Safety Speed Cut Thermwood Corporation ECabinet Systems

Cabinetmaking

You are not logged in. [ Login ] Why log in
(NOTE: Login is not required to post)

Uses for vacuum compressors

10/2/21       
Dan Cook

I have been vacuum veneering for years now and have several vacuum compressors. I would like to use them for hold downs and wondering how some of you have done this and what kind of fixturing did you build that worked. Any other ideas for use with vacuums?

10/2/21       #2: Uses for vacuum compressors ...
Dave L

Pretty much anything involving work holding can be done with vacuum. I even use vacuum for clamping a fence to the middle of my workbench (pneumatic fence on the edge). Boards (pic is corian) with seals on both sides are handy for all sorts of tasks. In simple applications 1/8-3/16" closed cell foam tape works fine.

For CNC router work holding I use 3mm round EPDM in groves. Two pieces of 1x 1/4" melamine (with routed vacuum channels) glued together works well - 2x 1/4" for second level clamping (pic).


View higher quality, full size image (1280 X 960)


View higher quality, full size image (1280 X 960)


View higher quality, full size image (1280 X 960)

10/4/21       #3: Uses for vacuum compressors ...
Kevin Jenness Member

Vacuum clamping is great for non-marring work holding especially for edge routing and the like. I have several simple fixtures made of a single layer of mdf, banded with p-lam and sealed to the bench and workpiece with 1/8" or 1/4" foam tape bedded in grooves around the perimeter of each face. A hole drilled in the edge and lined with a short section of vac hose to accept the vacuum hose nipple intersects with a hole drilled through the faces. For larger fixtures routing a grid in the faces is a good idea .

I tried using a similar fixture on my cnc spoilboard but could not get it to pull down on the ultralite mdf surface, so I put a flange under the fixture, screw it down to the spoilboard, and pull vacuum on the workpiece only. This is good for pieces too small to hold with the low suction generated by my home-made vacuum table.

10/4/21       #4: Uses for vacuum compressors ...
Dave L

Vacuum passes pretty freely through unsealed MDF, some folks claim it's enough to provide a suitable gasketless clamping surface. For airtight gasketed fixtures, coated MDF minimizes the amount of (PVA) sealing I have to do.

All my CNC router fixtures are mounted via m5 inserts in the spoilboard. While I haven't noticed a difference, even small part holding could benefit from topside channels.

10/6/21       #5: Uses for vacuum compressors ...
Keith Newton

To overcome the problem of holding large porous sheets, it isn't a problem of the pump, but the limitations of the air hose size. The math is simple in that each doubling of diameter, is a quadrupling of the area, so maybe take a look at plumbing.

A few years ago I had some pretty large template routing to do. Almost all shop vacuums pull -2psi, so over a large area that adds up pretty quickly. For instance, a square foot = 144" x 2 = 288#, and the simple fact that a 2" hose allows for some significant leaks without causing much of a drop.

I'm a small shop, and don't have a CNC router, so I'm not comparing a shop vac to the big guns some of you have.

10/6/21       #6: Uses for vacuum compressors ...
Dave L

Good shop vacs draw ~150cfm and may be able pull ~7 in Hg (if I did the 100 inch water column conversion correctly). My (tiny by industrial standards) veneering/clamping pump draws 3.5cfm and can pull 25 in Hg.

While clamping at ~7 in Hg may be enough in some applications, I believe the standard for veneering and clamping is ~20 in Hg.

The CFM needed depends on leakage and how fast the air needs to be evacuated. Note: Pump CFM ratings are at zero vacuum, e.g. 1.24 @ 0 down to .16 @ 20 for my tiniest pump (why it only clamps good when there's zero leakage).

10/7/21       #7: Uses for vacuum compressors ...
Kevin Jenness Member

There's a balance among the force needed for clamping vs the force exerted by machining, the vacuum level (often expressed in in. hg) and volume pulled by the vacuum source, and the area subject to vacuum and its porosity.

With a small pump pulling a moderately high vacuum like my Gast rotary vane pump at 24" hg you can hold a small part (<.5 sq. ft) securely for routing as long as it is not porous and has no holes. With my home-made cnc vacuum table using central vacuum motors pulling only about 7" hg pieces that small would break loose under typical cutting pressure, and even large warped pieces may not be pulled flat to the table. A melamine coated panel will be held down better than a piece of ultralite mdf. More power is better, but a low volume or low vacuum level can be adequate depending on the situation.

10/7/21       #8: Uses for vacuum compressors ...
Dan Cook

I would love to see some pictures or diagrams of how you made the fixtures you use. i love this site for all the sharing that we get to do. I think everybody benefits when we collaborate on ideas. This is what gives this trade a future in my opinion.


Post a Response
  • Notify me of responses to this thread
  • Subscribe to email updates on this Forum
  • To receive email notification of additions to this forum thread,
    enter your name and email address, and then click the
    "Keep Me Posted" button below.

    Please Note: If you have posted a message or response,
    do not submit this request ... you are already signed up
    to receive notification!

