Splicing bottles for water rockets

video Splicing bottles for water rockets
Splicing bottles together is technique often employed by water rocketeers to increase the volume of their rockets. Splicing involves gluing sections of bottles together to make a longer pressure vessel.

Because of the forces involved inside a typical rocket, and because PET plastic is very hard to glue, there are only a few existing glues that are suitable for the job. The most commonly used is PL Premium construction adhesive, but VISE and a small number of others can also be used.

Splicing is not as easy as joining bottles using a Robinson coupling, is permanent and is less predictable at which pressure it will fail, but it has the advantages of virtually unrestricted internal flow and potentially long pressure bodies can be made this way.

The technique presented here is based on previous work done by other rocketeers:

http://wrockets.trib-design.com/index.php?project=nick&page=splicing

In the following video tutorial we present a technique called 'symmetrical splicing' for joining two bottles. The same technique can be used for making much longer bodies. The join is just repeated for each section.

For more water rocket instructions visit: http://www.AirCommandRockets.com
30 comments
Aug 29, 2011. 2:41 PMmattman2 says:
ya could just melt it
Nov 25, 2008. 3:05 AMLftndbt says:
Very nice explanation. Any idea shich Sika product in AU would be most suitable. There seems to be hundreds.
Dec 20, 2008. 1:49 AMLftndbt says:
Hmmm, no clear available at bun nings. Oh well looks like black splices for me. I am starting to see the benefits of bottles over FTC and pressure pipe. My two stage rocket with drop away boosters is boardering on the same drag co-efficiency as a bottle rocket due to the drop away. I am thinking now a third stage done in bottles would give me a little more bang and air volume.
Dec 23, 2008. 7:54 AMLftndbt says:
This rocket have a custom quick change mech for the fins. I don't know if you have spotted these little clips/holders in any stationary stores but they make a great fixing method for the fins. They bite onto boards, especially celled boards commonly used for fins very well. It takes a great deal of force to remove the fin but it will pull out at an angle under great physical force.
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Jul 15, 2009. 3:04 PMcowscankill says:
How did you splice your bottles together?
Dec 28, 2008. 1:03 AMLftndbt says:
Yes I would definatley think that at a max G launch they would shift. Just looking for a identical fixing method that can replicate. They almost guarantee a perpendicular mount. If your ever in Bunnings they are the holders to the bay item signs. We hit them regularly with machines and the sign always breaks (which is hard plastic) before the clip releases the sign. I still intend on either applying a glue to set the fins or a method like you suggested.
Dec 21, 2008. 7:41 PMLftndbt says:
Not as yet, but i'll post pic of my pressure pipe rocket when it's done. I just finished a 7L spliced rocket body using the Sika 11FC. No neck to necks just straight through mid sections. That black Sika (as you would know) has a great advantage when a light is shown from behind it. You can easily see where you have spread the glue to thin or if you have missed a section... Now to just wait 5 days... hmmpppfffhhh!!!
Apr 12, 2009. 11:23 PMmicroman171 says:
Which sika do you use? I have found a range of the stuff in Mitre 10 in town :-).
Apr 13, 2009. 8:03 PMLftndbt says:
Air.command is like the jesus of water rockets, I see he answered your question. I use sika 11FC black.
Nov 27, 2008. 4:57 AMLftndbt says:
Ok great. That's off the shelf stuff. Tops!! Thanks.

Just as an estimated guess. What would you think this MOSS branded quad garden fitting would rate to? It appears to be cast steel coated in a golden layer. Ball valves look good. I was hoping around the 150PSI-200PSI mark.

I'm using this unit on this Quad metal launcher
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Nov 27, 2008. 6:53 PMLftndbt says:
Perhaps brass coated, but not solid. Will certainly take your advice, in regards to pressure testing it.
Nov 25, 2008. 6:05 PMLftndbt says:
Any chance I could convince you to do some of your write ups on Instructables?
The water rocketing community is in need of some good info.
I am sure everyone would love a write-up on how to build Polaron IV.

I was actually going to email you to request if I could use a shot of Polaron IV as the picture for my new water rocket group. Water rockets
Jul 13, 2009. 5:32 PMcowscankill says:
Hmm... I'm getting back into this stuff again. But how can I use this type method with only the same type bottles? I can't find any bottles wider than my 2L bottle.
Jul 14, 2009. 4:18 PMcowscankill says:
Oh! That's a really good idea. I might try that... and what about JB weld instead of the glue you use? It's strong and can hold hundreds (maybe thousands?) of PSI, and I think it will bond the bottle splice together well.
Jul 15, 2009. 12:13 PMcowscankill says:
I guess I will try the Gardena launcher with small soda bottles spliced together with JB weld before I try large scale.
Apr 9, 2009. 3:47 AMmicroman171 says:
Hey Mate :-) You're Aussie I take it? I'm Kiwi. I was wondering on what I could use for glue. I've never seen this PL or sikaflex stuff... How about regular epoxy? The 3min cheapo stuff? Or super glue? I can get super glue real cheap at $2 shops..
Apr 9, 2009. 3:19 PMmicroman171 says:
Thanks mate, will keep a look out. I really wanna build a rocket like one of your's, they look so cool!
Feb 15, 2009. 6:42 PMMattrox says:
Wow is saw one of your videos on metacafe you people are awesome
Feb 15, 2009. 11:48 AMmacrumpton says:
Exceptional instructable! I am not sure why you are using a sleeve rather than just cutting the bottoms off the bottles and sliding one over the other.
Jan 29, 2009. 9:49 PMKryptonite says:
Wow, that is done so professionally, thanks for posting. My speakers are currently broken so the writing in the video made it an exceptional video. Damn, that makes the way I did it look terrible, I'm envious now...
Nov 14, 2008. 5:31 PMcowscankill says:
Wooooooooooooow. A lot of work, but nice job!

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