I have a question on Chemistry.SE about secondary reactions producing something other than CO2, and from a bit of discussion there, the answer seems to be that there aren't any, but some of the original ingredients can get splashed up into the LPE.
So, has anyone tried doing that? If so:
- What was your setup?
- How did you clean the LPE afterwards, if at all?
- Was there any damage after a few days?
I'm thinking about a 3-step process, but I'm also wondering if it's even necessary:
- Run it on Baking Soda and Vinegar as planned.
- Run it on Water to rinse out whatever raw ingredients might have gotten into it.
- Run it on Air to dry out the water.
The water is probably from a garden hose, with the unsolved problem of how to hook it up to a Lego hose.
The air is probably from a shop compressor with the regulator turned down. I have a bicycle pump for testing, and a sports inflator needle to make the connection, but I don't think I want to pump it that much!
The reason to use Baking Soda and Vinegar at all, instead of just using Air in the first place, is to have a compact, self-contained system that can run itself around a track for a while, and be able to start and stop on command without over-pressurizing for lack of use or running out from constant use.
So, I've rigged up a pressure-regulated, motorized air pump to displace vinegar out of one small plastic water bottle, and into another that has the baking soda, which then creates the working gas.
I've seen a big bank of pre-pressurized soda bottles on an LPE-powered car, but that's just too bulky for what I'm doing.
Some pictures may help:
The water bottle sits horizontally, under the black "hold-down bridge", with the bottom against the RCX.
"Steam" locomotive with Walschaerts valve gear. And yes, it runs. :-) Both directions.
(Wires and sensors are in false color to show the connections.)
There's also a tender car with the other water bottle and the air pump to displace something out of it.