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Bag Stem Assembly w/ Free Lock-On Connector
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Regular Price:
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$6.90   ($6.05 Savings!)
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Product Description

Important Note
This item is the old version of our vacuum bag stem and the old version of our lock-on vacuum connector. You are buying the bag stem and we are including the compatible lock-on connector at no charge.

This bag stem is an easy way to connect a vinyl or polyurethane vacuum bag to the old version of the lock-on vacuum connector and vacuum hose. Each stem has air channels cut from the center intake to direct air flow quickly and evenly from the vacuum bag. The stem includes 1 zinc-plated brass stem, 2 zinc-plated heavy duty washers, 2 medium density foam grommets, 1 o-ring, 1 zinc-plated washer and nut.

The grommets are attached to the washers with an acrylic adhesive which prevent them from creeping if the vacuum bag stretches. With only a bit more than hand pressure, this combination also prevents elongation of the opening where the stem is placed. No cementing is needed and because of this, the stem can be moved from one bag to another if needed. It is an excellent option for one-time use vacuum bags made from disposable materials.


  1. Remove the zinc-plated nut, washer, and the top gasket ring from the bag stem assembly. Do not separate the metal washer from the gasket material.
  3. Insert the bag stem (with the lower gasket ring in place) through a 3/8" diameter hole in the vacuum bag.
  5. Place the other gasket ring back onto the bag stem with gasket side against the vacuum bag material.
  7. Install the washer and tighten the locking nut with finger pressure. Then turn the nut one full rotation with a wrench.

pg-warning-yellow.jpg WARNING: This product can expose you to chemicals, including lead, which are known to the state of California to cause cancer and birth defects or other reproductive harm. For more information visit

Why would I choose this stem instead of the flush-mount stem?
Since this stem is removable it is ideal for use with temporary or limited-use vacuum bags made from disposable material.

Why would I choose the flush-mount stem instead of this stem?
The flush mount stem, which is included with all of our vacuum bags, does not protrude and impress itself against the surface of the project being vacuum bagged. This means that the flush-mount stem can be set directly on top of the veneered project without marring the surface.

What makes this stem better than the flush-mount stem?
This stem is removable so it can be moved from bag to bag if you want.

What is the size of the large washers on this stem?
The diameter of the grommets is approximately 1.5"

What is the size of the lower portion of the stem shaft?
The lower threaded area is approximately .4" in diameter?

What is the thread size on the top of the fitting?
It is a standard Schrader thread which is .305" OD and 32 tpi.

Does this fitting work with the new version of the lock-on connector?
This fitting only works with the old version.

Does this stem have a valve inside?
No. Valves are a flow restrictor and since the vacuum source must stay attached to the bag during a pressing cycle, there is no point of having a valve inside the stem.

Why does the vacuum bag have to stay connected to the vacuum press after full vacuum is achieved?
Yes, because a perfect seal on a vacuum bag is virtually impossible. Here are some things to consider.

  • Sometimes the bag closure doesn't seat perfectly across the opening.
  • Sometimes the bag stretch a bit after full vacuum is created and will then need a bit of additional vacuum. This happens most often when there is a large project in the bag. You'll hear the vacuum system cycle off (if you have any auto-cycling system) and then turn on again for a few seconds. After that, it may not cycle again for several minutes or even hours.
  • After many uses some bags develop pin holes which can be almost invisible. In those cases, it's best to let the vacuum press keep the bag vacuum under control.

If the vacuum system is disconnected from the bag, you won't know if there is a leak because there is no vacuum gauge on the bag itself. If the bag is connected to a vacuum press system, you can easily see the vacuum level by looking at the gauge on the vacuum press. The vacuum inside the system is the same amount of vacuum inside the bag. If your vacuum press cycles on and off too frequently during a project pressing, you'll know there is a leak and if you can fix it. However if you can't fix the leak, at least the vacuum system will keep manage the vacuum in the bag until the panel is finished.

Product Reviews

  1. Great Economical Option

    Review by Shane Burkhart

    Works great, a fantastic option when making your own vacuum bags. I made my own economical bags buying bulk 20 mil vinyl from fabrics store and using clear tape to seal sides and Veneer Supplies vacuum bag closure- worked perfectly!

  2. Review from Sandusky, Michigan

    Review by Bill Bittner

    Thank you for the great service, I placed my order on Thursday and Saturday it was in my mail box. I am building a custom vacuum bag for laminating vacuum formed ABS plastic and a foam core. This valve stem assembly worked great for this application.

  3. It Was a Smart Move...

    Review by Christian M

    Web site is clean and informative. My order was received quickly and this part worked perfectly for my infuser. The "Also Recommended" section on the right saved me from missing parts...very happy about that. It was a smart move for me to get everything from one place... everything organized.

  4. 3 Years Now With No Leaks

    Review by Jim H

    I had a vinyl bag from another manufacturer and it leaked from day one. I was ready to throw the thing out when I saw this valve stem assembly. It was easily installed and has been working for over 3 years now with no leaks. Liked it so much I purchased a larger poly bag and now love both. You can't go wrong with Veneer Supplies.

  5. Super Easy to Install and Use

    Review by Kirk Davies

    Very good valve system, quick to set up and no leaks.

  6. Does The Job

    Review by Roger Cochran

    This is a great idea here. It does the job and its affordable. I've built several bags with this stem and it has never leaked.

  7. Doesn't Leak At All

    Review by Jay Miscivitski

    I think this is a great idea. I just built my 3rd vacuum bag with the parts from here and this nipple system is by far the best. Its simple and straight forward and doesnt leak. The vinyl reinforcements are a nice touch and really provide noticable strength at the connection point (a notoriously leak-prone area). Its remarkable that other manufacturers are not using the same idea because its about as good as I could ask for.

  8. I Was Thrilled

    Review by Spencer Grayson

    This stem was sent to me with the vacuum press system. At first, I thought it was a bit over rated but after trying the system and the stem together, I was thrilled!
    The bag I made was big and the stem worked perfect... the bag held its pressure for almost 40 minutes. This stem also looks more professional and since Joe's instructions say to not to glue the washers in place, the stems can be moved from one bag to another if you decide to upgrade.

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