7. Mistakes to avoid

Don't get bogged down in a process or a precise technological solution: first of all, stick to the principles that are possible in an assembly. For example, assembling two polypropylene substrates of the same type in a permanent, watertight manner gives you all the possible solutions:

• welding (by external heat, friction, hot material) ;

• bonding (cyanoacrylate, various sealants) ;

• screwing with gasket.