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Pressure Testing Splice Fail

Posted: Sun Mar 09, 2014 10:05 pm
by Water Rocket Expert
Today we did some pressure testing. I like to test my vessels for 1 1/4 times the objective pressure. The objective on this splice was 100 psi so testing to 125 psi was necessary to make sure the splice would work. The two splices on the right side of the vessel were complete 2 months ago and the failing splice on the left was done a week ago. This new splice used a new type of two liter bottle, one that did not match the regular kind. For this reason, we suspected a weak splice which led to failure. We used a small pancake compressor here to easily let in air while observing it on an HD camera. Below is the video of the pressure testing with the failure. Notice the splice failed on the left side, the one that was not done well. The Rupture left the split collar release damaged and the rest of the splices in need of straitening. Hopefully this will be fix within 2 weeks and I will post another test of the new splice.

Team S.P.W.R

Although I used this method long before, thanks to USWR for giving good instructions on the details that I found helpful.

P.S. The video is higher quality I downgraded it for uploading, much higher.

Re: Pressure Testing Splice Fail

Posted: Sun Mar 09, 2014 11:37 pm
by bugwubber
Water Rocket Expert wrote:Today we did some pressure testing. I like to test my vessels for 1 1/4 times the objective pressure. The objective on this splice was 100 psi so testing to 125 psi was necessary to make sure the splice would work. The two splices on the right side of the vessel were complete 2 months ago and the failing splice on the left was done a week ago. This new splice used a new type of two liter bottle, one that did not match the regular kind. For this reason, we suspected a weak splice which led to failure. We used a small pancake compressor here to easily let in air while observing it on an HD camera. Below is the video of the pressure testing with the failure. Notice the splice failed on the left side, the one that was not done well. The Rupture left the split collar release damaged and the rest of the splices in need of straitening. Hopefully this will be fix within 2 weeks and I will post another test of the new splice.

Team S.P.W.R

Although I used this method long before, thanks to USWR for giving good instructions on the details that I found helpful.

P.S. The video is higher quality I downgraded it for uploading, much higher.

Have you determined if the glue failed or did the PET delaminate?

And what's that weird fuzzy stuff on the ground?

Re: Pressure Testing Splice Fail

Posted: Mon Mar 10, 2014 7:14 am
by Water Rocket Expert
bugwubber wrote:
Water Rocket Expert wrote:Today we did some pressure testing. I like to test my vessels for 1 1/4 times the objective pressure. The objective on this splice was 100 psi so testing to 125 psi was necessary to make sure the splice would work. The two splices on the right side of the vessel were complete 2 months ago and the failing splice on the left was done a week ago. This new splice used a new type of two liter bottle, one that did not match the regular kind. For this reason, we suspected a weak splice which led to failure. We used a small pancake compressor here to easily let in air while observing it on an HD camera. Below is the video of the pressure testing with the failure. Notice the splice failed on the left side, the one that was not done well. The Rupture left the split collar release damaged and the rest of the splices in need of straitening. Hopefully this will be fix within 2 weeks and I will post another test of the new splice.

Team S.P.W.R

Although I used this method long before, thanks to USWR for giving good instructions on the details that I found helpful.

P.S. The video is higher quality I downgraded it for uploading, much higher.

Have you determined if the glue failed or did the PET delaminate?

And what's that weird fuzzy stuff on the ground?


The bottle was not a tight fit and the glue failed. Also it maybe that part of the bottle did delaminate.

The fuzzy stuff on the ground is crab grass, wicked grass that grows around here and is a pest. It overruns the yard like a virus and it takes professionals to remove it. Makes the yard brown because it is brown.

Re: Pressure Testing Splice Fail

Posted: Fri Mar 14, 2014 10:18 pm
by Water Rocket Expert
hello I have launched my repaired rocket again today. We get to the field, something is leaking...Launch at 60 psi, 104' 48 mph. That is strange because it went a lot higher last time at the same pressure, on the altimeter and visibly. Stupid me forgot to glue the PVC pipe together for other reasons so another video will be posted soon of another launch. Hopefully in the next week or two. These big rockets require going to the field to launch then. It isn't so much, hey, why not blast it off in the front yard; oops, maybe I should get the ladder before the rain gets to the electronics, ha. So instead of taunting you all, here is the video as well as apogee photo.Tell me what you think. Notice the split collar design release opening at liftoff.

Re: Pressure Testing Splice Fail

Posted: Fri Mar 14, 2014 11:20 pm
by bugwubber
Nice picture!

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 11:24 am
by Water Rocket Expert
Thanks, that pic is the apogee pic from 104'. Next time I won't forget to PVC cement the parts together. Question: has anyone ever found a cement like PVC cement but for PET. If coke made their bottle threads standard plumbing, and someone made PET cement, the water rocket world would change forever.

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 11:27 am
by Water Rocket Expert
I heard someone come up with the idea that a company like Estes could make water rockets and sell pre-charged water rocket motors, different amounts of water, pressure,volume, length, width. Sounds strange but may happen one day. They would be better off just making the rockets.

Check out these rumors and facts about CocoCola. http://www.coca-colacompany.com/contact ... mors-facts

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 4:35 pm
by bugwubber
Water Rocket Expert wrote:Thanks, that pic is the apogee pic from 104'. Next time I won't forget to PVC cement the parts together. Question: has anyone ever found a cement like PVC cement but for PET. If coke made their bottle threads standard plumbing, and someone made PET cement, the water rocket world would change forever.
There is a PET superglue. It is $40 a bottle.

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 8:34 pm
by Water Rocket Expert
But no cement?

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 10:32 pm
by U.S. Water Rockets1
bugwubber wrote:
Water Rocket Expert wrote:Thanks, that pic is the apogee pic from 104'. Next time I won't forget to PVC cement the parts together. Question: has anyone ever found a cement like PVC cement but for PET. If coke made their bottle threads standard plumbing, and someone made PET cement, the water rocket world would change forever.
There is a PET superglue. It is $40 a bottle.
It also has a pretty short shelf life.

Re: Pressure Testing Splice Fail

Posted: Sat Mar 15, 2014 10:33 pm
by U.S. Water Rockets1
Water Rocket Expert wrote:hello I have launched my repaired rocket again today. We get to the field, something is leaking...Launch at 60 psi, 104' 48 mph. That is strange because it went a lot higher last time at the same pressure, on the altimeter and visibly. Stupid me forgot to glue the PVC pipe together for other reasons so another video will be posted soon of another launch. Hopefully in the next week or two. These big rockets require going to the field to launch then. It isn't so much, hey, why not blast it off in the front yard; oops, maybe I should get the ladder before the rain gets to the electronics, ha. So instead of taunting you all, here is the video as well as apogee photo.Tell me what you think. Notice the split collar design release opening at liftoff.
Nice apogee photo. What camera were you using?

Re: Pressure Testing Splice Fail

Posted: Sun Mar 16, 2014 2:30 pm
by Water Rocket Expert
One of midlands sport cameras, they have two I think I am using the cheaper one. $50

Re: Pressure Testing Splice Fail

Posted: Sat Mar 22, 2014 10:31 pm
by U.S. Water Rockets1
Water Rocket Expert wrote:One of midlands sport cameras, they have two I think I am using the cheaper one. $50
What resolution is it?

Re: Pressure Testing Splice Fail

Posted: Sun Mar 23, 2014 12:21 am
by Water Rocket Expert
I'm pretty sure it is 640 x 420. I couldn't find the exact one but it looks like any of these but only like $50 or $60 bucks. Pretty rugged. I may post an image but not now..........running out of time..........gotta go!