Unions are not too hard to make Dougie but in the sizes that I use regularly they are pretty cheap to buy. So a while ago, I just stocked up from Blackgates (who don't do 1/16th I'm afraid). I view these rather like BA screws/nuts – I like to have them to hand and I check my stock levels before going to a show – so I can replace anything used.
Frankly, I have quite enough other jobs to do (that I either can't purchase or afford) without adding more to the list.
If you only need a couple once-off, then sure – knock a few up (which also assumes you have the material size to hand) but if you are going to need this size of union regularly, then why not just bite the bullet and order enough to make it worth while. They are small/light enough that even a packet airmailed from Aussie shouldn't break the bank.
Regards,
IanT