In industries like aerospace, aviation and electronics – where component reliability is critical – protective finishes such hot solder dip are incredibly beneficial. AOTCO is excited to announce that we now offer tin dip solder services, adding to our portfolio of other advanced metal finishing solutions.
As one of the few companies in the United States capable of performing these operations, we are pleased to offer our clients a proven method for improving solderability and long-term corrosion resistance for parts in harsh, high-stress environments.
The terms hot solder dip, hot tin dip (or hot tin dipping), tin reflow and flow brightening are sometimes used interchangeably, but there are some key differences between these processes.
Hot solder dipping involves immersing components into a molten bath of tin-lead alloy (typically a 60/40 split) at temperatures exceeding 370°F. This forms a durable protective coating that is made up of a thin intermetallic compound layer at the base, followed by a thick layer of pure solder.
Hot tin dip is similar, but the part is immersed in a molten bath of pure tin, which has a higher melting point at 450°F.
Tin reflow, or flow brightening, is a secondary process where a previously plated or dipped layer of tin (or tin lead) is heated again until it reflows, or melts slightly, to create a smoother, sealed finish. This helps improve the surface finish and helps mitigate any imperfections in the original plating.
This is, of course, distinct from other metal finishing services like tin electroplating that involves applying a tin coating through an electrochemical process – that is, where an electric current deposits tin onto the component. Electroplating typically results in a thinner, more controlled coating but it's more porous and less durable relative to hot dipping.
Also, electroplated coatings are more prone to oxidation and tin whiskers, which is why hot dipped tin is a more reliable option for harsh environments.
Hot solder dipping offers numerous advantages that make it the preferred choice for applications that need robust protection.
Key benefits include:
While hot solder dipping offers many advantages, it does have some limitations. The coating thickness is less precisely controlled compared to electroplating methods, which can make it less suitable for applications that need extremely tight tolerances. It should also not be used when the base part has fine details that could be obscured by a thicker plating layer.
The biggest advantage of parts and equipment that has been through a dip solder process is the long-term durability and reliability of those parts compared to regular tin lead plating or electroplating. Components treated with hot tin dip remain solderable for up to 15-20 years, far outlasting traditional tin-lead coatings, which may degrade after just a year.
For example, a member of the AOTCO team recently inspected a client’s warehouse located near a humid estuary on the East Coast. Remarkably, parts that had been stored there for over 15 years in a damp, muggy environment remained perfectly solderable – speaking directly to the long-lasting durability of our hot solder dip process.
Hot solder dip is an excellent choice for parts exposed to high temperatures, environmental stresses or corrosive conditions, making it the ideal solution for industries that demand long-term reliability and robust performance.
At AOTCO, we pride ourselves on delivering finishing solutions that stand the test of time. Our hot solder dip – and all our services – are engineered to provide unmatched durability and reliability. Whether you're in aerospace, defense, electronics, or any industry requiring reliable finishes, our team is here to meet your needs.
Get in touch with us today to tell us about your hot solder dipping needs.