    Your Name:
    E-Mail Address:
    Enter the correct numbers into the field below:
     

    Date of your Birth:



    Return to top of page

    Buy & Sell Exchanges | Forums | Galleries | Site Map

    FORUM GUIDELINES: Please review the guidelines below before posting at WOODWEB's Interactive Message Boards (return to top)

  • WOODWEB is a professional industrial woodworking site. Hobbyist and homeowner woodworking questions are inappropriate.
  • Messages should be kept reasonably short and on topic, relating to the focus of the forum. Responses should relate to the original question.
  • A valid email return address must be included with each message.
  • Advertising is inappropriate. The only exceptions are the Classified Ads Exchange, Machinery Exchange, Lumber Exchange, and Job Opportunities and Services Exchange. When posting listings in these areas, review the posting instructions carefully.
  • Subject lines may be edited for length and clarity.
  • "Cross posting" is not permitted. Choose the best forum for your question, and post your question at one forum only.
  • Messages requesting private responses will be removed - Forums are designed to provide information and assistance for all of our visitors. Private response requests are appropriate at WOODWEB's Exchanges and Job Opportunities and Services.
  • Messages that accuse businesses or individuals of alleged negative actions or behavior are inappropriate since WOODWEB is unable to verify or substantiate the claims.
  • Posts with the intent of soliciting answers to surveys are not appropriate. Contact WOODWEB for more information on initiating a survey.
  • Excessive forum participation by an individual upsets the balance of a healthy forum atmosphere. Individuals who excessively post responses containing marginal content will be considered repeat forum abusers.
  • Responses that initiate or support inappropriate and off-topic discussion of general politics detract from the professional woodworking focus of WOODWEB, and will be removed.
  • Participants are encouraged to use their real name when posting. Intentionally using another persons name is prohibited, and posts of this nature will be removed at WOODWEB's discretion.
  • Comments, questions, or criticisms regarding Forum policies should be directed to WOODWEB's Systems Administrator
    (return to top).

    Carefully review your message before clicking on the "Send Message" button - you will not be able to revise the message once it has been sent.

    You will be notified of responses to the message(s) you posted via email. Be sure to enter your email address correctly.

    WOODWEB's forums are a highly regarded resource for professional woodworkers. Messages and responses that are crafted in a professional and civil manner strengthen this resource. Messages that do not reflect a professional tone reduce the value of our forums.

    Messages are inappropriate when their content: is deemed libelous in nature or is based on rumor, fails to meet basic standards of decorum, contains blatant advertising or inappropriate emphasis on self promotion (return to top).

    Libel:   Posts which defame an individual or organization, or employ a tone which can be viewed as malicious in nature. Words, pictures, or cartoons which expose a person or organization to public hatred, shame, disgrace, or ridicule, or induce an ill opinion of a person or organization, are libelous.

    Improper Decorum:   Posts which are profane, inciting, disrespectful or uncivil in tone, or maliciously worded. This also includes the venting of unsubstantiated opinions. Such messages do little to illuminate a given topic, and often have the opposite effect. Constructive criticism is acceptable (return to top).

    Advertising:   The purpose of WOODWEB Forums is to provide answers, not an advertising venue. Companies participating in a Forum discussion should provide specific answers to posted questions. WOODWEB suggests that businesses include an appropriately crafted signature in order to identify their company. A well meaning post that seems to be on-topic but contains a product reference may do your business more harm than good in the Forum environment. Forum users may perceive your references to specific products as unsolicited advertising (spam) and consciously avoid your web site or services. A well-crafted signature is an appropriate way to advertise your services that will not offend potential customers. Signatures should be limited to 4-6 lines, and may contain information that identifies the type of business you're in, your URL and email address (return to top).

    Repeated Forum Abuse: Forum participants who repeatedly fail to follow WOODWEB's Forum Guidelines may encounter difficulty when attempting to post messages.

    There are often situations when the original message asks for opinions: "What is the best widget for my type of shop?". To a certain extent, the person posting the message is responsible for including specific questions within the message. An open ended question (like the one above) invites responses that may read as sales pitches. WOODWEB suggests that companies responding to such a question provide detailed and substantive replies rather than responses that read as a one-sided product promotion. It has been WOODWEB's experience that substantive responses are held in higher regard by our readers (return to top).

    The staff of WOODWEB assume no responsibility for the accuracy, content, or outcome of any posting transmitted at WOODWEB's Message Boards. Participants should undertake the use of machinery, materials and methods discussed at WOODWEB's Message Boards after considerate evaluation, and at their own risk. WOODWEB reserves the right to delete any messages it deems inappropriate. (return to top)


  • Forum Posting Help
    Your Name The name you enter in this field will be the name that appears with your post or response (return to form).
    Your Website Personal or business website links must point to the author's website. Inappropriate links will be removed without notice, and at WOODWEB's sole discretion. WOODWEB reserves the right to delete any messages with links it deems inappropriate. (return to form)
    E-Mail Address Your e-mail address will not be publicly viewable. Forum participants will be able to contact you using a contact link (included with your post) that is substituted for your actual address. You must include a valid email address in this field. (return to form)
    Subject Subject may be edited for length and clarity. Subject lines should provide an indication of the content of your post. (return to form)
    Thread Related Link and Image Guidelines Thread Related Links posted at WOODWEB's Forums and Exchanges should point to locations that provide supporting information for the topic being discussed in the current message thread. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related Link that directs visitors to an area with inappropriate content will be removed. WOODWEB reserves the right to delete any messages with links or images it deems inappropriate. (return to form)
    Thread Related File Uploads Thread Related Files posted at WOODWEB's Forums and Exchanges should provide supporting information for the topic being discussed in the current message thread. Video Files: acceptable video formats are: .MOV .AVI .WMV .MPEG .MPG .MP4 (Image Upload Tips)   If you encounter any difficulty when uploading video files, E-mail WOODWEB for assistance. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related File that contains inappropriate content will be removed, and uploaded files that are not directly related to the message thread will be removed. WOODWEB reserves the right to delete any messages with links, files, or images it deems inappropriate. (return to form)
    Limtech Industries, Inc. Lamello
    Today's Sponsors

    Become a Sponsor today!