So to help keep primary and first mirrors clean I was going to enclose the tube and such in a gas tight enclosure.

The tube will be on the gantry and only the final optics will be flying back and fourth.

Would argon be a good choice?

Or would I be better off just flowing clean compressed air over them and not make it gas tight?

Newbie and my laser is open and wanted to limit damage to mirrors etc. when used by lazy (me) operators who forget to clean primary mirrors often.
Slam don't want dust to settle on mirrors between uses so I only have to clean the flying optics before each use.

Go easy if I am way off just tell me it's a bad idea and why.

Thanks so much JC