Technical Support

How cold spray zinc protects steel

Cold spray zinc is not a paint that happens to contain zinc. It is a zinc coating applied like a paint. The dry film carries ≥96% metallic zinc, so when the coating is scratched through to the steel, the surrounding zinc becomes the anode and corrodes first — exactly the mechanism that protects a cut edge on a hot-dip galvanized member. That is why it can be used on its own, without a topcoat, in C3 environments, and why it can be left as a base layer under a full system in C5-M.

Surface preparation

Surface preparation is what determines whether a zinc coating performs. The TDS requires Sa 2.5 (ISO 8501-1) with a profile of Rz 40–75 µm and priming within four hours of blasting. Cold spray zinc bonds mechanically and electrically — on a poorly prepared surface the zinc cannot make continuous contact with the steel, and the sacrificial circuit simply does not close.

Galvanized surfaces in repair work need a different approach: degrease, high-pressure fresh-water wash to remove soluble zinc salts, then power-tool abrade local rust before applying the zinc. White rust left in place will sit between the zinc coat and the steel and fail early.

Steel temperature must stay 3 °C above dew point. In coastal and tropical sites this is the most common cause of premature failure — steel that looks dry in the morning is often at dew point by mid-afternoon.

Coating systems by corrosivity category

C3 — Urban and industrial atmosphere

Surface prepSa 2.5 / St 3 
BaseZD96-160 µm
SealerZB18-1240 µm

C4 — Industrial and coastal

Surface prepSa 2.5 
BaseZD96-180 µm
IntermediateZD618050 µm
TopcoatZD643050 µm

C5-M — Marine atmosphere

Surface prepSa 2.5 
BaseZD96-180 µm
IntermediateZD608060 µm
TopcoatZD643060 µm

Where it is made

Our cold spray zinc is produced at our partner plant in Wuxi, Jiangsu — the source of every drum we ship. Six views below are the actual shop floor: mixing lines, automatic dispensing, filling and the finished-goods warehouse.

Main production hall — Mixing lines arranged under the steel structure, with a dedicated green safety route through the hall.
01Main production hallMixing lines arranged under the steel structure, with a dedicated green safety route through the hall.
Process walkway — Marked walkway between mixing bays — keeps forklift and pedestrian traffic apart during filling.
02Process walkwayMarked walkway between mixing bays — keeps forklift and pedestrian traffic apart during filling.
Filling and palletising — Filled pails palletised beside the plant; a full pallet leaves on one stretch-wrap.
03Filling and palletisingFilled pails palletised beside the plant; a full pallet leaves on one stretch-wrap.
Automatic dispensing — Automatic dispensers and pigging lines under the tanks — batch weights are closed by weight, not by operator judgement.
04Automatic dispensingAutomatic dispensers and pigging lines under the tanks — batch weights are closed by weight, not by operator judgement.
Mixing bays — Dispersers and tanks along the hall, each bay with its own drum-filling station at the end of the line.
05Mixing baysDispersers and tanks along the hall, each bay with its own drum-filling station at the end of the line.
Finished-goods warehouse — Racked storage for packed pails and cartons, held until the container is booked.
06Finished-goods warehouseRacked storage for packed pails and cartons, held until the container is booked.

Photos taken at the production plant. Brand names and product marks that appear on the packaging belong to their respective owners.

Export supply chain

Supplying coatings to a project overseas is not only a matter of the drum price. The chain below is what we handle between your purchase order and the material standing on site — and it is where most export orders quietly go wrong.

01

Export packing

Pails and drums are palletised, stretch-wrapped and steel-banded for sea freight, with desiccant and edge protection on request. Pallet marks, shipping marks and buyer labels can be applied in our warehouse.

02

Dangerous goods compliance

Solvent-borne coatings ship as dangerous goods. We classify each SKU (UN number, class, packing group), supply the MSDS in the buyer's language on request and arrange the export packaging certificate required for the booking.

03

Documents

Commercial invoice, packing list, TDS and batch COA issued together, with the MSDS on request, so customs and the consultant on site work from the same numbers.

04

Booking and customs

Shipment from Shanghai or Ningbo, LCL or FCL, on FOB, CFR, CIF or DAP terms. Dangerous goods slots are booked in advance — tell us the target window and we hold space against it.

05

Delivery to site

Port-to-site delivery in Asia, Africa, the Middle East and the CIS, including inland trucking and, where required, delivery duty paid to the construction site with the paperwork the site consultant asks for.

06

Lead time and payment

Standard stock items are prepared in about one week; made-to-order batches depend on the factory schedule and are confirmed in writing before the order. T/T in advance as the default; other terms on a confirmed order basis.

Further reading

Technical note · 10 min read

Cold galvanizing vs hot-dip: the comparison most articles get wrong

Zinc mass per square metre, not thickness in microns, is what decides whether cold spray can replace hot-dip. The arithmetic, the boundary cases, and where the substitution fails.

Read the note →

Documents

TDS library →

Not sure which grade fits your environment?

Send us the structure, the steel condition and the corrosivity category (C2 to CX). We reply with a coating system, film builds and a delivered price.

Request a quote