MDPE and PVC are different animals.
(11-30-2016, 12:05 PM)awemawson Wrote: [ -> ]MDPE and PVC are different animals.
Absolutely yes. I was trying to point out some of the issues using plastic piping on compressed air systems.
I should have referred to nylon tubing such as this:
http://www.rockler.com/rapidair-compress...lon-tubing One of the big issues as I see it would be the use of CI fittings with tubing. They would simply be the wrong application. There are specifically designed couplings to be used for PEX and for nylon.
"When I move the compressor outside, reinstalled piping with galvz. Just seems like a sounder way of going about it."
Galvanized pipe, fittings etc. should never be used in a fluid power system such as compressed air. The galvanize coating will deteriorate sending small particles into any and every thing connected to the system destroying them. It will not happen overnight, but it will happen.
This is why one does not use galvanized pipe in either a natural gas or propane system as it will destroy the regulator.
If you're concerned about rust either paint the outside of the black iron pipe or cover it with electricians tape.
It's hard to beat cast iron for compressed air. It's strong, rigid, inexpensive and won't fail if it gets banged. It's also handy as hell to hang stuff on, just because you can.
Tom
I use PEX here for the air. Max pressure is 120-125 PSI and I was told the PEX I'm using is good to 250 PSI.
I thought it would have a pressure rating in that range Vinny, but all I could find on line was what I posted, (on another page and don't remember). Will look at the water lines in the shop for a rating. Think it was about 3500 feet I ran for radiant heat in the shop and house.
(11-30-2016, 06:00 PM)TomG Wrote: [ -> ]It's hard to beat cast iron for compressed air. It's strong, rigid, inexpensive and won't fail if it gets banged. It's also handy as hell to hang stuff on, just because you can.
Tom
Which is why my shop uses CI for the compressed air. Cut to length and use a pipe threader in the lathe to cut the treads (manual turning of the spindle).
Worked in one shop in FL that used schedule 80 PVC and glued fittings for the compressed air. It was located just above the drop ceiling and you should have seen the mess when a joint came apart. Not just ceiling tile, but several needed to change their drawers.
Luckily just the joint came apart instead of a pipe blowing which tends to send shards a flying. PVC also becomes brittle with age and even more so when exposed to light.
(11-30-2016, 07:36 PM)f350ca Wrote: [ -> ]I thought it would have a pressure rating in that range Vinny, but all I could find on line was what I posted, (on another page and don't remember). Will look at the water lines in the shop for a rating. Think it was about 3500 feet I ran for radiant heat in the shop and house.
Typical home water pressure is 40 to 80 PSI.
I used copper pipe for the shop. The light residential Type M has a working pressure of 430 psi for 1/2 and 350 for 3/4. I run the compressor at 140 psi giving me a factor of safety of 2 1/2.
(11-30-2016, 09:17 PM)f350ca Wrote: [ -> ]I used copper pipe for the shop. The light residential Type M has a working pressure of 430 psi for 1/2 and 350 for 3/4. I run the compressor at 140 psi giving me a factor of safety of 2 1/2.
I also used copper, just up one level to Type 'L', in 1/2, 3/4 and 1" sizes with Stay-Brite silver bearing soldered joints. I really like how easy it is to work with and modify as needed. The compressor is at 175 but right after the dryer there is a regulator that drops it to 135 for the copper distribution into the garage and all around the workshop.
Do you chaps REALLY mean cast iron for your pipe. Surely not, it's far too brittle. Black iron fittings are usually malleable iron, and the pipe is mild steel