Compare the process before comparing quotations
| Decision | Zinc electroplating | Hot-dip galvanizing |
|---|---|---|
| How the coating is applied | Zinc is deposited electrochemically | Prepared steel is immersed in molten zinc |
| What to identify | Process, agreed coating specification and any post-treatment | Process and the applicable hardware/coating specification |
| What to clarify | Required protection, appearance and fit for the intended environment | Required protection, coating acceptance and fit after processing |
| What the name alone does not prove | Service life, part strength or project compliance | Service life, part strength or project compliance |
The American Galvanizers Association distinguishes electroplating, mechanical plating and hot-dip processes. Its fastener guidance describes electroplating as generally smooth and relatively thin. Appearance is not a reliable substitute for the specified process. Read AGA’s zinc-coating comparison.
Why preparation belongs in a process discussion
AGA describes cleaning, pickling and fluxing before immersion in zinc. Its Hot-Dip Galvanizing Process animation visualizes preparation tanks, the zinc bath and inspection. At about 0:26 the preparation stages are visible; by about 1:16 the bath and inspection stages are shown. This external educational animation does not show our factory or establish our coating performance. Read the accompanying process explanation.
Ask how the finished threads will fit
AGA’s threaded-parts guidance explains why the added zinc must be allowed for in mating threads. Its discussion includes oversize internal threads for galvanized bolted assemblies. The correct treatment belongs on the applicable part and assembly specification; this is not an instruction to retap any finished safety-critical part. Read the threaded-parts guidance.
Put these questions in the quotation: Which mating components are included? Is fit checked after finishing? Which drawing revision and acceptance method apply? Who reviews a coating substitution?
Agree the evidence before ordering
- State indoor/outdoor exposure and any project-specific corrosion requirement.
- Name the intended coating process and ask for the applicable specification and edition to be identified.
- Agree the required inspection record, sampling basis and treatment of mating threads.
- Ask for discrepancies to be listed before approving samples or a repeat order.
Do not convert salt-spray hours into guaranteed field-service years. AGA cautions that accelerated zinc-coating tests do not reproduce the protective patina’s real-world behaviour. Source and limitations.
Return to beam clamp selection, strut compatibility or the RFQ checklist.
Sources and scope
- AGA: Zinc Coatings for Fasteners
- AGA: Threaded & Moving Parts
- AGA: Batch Hot-Dip Galvanizing Production Process
- AGA: Hot-Dip Galvanizing Process animation
External sources explain general principles or their own products. They do not certify Support Hardware products. Confirm final specifications against the approved drawing, quotation and applicable project requirements.