10 Steps to the Complete Rust Protection of Your Vehicle
In Ireland, rust never sleeps. Salted winter roads, constant damp and years of road spray mean corrosion is working on the underside of every car, van and classic on our roads. The good news is that a proper rust-proofing job stops it in its tracks — and it’s the same process the professionals use. Here are the 10 steps to complete rust protection for your vehicle, with the exact products for each stage.
What you’ll need
- Chlor-X Salt Remover + a traffic-film remover
- FE-123 Rust Converter
- Corrolan Penetrator & Corrolan Active for cavities
- Your chosen underbody wax (see Step 8)
- Injection kit or Schutz gun + 10 mm plugs
Chlor-X Salt Remover
FE-123 Rust Converter
Corrolan Penetrator
Corrolan Active
Techshield Underbody SchutzClean it right down
Power-wash or steam-clean the underside, using Chlor-X Salt Remover and a traffic-film remover (TFR). Road salt is the number-one cause of Irish rust, so flushing it out first is the most important step of all.
Treat the rust
Scrape off flaking paint, old wax and loose rust, then treat whatever rust remains with FE-123 Rust Converter. It chemically converts active red rust into a stable, paintable black surface so it can’t spread under your new coating.
Make your access
Drill 10 mm holes where needed to inject enclosed sections, and open up access to the known rust traps — sills, box sections, chassis rails and door bottoms.
Cover exposed breaks
Mask off or cover any bare edges, breaks or fresh welds you don’t want wax to reach.
Strip the trim
Remove wheel-arch liners and heat shields, and cover the exhaust so hot components stay wax-free.
Prime the deep rust
For heavy rust inside cavities, pre-inject with Corrolan Penetrator — a thin lanolin wax that creeps deep into seams and drives out trapped moisture.
Seal the cavities
Inject box sections and cavities with Corrolan Active, the self-healing cavity wax that flexes with the vehicle and keeps pushing water out long after it’s applied.
Choose your underbody finish
This is the decision point — pick the finish that suits how you use the car. Here’s how the options compare:
| Finish | Film | Colour | Re-coat | Best for |
|---|---|---|---|---|
| Techshield Underbody Schutz | Tough, elastic bitumen underseal | Black | ~5 years | Stone-chip and gravel protection, tough black finish (not over-paintable) |
| Corrolan Pure | Sticky, medium-build lanolin | Honey / translucent | ~2 years | Natural & self-healing, inspect the metal |
| Techshield MIL-SPEC | Dry, high-build | Light brown / translucent | ~5 years | Tough dry finish you can still see through |
| Techshield High-Temp Clear | Dry, low-build | 100% clear | ~2 years | Heat areas near the exhaust, invisible |
Not sure which to pick? Read our lanolin rust-proofing guide or our Waxoyl alternatives guide.
Coat the underbody
Apply two coats of your chosen Rustbuster wax across the underbody, letting each coat flash off before the next.
Plug and finish
Refit 10 mm injection plugs, wiping a little underbody wax onto each hole before it goes in to seal the access points for good.
Keep it protected
Car manufacturers recommend an annual inspection with a top-up injection where needed — and we suggest exactly the same. A quick check each autumn, before the salt goes down, keeps your protection working year after year.
Chassis too far gone for wax alone? See our chassis restoration guide for stripping, repairing, priming and painting.
Rust protection FAQs
Can I rustproof my car myself?
Yes. With the right prep and products — a salt remover, a rust converter and cavity and underbody waxes — this 10-step process is well within reach for a competent DIYer. The main investment is time and some cavity-injection equipment.
How often should I re-treat it?
Inspect it every year, ideally each autumn before the roads are salted. Depending on the finish you choose, plan to re-coat roughly every 2 years (lanolin waxes) to 5 years (Techshield Underbody Schutz).
What is the best underbody wax?
It depends on your priorities. Choose Techshield Underbody Schutz, a bitumen underseal, for maximum durability and a tough black finish, or Corrolan Pure for a natural, self-healing lanolin coat that lets you inspect the metal. See the comparison in Step 8.
Do I need to remove all the rust first?
You don’t need bare, shining metal, but do remove loose, flaking rust and treat what remains with FE-123 Rust Converter before you seal. Trapping active rust under wax simply lets it keep spreading unseen.
Ready to protect your vehicle? Browse our full range of underbody and cavity waxes, from tough black Techshield to natural, self-healing Corrolan lanolin waxes.
