In normal retail use paint tins are not made of stainless steel (relevant when used for making cantennas for radio astronomy)
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.