Architectural Woodworking

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

Balancing Glue Volume in Vacuum Press?

12/21/15       
TdB Member

I work for an architectural millwork company that often laminates custom solid-core doors and presses them in a vacuum press.

We've had large doors (10'+) warp slightly (1/8" to 3/16") occasionally and we've discussed the cause at length. Currently, the owner is emphatic that the glue previous warpage was caused by applying unbalanced/unequal amounts of glue to the front and back of the door core.

The claim is not that the joint is starved, but rather EXCESS glue is applied to one side, causing increased moisture to warp the panel.

I'm unsure of this claim because it seems to me that, under vacuum pressure, the excess would be forced out from the joint, leaving roughly equal amounts on both sides of the core.

We do not have problems with trapped glue and bubbles in our laminations.

Is this claim plausible?

12/22/15       #3: Balancing Glue Volume in Vacuum Pre ...
Geoff

What are you using for adhesive?

12/22/15       #4: Balancing Glue Volume in Vacuum Pre ...
Tom Gardiner

In my experience laminating panels with PVA in a vacuum frame press, how I handle the panels after pressing is as important as glue application to ensure flat pressings.
Don't leave the doors in the press beyond pressing time. Both sides of the door must have equal exposure to air to allow even evaporation of glue moisture. Guard against fans or heaters blowing on one face. If you are going to stack doors, sticker between doors and cover the exposed face with a sheet of ply with sticks for a stand-off.
It wouldn't hurt to ensure you have consistent glue application with a hopper glue roller, I use a 6" Pfohl roller. It speeds up the process and will probably save you glue.

12/22/15       #5: Balancing Glue Volume in Vacuum Pre ...
TdB Member

"What glue are you using?"

We're using Titebond I and III to apply paper-backed veneer, 1/4" solid, and G2S sheets to particle-core door cores.

"Don't leave the doors in the press beyond pressing time. Both sides of the door must have equal exposure to air to allow even evaporation of glue moisture. Guard against fans or heaters blowing on one face. If you are going to stack doors, sticker between doors and cover the exposed face with a sheet of ply with sticks for a stand-off."

We follow all of the practices you've listed.

"It wouldn't hurt to ensure you have consistent glue application with a hopper glue roller, I use a 6" Pfohl roller. It speeds up the process and will probably save you glue."

This is exactly my question: would excess glue really affect the process because the press should be eliminating most of the excess, therefore glue cannot be applied in 'unbalanced' amounts.

Typically we use a scraper to spread the glue out broadly while a co-worker follows with a fine bristle roller to even out the coverage.

12/23/15       #6: Balancing Glue Volume in Vacuum Pre ...
Tom Gardiner

In my opinion I would think that too much glue will cause problems. A vacuum press is not like a hydraulic press in that the platens of a hydraulic press are massively stiff and flat. As pressure is applied the press has the power to squeeze out excess glue. But a 5/8" sheet of melamine on top of your glue up is flexible and may not squeeze all the excess out.
I made the mistake once of gluing 3/16" veneers of quartered Douglas Fir onto a door core with Titebond 3. The fir warped enough to overcome the vacuum force and ruined the job. The lesson was while vacuum press forces are large, it can't overcome the forces caused by wood that wants to move. I wouldn't rely on a vac press to take care of excess glue. It is much better to control it in layup.

12/23/15       #7: Balancing Glue Volume in Vacuum Pre ...
Joel Member

The too much glue potential problem has been covered.

Cure time is another potential. Tight bond 2 or 3 I would let cure in warm environment 24 hours, then take it out and let it breathe equally on both sides, stickered flat.

Are you guys using a flat tortion box platten kerfed for air evaluation and even pressure distribution? Any breathable mesh? This will help kep the material dead flat during the pressing.

Uniobond 800 is a great adhesive, but more expensive. It's rigid so you will have much less chance of warpage.

If your glue is fully cured, you will be fine in what you describe. Add some heat, and add some cure time...

Hope helpful.

12/23/15       #8: Balancing Glue Volume in Vacuum Pre ...
Damir Dehlic  Member

Hello

We do a lot of doors with raw veneers in hot press and the thing causing panels to warp is the fact that one side gets the glue and the veneer first and starts to swell and the panel is unbalanced.

It gets worse if the venner is laid horizontaly on the doors.

The panel will always warp toward the side that gets the veneer and glue first.

Damir

1/23/16       #9: Balancing Glue Volume in Vacuum Pre ...
D. John Bishop

Unfortunately I have had this very exact issue. It’s very possible, we had the exact thing happen and tore several laminations apart to see what the exact cause was and it was uneven/assess/ or too little glue. We found that the actual layer of glue is critical to a proper lamination; we started using a glue roller system. They are a bit pricey and I always wondered why anyone would pay that for a silly clue spreader. Now I know. The exact same issue can wreak havoc under veneers.

We did not think it to be possible either until we all had a powwow like you guys and decided to just tear them up. We all agree the issue was as mentioned above, changed to glue spreader or a specialty nap roller but even then with that you much be very careful to be certain you are applying roughly the same amount of glue (millage) to all surfaces. Best of luck.

DJB

1/23/16       #10: Balancing Glue Volume in Vacuum Pre ...
Larry

I'm pretty sure a vacuum press will not squeeze out the excess glue. Therefore both sides need uniform coverage. 1/4" solid is too thick to use as a veneer.


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)