Is your aluminum lid anodized? If so, it will not leach aluminum oxide into your water.
Ok Thx, I wondered if that might make a difference or not. 1 of the lids is spray painted black (not Kryon Fusion though -- who knows, could be why that BBXB hasn't been feeling super over last couple of months), but the other (one I'm working on now) I 'think' is anodized. If so though it's pretty light, 'cuz it scratches easily; also there are quite a few cut end pieces where it of course isn't anodized. Also not sure what the rivets are made of. Probably might be ok if it is anodized, but again better safe than sorry; new version will be totally non-mettalic.
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On white PVC you can colour tint with tie-dye stain. The stuff used for T shirts. You need very hot water to soak and see several baths. As the PVC pipe is long, I use a wider diameter PVC pipe with end cap as the bathing container.
Black comes out slightly patchy so may not work as well as paint but doesn't scratch off like paint would.
Interesting, appreciate the tip, might consider that with the 2nd lid after I see how this one looks in blue.