SpudFiles

I think this deserves it's own topic thread.
Starting towards the middle of page two on my "help with a rain bird topic"here; the discussion went towards modifying my rain bird sprinkler valve's blowgun so that the blowgun or some other mechanism at the end of the hose would be able to open the valve via pulling a string at some child-safe distance away from the actual cannon.

Anyone have any previous luck with remote firing mechanisms of any kind, or have any helpful suggestions for this application?

I think that if i could find a small 3/8 I.D. stainless steel ball valve (same I.D. as the air hose i am working with) that the combination of it being a small ball-valve *and* being stainless steel, it would take less effort to pull the valve lever with a string. ???? Am i out in left field here?

Tom

due to the extremly large pilot volume of having a 3 -7 foot hose with a blowgun on it there would be an extreme inefficiency but having a short hose and a string would be fine. have you ever thought about maybe using a high torque servo to actuate the lever on the blowgun, can't be more than a couple pounds on pressure needed to activate the blowgun, and just use a remote control to fire the cannon.

if however you build the gun right aside from kids running in front of the cannon, and if you don't use it in freezing temperatures then there really shouldn't be any kid safety issues, but there is always that chance so i understand. i think if you were to mount that blowgun directly to the valve and use a nice nylon string of something like that would add a certain level of umm nostalgia maybe to the cannon. would be cool to see anyway

oops.... ummm, freezing temperatures?????
We were planning a "family play day" using these things after Christmas dinner (lunch).... is there something i need to know?

PVC tends to get brittle in cold temperatures so be careful.

ball-valve-on-a-string is a good diea for remote triggering, provided the launcher is adequately supported - you won't want a Wiley Coyote style incident where the launcher ends up pointing at you

jackssmirkingrevenge wrote:PVC tends to get brittle in cold temperatures so be careful.

ball-valve-on-a-string is a good diea for remote triggering, provided the launcher is adequately supported - you won't want a Wiley Coyote style incident where the launcher ends up pointing at you

Even Sch-40???

~~~~~~~~~

This cannon is going to be mounted "field cannon" style, like this:



So it will be pretty sturdy as the cannon itself will be affixed to the wheeled carriage i am building.

That help any?

i think string activated blowgun would be better just cause a ball valve might be a little tough to pull on. and i would make sure there is a stake behind the support on the ground. as far as the temperature goes just make sure to keep it kind of warm maybe make it removable from cradle so you can take it in and warm it up a bit. I wouldn't let it get below 40 - 45 degrees F and try and fire it. keep it above that temp and you should be fine. if it gets cold to the touch around ambient temp time to warm it up

CarriageGuy wrote: Even Sch-40???

Yes. Go to the search tool, top right centre of the page below 'Forum' and search the forum for some old topics on PVC in cold, there have been quite a few in the past week.

A ball valve is a better idea, at least once you open it it stays open.

Even Sch-40???

Regardless of the thickness, the cold will make it brittle - but to what extent that will affect the strength of the material, I can't quote you any figures.

i think i will do the search Mr. Crowley described and see what comes up, (sorry, i am a newbie) i hadnt even considered cold weather effecting that pipe.





Merged:


I will also call my friend who has been in the plumbing supply business for over 20 years and ask him if there are any actual written down factory specs on temp-vs-PSI failure ratings on schd-40 pipe.

I will post that in a new topic when i get it.

~~~~~~~~~~~~~

BACK TO THE TOPIC AT HAND....

Anyone have any other ideas on a remote firing mechanism???

Go with the ball valve and string, it's simple, easy, reliable and you get the same pulling chord action you get with real artillery

Are the stainless steel ball valves any easier to open/close than the brass ones??

I'm currently in the process of modifying a cordless phone to act as a remote.

I'm following this guide: http://www.angelfire.com/80s/sixmhz/rcphone.html

The only difference is I'm not impressed with the reciever amplifier he used, so i'm going to make my own that will give a constant pulse.

I'll let you guys know how it goes if I ever get around to finishing it.

[quote="CarriageGuy"]Are the stainless steel ball valves any easier to open/close than the brass ones??
Every single valve is different. By what percentage nobody knows...
This is because every single valve is different....

CarriageGuy wrote:Are the stainless steel ball valves any easier to open/close than the brass ones??

Lube a ball valve to make it easier to open.

Instead of a ball valve or blowgun, you can also use an electrically activated valve to fire your mod'd sprinkler valve.

Get another Rainbird valve and use it in place of the blowgun. Leave this second valve's solenoid in place and run a pair of wires from the valve to your remote firing location. Touch a 9V battery (or two of'm in series) to the wire ends to fire the gun. Since this second valve is just piloting the first, it doesn't need to be mod'd in any way to get good performance.

Or, scrounge up a small diaphragm valve from a dishwasher or clothes washer water supply line. Use this valve in place of the blowgun and fire remotely as described above.


If you are concerned about the PVC in cold weather, or about the pressure capabilities of the gun in general, you can also remotely pressurize the gun. Tap a male quick-connect into the gun. Run a compressor hose from the gun to your remote firing location. When ready, connect the hose to your compressor and pressurize the chamber from a safe distance. If you decide to not fire the gun (or there is a problem with the remote valve) you can disconnect the air hose and the chamber will vent.

Edit: You might also want to take a look at the SpudWiki on remote firing.