PET bottles that don't fit 1/2" PVC

Discussions about rockets, construction materials, adhesives, nozzles, nosecones and fin design.
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

PET bottles that don't fit 1/2" PVC

Post by bugwubber »

Our family took a 6000 mile expedition this summer visiting a huge chunk of the western half of the US. In the middle of it all, we stopped by Sequoia National Park in California to teach a Water Rockets class at their Dark Sky Festival in July.

While I was there in CA, we found numerous carbonated beverage bottles of various sizes that would not mount on a 1/2" PVC pipe. The throat of the bottle nozzles appeared to be up to 1mm smaller than the outside diameter of standard PVC pipe.

I kept a sample of them so I could examine them more closely. Pictures and videos to follow.
Bugwubber

Team S.P.E.W.
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

Re: PET bottles that don't fit 1/2" PVC

Post by bugwubber »

Here's a sample of the narrow bottles followed by a couple normal sized bottles.
[youtube][/youtube]
Bugwubber

Team S.P.E.W.
User avatar
Blenderite
WRA2 Member
WRA2 Member
Posts: 442
Joined: Mon Apr 09, 2012 3:49 pm

Re: PET bottles that don't fit 1/2" PVC

Post by Blenderite »

Maybe the PVC expanded :shock:

More likely, they are making them smaller to reduce costs and save the planet.
-Blenderite

Check out my YouTube channel: https://www.youtube.com/c/Blenderite

"Get it right, then go for GREATNESS!"
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

Re: PET bottles that don't fit 1/2" PVC

Post by bugwubber »

DogLover wrote:Maybe the PVC expanded :shock:

More likely, they are making them smaller to reduce costs and save the planet.
They didn't fit on my 5x launcher so I used that stubby launcher to test the bottles. Once I unpack, I'll take some measurements.
Bugwubber

Team S.P.E.W.
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

Re: PET bottles that don't fit 1/2" PVC

Post by bugwubber »

PVC measures 21.42mm Normal bottles are measuring 21.5-21.6. These bottles are measuring 21.4 and smaller.
Bugwubber

Team S.P.E.W.
User avatar
U.S. Water Rockets1
WRA2 Member
WRA2 Member
Posts: 1778
Joined: Sat Feb 03, 2007 3:24 pm

Re: PET bottles that don't fit 1/2" PVC

Post by U.S. Water Rockets1 »

bugwubber wrote:Our family took a 6000 mile expedition this summer visiting a huge chunk of the western half of the US. In the middle of it all, we stopped by Sequoia National Park in California to teach a Water Rockets class at their Dark Sky Festival in July.

While I was there in CA, we found numerous carbonated beverage bottles of various sizes that would not mount on a 1/2" PVC pipe. The throat of the bottle nozzles appeared to be up to 1mm smaller than the outside diameter of standard PVC pipe.

I kept a sample of them so I could examine them more closely. Pictures and videos to follow.

Are you going to do a write-up regarding the Dark Sky Festival? That would be very interesting.
Team U.S. Water Rockets
Visit USWaterRockets.com
Visit our Blog
Tune in to our YouTube Channel
Visit our Facebook page
Visit our Twitter Page
Opportunity is missed by most people because it is dressed in overalls and looks like work. --Thomas Edison
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

Re: PET bottles that don't fit 1/2" PVC

Post by bugwubber »

U.S. Water Rockets1 wrote:
bugwubber wrote:Our family took a 6000 mile expedition this summer visiting a huge chunk of the western half of the US. In the middle of it all, we stopped by Sequoia National Park in California to teach a Water Rockets class at their Dark Sky Festival in July.

While I was there in CA, we found numerous carbonated beverage bottles of various sizes that would not mount on a 1/2" PVC pipe. The throat of the bottle nozzles appeared to be up to 1mm smaller than the outside diameter of standard PVC pipe.

I kept a sample of them so I could examine them more closely. Pictures and videos to follow.

Are you going to do a write-up regarding the Dark Sky Festival? That would be very interesting.
Yes just trying to get pictures and things together. Have a missing camera chip that I'm hoping to find unpacking. Hoping I didn't leave it in San Francisco.
Bugwubber

Team S.P.E.W.
User avatar
ptx
WRA2 Member
WRA2 Member
Posts: 74
Joined: Wed Feb 27, 2013 6:00 pm

Re: PET bottles that don't fit 1/2" PVC

Post by ptx »

no good news, the trend seems to be reduce the sizes.
Not so long ago new smaller caps were also introduced with a smaller thread.
Also it is becoming more difficult to find bottles with a straight contour.
Challenges...
ptx
User avatar
Blenderite
WRA2 Member
WRA2 Member
Posts: 442
Joined: Mon Apr 09, 2012 3:49 pm

Re: PET bottles that don't fit 1/2" PVC

Post by Blenderite »

I am placing an order for 1000 pre-forms, just in case.
-Blenderite

Check out my YouTube channel: https://www.youtube.com/c/Blenderite

"Get it right, then go for GREATNESS!"
User avatar
bugwubber
WRA2 Member
WRA2 Member
Posts: 1087
Joined: Wed Dec 19, 2012 2:47 am

Re: PET bottles that don't fit 1/2" PVC

Post by bugwubber »

DogLover wrote:I am placing an order for 1000 pre-forms, just in case.
Did you come.up with a blow mold or will you.be attaching the nozzles to ftc?
Bugwubber

Team S.P.E.W.
User avatar
U.S. Water Rockets1
WRA2 Member
WRA2 Member
Posts: 1778
Joined: Sat Feb 03, 2007 3:24 pm

Re: PET bottles that don't fit 1/2" PVC

Post by U.S. Water Rockets1 »

bugwubber wrote:
DogLover wrote:I am placing an order for 1000 pre-forms, just in case.
Did you come.up with a blow mold or will you.be attaching the nozzles to ftc?
Blow molding the bottle preforms is not terribly difficult. You can blow mold into a simple PVC pipe. This solves the issue of trying to mold an entire bottle because the enclosed mold will trap air if it has a bottom. Getting rid of the bottom allows the air to come out of the mold, and since you usually cut off the bottom of the bottle, the poorly formed bubble that forms on the end is cut off anyhow.

The real problems come from uneven wall thickness and poor pre-stressing the PET molecules due to uneven heat and the lower pressure you will likely be molding with. You won't get the same strength across the circumference from one bottle to another.
Team U.S. Water Rockets
Visit USWaterRockets.com
Visit our Blog
Tune in to our YouTube Channel
Visit our Facebook page
Visit our Twitter Page
Opportunity is missed by most people because it is dressed in overalls and looks like work. --Thomas Edison