Short answer: dry ice removes light surface rust and flash corrosion well, but it is not a structural rust-removal tool. The reason is physics — CO₂ pellets are softer than cured paint, let alone scaled steel. If you need to take a pitted, decade-old crane down to bright metal, dry ice is the wrong choice. If you need to lift flash rust off a fabricator's stainless line before coating, dry ice is excellent.
What dry ice handles well
- Flash rust on freshly fabricated steel and stainless
- Surface oxidation on aluminum, brass, and copper
- Rust bloom under decals, vinyl, and graphics
- Mill scale on light gauge steel (with appropriate pressure)
- Corrosion in electrical cabinets and busbar lugs where water can't go
What dry ice won't touch
- Heavy structural rust scale on weathered steel
- Pitted corrosion that has eaten into the substrate
- Rust that has bonded chemically with the underlying metal
- Anywhere the spec calls for SP-6 commercial blast or whiter
Why the difference matters
Pellet hardness sits around Mohs 2 — softer than copper, aluminum, paint, and any cured industrial coating. The cleaning action comes from kinetic impact, thermal embrittlement, and the 800-fold gas-expansion lift, not from abrasive cutting. Loose corrosion lifts. Bonded rust does not.
What we recommend instead for heavy rust
For SP-6 / SP-10 / SP-5 specs, sponge blasting, garnet, or coal slag is the right tool. We will tell you that on the site walk and refer you out — sending dry ice at structural rust burns pellets without progress and wastes your money. Where dry ice fits is the surface-prep step right before coating, lifting flash rust and contamination that would otherwise hold the new coating off the substrate.
The hybrid approach
Many real jobs combine methods: media blast for the heavy lift, dry ice for the precision surfaces (electronics, hydraulics, polished aluminum) that media would damage. We coordinate the sequence so the dry ice work doesn't get re-contaminated by the abrasive work next door.