Cracking veneer

      Why are cracks appearing in a veneered mantelpiece a year after construction? March 21, 2002

Q.
A mantelpiece I built almost a year ago is now showing cracks along the grain. The job consists of five large boxes of MDF with a birdseye maple veneer. This is mounted to a wood frame over a brick face on an exterior wall. I used a water-based contact adhesive and feel comfortable with the amount of coverage I got and the bond. I may have applied too much lacquer too quickly when finishing. It seems the only solution is to scrap the project and re-veneer. I haven't checked the moisture content yet. Any ideas?

Forum Responses
Are these boxes 3-sided or 4-sided? Are the splits on all sides or all in one area? Did you veneer all sides, including the side that was attached to the wall? Is the problem area splitting or checking? Are the splits coming through the finish? Do you see any blisters? What type of pressure was used?

Locke Wilde, forum technical advisor



From the original questioner:
The boxes are three-sided with either a top or bottom. They are 3-5" deep and there is no veneer facing the wall. The splits or checks are oriented with the grain and are on all surfaces. The customer did not describe any blistering or delamination and I haven't seen the problem yet, but he is knowledgeable enough to report accurately. He described the checks as hard to see except in a certain light, but he can feel them under his fingers. Before, there was a mirror finish, so these must be coming through the finish. I used a veneer scrapper to achieve the bond.


Maple is the worst species for movement and splitting. Did you seal the backside of the MDF board (did you seal the inside of the box?)? You got moisture from somewhere. In the home, after the heat was turned on and off a few times, the material began to dry out, the adhesive lost its bond and splits appeared in the face.

You might have luck with the following. With a mixture of denatured alcohol (70%) and water (30%), wipe down the face with a clean, lint-free rag. You should be able to see the splits start to close up. If this does occur, the next step is to get a better bond. Take an iron set at 190 degrees or between cotton and wool and heat the face. Apply pressure with a scrapper and wipe again with the alcohol solution to remove heat. Let stand 24 hours, sand with scotch-brite (grey) and spray a light topcoat. This will work if the splits are not real bad.

Locke Wilde, forum technical advisor



From the original questioner:
I do not recall if I sealed the backside of the MDF. I do know I sealed all raw edges. Do you think there is condensation between the brick and MDF? Is wiping down with alcohol and water supposed to remove all the finish or just some? Will this affect the stain color? Will this keep the checks from reappearing?


The purpose of adding the water and alcohol is to make the veneer face swell and close up the splits. It will not remove the finish. If the splits do swell up and go away, that will indicate that you did not have a proper glue bond. You did not apply enough pressure or you did not apply enough adhesive or both.

Locke Wilde, forum technical advisor



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: Veneer

  • KnowledgeBase: Veneer: Techniques

  • KnowledgeBase: Woodworking Miscellaneous

  • 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 © 1996-2016 - 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