Spider Spitter 2

A giant spider really needs to spit webbing at trick-or-treaters. For many years we used a spider spitter that shot shaving cream.

This year, we built a gadget to spit a stream of water, which is easier to clean up.

To be truthful, I got the idea to build this while putting together a couple more Haunt Air Managers (HAM). I noticed that my collection of solenoid valves from the electronic swap meet contained a 2-way valve, which isn't that useful for pneumatic effects. So I got to thinking what I could do with it....

Construction
Lessons Learned

Construction

The gadget is very simple. It hooks up to the water hose (so you don't have to refill it), is triggered by a solenoid valve, and squirts through a nozzle.

[photo] We started with a solenoid valve similar to that used for pneumatic projects. The difference is that this one happened to be rated for liquids and is just a 2-way valve.

The hardest thing to do was to find plumbing fittings that could go from a hose connection to 1/4" NPT. As you might expect, we didn't find a single fitting that did this, and ended up doing it the hard way.

[photo] This is the input to the solenoid valve.

[photo] The output of the solenoid valve goes to a hose barb and some light plastic hose.

The parts list:

hose connector
1/2" -> 1/4" bushing
1/4" NPT nipple
2-way solenoid valve
hose barb with 1/4" NPT threads
hose clamp
a length of hose
nozzle

If you don't have a nozzle, you end up with greater volume at lower pressure. You want a thin stream, not to soak the TOTs.

Lessons Learned

For a nozzle, I used the business end of a glass eye dropper. I pushed the thin tubing from the solenoid into the wide part of the dropper, and sealed over it with heat-shrink tubing.

This made an excellent spitter, but I wasn't careful enough when I first tested it. When the valve was triggered, the rush of water out forced the dropper and hose to scoot back, flailing around. By the time I turned it off, the glass tip had struck something and cracked.

So, tie it down or hold it firmly for testing!

Thank you for visiting. Your comments are welcome.
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