Drying Logs in a Vacuum Kiln

      Heavy timbers dry rapidly in a vacuum kiln. October 26, 2013

Are there any schedules available for drying 24/4 white pine? This material will be used in log home construction. I was told the desired final MC is 18%. Also any indications on how long from green this will take to dry?

Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Any chance you could drill a large hole lengthwise through the center to make drying easier and reduce weight? Are a few checks okay? Or maybe you can kerf it? Do you want 18% MC in the core, so that the shell will be somewhat drier? Or is 18% an average?

As 12/4 would take around 3 months, I would guess that 24/4 is no less than 7 months for a quality piece and possibly longer. For that reason, we would expect to air dry first for nine months or so before going into the kiln.

From contributor D

Click to View Member Profile

I'm sorry to be always making crazy sounding claims, but a vac kiln can dry 6" pine squares to 18% in about 6 days. Heart center means a crack at least on the side nearest the pith.

From Professor Gene Wengert, forum technical advisor:
Indeed, I should have mentioned vacuum drying as a reasonable option.

From the original questioner:
Thanks for the responses. The customer told us that someone else who was drying this previously was doing it in 21 days. Quite frankly I have a hard time believing that, but that's what they claim. I must believe they are tolerant to checking. With this material being used in log home structure I think they would not want large open splits.

The core target is 18%. I don't think drilling out the core would be an option but it might be worth asking. We need to go visit these people and see the condition of the material they already have. Also do some sampling while we are there to confirm MC.

From contributor L:
We have a great many kilns installed drying eastern white pine for log homes. The most common sizes are 6x8 and 8x8.

They should be dried in 1-1/2" stickers. The usual standard is 15% at a depth of 1-1/2". Several mills dry in two weeks and sell all they can produce. Others take 4 weeks and the longest I know took six weeks. The pine is going to check any and people don't seem to mind. One mill pressure treated logs with PEG and didn't dry. The logs didn't shrink. I think they are closed now.

From contributor D

Click to View Member Profile

15% at a depth of 1.5" is interesting. When I was experimenting with softwood beams, I was getting 15% at the core. I'm currently working on a kiln for installation in Russia. They want to dry 40' squares for log homes. I was recently reviewing some old process logs and saw one where I got the beams dry in 2.8 days. That's less than 3 days to get the core under 20%.

From contributor E:
Wow… How big is the log home if each log is 40' square?

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: Primary Processing

  • KnowledgeBase: Primary Processing: Kiln Operation

    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