The best always used to be Aerolite 306 - but sure if it's still available. I've used cascamile in the past but now I've started to use a Polyurethane? glue which is gap fitting and does foam a little whilst setting and does seem to work very well. Balcotan ? is a recognised make - mine was an equivalent from Toolstation but it does go hard if you lose the cap!!
PS not sure if it is polyurethane glue, someone will be along soon to correct me......
See:- http://www.robbins.co.uk/Pdf Files/pl5_balcotan.pdf Cascamite appears to be used for interior woodwork.
I've used epoxy glues on teak and its worked very well. Stands up to a lot of water on it and very heavy daily use, also has good gap filling if your not a joiner and dries clears as well.
Cascamite is now renamed Humbrol Extramite, presumably to ensure that no one buys it anymore as they don't know what it is - brilliant marketing strategy, that!
The bumph (google is your friend...) says "Cascamite is a waterproof, synthetic resin adhesive for use on general joinery - especially outside woodwork and boat building.Supplied as a powder to be mixed with water"
If you plan to use an epoxy be advised that it may not work well on timber with a high oil content.
You can improve this situation by cleaning the timber with Acetone just prior to the application of the epoxy.
For a stronger bond, first clean with plenty of Acetone then apply coats of a thinned of epoxy resin till no more soaks in (3 or 4 normally), apply wet on tacky to avoid sanding.
Let this cure then clean again with Acetone before a light sanding to remove the high gloss; clean again and apply a mix of epoxy resin and Micro-Fibres mixed in to a peanut butter consistency.
Take care not to over clamp the joint, it should be a couple of mill wide when done.
Also Note: Most epoxy resins are not UV stable so you may have to do a little bit of painting just over the exposed epoxy to finish.
I used Polyproof which seems to be Cascamite Cascophen - it was recommended for teak, and deals with oilier woods well like teak. Lovely to work with - and has lasted well.
Link below