Need to seal a plastic bottle

[Travis]

Bought a $10 pump squirt gun, and within an hour it sprung a leak. It's two pinhole breaks right where that that extended bit meets the case. I tried covering in gorilla glue and duct tape, but the air pushes right through once I start pumping in air. I also have a hot glue gun that I might try. Any thoughts on the repair?

[APowers]

Any way you can get the glue on the inside of the hole, so that the air pressure increases the seal rather than blowing it off?

Other thought: maybe dangerous, depending on how thick the plastic wall is, but melt the pinholes closed with a soldering iron?

Other thought:

[Travis]

Someone on reddit suggested a little bit of solder, but I don't own one. They also suggested a "screw and a lighter" as an alternative to the solder, but I'm not sure what technique they're suggesting. Melt the tip of the screw into the hole?

[GuitarStv]

Solder will not work.  Solder is melted metal, and it won't adhere to plastic.  (It doesn't even adhere properly to metal unless you get the pieces to the correct temperature.)  Although better than solder, I doubt that hot glue from a glue gun will hold for long either.

I'd use some two part epoxy.  Mix it up and apply it liberally over the seam where the holes are.  Epoxy tends to hold very well on plastic and is used to seal leaks on boats all the time.

[lthenderson]

Sealing pressurized leaks are the hardest. I would just get a new squirt gun as most fixes will cost more than the cost of the gun. But if you happened to have some two part epoxy meant for plastics laying around, I might try that first.

[Boll weevil]

Another problem you’re probably going to have is getting the solution to stick - the tank is probably polyethylene or polypropylene and neither takes typical glues very well.

Repair from the inside if possible. The holes sound small and I’m not sure the epoxy will work if simply applied to either or both sides... you may want to enlarge the holes so that you have a plug that flares out on both sides rather than a patch that’s relying solely on surface adhesion.

[HPstache]

JB Weld for plastic would certainly fix it, not sure if it's worth the price though?

[APowers]

Someone on reddit suggested a little bit of solder, but I don't own one. They also suggested a "screw and a lighter" as an alternative to the solder, but I'm not sure what technique they're suggesting. Melt the tip of the screw into the hole?

I didn't mean to imply using solder; just the iron, in order to melt the hole closed.

If you can get a dab of jbweld or two part epoxy on the inside, that seems like a good idea to me.

[Wrenchturner]

what others have suggested; also try abrading the surface where you're applying adhesive.  smooth plastic doesn't take adhesives very well.

[BTDretire]

Loctite does make a glue for polyethelene, available at Lowes and Home Depot.
 I haven't used it, not sure how good it would be under pressure.
Also it will be about 1/2 the cost of the water gun!
 I have fixed polyethelene using my soldering iron and some filler polyethelene,
but it is a bit of a trick, especially if that tank is thin.

[tawyer]

Definitely some kind of weld, i.e., that melts the plastic. Given you have a glue gun, I would do that first. Otherwise two-part epoxy. To prep the surface I would sand, rinse, and degrease for best results.