ePlasics® stocks and sells the complete line of IPS Weld-On industrial plastic adhesives.
IPS #3 is water-thin, quick drying and is mostly Methylene Chloride in composition. Good for gluing small parts where fast drying is required and bond strength not as critical. Most typically used in solvent welding applications.
IPS #16 is clear syrupy or bodied and fast drying. Great where the parts don't fit exactly right, for putting a bead inside a box you are trying to make water-tight, or for bonding applications where a bubble-free bond is not required (bonding solid colors for instance).
IPS #40 is mostly acrylic monomer in composition and is a 2-part mix. This is the adhesive used by professionals for making aquariums and other bubble-free and highly structural bonds. It is the strongest of all the Plexiglass glues, and requires a bit of skill in its application. Excellent for bonding Plexiglass to Lexan and other materials as well.