In normal retail use paint tins are not made of stainless steel.
Here’s the breakdown:
✔ What paint tins are made of
Most commercial paint cans are made from tin-plated mild steel (“tinplate”).
This steel is:
- cheap
- easy to form
- solderable
- corrosion-resistant enough for paint
- magnetic (useful to check)
✔ Why they aren’t stainless
Stainless steel would:
- cost far more
- be unnecessary for paint chemistry
- be harder to solder/roll-seam in mass production
- be more difficult to crimp for lids
Paint manufacturers simply have no reason to use stainless.
✔ Are there any exceptions?
Very rare. You might encounter stainless cans only in:
- laboratory chemical storage
- small specialty sample containers
- high-purity solvent containers
But not consumer paint tins from DIY shops.
✔ How to check your tins
If a magnet sticks strongly → mild steel or tinplate, not stainless.
(Weak attraction might indicate ferritic stainless, but paint cans virtually never use it.)
If your question is about RF construction: tin-plated steel is perfectly fine for waveguides, chokes, and feedhorns. The conductivity is lower than aluminium but still excellent at 1.42 GHz.