yeah, I couldn't find a cheap thing to use as the basin, so I started looking around the store and decided to buy a storage tub. now I wish I'd bought a deeper one, but whatever.
I lined the thing with a shower curtain because it was nowhere near plumb or water tight...
and yeah, that's a 5 gallon bucket.
I'm very interested to see how much water I use on a typical poster job.
*edit - I painted it with some waterproof deck paint the guy said would work great. Having built it and knowing what a shit job I did, I expect to have to build a new one in the spring, but it should get me through the winter.