Glue, resin and tar are 3 products used to combine materials together. As such, they are useful to build a specific part of a device, ... They should however only be used to combine materials of one specific part, and not to combine parts together. This, as these parts secured together with these substances are difficult to separate afterwards, and would then make repair, maintenance, ... more difficult. Also, they would no longer adhere to the cradle-to-cradle design principles.
Glue
Some glues can be made DIY:
- casein glue (milk, vinegar, baking soda)
- flour + water glue
- flour + water + sugar glue
- gelatin + glycerine glue (or "book binding glue")
See http://kwc.org/mythbusters/2006/01/mythbusters_paper_crossbow.html --> Add additional homemade glues
Resins
Resins also include pitch. See http://en.wikipedia.org/wiki/Resin