Abstract: A purge plug for welding applications is provided that can be interchangeably used to seal tubing, pipes, or the like of various diameter or cross-sectional area. The purge plug has a central body with a male connector and a diffuser disposed on the end portions. The purge plug also includes one or more flexible seals annularly disposed around the central body. In some implementations, the diameter of the flexible seals is slightly larger than the diameter of the tubing or pipe. When the purge plug is inserted into the tubing or pipe, the resiliency of the seal allow the seal to expand mechanically and flex against the inner walls of the tubing, thus sealingly engage with the inner walls.