Check out a recently finished Legio Astorum Warlord of a blogger buddy GunGrave at his blog A Gurdsmans Guide To Glory
I scored the Carapace Reaver Laser Blasters where the glue would go to provide a better surface area for bonding and then applied the JB Plastic Weld.
Whilst the main 'Secondary' weapons were drying, I assembled the Mauler Boltcannons and TL Lascannons - yes the Titan has the armament of a Landraider as secondary weapons ;) These could then be left separate from the titan for ease of painting later. The guns were slotted into the mounts but the base plate of the mount left separate so they can be affixed to the Titan Weapon Mounts after painting.
The Main body of the Laser Blasters sits in the Weapon Mount, and the Piston Assembly out of the box sits nicely in place without the need for clamps or trimming, so I glued these parts together in one sitting (no photo) and left to dry, gravity doing the hard work. The pistons which held the barrels in position were then glued in place later - I was going to leave off for painting but had some spare wet epoxy at some stage, so went ahead and glued after the barrels were in place. Below you can see the Weapon Mounts in place and no pistons.
Thanks for dropping in. Not much basic construction left... The main arms when bought will be a similar method, and I will post how I mount them into the Titan arms in due course!