How do I join aluminium box section.

[Ascalon]

Hi,
I have a number of six foot long anodised aluminium rectangular box sections. These are hollow and have a cross section of half an inch by one inch. I would like to join them together in pairs by splinting a foot long section across the ends of two of these sections. The splint would be attached to the face of the one inch dimension. Riveting would be good but there are difficulties in obtaining rivets long enough to pass through a pair of these sections. Does anybody know of rivets that might do the job ? Alternatively, any suggestions as to how these sections may be joined would be welcome. Thanks.

 

[Tigercubrider]

What sort of loading?
What is the internal measurement?

You might be lucky enough to find either a bar or box section that would slip inside.
Pop rivets would be fine, they don't need to pass through- just rivet each side
If you have a good fit, you can also use a glue

 

[Alec_t]

Alternatively, any suggestions as to how these sections may be joined would be welcome.

Braze or weld?