[Gooserider]

Bonding plastics is a nasty and difficult issue to deal with, as there are so many different sorts, and each has it's own set of properties, including what adhesives will work, and which ones won't.

Plastics tend to be difficult to bond to, so most 'generic' adhesives are going to be iffy at best. A few random thoughts that might be of use...

1. Generic names like 'polycarbonate' or 'polyethylene' can encompass several different sorts of plastic, try to get a more specific name, preferably one that identifies the particular plastic as narrowly as possible.

2. Look at manufacturer's websites or spec sheets for the plastic you are considering to find out what the reccomended adhesive's and / or glueing techniques are.

3. Mixing different sorts of plastic is very problematic, as it is necessary to find a glue that will work with BOTH materials. It is better to avoid this as much as possible.

4. In addition to glues, it might be worth considering 'welding' the plastic together if that is an appropriate technique for that type of plastic. (Harbor Freight, and presumably other places, sells plastic welding units for fairly short money although they also need an air compressor)

5. Glues that work by fusing the parts together by making a 'solvent weld' are usually better than those that just make a glue bond. (example - PVC pipe and fittings)

6. I would reccomend AGAINST the comments above about using silicon sealant on top of a glued seam "in case you missed a spot" . A properly done glueup should not leak, if it does, re-do or fix the leak properly. Silicone seal on top of a leak is a kludge at best, and a leak waiting to happen later more likely.

7. It might be worth making some practice joins with scrap material if using a technique that is new to you, especially if there are considerations about needing to work quickly, or use other special tricks. Test gluing is also reccomended when using material that is salvaged or purchased without a manufacturers spec in order to verify that the material has actually been identified properly, and the glue being used will work.

8. When designing, keep in mind that glue plus a mechanical backup is better than glue alone (such as threaded fittings, use of screws and bolts, or even just a mechanicaly sound joint like a PVC pipe and it's fitting)

Hope this helps,

Gooserider