Soda Bottle Fusing? Anyone ever successfully joined two soda bottles either by heating fusing or by adhesive glue?

I want to take standard 2-liter soda bottle and join a few of them together into a short column.  The seam or joint needs to be able to hold together and be air-tight and withstand some pressure. I want to submerge the bottles in the water, and so the joints must be able to withstand the forces against the outside of the bottles.  Anyone tried fusing the edges together again; like cutting the bottoms off of two bottles and joining the two cut edges together to form a double length bottle?  If so, how did you do it?  Any special equipment?  Thanks in advance!

Jayefuu7 years ago
OR if you really want to cut them up, follow this instructable:
https://www.instructables.com/id/Splicing-bottles-for-water-rockets/
Jayefuu7 years ago
I assume you want it for flotation? If you cut them up, joining them back together watertight will be a nightmare. I'd keep the bottles whole then join them together with sleeves made from bottles with the top and bottom cut off. Then it doesn't matter if the joints leak, it'll just be to hold them together. 

Make sense? If not let me know and I'll draw you a pretty diagram.