Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Page 3 of 3 FirstFirst 123
Results 31 to 36 of 36
  1. #31
    Join Date
    Oct 2004
    Location
    nsw
    Age
    52
    Posts
    595

    Default

    Major hiccup in the plans today. Went out and pulled out all the Swamp Oak from where it was stored, sorted it into piles to determine which pieces would suit what parts of the bench design. It took ages, and was damn heavy as well -. Then final moisture measurements showed that it was all still too wet to use.

    Pete, I take your point on the possible correction required, but as a reference, I went and measured the Jarrah that I have, that was supplied kiln-dried, and it reads only 13% compared to 17-19% across all the Swamp Oak. Given there are so many variations in exact Specific Gravity (depending on which website you refer to), I wouldn't want to bet my house that it IS exactly 17-19% but one thing is clear - it contains, on average, at least 4-6% more moisture than the Jarrah.

    This leads me to the conclusion that it still has some drying to do.

    So I packed it all away again, and went and did something else. When I get time, I'll have to sort through my cube of 2in Jarrah boards to find suitable stock. By that time, hopefully my new vises will arrive from the US, and I can finalise the design.

    TN

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Age
    2010
    Posts
    Many





     
  3. #32
    Join Date
    Feb 2011
    Location
    Bathurst NSW
    Age
    82
    Posts
    530

    Default

    Annoying? Disappointing? Probably both, but perhaps better to hang off and bide your time to get the finished job you want.

  4. #33
    Join Date
    Feb 2003
    Location
    back in Alberta for a while
    Age
    68
    Posts
    12,006

    Default

    Quote Originally Posted by TimberNut View Post
    Major hiccup in the plans today. Went out and pulled out all the Swamp Oak from where it was stored, sorted it into piles to determine which pieces would suit what parts of the bench design. It took ages, and was damn heavy as well -. Then final moisture measurements showed that it was all still too wet to use.

    Pete, I take your point on the possible correction required, but as a reference, I went and measured the Jarrah that I have, that was supplied kiln-dried, and it reads only 13% compared to 17-19% across all the Swamp Oak. Given there are so many variations in exact Specific Gravity (depending on which website you refer to), I wouldn't want to bet my house that it IS exactly 17-19% but one thing is clear - it contains, on average, at least 4-6% more moisture than the Jarrah.

    This leads me to the conclusion that it still has some drying to do.
    TN

    your swamp oak is probably not too wet to use.

    If your Jarrah was kiln dried and still relatively new in your environment I suspect that your meter is measuring high
    AFAIK, kiln dried wood is arround 8-10% moisture, while air dried wood equilibrises at around 14%. If you're measuring 13% in the KD Jarrah, your Cassurina is possibly around 12-15% and so OK to use. Of course if you've had the Jarrah a long time and it's been able to absorb significant moisture, then the 13% you're measuring is the true reading.

    However, leaving that asside -- you're planning to use the Swamp Oak to build a workbench, not an intricate cabinet or chest of drawers where wood movement could be problematic.
    So what would happen if the timber dried out after you built the bench?
    well,
    the top would get a little narrower as it dried -- how much narrower would depend on how you arrange the boards in the top -- as long as you allowed for the movement this is not an issue and with the Roubo (please excuse my spelling) design, it would not matter a damn
    the frame might distort a bit, and then again it might not -- even if it did warp a little, the warping wouldn't translate into pulling a thick top out of flatness.

    Christopher Swhartz has build many benches, some out of wood so green the moisture was almost running out of the timber. As I recall, the worst shrinkage he has seen in a bench top merely served to tighten up the whole structure of the bench
    regards from Alberta, Canada

    ian

  5. #34
    Join Date
    Nov 2004
    Location
    Millmerran,QLD
    Age
    73
    Posts
    11,057

    Default

    TN

    Wood tends to assume moisture from the environment. If you kiln dry down to, say 8% and take it out west, it will probably stay around that because of the arid region. If you live in a coastal region or anywhere with high humidity the timber will re-absorb and come to perhaps 12% or maybe even more in extreme circumstances.

    I wouldn't be too pedantic about exact values as clearly correction tables vary a little. There again, so does the timber itself. I would think for a workbench around 12% is dry enough for for all practical purposes. In general the value will actually be 1% -2% higher than your moisture meter reading.

    Correction tables show that the equivalent values are not alway linear, but for your purposes you can take them as so. As far as I know all moisture meters are callibrated to suit Douglas Fir (which is Oregon in Oz). I couldn't find anything for Swamp Oak (C. Glauca ). I think it is also called She Oak, but River Oak (C. Cunninghamiana) is also called She Oak. Again don't be concerned as all the Casuarinas appear to be similar in their correction factors

    If you just restack the timber together, I am doubtful if it will dry further or at least not in a reasonable period of time and maybe not evenly. You should dry it using stickers (spacers) and stack it very, very evenly with some extra weight on the top boards.

    As your timber does not have much more drying to do, if you have the space, consider putting it outside with a clear plastic over the top like a greenhouse, but not touching the timber. A crude frame will suffice. I think a fortnight of this would bring the MC to where you want it. Keep monitoring and don't worry about UV stable plastic: It's only going to be there for a couple of weeks.

    I recently made a bench, but want a "pretty bench" and I too was looking at benchcrafted etc for vices.

    The Casuarinas are very impressive with their most distinctive medullary rays. I have made knife handles with them and have a pepper milI too, but nothing large so I will look forward to seeing a bench.


    Regards
    Paul
    Last edited by Bushmiller; 1st August 2011 at 08:57 AM. Reason: Correcting night time spelling!
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  6. #35
    Join Date
    Nov 2006
    Location
    Rockhampton
    Age
    62
    Posts
    2,236

    Default

    Good advice there from Ian and Paul, I did a little experiment with some small blocks of green wood a while back, I noted the wet wieght (just used cheap kitchen scales) on the block of wood every month and what would be 18 months or more now the wieght has stopped reducing at the same rate as it was and it looks like it is just going to fluctuate up and down by 20 or so grams (mind you there could well be that much inaccuracy in the scales) point is that the wood looks like it has stopped drying so your Sheoak is probably as dry as it is going to get given the storage conditions and the local weather.

    One block started at 4380g 7/11/9 and is hovering at about 3000g whether there is more to come out I'd have to check it against the average 12% dry density for that species and make some judgement about further forced drying...... or not! anyway food for thought....

    Pete

  7. #36
    Join Date
    Feb 2003
    Location
    back in Alberta for a while
    Age
    68
    Posts
    12,006

    Default

    A bit more to what I posted above

    it looks like the drying shrinkage for Casuarinas is in the range 5% radial and 9% tangential
    if you timber is down to 17 - 19%, most of this shrinkage will have already occured

    for a bench, shrinkage from the residual drying is not worth worrying about -- allow for it in the design then forget about it
    regards from Alberta, Canada

    ian

Page 3 of 3 FirstFirst 123

Similar Threads

  1. Bench - big, solid, cheap, no tools, no bench to build on
    By Clinton1 in forum THE WORK BENCH
    Replies: 84
    Last Post: 17th June 2010, 11:16 PM
  2. Bench Drill Press options
    By Packrat Pete in forum GENERAL & SMALL MACHINERY
    Replies: 6
    Last Post: 31st January 2008, 09:56 AM
  3. Bench vice?
    By Santalum in forum HAND TOOLS - UNPOWERED
    Replies: 3
    Last Post: 4th February 2007, 12:20 AM
  4. Vice for this bench
    By dazzler in forum HAND TOOLS - POWERED
    Replies: 16
    Last Post: 19th June 2005, 09:45 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •