The importance of balanced finishes

      or in this case, do unto one side of your project what you did to the other. 1998.

by Professor Gene Wengert

I have a question about warping. I made several humidors out of oak which I finished with a spar urethane and had great success, no warping. I was looking for a better finish so I tried tung oil which resulted in a warped top. I finished the inside with a urethane and the outside with the tung oil.

The top cupped towards the tung oil finish which was the lower humidity side. I sanded the top and evened out the humidity levels and the top straightened out. If I apply a urethane finish to the exterior or dry side now that it is straight, should it solve my warping problem?

The warping you experienced is because the top side dried out faster than the bottom side. The urethane is a very good vapor barrier, so the humidity from the humidor is not a factor; the bottom side (or inside) didn't dry out very much at all. But the outside dried more quickly because the tung oil is not a vapor barrier.

The general advice is to finish both sides the same. Your suggested repair is okay.

Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.

Click on Wood Doctor Archives to peruse past answers.

If you would like to obtain a copy of "The Wood Doctor's Rx", visit the Wood Education and Resource Center Web site for more information.

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: Finishing: General Wood Finishing

  • KnowledgeBase: Wood Engineering: Wood Properties

  • 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