In formwork plywood, the boiling test is a standardized laboratory method to measure how well veneers remain bonded under extreme moisture and temperature. Test pieces are submerged in boiling water for a defined number of hours, then cooled and inspected for delamination, swelling or bond failure.
For WBP (Weather and Boil Proof) melamine or phenolic glue systems, longer boiling times indicate stronger, more water-resistant glue lines. In practice, the boiling hour rating gives buyers a clear indication of how the panel will behave under repeated wetting, drying and concrete pouring cycles.
Boiling tests do not measure glue content alone – they show the combined effect of glue formulation, resin content, pressing temperature and production control. When a panel withstands longer boiling cycles without delamination, it means the bond strength between veneers is high and less sensitive to moisture.
This is why technical buyers use boiling hours as a proxy for durability: higher boiling-hour classes usually correlate with better structural stability, reduced edge opening and a higher potential number of safe reuses on the job site.
Different formwork grades are associated with characteristic ranges of boiling hours and glue content. The table below shows typical structures and expected reuse ranges under normal site conditions.
Boiling hours define the potential of a panel, but site practice decides how close you get to that potential. Rough stripping, dropping panels, or using inappropriate tools can damage edges and faces long before the glue line fails.
To protect lifespan, contractors should:
Concrete mix design and release agent also influence how quickly a panel wears. Harsh mixes, high cement content or poor vibration can increase abrasion and mechanical stress on the surface.
Using a compatible release agent, applied in the correct dosage, reduces sticking and stripping stress. This not only improves the concrete finish but also helps high-boiling-hour plywood reach its expected reuse range.
A serious supplier does not rely on glue supplier claims alone – it verifies boiling hours through regular in-house or third-party testing. At FOMEX, representative samples are taken from production, cut to test dimensions and subjected to boiling cycles matching the target grade.
After boiling and cooling, panels are inspected for signs of delamination, core void opening and excessive thickness swelling. The results are recorded against batch numbers so that each grade (e.g. 6–8 h, 10–12 h, 15–20 h, 36–48 h) is monitored over time.
Controlling average boiling hours is not enough; buyers need consistency from shipment to shipment. FOMEX links boiling test results, moisture data and other QC parameters to production lots and can provide summaries on request.
This documentation, combined with pre-shipment inspection and loading photos, helps importers trace performance back to specific batches and demonstrate due diligence to their own customers and auditors.
To move beyond generic product names, buyers should include boiling-hour requirements directly in their RFQs. Useful questions include:
These questions quickly reveal whether a supplier truly understands technical specifications or is only selling by price and broad descriptions.
A clear technical datasheet for formwork plywood should list glue type (e.g. WBP melamine), boiling hours, moisture content, thickness tolerance, core species and expected reuse under standard conditions.
When reviewing datasheets from different suppliers, buyers should:
Using boiling hours as a central comparison parameter makes supplier evaluation more objective and reduces surprises once panels reach the site.
FOMEX engineers can help you translate project requirements and reuse targets into the right boiling-hour class and plywood grade – from entry-level 6–8 h products up to heavy-duty 36–48 h solutions.
Email: qc@fomexgroup.vn ☎ WhatsApp: +84 877 034 666