Water blasting is one of the quickest ways to blast away dirt, grime, and road film from your vehicle — and in New Zealand, where high-pressure washers are a household staple, it's the go-to for a quick exterior clean. But get too close to your plastic trims, and you could be doing more harm than good. Here's what you need to know before you pull the trigger.
The Problem with High-Pressure Water and Plastic Trims
Plastic trims are designed to handle normal washing. What they're not designed for is a concentrated jet of water at close range. Here's why that matters for NZ car owners:
1. Water Intrusion Behind Seals
Plastic trims are often held in place with adhesive, clips, or rubber seals. A high-pressure jet aimed directly at the edge of a trim can force water behind the panel, leading to moisture trapped against your bodywork — and eventually, rust. In NZ's humid coastal conditions this is a particularly serious risk.
2. Lifting and Peeling Trim Edges
Over time, adhesive-backed trims can start to lift at the edges. Water blasting at close range accelerates this dramatically. Once the edge lifts, dirt and water get underneath, and the trim is on borrowed time.
3. Fading and Surface Damage
Unpainted plastic trims are porous. A sustained blast of high-pressure water can strip away any protective coating or dressing that's been applied, leaving the plastic exposed to UV damage and accelerated fading. New Zealand's UV levels mean plastic degrades fast once its protective layer is gone. This effect also removes trim restoration products like Cerakote Ceramic Trim Coat if sprayed directly at close range.
4. Cracking on Older or Brittle Plastic
On older vehicles, plastic trims can become brittle with age. High-pressure water at close range creates enough physical impact force to cause micro-cracks or even visible cracking on already-stressed plastic.
Safe Water Blasting Distances for Plastic Trims
- Keep the nozzle at least 40 cm away from any plastic trim, seal, or rubber edge.
- Use a wider fan nozzle (25°–40°) rather than a zero-degree pencil jet near trim areas.
- Reduce pressure when working around door seals, window rubbers, and bumper trim edges.
- Never blast directly at trim edges — work parallel to the surface, not into it.
What to Do Instead
For plastic trims, a gentle hand wash with quality car shampoo and a soft microfibre cloth is always the safest option. Follow up with a dedicated plastic trim restorer or protectant, such as the Cerakote Ceramic Trim Coat or DIY Detail Plastic Trim Restore and Protect, to keep the surface conditioned, UV-resistant, and looking sharp.
If you're using a water blaster for a full exterior wash, rinse trim areas first from a safe distance, then switch to hand washing for the detail work around edges and seals.
How to Restore Trim Already Damaged by Water Blasting
If your plastic trim has already gone grey or chalky from years of UV exposure and aggressive washing, the good news is that it's fully reversible. The Cerakote Ceramic Trim Coat Restoration Kit ($64.99, available from Shineworks NZ) works by bonding a ceramic layer directly into the pores of the plastic — restoring a deep factory-black finish and providing ongoing UV protection that won't wash off.
Unlike silicone dressings that wash away in the next rain, the ceramic bond is permanent. It's the same technology used in professional ceramic coatings, in a simple wipe-on kit designed for home use. No power tools, no professional installer — just clean, dry trim and 30 minutes of your time.
Compare the options available in NZ:
| Product | Technology | Durability | Price |
|---|---|---|---|
| Cerakote Ceramic Trim Coat | Ceramic — permanent bond | Years | $64.99 |
| Bowden's Own Mr Black | Polymer coating | Weeks to months | ~$25–$35 |
| Solution Finish Black | Polymer coating | Months | ~$30 |
| Generic trim dressing | Silicone | Days to weeks | ~$10–$20 |
| DIY Detail Plastic Trim Restore and Protect | UV-protective coating | Reapply periodically | $129.99 |
Protect Your Investment
Your car's plastic trims are more than cosmetic — they protect edges, seal out moisture, and define the finished look of your vehicle. A few seconds of careless water blasting can cause damage that takes real money to fix. Once you've restored your trim with a quality ceramic product, maintaining safe washing distances is all it takes to keep them looking sharp for years.