Help me find a pressure/vacuum tank!

[Rick]

@HongKongFooey

The problem is that pressurizing the pipe with compressed gas isn’t the same as pressurizing with water which the PVC pipe was made for.

I’m gonna have to ask for a cite on that.

[HongKongFooey]

@Rick

I’m gonna have to ask for a cite on that.

Certainly:
Here’s one from an OEM

They also caution against using their product to store or convey air or other gases or failing to vent trapped air. It is increasingly common for such practices to void any warranties. Many accidents have been reported as a result of air testing or trapped air. Most manufacturers of plastic pipe and fittings have had to investigate field failures caused by either air testing or trapped air.

osha

An employee in a Texas plant was injured recently by a rupture in a PVC compressed air line. Plastic projectiles from the point of rupture caused lacerations of the employee’s hand. This is noteworthy because the Plastic Pipe Institute, in its Recommendation B dated January 19, 1972, recommends against the use of thermoplastic pipe to transport compressed air or other compressed gases in exposed plant piping.

The state of Washington has notified the public that PVC pipe is not to be used in compressed air systems

Yahoo! Answers

PVC-U (Polyvinyl chloride, unplasticized) - Highly popular due to its availability and relatively low cost. PVC pipes are available in a wide variety of sizes and pressure ratings. In industry, however, they are illegal for compressed air applications—if they are damaged under pressure the plastic can fail explosively.

ABS (Acrylonitrile butadiene styrene) - Another popular plastic piping material, more expensive and less common than PVC but available in the same sizes and pressure ratings. Unlike PVC, it is used in compressed air systems as it splits rather than shatters on failure. It also has a greater temperature tolerance (-40°C to +80°C compared to 0°C to +60°C for PVC).

ETA: It’s illegal here too by the way but happens all the time on various sites especially in mines where they are exempt from many of the provincial health and safety regulations.

[mga405]

Hi, I new to this forum, but I do this to stabilize wood to make knife handles. i use a 2 1/2 gal pressure pot originally made to be used with a paint spray gun. I have it hooked up with pressure line, vacuum line and use a metering tube with a valve to let in epoxy resin/ and or dye. Works great up to about 100psi pressure and 20+ hg vacuum.

[mga405]

I forgot to mention-I got mine at Harbor Freight, new for under $100.

[CutterJohn]

@Rick

I’m gonna have to ask for a cite on that.

Pipe failure with a gas is much more catastrophic than with a liquid, as the gas can expand far, far more. This makes the pipe fragments fly all over the place. When the same piping is burst with a liquid inside, only a small amount of liquid needs to escape before the pressure is equalized, as liquids compress only a very small amount when under pressure.

Its a concern over pipe failure… So long as the pipe doesn’t fail, then of course it would perform just fine with a gas inside. Its just unsafe to do so.

[CutterJohn]

oh, and http://www.graco.com/Internet/T_PDB.nsf/ProdGroups/FinishingAccessories

Drat… it seems I was beat too it.

[CutterJohn]

@mga405

I forgot to mention-I got mine at Harbor Freight, new for under $100.

This one? [http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93119](Heres the one from harbor freight… http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93119)

[mga405]

That’s the one 2 1/2 gal for 79.95 and a 5 gallon for 99.95. i can send a you a pdf file that showsn step by step what I did with pictures showing steps.