I think people donating on Patreon get the whole "predictable income makes an artist's life an awful lot easier" thing, if you're looking for a tactful way to approach the topic.

Saying that you'd like to be able to make it your full time job is a very reasonable thing as well, and I imagine people get that you need some kind of salary to do it.

Both of these are things that I, if I were a frequent visitor to your site, would have a pretty good incentive to make happen.