Back with yet more silly questions, I'm afraid! Can I convert a standard kitchen sink to use in my custom folding camper? I know the wastes are different sizes, but can I just use a 40mm to 21mm waste reducer, or am I setting myself up for problems? The kitchen sinks are a better size for what I want, and considerably cheaper!
I think the answer to that is that you can pretty much do what you want, if you're making a custom one. I've not done it, myself, but I think the main thing to watch for is not so much the waste pipes, but the taps. If you were using a normal domestic tap to supply the sink, I'm not sure a normal 12V pump would be up to the job of applying sufficient pressure to the wider bore pipes. Otherwise, you should be fine.
------------- The one good thing about being wrong is the joy it brings to others..
Many thanks - for the time being water is going to be supplied by the very basic route of a drinks dispenser, until I decide whether I need a pump, so there won't be any pumps to worry about!