Sealing Ultralight MDF Shop Jigs

      Ideas for quick sealing of MDF. January 14, 2009

We use ultralight MDF for a lot of shop jigs. It’s convenient, flat, and stable. It is however a real pain to seal. We don't need a finish grade coating, just a sealant for long term stability (and so spilled coffee doesn't ruin the jig).

Does anyone have any suggestions - especially on the "end grain" cuts. We currently do a three coat water base poly with sanding and that’s way too much work. It takes much longer than building the jig.

Forum Responses
(Finishing Forum)
From contributor A:
Bull's Eye clear shellac.

From the original questioner:
Shellac was my first thought, but the shellac sucks right in and takes more coats to seal than the water.

From contributor R:
Have you tried Glue size? Wood glue slightly thinned with water.

From contributor J:
One heavy coat of lacquer vinyl sealer will seal MDF.

From contributor G:
If it doesn't have to look pretty, one coat of heavy bodied primer, aggressively sanded back and one topcoat of whatever you like.

From contributor I:
If you can machine sand the end grain cuts to 400 grit or higher, they should seal much better for you.

From contributor C:
I have sealed a lot of MDF edges and tried everything. I sand with 100 grit then flood Bullseye dewaxed shellac on with a bit of lamb’s wool until it doesn’t want any more. For me sanding finer before doing this is a waste of sandpaper and time. Sand the result with 150 and you are ready for any primer or topcoat.

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: Knowledge Base

  • KnowledgeBase: Finishing

  • KnowledgeBase: Finishing: General Wood Finishing

    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 © 1996-2017 - 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