epoxy

Not much to go on. Surface preparation is more important than adhesive selection. If water beads up on the surface to be bonded, forget it. You must abrade or somehow roughen the surfaces to accept the adhesive. This will allow water to "sheet", not bead.

Use any unfilled epoxy. The longer it takes to cure, the better the bond. Don't use too much, it makes clean-up harder.

Acrylic adhesives are OK, but some aren't very water resistant.

Why epoxy?

Which plastic?

Polystyrene, for example, responds well to butanone (a.k.a. MEK, two names for the same solvent) and dichloromethane, which can be used to carry out a chemical weld between two surfaces.

Thankx guys for the help.Can I post a pic of the parts I need to glue?Iam not sure the typ of plastic it is its clear I know thats not much help.

Yes, pictures are good. It might give us a hint of the material, too.

lol its not a good photo but thats the pieces I have to glue

Are the pieces hard or soft?

they are hard

the parts are from a fishing float

So, for lack of a better example, this looks like a ball point pen "front piece" and ink cartridge.

What does it do?

Never mind.

Fishing float.

OK

we have a major problem with the glue its holding up are production.it has to be clear and strong plus water tight

any ideas ?

Maybe a solvent bond? If they are vinyl you might fuse them with MEK or acetone.

Need better photos that show the bond line detail. Or, hand sketch of cross section of both parts, mated.

hI Lynlynch I just found out the plastic type is pet-g .Iam sorry Iam not much into plastics,but Iam in kinda of a pinch to figure this problem out so any info would be great thankx.