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Confused as to setup of pressure pots

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  • Confused as to setup of pressure pots

    Hello
    I am sorry for this old question BUT I am confused as to how the pressure pot used by HWSNBN for his castings both works and is physically constructed and how it operates. I thought one introduces a set pressure into the pot with the rubber molds inside and that forces air bubles to shrink in the mold. However I hear that a vaccum is the way to go to draw out the air bubbles.

    Question from what I see in the pictures of HWSNBN`s work shop and his pot. Which is his method and how is the setup made and how is it run? Details PLEASE.

    Thanks for your time and help.
    George

  • #2
    Originally posted by george View Post
    Hello

    I am sorry for this old question BUT I am confused as to how the pressure pot used by HWSNBN for his castings both works and is physically constructed and how it operates. I thought one introduces a set pressure into the pot with the rubber molds inside and that forces air bubles to shrink in the mold. However I hear that a vaccum is the way to go to draw out the air bubbles.

    Question from what I see in the pictures of HWSNBN`s work shop and his pot. Which is his method and how is the setup made and how is it run? Details PLEASE.
    Thanks for your time and help.

    George
    Good questions, George. If they were not I would let you know in no uncertain terms.

    I assume you're talking about the application of pressure/vacuum during the polyurethane plastic resin casting.

    Subjecting the still liquid state catalyzed resin to pressure crushes significantly sized air-bubbles trapped in the mix (through catalyst mixing and/or water contamination) back into solution -- the bubbles go away producing a casting that is pock-mark free.






    Subjecting the above tool to vacuum increases the size of the bubble to the point where buoyancy forces them to the surface of the tool cavity and out the sprue and vent network.







    In either case, the process produces pock-mark free castings.

    Pressure casting is for simple cavity shapes that vent easily. Vacuum casting is for parts of complex and/or very thin wall thickness.

    And there is centrifugal casting and roto-castting, but those are techniques for a later discussion.

    David
    "... well, that takes care of Jorgenson's theory!"

    Comment


    • #3
      I would add curing time makes a difference on what you use. Vacuuming can take a longer period of time with the possibility of having a really ugly piece should it setup before the bubbles begin to collapse.So, if you are using say a short cure time like a 5 minute resin.....pressure is the better choice. It can be as simple (yeah - if anything really goes simply) as mix pour into mold, close pressure pot, and add pressure and wait to cure. In my mind anyways.
      If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

      Comment


      • #4
        Hello
        Thank You Both for the information. I am going in the direction of pressure pot work with a Slow cure material for my casting.
        Last question, instructions needed in the actual making /setup of the pressure pot, what is needed parts are needed to make it work and what is the working air pressure sent into it?
        Thanks Again
        George

        Comment


        • #5
          George,
          Look at the pictures. You are removing the pressure gauge on the paint pot and adding a quick disconnect. Your compressor has a gauge on it that will tell you the PSI you are working at.
          If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

          Comment


          • #6
            Originally posted by george View Post
            Hello
            Thank You Both for the information. I am going in the direction of pressure pot work with a Slow cure material for my casting.
            Last question, instructions needed in the actual making /setup of the pressure pot, what is needed parts are needed to make it work and what is the working air pressure sent into it?
            Thanks Again
            George
            Buy this:
            https://www.amazon.com/TCP-Global-2-...s=pressure+pot

            Working pressure for resin casting is 30 psig.

            Get a compressor with an attached volume tank and you're off to the races.

            David
            "... well, that takes care of Jorgenson's theory!"

            Comment


            • #7
              Hello Again
              Thank You both for the help / Tips. Already have a 20 gal compressor with gauge and spare fittings. Just got to source a local 10litre 2 1/2 gal pot.
              Thanks Again for the help.
              George

              Comment


              • #8
                Is there a Harbor Frieght in your Area?
                https://www.harborfreight.com/2-1-2-...ank-66839.html
                or any home improvement or hardware store should have these.
                If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                Comment


                • #9
                  Hello
                  Thanks for the link trout.
                  I`m in Canada and we have a similar company here that from time to time has sales on those items also. Now that I know, I will keep my eyes open for it here in Canada.
                  Thanks Again for ALL the help.
                  George

                  Comment

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