comments:
Get a set of silicone hole plugs for painting and powder coating. Like these: https://a.co/d/0grUreon Next drill a 1/4" hole in them and use a 1/4" steel bottle brush to ream the hole out. Then insert a 1/4" tube into the plug and attach your purge line to that. Make another plug with a hole in it and put it on the other end to allow the gas to flow out. Then use a solid plug to plug all other outlets. You can also cut a "V" out of the tapered edge to let the gas escape if you don't want to drill another one. If you're welding close to the silicone plug use aluminum foil instead, but be aware that it's pretty easy to have the foil come off. A band clamp can help keep it on if that becomes a problem. FYI, the bottle brush will be full of silicone but it works like a charm.