Best way to plug hole in railing tube?

[SPembleton]

Hang a totally irrevelant bracket and ask people to guess what it is.  It's a conversation starter.

[Stu Jackson]

Hang a totally irrevelant bracket and ask people to guess what it is.  It's a conversation starter.

I tried that yeqars ago, Steve.

No one ever guessed it was a Loran antenna.

The "younger crowd" said:  "What's Loran?" 

As they wandered off texting on their stupid-phones.

[Indian Falls]

if the hole will take a 1/4-28 tap....  tap the hole so that just a few threads get cut.  Don't want to tap it so you can screw a set screw in with fingers.  Buy a .19 cent 1/4-28 stainless set screw about 3/8 long.
Use JB weld when you force this setscrew into the partially tapped hole about 1/3 of the way.
After the JB weld is cure you can cut the setscrew off flush and gently file and and sand the stud flush.
It's a bit of polishing work to do and less than if you weld that hole shut, but if you're like me I'm usually sitting there with a beer anyway.  search You tube for best ways to polish fresh welded stainless.
Do not impart heat during your finishing process. anything over 200 degrees is bad for epoxy and jb weld is basically an epoxy.