VCI Paper vs Silica Gel vs Rust Inhibitor
เลือกวิธีป้องกันสนิมเก็บ/ส่ง

**Three different mechanisms** — choose by storage duration + packaging type: • **VCI Paper / Film (Volatile Corrosion Inhibitor)** — paper/film coated with amine-based inhibitor (ammonium benzoate / sodium nitrite) that slowly evaporates and adsorbs onto steel surfaces as a molecular film. **Works in closed or semi-closed systems** (boxes/bags/containers). Service life 2-5 years sealed • **Silica Gel (Desiccant)** — physically adsorbs moisture from air (no chemical reaction). Reduces RH < 50% → corrosion stops. **Requires fully sealed enclosure**. Dosage scales by air volume (1 packet 30 g per 5 L air). Service life 6-18 months • **Rust Inhibitor (Liquid film)** — coats steel directly with oil/wax film — Tectyl / Cosmoline / ORAFON Rust Stop. **Thickest film** — protects even outside enclosure. Service life 5-10 yrs indoor, 1-3 yrs outdoor **Rule:** High-value + long storage + returnable spares → **Rust Inhibitor**. Ocean freight + quick unwrap → **VCI Paper**. Cabinet/room humidity control → **Silica Gel**

Three main standards cited in Thai government TORs (Defense Procurement, Royal Thai Navy, SRT spare parts warehouse): • **MIL-PRF-3420G** (US Military, 2019 ed.) — VCI paper for military spares. Requires VCI loading ≥ 13.5 g/m² + ≥ 2-year protection sealed + non-carcinogenic amine (replacing old sodium nitrite). Multi-metal grade for steel, copper, brass, aluminum • **ASTM A924** (American Society for Testing) — VCI testing methodology used to verify performance across brands. Test methods: bell jar 60 days + hot-cold cycle • **Mil-D-3464E** (US Mil, updated 1987) — silica gel mil-spec. Defines cobalt-free indicator dye (new — old used cobalt chloride blue→pink), **Type I** (8 g packet) for small boxes, **Type II** (16/32 g packet) for large boxes/containers • **ISO 21006** (International) — VCI multi-metal performance, rarely cited in Thai TORs **Most Thai government TORs** cite MIL-PRF-3420 (VCI) + Mil-D-3464 (silica) together. **Never use non-mil-spec VCI/silica** for military/aerospace work

**Standard export procedure for 30-60 day transit + 70-95% RH + salt air:** 1. **Clean** — light sand + wipe clean, remove finger oil with IPA 2. **Apply VCI Oil / Rust Inhibitor** — thin coat on surface (small parts) or spray Tectyl 506 (large parts / automotive) 3. **Wrap with VCI Paper** or place in VCI Bag (must be multi-metal MIL-PRF-3420) 4. **Add Silica Gel** 30-60 g per 1 m³ air volume (reduce initial humidity) 5. **Insert humidity indicator card** (10% / 20% / 30% RH) on box — destination check 6. **Seal with stretch film + vacuum seal** (if possible) or heat-seal the bag opening 7. **Export labeling** — ASTM D3951 (Commercial Packaging) for EU/USA, GB/T 13384 (China) **Saha standard pack:** VCI paper KraftPro 80 gsm + 4× silica gel 30 g + humidity card + Tectyl 506 spray + 5-layer corrugated box. ~฿180-250 per 5-10 kg item

Three main liquid rust inhibitor brands — differ by film, application, and price: • **ORAFON Rust Stop** (Thailand made, distributed by Saha) — wax-based film 30-80 µm DFT, moderate water + UV resistance, ฿180-320/L (5L + 20L pail), used on railway parts + agricultural machinery + storage 2-5 yrs. MOQ 5 L. **Domestic default** • **Tectyl 506 / 506 EH** (Valvoline / Daubert Chemical) — petroleum-based 50-150 µm film, salt spray ASTM B117 1,000 hr, ฿580-980/L imported, used in automotive OEM + marine + offshore. **Export overseas** standard. Tectyl 506 EH = enhanced UV (better outdoor) • **Cosmoline 1043 / 1100** (Houghton / Quaker Houghton) — heavy wax 200-500 µm film, **hardest** — requires heating for smooth coating. Used for 10+ yr military preservation / aircraft mothballing / reserve weapons storage. ฿1,200-2,500/L imported **Rule:** Indoor short-term → ORAFON, Export marine → Tectyl, Long-term military preservation → Cosmoline. Saha supplies all three (Tectyl + Cosmoline 4-6 week lead time)

Saha stocks complete + provides full documentation for military / SRT / export TORs: • **VCI Paper KraftPro** (80 / 100 / 125 gsm) — MIL-PRF-3420 multi-metal cert, COA per batch, MOQ 1 roll 500 m², ฿140-240/m². Bangkok delivery 3-5 days • **VCI Bag / Film** (LDPE 75-150 µm) — MIL-PRF-3420 + ASTM A924, all sizes 200×300 to 1,200×1,500 mm, ฿8-45/each • **Silica Gel** Mil-D-3464E Type I/II — orange indicator (cobalt-free), 8/16/32/100 g packets, ฿4-15/packet. MOQ 1,000 packets • **ORAFON Rust Stop** wax film — ฿180-320/L, MOQ 5 L, Bangkok delivery 1-2 days • **Tectyl 506 / Cosmoline** imported — ฿580-2,500/L, 4-6 week lead time, MOQ 25 L **TOR documentation Saha provides:** mil-spec COA + batch number + Material Safety Data Sheet + non-carcinogenic amine cert + manufacture/expiry date + ASTM B117 salt spray report + 1-year shelf-life warranty. Quote request — specify part + storage duration + shipping mode → 2-3 brand spec sheet + budget within 24 h.