I've been using 4 oz squeeze bottles, available at Hobby Lobby for $.99, instead of syringes when casting small parts. The bottles have a fine nozzle, and I find it easier to control flow by squeezing rather than pushing a plunger (recent hand surgery could have something to do with that). They are also easier to fill and to clean: I just dump an oz of acetone into them, shake for a few seconds, then empty through the nozzle.
I make my small boats about ten at a time, with about two oz of materials. It takes me about 30 seconds to mix the materials and get them into the bottle, then about two and a half minutes to fill the molds, which leaves plenty of time to get the acetone in before everything turns gooey.
The bottles seem to last longer than the syringes, as there is no seal between the plunger and barrel of the syringe, which always goes first with increasing friction. Of course, you can probably get syringes for free for a reasonable number, but I'm on about my hundredth pour (or squeeze) with my current bottle.
