Thread: pvc air lines?

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hey all you crazy kids out there surfing the web,

I'm trying to set up my garage (its a big garage) with airlines. I only officially have the place for a year, so I want to go inexpensive. I know a few shops in town have PVC for their airlines. Does anyone know of major drawbacks for using PVC for short term? I've heard many opinions, but I want info from someone with experience. thanks for your help.
Jason

Jason,

Pvc for (2) years now. No Problems yet. My garage is heated, is yours? if not worry about freezing. Just secure and run them out of harms way.

Do you have a air dryer?

A remote drain really helps also.

Good luck,
Joe

We have about 12000 sq ft with overhead air lines...copper but PVC would be the same. Tips: you can install the system so that it drains to one corner and put your drain there. The tilt doesnt have to be much but you want the condensation to run down hill to the drain. Tip 2: when you install a tee for a quick disconnect, install the tee so that the pipe exits the main line upward so condensate will not drain into your quick disconnect. Then from the upward pointing tee, route the pipe so it turns back down to where you want it. Tip #3 use the thick wall PVC (schedule 40) and pay attention to the rating (I think 3/4 is rated 200 psig).
Tip #4 install a dryer if you can. compressor dryers are cheap new ($800) and really cheap used. most of the time you can find one that needs a freon charge Tip #5 put a drain on your compressor tank and drain it often

PVC is not rated for air line use. I can not recommend it's use in compresed air lines.

Having said that here are some things I would consider if I was running PVC air lines in my shop.

Schedule 80 is rated for higher pressure when glue joints are used. With threaded joints it has about the same rating as Schedule 40 with glued joints. Two stage compressors build up a lot of tank pressure.

White Schedule 40 is not UV resistant. It will fail in time if exposed to direct sunlight.

The strength of both Schedule 40 and 80 pipe/tubing/lines decreases as it gets hot. Compressed air coming out of the tank is hot. Be prudent, use iron pipe for the first 10 or 20 feet.

Plastic air lines usually fail at the joints. There are two things you can do about this. First use fresh glue and pipe cleaner. If you do not like the purple stuff look for clear, it is available. Second, never, not ever, open the air valve at the tank in a single motion. Open it slowly and let the pressure in the lines build up over a minute or so. A suden jolt of pressurized air will blow a joint apart.

Bib is right about not being rated for compressed air use. The stuff is terrible when exposed to UV.....that's why it is painted or covered when exposed outdoors.

Also, you should consider taking the pressure off the system when you are not using it.....nothing worse than coming home from work and finding that your compressor has been running all day.....well, there are things worse but you know what is meant.

Why not consider a copper system? A 10 ft length of 1/2 copper is about $10. For a 30 ft x 30 ft garage, you can do the perimeter of three sides for 9 sticks plus the verticals plus the fittings. Sweating copper is super easy.

mike in tucson

i've used pvc since 79. i've never had a failure of any kind. the big plus is it's easy to replace your lines every 5 years or so. helps keep the oil and stuff out of your paint booth.

I run Black iron and galvanized pipe, 1/2" threadded, it's ANSI rated for air use to 160 PSI, is very simple, I used 3/4 " PVC hangers on every rafter to mount it and in most cases is pretty inexpensive, more than PVC but in my opinion it is worth it. also dissassembles easly as it assembles so you can take it apart, and take it with you when you leave. Just don't buy long sections ( like under 8' ), that way you can couple them togther with the couplers, and if you ever want to expand, you replace the coupler with a Tee, and go from there, also allows you to put all the stuff in the back of a truck when you move, so you can install it there.

thanks for your help. has anyone had problems with fisheyes in your paint because of the mold release used on the PVC pipes? I've heard a few legends about that.
Jason

I just painted my car back in June with a pvc system that was about a year or so old with no problems with fisheyes I used 3/4 inch White Schedule 40 that is rated at 400psi with no problems

When I first put it in I made the mistake one night of setting up a patio heater inside the garage and after about 1/2 hour my son said whats that smell well low and behold I had put the heater right under the pvc air line and with 150psi in the line it swelled up from 3/4" to about 1 1/2" but never blew a hole in the pipe
The next day I just cut out the piece and put in another
That was the last time I brought the heater in

MM64

I still prefer pipe, 3/4 in works good for me.

glad to see this thread on PVC air lines, i was thinking of doing the same thing. I ran new plumbing in the house some months ago and got some extra pipes around and i've heard of people useing it without problems, but have heard of problems too.

If i decide to do it i think i will run a small screw in all of the conectors just to be safe.

Originally posted by robot
... Also, you should consider taking the pressure off the system when you are not using it.....nothing worse than coming home from work and finding that your compressor has been running all day.....well, there are things worse but you know what is meant.

I "rigged" an electrical system - relay - with a switch and an indicator light at the man door of my shop. On the way out - for the day or night - I turn off the power to my compressor. The compressor is up on the second floor of my shop so I also have a electric solinoid actuated DRAIN valve atached that allows daily draining of the tank. (by a switch in the shop)

Why not consider a copper system? A 10 ft length of 1/2 copper is about $10. For a 30 ft x 30 ft garage, you can do the perimeter of three sides for 9 sticks plus the verticals plus the fittings. Sweating copper is super easy.

mike in tucson

I aggree. I used 3/4" copper through out my shop.

Because I have a sandblast cabinet at the opposite end of the shop from the compressor; the larger diameter allows for more air flow.

In areas where something might bang into the drops, I slid the copper through pieces of iron pipe before mounting on the walls.

My last shop was piped with iron pipe, and after 15 years of use I was surprised how much rust had formed inside. Even galvanized pipe tends to rust at the joints.

Copper air lines aren't subject to any rusting

PVC for compressed air is illegal. Reason being already covered for the most part here already. I can get you all the micro-engineering data but my shop had many failures in the pvc airlines. If your system puts out any oil, whether it is for your air tool or just inefficient oil/water separater, the oil will degrade the pvc from the inside. I have seen it blow out at joints, in the middle of 20' sticks of pipe and blow the molded fittings to pieces too. My business dealt with pvc fabrication and large fitting manufacture.

There is approved plastic pipe for compressed air and it is oil resistant and has fiber in the matrix. It is a glued system too. The only failures I saw in that pipe was due to outside impact or poor glueing in the assembly.

My own preference is copper after replacing all the lines with it at work. I use it in my home shop as well. I really like that the copper adds no rust too.

You could 'get away' with the PVC, bit I'd recommend copper pipe.

Originally posted by MrMopar64
I just painted my car back in June with a pvc system that was about a year or so old with no problems with fisheyes I used 3/4 inch White Schedule 40 that is rated at 400psi with no problems

When I first put it in I made the mistake one night of setting up a patio heater inside the garage and after about 1/2 hour my son said whats that smell well low and behold I had put the heater right under the pvc air line and with 150psi in the line it swelled up from 3/4" to about 1 1/2" but never blew a hole in the pipe
The next day I just cut out the piece and put in another
That was the last time I brought the heater in

MM64

www.rgkustoms.com

Word for word what I was going to write up with one of those 150,000 btu heater after winter we looked up and so what looked like a snake that ate a big rat, cut it out and it is fine, has been in service for about 18 years but I am not recommending it. Ed ke6bnl