Vacuum Table 101

Discussion in 'Investment casting Block method' started by Jason, Nov 27, 2020.

  1. Jason

    Jason Gold

    Here it is boys! If you can afford to drop the bucks, then here is the link to plug and play!

    Now for the rest of us on planet earth, casting is a H O B B Y and not a business. So If you ever wanted to peak under the skirt of one of these and see what makes them tick and why so expensive, here is your front row seat to the peep show!

    You'll see it's DEAD NUTS simple and it could be replicated for peanuts.... I'll try to explain what you are looking at by each photo.

    This is the top. Now the brass thing at the top is controlled with the valve on the bottom right of the table. This only allows INTO the chamber to release it. When in use, the bottom valve is closed.

    Lift up the main silicone pad and YUP, that's 5/16" hole. That's all!

    Cover your eyes kids! Underside of the table. The top black is the gauge to let you know how much vacuum you are pulling and the middle black is the main vacuum hole in the middle of the table. The block on the left is just the collector point for all these hoses. No black magic there and you can skip all this bullshit. The white hose allows air into the block and the bottom hose allows air into the chamber when domed. (brass fitting on top)


    Here is a real deal flask. THIS is how you keep your wax from floating. What happens is you build your wax tree in the rubber ring on the right. It has the perfect shape for funneling the metal into the flask. After you build your wax on the base, you stick it on the bottom of the metal pipe. Then you fill it with investment and place it under the dome. Once the investment is hard, you remove the bottom rubber and stick the metal flask in the kiln upside down to melt out the wax.


    This is how we vac investment. You can't see it here, but that brass fitting from the first photo is also under the dome. When finished sucking, you open the valve on the top and then you can remove the dome.


    Imagine this flask is solid, the wax has been melted out and it's just come out of the kiln up at metal pouring temp. Prior to dumping in metal, I add this orange silicone pad. This closes my extra holes in the main pad and offers a cheap surface for the screaming hot flask to sit on. Flip the pump on prior to setting this over the hole. This way, you'll KNOW you are pulling a vacuum on the flask... You'll hear the pump draw down as it works hard sucking through the investment.

    With the pump on, the flask up to temp, dump in the metal. Let suck for a minute after the pour... Longer if your piece is really big.
    That's it! SUPER EASY! You could build this table in about 20mins with a single piece of 1/4" aluminum plate (steel would work too). Just stick some feet on it, and a fitting that connects to your vacuum hose right in the middle. skip the gauge, skip the valves... Just a hole and a hose with a vacuum pump on the end of it.... Now I expect to get sued by RIO any day.:rolleyes:

    One thing I left out is the table sits on springs. They are there to allow you to agitate the dome while pulling a vacuum as this helps bring air bubbles to the top of your flask during degas. The real design from what I can tell here is the idea to prevent you from sucking metal into you vacuum pump in the even of a failure. The block under should help prevent this, but I will tell you we have sucked gold INTO a vacuum pump a time or too! :mad:

    Now that I've shown this, I expect to see one of you crafty types to knock this table off! Post a photo of your version here! I'll be happy to answer any questions about this simple table to help you save a few bucks.
    Last edited: Nov 27, 2020
  2. Jason

    Jason Gold

    If one of you guys decide to build one of these, please post your work here! I'd like to see what you fabricate! ;)
  3. Peedee

    Peedee Silver

    I would have a go but I have no need for a vac table, besides my employer might get suspicious of the loss of 2024 batched sheet going missing.

    Maybe someone will step up and have a pop at it,

    I do have a fancy for making another vac table for plastic forming.. but that's a way down the list.
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    I did this 10 years ago. That's all my table is, an aquarium stand with a 1/4" sheet of aluminum with a hole drilled in it.
    Rio grand sells the silicone sheet and bell jar for the top. I also have a piece of 12" dia pvc to raise the bell jar higher for the big flasks....
  5. bill

    bill Silver

    This is how I got started and what still use. I had a saw I wasn't using for the stand. The aluminum side cover off of a Mac Tower, a rubber press blanket from a commercial printing press and one old flower pot i found under the stairs. HF vacuum pump bleed off valve and gauge I had from a hand pump I put inline.

    IMG_3043.JPEG IMG_3044.JPEG

    Months later I built this for pouring. Previously I used gravity or steam when casting.
    This was basically free already had the fire brick and hose just needed the gauge.
    One old Gast Vacuum Pump System from an old
    printing press that was being scrapped - free
    wood pallet - free
    firebrick a gauge and some hose.

    The center piece is the main chamber and draws from the bottom only. Exhaust pipe from auto zone was used to fit and make the vacuum seal. Castings using those flasks will fit directly into the seal. Seal was made with Mold Max 60 also the rectangle seal that is specific to the stainless flask next to it. Other adaptors for other things applications. They all fit into the main chamber. The flat board has press blanket material on it as well. That needs replaced.

    IMG_3046.JPEG IMG_3045.JPEG
    Last edited: Feb 21, 2021
    Jason likes this.
  6. JBC

    JBC Copper

    12" PVP is brilliant!

Share This Page