Biscuits for edge-gluing solid stock?

      and solution. July 18, 2000

I have noticed the tendency for wood to compress above a biscuit joint in solid wood. This has happened every time I've used this method to join panels, and therefore I have ceased to do it until I can find a way to eliminate the problem. Any suggestions would be appreciated.

The only reason to use any type of reinforcement in joining solid wood into panels is to align the edges in order to minimize machining and unnecessary material loss.

I'd say that biscuits are a poor choice for alignment since they intentionally leave quite a bit of space/clearance between the biscuit and slot to allow the biscuit to swell when water-based glue is applied.

If your goal is actual joint strengthening, donít bother. The joints, if machined on properly dried lumber, using appropriate adhesive and clamping techniques, will not require any further reinforcement. The joint should be at least as secure as the surrounding wood if standard edge-gluing practices are followed.
Michael Poster, technical advisor

Sounds like you may be finish-sanding your panels too soon after glue-up.

The wood swells more around the biscuit due to the larger amount of glue, and the swelling of the biscuit within the joint, as Michael mentioned. If you sand everything down flat before the area has a chance to completely dry, a depression is created at the biscuit when it does finally dry.

I agree with Michael, the biscuits probably won't add strength to a properly prepared edge joint. If you are just using them for alignment you might try not gluing the slots, and see if that helps.

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?

Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Woodworking Miscellaneous: Accessories

  • KnowledgeBase: Adhesives, Gluing and Laminating: Glues and Bonding Agents

  • KnowledgeBase: Adhesives, Gluing and Laminating: Gluing and Clamping Equipment

  • KnowledgeBase: Woodworking Miscellaneous: Woodworking

  • KnowledgeBase: Knowledge Base

    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.

    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2019 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB

  • WOODWEB - the leading resource for professional woodworkers

      Home » Knowledge Base » Knowledge Base Article