 °C, clearly lower than steel. | Not in the hot zone. | We cut it, but not for this |
| Corten (weathering steel) | Popular in ready-made garden fire pits; shops usually sell about 3 mm. | Not covered here. | We do not cut it |
| Galvanised sheet | No. Heated galvanising gives off harmful fumes (box below). | No. | We do not cut it |
| Painted or coated sheet | No. An ordinary coating is not made for contact with fire. | No. | We do not cut it |
Which thickness
There is no standard for fire pit thickness, so this is practice from guides, forums and shops, not research. Guides and forums advise about 5-6 mm (3/16-1/4 inch). Ready-made weathering-steel fire pits in shops are usually 3 mm (hence about 3-6 mm), and sheet of 2 mm or thinner is often described as risky.
The reason is simple: sheet next to the flame heats quickly while the rest stays cool, which creates stress, and thin sheet warps. Thicker sheet holds its shape better but is heavier and costs more.
From our range, the thickest mild steel, up to 5 mm, comes closest to that advice. We do not cut above 5 mm. We do not guarantee how long a finished fire pit lasts: that depends on the design, the welds and how it is used.
Galvanised steel: not for a fire pit or grill
Do not use galvanised sheet where there is fire. Zinc melts at about 419 °C, and heating galvanised steel produces zinc oxide fumes. Breathing them can cause so-called metal fume fever: chills, fever, muscle aches, nausea and cough, usually passing after about a day.
Workplace safety bodies describe this in connection with welding and heat treatment of galvanised steel. They have not studied fire pits or grills directly, but sheet next to a fire easily passes the melting point of zinc, so caution is justified. Do not put food on galvanised sheet either, especially acidic food.
Which parts you can order from us
A laser cuts flat parts. A fire pit or grill is put together from them by bending and welding, which you do yourself or give to a metalworker. You can price these shapes straight away on the cut-to-size pages:
- base and sides: circle or rectangle,
- hoop or frame: ring,
- grate, sieve or guard with holes: perforated plate,
- brackets and supports: flat bracket,
- foot for a post: post base plate,
- plate with a name or number: nameplate.
What we do not do
You draw air holes, handles and decorative cut-outs in the DXF file: the minimum hole is 1.0 × the sheet thickness, and the web between holes at least 1.0 × the thickness.
- Bending, welding, painting and tapping.
- Corten, galvanised and coated sheet: they are not in our price list.
- Parts from a 3D body without a flat pattern: we need a flat file (DXF, SVG, PDF) or the dimensions of a cut-to-size shape.