You can get three foot lengths of 17/32 brass on Amazon. Price isn't too bad (about $35-40) given there are generally a pack of three of them, in the three foot lengths. For example https://www.amazon.com/9117-Round-Brass-0-014-Pieces/dp/B000BQQ3BI/ or https://www.amazon.com/K-S-Brass-Tube-Bulk/dp/B002SUBUGS/

Granted I am not sure about availability in other countries than the US.