Pipe thread tape, otherwise known as teflon tape, is a crucial aspect of plumbing. What's one mistake you should never make with teflon tape as a DIYer?

Once it's too tight you have to start over.<P>Straight thread fittings use an O-ring or some other means of sealling where as mentioned pipe thread is tapered. Getting fittings to line up is easy.

For the axle, yes, do use threaded PVC or pipe, BUT, only have one end screw in. On the other end use a piece of PVC or pipe that is NOT threaded and just larger than the axle.

The unbraced welded subassembly was subjected to story drifts up to 4.34% with no damage. The unbraced threaded subassembly began to leak at 1.08% story drift. The welded piping subassemblies exceeded ...

This video from the Copper Development Association demonstrates how to properly braze threaded copper adapters to avoid leaks and failures when installing medical gas, HVAC and refrigeration systems.