There are different ways to stick things together. Depending on the material, there is always the right glue, paste, sealant or mucilage for the job. In any case it is always good to follow the instruction on how to use any of them to be able to arrive at the best expected result.
Take for example, epoxy resin mixing is done in such a way you really have to follow what is directed. You also have to be warned that contact on your skin can be harmful that is way proper care should always be taken.
Stick it right and you will seal it right.