Announcement Announcement Module
No announcement yet.
Using the OF45150 for Inflation? Page Title Module
Move Remove Collapse
Conversation Detail Module
  • Filter
  • Time
  • Show
Clear All
new posts

  • Using the OF45150 for Inflation?

    Forgive me if this is the wrong forum, I'm new here.

    Lately I've gotten into pressure casting; I put a mold with liquid plastic into a pressure chamber and push it to about 60-70 PSI, crushing bubbles down and locking them in for smooth casts.

    I love my OF45150 Twinstack, it has more than enough power for putting my chamber under pressure, but I'm a little unsure how to keep a continuous stream of air going at the outlets. Maybe I'm just missing something? I'm pretty sure this compressor can be used for inflation, right?

    My first thought was that I'd have to attach the compressor to an air inflator (something like this), and then hook that to the pressure chamber with a quick release. Turn on the air compressor, bring it up to speed, and then pull the trigger on the air inflator to start pumping air into the chamber.

    Even so, I was wondering if anyone here had any other advice. For the record, here's my pressure chamber. Also, the quick release valve on the lid where I'd hook up the hose leading to the air inflator/compressor/whatever air source. Fittings aren't a problem, I have quick releases of all types, I just wanted to know if there's any way to directly hook the Twinstack up to the chamber and put it under pressure. Or, would I need another tool like an air inflator/air gun?

    Thanks for any and all help, it's greatly appreciated.

  • #2
    Re: Using the OF45150 for Inflation?

    I'm not sure of your air flow requirements and pressure needs. Can you bring the tank up slowly or do you need instant or very rapid rise in pressure to happen to the mold, before material sets up, etc.? For instance, blow molding a hot resin may require a rapid action, as opposed to some other application.

    If slow pressurization is okay, then the chamber will simply act like any other air receiver, rising to the maximum setting of the compressors regulator. The time it takes will of course depend on the size of the vessel or chamber and the CFM/Pressure output of the particular compressor.

    For instance, if you were inflating a large tractor tire, you'd simply set the regulator to the pressure required and the compressor would pump air until the regulator sensed equilation with it's setting and the tire. Given the same pressure, a smaller tire (vessel or chamber) would inflate faster than a larger tire (vessel or chamber).

    I hope this helps,



    • #3
      Re: Using the OF45150 for Inflation?

      Just treat your pressure vessel as an air tool, hook a hose between the compressor and the vessel. Bring your compressor reservoir tanks up to the max pressure set the regulator to about 80 PSI just a bit higher than what you need in your vessel and connect the hose between the compressor and vessel. Open the petcock on your 'quick release valve' (appears closed in pick) and use the regulator on you vessel to set the chamber pressure


      • #4
        Re: Using the OF45150 for Inflation?

        Basically, I just need the chamber to act as the receiver. Slow pressure build-up is fine; the OF45150 can do 90 PSI at 4.9 SCFM, which is perfect. I need to cast around 60-70 PSI, and my chamber is 4.5 cubic feet, so I'd just need to get the compressor running and turn the knob to around that.

        The resin sets in about 20 minutes after mixing, but that's more than enough time, I think. And with the OF45150's power, it'll pressurize my tank to 60 PSI in about a minute, possibly less.

        I'm just wondering if I'd need an extra tool like an air inflator to serve as a "middle man" between my compressor and chamber, though. The Twinstack powers up and gets to 150 PSI, then the safety kicks in. The thing is, if I want the air to discharge, I need a trigger from one of the outlets (a nailer or something similar). If I have an air inflator attached (like the one in the previous post), I could just pull the trigger and release the air from the compressor.

        But, I'm just wondering if I really do need something like that. After getting the compressor powered up, I can't simply hook my chamber up to one of the outlets, no air flows without a trigger. But, is there any way to hook the compressor up to the chamber directly and get a continuous airflow to pump it up?

        Wbrooks - That's the thing, though. I tried that, but it didn't work. I got the compressor to the 150 PSI, hooked my hose to an outlet, and then hooked it to the pressure chamber. I opened the quick release on the lid, and... nothing. No air flow from the compressor to the tank. Which I found odd, since I used a smaller (very old) compressor in the same manner and got it to 20 PSI (before the compressor gave up the ghost). In other words, simply hooking a hose from compressor to chamber and then opening the valve didn't work - no air flow!

        I'd be happy to post some pictures if they'd help out, though. Thanks again.
        Last edited by Obsidian; 08-17-2007, 12:48 AM.


        • #5
          Re: Using the OF45150 for Inflation?

          The simple answer, as to whether you can directly hookup your compressor to your chamber, is YES!

          I don't have that particular compressor, but I did have a twin-tank Ingersoll-Rand and presently have a 33-gal oil-less Craftsman. My I-R compressor had a shut-off at the outlet and my Craftsman had a simple quick-disconnect. With the latter, when you attached the hose to the quick-disconnect, the hose to the tool would be immediately pressurised, and of course the tool itself. With the I-R compressor, you had to open the compressor's discharge valve.

          I much preferred the use of a shut-off valve in the discharge line, before the quick-disconnect as it makes it easier to plug into an unpressurized fitting. My Craftsman is now fitted that way.

          The point is, I don't know how your Ridgid is set up. But, it really doesn't matter as long as you know one way or the other whether the hose gets pressurized when you plug it in to the fitting, or you have to turn a valve on the compressor to do so. Your description to W.Brooks, sounds like either your hose fitting didn't actuate the compressor's quick-release, the compressor has a valve in the discharge that needs to be opened, the hose you used was plugged, or there's something on the chambers inlet. You of course know what your dealing with. The point is that with a straight hose connection between the compressor discharge and the chamber there should be nothing preventing the compressor regulator from pressurizing your chamber to the desired pressure.

          So, you could just have a hose plugged into the compressors discharge connector and have the other end plugged into your chambers inlet connection. You would adjust the compressor discharge regulator to the desired pressure for your chamber and the compressor would run, filling the chamber, until it reached the pressure set on the compressor regulator.

          This would be the most desireable, IMO, as long as you had a shut-off valve on the compressor's discharge. If not, then you should really have a shut-off in the line between the compressor and the chamber. Currently, the device you showed, is acting as the shut-off... albeit, with a "trigger" action. I can understand why you wouldn't want to stand there holding the trigger closed!

          They do make air hoses, of varying lengths, for the soul purpose of connecting between the compressor's discharge and whatever the owner wished. Most often, that's an internal air distribution system in the shop; but it could be for a larger air receiver or other device.

          Home Depot carries a short "lead-in hose" made by AMFLO (30L-30B). The SKU# is E484-820 and the price was $12.97 about a year ago. I think it was less than two foot though. You could check with HD, Lowes, or Sears. You could also check with your local farm and tractor supply store or if you're in a major metro area, look for a compressor retailer or service center.

          I hope this helps,

          Last edited by CWSmith; 08-17-2007, 03:11 PM.


          • #6
            Re: Using the OF45150 for Inflation?

            Eeehehe, I feel sheepish now.

            I figured out what was happening, I thought it had something to do with the compressor, but I was wrong. Turns out the pressure gauge on my tank is broken, which is why I wasn't getting any readings. A little tinkering and small tests revealed it's finally given up the ghost. I also attached the hose to the lid itself and felt the opening - yes, indeed, I was getting airflow. Right after, I had one of those, "Why didn't I just think of that before...?" moments.

            Okay, problem solved, thanks for your help, guys!


            • #7
              Re: Using the OF45150 for Inflation?

              Thanks for posting the answer. Stick around and show us a finished product when you get one done