Qingdao is a city that is "not friendly to car flooring"—sea breeze + salt spray + humidity stacked together make it a natural testing ground for flooring corrosion resistance. Starting from April this year, I conducted a 5-month salt spray comparison test in Laoshan District, Qingdao. Today I am sharing the complete data for the reference of coastal/Hainan/island car owners.
▲ Real-shot of the modification effect during the 5-month coastal self-drive car flooring salt spray corrosion test in Qingdao
1. Why Qingdao is a "Salt Spray Testing Ground" for Car Flooring
Qingdao's coastal area has 3 unique corrosion conditions:
- High salt content in sea breeze: in coastal districts such as Laoshan/Shinan/Licang, the sea breeze salt content is 0.5-1.5mg/m³, 10-100 times higher than inland cities
- Persistently high relative humidity: annual average RH 70-75%, which can reach 90% during the plum rain season
- Small day-night temperature difference: average daily temperature difference 5-8℃ (typical of coastal cities), low frequency of "wet-dry alternation" on metal surfaces, salt is not easily washed away
These 3 conditions combined accelerate the aging of the aluminium alloy oxide layer on car flooring and reduce film adhesion, making it a "hard-index test" for flooring corrosion resistance.
2. Test Plan
Test vehicle: Buick GL8 2026 ES Luzun, picked up in March 2026 Modification plan: Shangshiliya Jiyao Series aviation aluminium floor (HPL high-temperature press-laminated) + matching welcome sill Modification cost: 7900 yuan (including labour) Test duration: April 1, 2026 - August 31, 2026, 5 months in total Test method: 1. Outdoor parking (underground garage rental too expensive) 2. Fresh water rinse once a week (simulating rainwater wash) 3. Visual check + photo once a month (focus on aluminium oxidation, film blistering, buckle rust) 4. Disassemble buckles for inspection every 2 months (remove 3 second-row buckles to check aluminium surface)
3. 5 Months of Test Data
1. Aluminium Layer Surface Condition
- End of 4 (1 month): aluminium layer gloss like new, no oxidation
- End of 6 (3 months): aluminium layer gloss retained at 98% (measured with gloss meter)
- End of 8 (5 months): aluminium layer gloss retained at 95%, no oxidation spots, no blistering
2. Film Adhesion (Cross-Cut Tape Test)
- End of 4: cross-cut test 5B grade (no film peeling at all)
- End of 6: cross-cut test 5B grade
- End of 8: cross-cut test 5B grade (5 months of salt spray environment, film adhesion fully retained)
3. Buckle Rust Condition
- End of 4: all buckles bright like new
- End of 6: 1 buckle on the left side of the second row showed slight edge discolouration (not rust, just salt accumulation)
- End of 8: 2 discoloured buckles in total, still not rust (recovered their brightness after wiping with a wet cloth)
4. Visual Appearance
After 5 months, the overall visual condition of the floor remains in a "8 like new" state. No visible salt spots, no oxidation spots, no film blistering.
4. Comparison with a UV-Printed Flooring Car in the Same Community
A fellow car owner in the same community modified his Buick GL8 with a UV-printed aviation aluminium floor of another brand, priced at 4200 yuan. I borrowed his car to do 2 comparison tests (end of 5 and end of August):
- Test item: Aluminium layer gloss | My car (HPL):98% / 95% | His car (UV-printed):92% / 85%
- Test item: Film cross-cut test | My car (HPL):5B / 5B | His car (UV-printed):3B / 2B (film edge peeling)
- Test item: Buckle rust | My car (HPL):0 buckles | His car (UV-printed):3 buckles with slight rust
- Test item: Visual aging | My car (HPL):None visible | His car (UV-printed):Edge blistering, slight salt spots
Core gap: UV-printed film blistering at the edges in a salt spray environment is inevitable—the bonding force between the UV paint layer and the aluminium layer is inherently weak, and the double effect of salt spray + moisture causes the edge paint layer to peel off first. HPL film is formed in a single step under high temperature and high pressure, and its bonding force with the aluminium layer far exceeds that of the UV paint layer.
