Q1: What is the minimum VCI protection required for ocean freight to Southeast Asia?

For a 20ft container (approx. 33m³), use a minimum of 20–25 VCI emitter sachets (40g each), distributed evenly throughout the container. Supplement with VCI film wrapping for individual parts or SKUs. Desiccant: minimum 1kg of silica gel or equivalent, distributed across floor level and mid-height positions.

Q2: Can I use rust prevention oil instead of VCI packaging?

Oil provides good protection but has drawbacks: it makes parts dirty (requires cleaning before assembly), it can be removed during handling, and it does not protect internal cavities or blind holes. VCI + light oil is the standard for precision parts. For raw forgings or unfinished castings, oil alone may suffice — specify the type clearly (WD-40-style solvent-depositing oil for short-term, RP-7000-type film-forming oil for longer protection).

Q3: Are wooden crates always required to be heat-treated?

Yes, for international shipments under ISPM-15 regulations. All wooden packaging material (crates, pallets, skids, dunnage) used in international trade must be either heat-treated (HT, min. 56°C core temp for 30 min) or fumigated with methyl bromide (MB, being phased out). Heat treatment is preferred. The supplier must apply an official ISPM-15 mark (the IPPC logo with country code and producer number) to each crate. Accept only crates with legible marks — unmarked wooden crates risk being seized or incinerated at destination.

Q4: How should precision-machined shafts or threaded parts be packed?

Individual VCI poly bags for each part. Soft foam or VCI paper wrapping at all machined/threaded surfaces. Place parts in custom-molded EPS foam inserts or compartmentalized wooden blocks with recessed cavities. Never allow machined surfaces to contact each other directly — even slight movement will cause micro-abrasion damage. Threaded ends should have plastic thread protectors (VCI-impregnated if available). Bundle groups in VCI stretch film before placing in crate.

Q5: What’s the difference between a “closed crate” and an “open crate” for metal parts?

A closed crate has solid side walls and a solid lid, providing full environmental protection against dust, moisture, and physical intrusion. An open or slatted crate has gaps between boards — it protects against impact but offers minimal environmental sealing. For sea freight, where containers can experience condensation and “container rain,” always use closed crates for machined or bare metal parts. Open crates are acceptable for well-protected internal parts within a sealed container.

Q6: How do I handle a shipment of mixed metal alloys (steel + brass + aluminum)?

Separate each alloy family into its own VCI bag or VCI-lined compartment. Different metals have different galvanic corrosion potentials — when electrically connected by moisture, dissimilar metals accelerate each other’s corrosion (galvanic coupling). Brass and copper are particularly aggressive; keep them isolated from steel components. For mixed loads, use neutral (pH 7) VCI formulations designed for multi-metal applications.

Q7: Who is responsible for export packing — buyer or supplier?

Typically the supplier, under standard Incoterms EXW or FOB. However, the buyer must specify packing requirements explicitly in the purchase order — do not assume the supplier knows your requirements. For OEM sourcing, include a detailed “Packing Specification” document as an attachment to your PO. This should specify: packaging type, VCI requirements, labeling format, inspection requirements, and which party bears the cost of packaging.

Q8: What is “container rain” and how do I prevent it?

Container rain occurs when warm, humid air inside a container cools below its dew point, causing moisture to condense and drip onto cargo. It can occur when a container that has been sitting in the sun (interior 40–60°C) is opened in a cooler environment. Prevention: desiccant packs (absorb initial humidity), silica gel floor mats, VCI/desiccant combination products, waterproof inner container linings (polythene film), and container desiccants placed on the container floor before loading. Ventilated containers are NOT recommended for metal parts — they allow humid outside air in.

Q9: Should I use air freight instead of ocean freight to reduce transit damage risk?

Air freight dramatically reduces transit time (days vs. weeks) and thus corrosion risk, but introduces higher handling frequency and vibration during loading/unloading. For high-value, time-critical OEM components, air freight may be justified. For standard custom metal parts with adequate VCI packaging, ocean freight in a properly packed closed crate is sufficient. The packaging quality matters far more than the transport mode.

Q10: How do I verify my supplier’s export packing quality before placing a large order?

Request a sample packing for 1–2 units before the production run. Conduct a pre-shipment inspection (PSI) for the first order with a new supplier. Ask the supplier for packing photos at each stage of the process. Include packing specifications in your purchase order with a compliance checklist. For ongoing orders, use periodic unannounced inspections or request a video walkthrough during loading.