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Water in Gardena Launcher

Posted: Sun Nov 05, 2017 1:27 pm
by Thort
Hello everyone,

I'm building a gardena launcher and I've realised that when I'll fill the rocket with water it will fall in the PVC pipes. Is this going to be a problem? Is it possible that the water enters in the compressor? Which is the best way to solve that?

Thanks for your answers

Re: Water in Gardena Launcher

Posted: Mon Nov 06, 2017 2:22 am
by anachronist
That's one reason I don't use gardena nozzles.
However, you can make a one-way valve in the launcher part, from a ball bearing and a cone (like the end of a ball point pen). This is done with 2-stage mechanisms that use a gardena connector between the stages. See this tutorial: http://www.instructables.com/id/Water-R ... Mechanism/ and you'll see the one-way valve starting at step 12.

Re: Water in Gardena Launcher

Posted: Tue Nov 07, 2017 2:19 pm
by Thort
I'm not sure it will adapt to my launcher.
The launcher I built it's similar to this one http://www.uswaterrockets.com/construct ... torial.htm
What do you think about this system?. It isn't perfect but it looks like it works:

Re: Water in Gardena Launcher

Posted: Tue Nov 07, 2017 3:56 pm
by anachronist
Step 3 in that web page is ridiculous. Don't bond a schrader valve to a PVC pipe. Use a tank valve with an NPC adapter. Or better still, use compressor fittings as shown in this post. Compressor fittings are cheap and reliable.

In the picture in step 6 or 7, you'd want that gardena release part to be attached to a PVC check valve, like this one at Home Depot. You'll still get a bit of water in the vertical part but at least it won't fill up the launcher pipe.

Re: Water in Gardena Launcher

Posted: Sat Feb 17, 2018 8:20 pm
by Spoolio
I don't know about that... I put the shrader valve in the PVC--it's been working fine up to about 130 psig or so. If it works, it works...
Need to put in an antidrainback or launch abort valve. Haven't gotten to that yet.

Re: Water in Gardena Launcher

Posted: Sat Feb 17, 2018 9:08 pm
by anachronist
Seems to me like the safety risk and the extra work and mess of bonding metal to plastic isn't worth the trouble, when compressor fittings are simpler and cheap. But as you say, if it works, it works.

My big problem is the o-ring fitting, for non-gardena launchers. It's hard to bore out a PVC pipe precisely enough to fit a 5/8" copper sleeve inside. My launcher has a slow leak, I think because of that.