Need an L-shaped square aluminum tube 25x25mm

[maeron]

Where can you find such things?

It can just as well be 20x20mm or 30x30mm

However, the L-shape should be at least 150*450mm

Where do you find such things?

 

[Demmpa]

Contact a blacksmith shop and they will make one for you. In order for them to be able to make one for you, they will probably want a sketch/drawing of how it should look.

 

[cpalm]

Depending on what you need them for, there are also those square tube systems with various T and L pieces that can be used to splice the tubes together in different constructions.