For Ali chain beware of cheap ebay ring mail.
Ideally you want rivited mail, otherwise you will be leaving little rings all over the battlefeild
Its also worth poiting out that ali chain counts as medium armour, which is the same as leather. If you have the skills id just have a leather breast plate and cover your arms and lower legs with leather vambraces and greaves.
If you do want ali chain then look at epic armouries chain. Its butted but the arm pits are rivited. Its also steel i beleive.
I hear allbeststuff is pretty good, but remember to include import duty in the price (they are Indian). As Wander points out, aluminium is softer than steel and will tear apart if butted.
What’s the reason for picking aluminium?
Practicality? It doesn’t risk rot or cracking like leather, and won’t rust like, non-coated steel.
Weight? If price isn’t a major turnoff, then Ringmesh is even better as it’s welded steel and basically impervious to larp accidents. Short sleeved one of those will set you back a couple hundred quid inc postage.
Price? It’s a lot cheaper than getting good coverage out of 3mm thick leather. The other good budget option is second hand “butcher mail” or "aluminium disc aprons. They often come up on ebay and don’t need much work to modify into looking a bit more armour-y. @Geoffrey_Willoughby got hold of I think 3 and wears them as front, back and shoulders.
I’d have a think about just getting a steel breastplate to go with that. You’re getting arm and leg coverage out the leather anyway, and if you go with just the breastplate not the back it’s cheap and pretty light (about 3kg) This does leave you vulnerable to backstabs, but that’s less of an issue in battles especially as it’s arrow proof from the front.
If its cost, basic butted steel mail is often cheaper, though you can get indian Rivetted ali mail on ebay that hold up pretty well, though i wouldnt waste money on butted Ali mail tbh.
Heavy armour is considerably better than 1 extra hit when archers are in play but a bit of a waste against the Jotun. Wieght i can certainly understand as my knees slowly expire