Which seam will require soldering or fastening to ensure it stays together?

The Pocket Lock seam requires soldering or fastening to ensure it remains securely together. This type of seam involves folding the edges of the metal into a pocket shape that can be locked into place. To maintain the integrity of the connection and prevent separation or leakage, it is essential to utilize additional fastening techniques such as soldering. This practical fastening approach is commonly used in HVAC applications where a strong, durable, and airtight seal is necessary.

In contrast, other seams like the Pittsburgh seam and the Button Lock can achieve a secure connection through mechanical interlocking and do not necessitate soldering. The Groove Seam typically relies on pressure to maintain its integrity as well, thus further highlighting the unique need for fastening in the case of the Pocket Lock seam.