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What PSI have you achieved with meld launcher?

Discussion about Compressors, hose, pipes, fittings, launchers, release mechanisms, and launch tubes.
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sletts02
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What PSI have you achieved with meld launcher?

Post by sletts02 » Fri Jul 11, 2014 3:22 am

What's the typical PSI you achieve with a meld/bump style PVC launcher (where you heat the section of PVC to create a small friction seal).

I seem to be stuck around 60psi, maybe my bump isn't uniform enough? I'm wanting to try a higher pressure but not sure if it's even feasible with this style launcher.

Enlighten me :D!



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U.S. Water Rockets1
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Re: What PSI have you achieved with meld launcher?

Post by U.S. Water Rockets1 » Sat Jul 12, 2014 10:23 pm

sletts02 wrote:What's the typical PSI you achieve with a meld/bump style PVC launcher (where you heat the section of PVC to create a small friction seal).

I seem to be stuck around 60psi, maybe my bump isn't uniform enough? I'm wanting to try a higher pressure but not sure if it's even feasible with this style launcher.

Enlighten me :D!
Why not just make an o-ring launcher? They can handle 100's of PSI with PVC, and a lot more with metal launch tubes. It's not difficult, and we have some tutorials on how to do it on our YouTube Channel. Don't count out the design.


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sletts02
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Re: What PSI have you achieved with meld launcher?

Post by sletts02 » Sun Jul 13, 2014 12:43 am

U.S. Water Rockets1 wrote:
sletts02 wrote:What's the typical PSI you achieve with a meld/bump style PVC launcher (where you heat the section of PVC to create a small friction seal).

I seem to be stuck around 60psi, maybe my bump isn't uniform enough? I'm wanting to try a higher pressure but not sure if it's even feasible with this style launcher.

Enlighten me :D!
Why not just make an o-ring launcher? They can handle 100's of PSI with PVC, and a lot more with metal launch tubes. It's not difficult, and we have some tutorials on how to do it on our YouTube Channel. Don't count out the design.
I tried 3 times with no success with the o-ring unfortunately. Each time it seems to leak air. Perhaps I don't have the right sized / quality of o-ring?

I've tried every applicable o-ring from this pack: http://www.bunnings.com.au/kinetic-asso ... k_p4920305 All of them leak to some degree.

I tried the another meld/bump and got to 90P psi today which was good.



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bugwubber
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Re: What PSI have you achieved with meld launcher?

Post by bugwubber » Tue Jul 15, 2014 2:39 pm

The first launcher I made used this method. Don't think I ever went over 65 without having to hold the rocket down. I recall someone heated up the pvc and then force screwed in steel male NPT fitting to produce a better ramped swell in the PVC.

From my own experience, the ideal o-ring for 1/2" pvc has been the type BUNA N size "-208" hardness 75 DN o-ring. Never had an issue with leaking up to 110psi.


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Blenderite
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Re: What PSI have you achieved with meld launcher?

Post by Blenderite » Tue Jul 22, 2014 5:55 am

Personally I have never had a problem with the o-ring style launcher. Do you have pictures of the one you built?

As for the bump launcher, I have not heard people using it past 90psi.


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