Hi Ron:
I have used the RS 5 ft. antenna masts before and this is what I experienced with them...
There is a swaggered end which will lock into the next section but if the fit is loose then I would make up a small amount of epoxy to cement the pieces together.
If you plan to join two or more sections together and mount them above the roofline where high winds could be a factor, then I would definitely use several guy wire clamps to secure the mast and prevent buckling.
You didn't specify how you plan to use them, so I've given you the various ways that I have mounted them in my setups. Hope this helps you.
Russell