Are Brazed, soldered, or welded joints able to be coated? Are there compatibility problems with the coating? Let’s discuss each of these questions in detail.
First let’s discuss brazing and soldering. Customers usually have 3 concerns about processing solder and braze joints in customer-supplied parts:
In this blog post you will learn:
|
Let’s discuss the third concern first. It is common for the coated solder/ braze joint area to appear “hazy” after processing. Though the coating performance should not be negatively affected, the customer can expect a different visual appearance in the brazed or soldered areas.
Brazing is a joining process where metals are bonded together using a filler metal with a lower melting point than the base material. Heat, via torch or furnace, is used to liquefy and allow the flow of filler metal (via capillary action), which then cools, solidifies, and joins the base material. Additional materials, such as flux, may be used to prevent the accumulation of oxides and other undesirable contaminants in the filler metal.
Brazing and soldering are typically defined by the melting temperature of the filler material, with brazing joints rated to withstand temperatures over 450°C whereby solder joints can fail above 370°C. Most braze joints will survive our process, however it’s our experience that vacuum nickel brazing yields the best coating appearance.
Recommendations for braze joints:
Solder filler material may have some of the same components as found in braze materials, such as silver and copper, but it is also alloyed with metals such as tin, bismuth, indium, zinc, antimony, and gold. Solder is applied at a lower temperature than brazing and typically contains metals with a lower melting temperature. The lower application temperature of solder means that the joint will likely fail when exposed to our elevated process temperature. The resulting joint failure may also contaminate the process and result in compromised coating quality.
Recommendations for solder joints:
A note about silver soldering. Silver soldered components are typically not soldered, but rather brazed. Most “silver solder” joints will survive SilcoTek’s processing but may appear hazy after the coating deposition.
Learn how to get the most out of your products and our coatings. Get our Coating Properties Quick Reference Guide.
SilcoTek can coat over high-quality welds, such as those listed in our material compatibility guide, without process contamination and with excellent coating appearance
SilcoTek is able to coat over welded and brazed parts if the joining process involves a TIG/ MIG weld, vacuum-nickel brazing, or a silver solder that can withstand up to 450°C. Please see our Technical Insight, “Recommendations for Coating Components with Braze and Solder Joints” to learn more. Contact our Technical Service Team if you have questions about process compatibility or coating performance. We're here to contribute to solving your product contamination problems.
Stay current with the latest in coating technology. Subscribe to our email and blog or follow us on LinkedIn.