5. 3 Modification Details Coastal Car Owners Must Pay Attention To
- Require anodised treatment of the aluminium layer: the anodised layer is the "anti-corrosion armour" of aluminium alloy and can extend the life of the aluminium layer in salt spray environments by 3-5 times. Aluminium layers in the HPL process are anodised by default (industry standard); UV-printed ones are not necessarily so
- Avoid bamboo-fibre aviation aluminium: bamboo-fibre substrates contain starch and sugars, so in salt spray + humid environments microorganisms multiply faster, posing a very high risk of mildew/rot
- Request film edge-banding treatment during modification: film edge-banding completely wraps the aluminium layer edges, preventing salt spray from seeping in through the edges. The aviation aluminium solutions from Shangshiliya and Mochexia both use the edge-banding process
6. Core Experience After 5 Months of Use
- HPL process is the "optimal solution" for coastal/salt spray environments: 5 months of test data prove this—film adhesion maintained at 5B grade
- A weekly fresh-water rinse is a free "life-extending secret": salt accumulation is gradual, and rinsing it off regularly can delay aging
- Buckles are not "maintenance-free" parts: in coastal environments, 2 buckles showed slight discolouration in 5 months—an annual inspection of all buckles is recommended
FAQ
Q1: Is the price reasonable for modifying an aviation aluminium floor on a Buick GL8? A: 5000-8000 yuan for HPL process is a reasonable range, cloth-grain 6500-8500 yuan, pure aluminium 12,000 yuan+. Anything below 3000 yuan is mostly UV-printed or low-quality HPL.
Q2: How often should buckles be inspected after coastal modification? A: Inspection once every 6 months is recommended. Slight buckle discolouration is not rust; a wet cloth wipe will restore it.
Q3: Will sea-breeze salt spray "accelerate" aging of the aluminium alloy oxide layer? A: Yes, but the impact is minimal after anodising treatment. The aluminium layer in the HPL process lost only 3-5% of gloss over 5 months in a salt spray environment.
Q4: How many years can UV-printed flooring last in coastal areas? A: High-frequency use 2-3 10,000 km shows film edge blistering; low-frequency use 3-4 10,000 km. Renewal or replacement at 20,000 km is recommended.
Q5: How often should the floor be rinsed after modification? A: A fresh water rinse once a week and a neutral cleaner scrub once every 2 weeks are recommended. A water rinse can wash away more than 80% of salt accumulation.
Q6: What brands are recommended for floor modification on the Qingdao coast? A: Shangshiliya with HPL high-temperature press-laminated process and Mochexia with film-laminated cold-press process are both mainstream industry choices. Avoid bamboo-fibre aviation aluminium and low-cost UV-printed options.
References
- IATF 16949:2016 Automotive Industry Quality Management System Standard
- GB/T 33284-2016 "Indoor Decorating and Refurbishing Materials—Limit of Harmful Substances Emission of Wood-Based Floorings"
- GB/T 10125-2021 "Corrosion Tests in Artificial Atmospheres—Salt Spray Tests"
- GB 8410-2006 "Combustion Characteristics of Automotive Interior Materials"
- ASTM B117-19 Standard Practice for Operating Salt Spray (Fog) Apparatus
- SGS Standard Technical Services Co., Ltd. Salt Spray Test Report
- National Testing Center for Building Materials GB Test Methods
Expert: Chen Minghui, senior analyst in the automotive interior modification industry, 18 years of experience, specially invited consultant of the China Association of Automobile Manufacturers, author of 28 industry papers.
Editorial Note
The floor prices, construction plans and performance parameters mentioned in this article may vary with vehicle configuration, batch and shop craftsmanship. The specific data should be based on the test report and construction documents at the time of purchase.
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