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Thread: Baltic birch for sacrificial block

  1. #1
    Join Date
    Jul 2009
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    West Boylston Massachusetts
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    Baltic birch for sacrificial block

    I have some Baltic Birch plywood scraps. I often used plywood for waste blocks with a faceplate.
    Is the glue in Baltic Birch as strong as exterior plywood same or less strong?
    Thanks in advance, Kevin

  2. #2
    Conventional wisdom is that plywood is risky for waste blocks. I have used Baltic Birch for waste blocks with great success, not so much because of the glue, but because the plys are free of voids, and are all hardwood throughout. Exterior plywood has frequent voids in the inner layers, and is normally fir or some such soft wood. I myself would never use exterior ply for a waste block

  3. #3
    You may be able to get away with it, particularly on smaller pieces, but solid wood is FAR stronger.

    robo hippy

  4. Please save yourself from a very preventable injury.....the centrifugal forces on a larger blank can easily shear the laminations on birch ply. Use hardwood blocks in face grain orientation with strong glue......preferably something like Tite-Bond. CA glue can be brittle and your piece becomes a missle.
    Remember, in a moments time, everything can change!

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  5. #5
    Join Date
    Feb 2003
    Location
    Green Valley, Az.
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    1,202
    Why use any kind of plywood for a glue block when plain wood is safer?

    Med. CA glue is my choice for a glue. I use glue blocks a lot and have used CA on many hundreds of pieces with NO failures. If the wood is wet Tite Bond won't work. CA does.
    Last edited by Wally Dickerman; 08-19-2015 at 4:47 PM.

  6. #6
    Join Date
    Apr 2015
    Location
    "Brownsville", North Queensland, Australia.
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    You haven't said how big the projects are or how far they may be extended past the waste block / turning blank interface? Or how large a cross sectional area will exist between the waste block / turning blank?

    I agree with most of the comments about the safety of using ply as waste blocks. If there are more suitable materials available then use them. There is no one correct answer - ply is suitable as a waste block IF you stay within the materials properties & limits, however it has hazards you must be aware of.

    Using ply with a face plate & screws is a better choice than turning a tenon and using a chuck. The hazard with the most significant risk with any ply is delammination but that is no different to using a solid wood with straight grain that shears / splits easily.

    I have used marine ply as waste blocks on a screw chuck for small projects and there are plenty of turners who have turned items made completely from birch ply, so it has been done and safely. Google "ply wood bonding types" which should direct you to information on the types of glues and their strength. http://fennerschool-associated.anu.e...d/glueing.html

  7. #7
    Join Date
    Feb 2003
    Location
    Chappell Hill, Texas
    Posts
    4,741
    There are different grades of Baltic Birch plywood. I have had LOTS of BB delaminate over the years. I would never trust it in sheer.

  8. #8
    Join Date
    Feb 2008
    Location
    lufkin tx
    Posts
    2,051
    My experience is just like Wally's up to 125#green endgrain vase blocks. Us old greybeards have done everything stupid several times--listen to him.

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