Wednesday, August 7, 2013

Reinforced PVC tube and perfect PVC cutting tools

I found out that to reinforce long PVC tubes I can just inert a 1/2" EMT conduit into a 3/4" PVC tube.  The combined price is still less than a 2" by 4" piece of wood with the same length.

But why?

A PVC pipe is quite flexible if you look at a 3/4" piece with a length of over 6'.  You can break it up into sections, adding supports in the middle.  But those fittings are also the weak points.  Sometimes you just need a straight long piece of pipe.  Fittings are more expensive (stronger) than the pipes.  You can go thicker but the price of pipe and fittings increase exponentially.

EMT conduit is much stronger and cheaper.  However, there's no easy and neat and cheap way to fit them together.  So I get best of both world by inserting a EMT into a PVC.  For example, a reinforced 3/4" pipe can support an adult bicycle, while you can just put together such a shelf with only PVC fittings.  Also you can add fancy couplings along the pipe without weakening the reinforced pipe.

The advantage of EMT pipe is that it can be cut easily.  Saws are a pain, especially if you have a hand-held jigsaw.  It dawn on me that there may be EMT pipe cutters that is specialized for the job.  There are.  They are the roller blade types for copper pipes.  I use my copper pipe cutter on EMT pipes and it's good.

It dawned on me that why don't I use the copper pipe cutter on PVC pipes.  Excellent.  The shear types is convenient but it's increasing hard for thicker types.  The edge will never be perfect - always at some angles to the pipe length rather than perpendicular.

Someone uses table saws for PVC, which is a mistake.  Saws will generate heat, which will melt the plastic that is a environment concern.  Pipe cutters have no saw dust to breathe in, and they are the most precise among saws and shears.