Trasmetal designed and built for TML – an Abruzzo-based manufacturer of boilers for domestic hot water – a new automatic enamelling plant, enabling the company to bring in-house a production stage previously outsourced to third parties.
The technical challenge was to develop a “made-to-measure” plant able to meet TML’s specific requirements — significant wall thicknesses and high operating pressures. Trasmetal’s solution stands out for its choice of spray pre-treatment rather than dip pre-treatment: since only the boiler’s internal surface comes into contact with the sanitary water and needs to be enamelled, treating the entire component would have meant higher chemical consumption and more complex wastewater management. The pre-treatment cycle comprises 8 stages (degreasing, rinsing steps, pickling, passivation), followed by application of the porcelain enamel through two in-line flow coater machines, drying, and firing at 800–850°C with controlled cooling.
A key strength of the project was the joint optimization of the drying cycle: the presence of multiple heat exchangers inside the same boiler requires highly variable drying times (from around half an hour for empty units up to an hour and a half for those with two or three exchangers), calibrated by Trasmetal together with TML to eliminate any residual moisture before firing.
The value of the project lies in combining two complementary skill sets: the plant manufacturer’s technological expertise and the customer’s in-depth knowledge of its own product — a direct dialogue with ownership that made it possible to develop a more efficient process with a lower environmental impact, thanks to reduced use of chemicals and waste.
The full article is available at the following link: https://www.ipcm.it/en/open/ipcm/2026/100/196-200.aspx
“A strategic choice for growth: TML invests in boiler enamelling”, in ipcm_International Paint&Coating Magazine n. 100, pg. 190-194.
