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Thread: Polywood for outdoor furniture

  1. #1
    Join Date
    May 2009
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    Polywood for outdoor furniture

    I am contemplating building a couple of Adirondack chairs out of polywood type material. Advantage would be not having to finish them or worry about the elements. Does anybody have experience with this material in terms of shrinkage and expansion? And is it too flexible? And if adhesive is needed what works best?

  2. #2
    Bernie

    I have built quite a few chairs, chaise lounges and tables from poly lumber. It is easy to work with but there are several things I have learned via a bit of trial and error. First, unless you buy the structural rated material it is very flexible so you will need to plan accordingly. As far as I know, including talking to the mfg, you will not have any success with glue. I have used ca glue to hold plugs in screw holes but that’s it.
    All joints will need to be mechanically fastened with screws or bolts. I have had good luck using my domino with shop made plastic dominos.
    One surprise I learned the hard way is if you rip a board long ways, both parts will curve a bit. If you can design with existing profiles life is a bit more predictable.
    Poly lumber will shrink and grow lengthwise with temperature but not very much across. Just the opposite of wood.
    I hope this helps. Let me know if I can help.

  3. #3
    We have several HDPE adirondack chairs. Far superior to wood for yard use, IMO (unless in the sun). No adhesives on these, just stainless fasteners. I think we paid around $200 each for them. I could have made them but for that price, not worth my time. Might be something to consider.

    Erik
    Ex-SCM and Felder rep

  4. #4
    Join Date
    Apr 2018
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    Cambridge Vermont
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    Another option would be to use one of the exotic hardwoods used for decking. They last forever and don't splinter like pressure treated. If you don't mind them turning gray they will last decades as long as you use stainless fasteners.

  5. #5
    They’ll also be a pain to move. I made a medium sized bench out of Ipe and it is fun to ask someone to move it. They approach it expecting it to be easy to lift and react like it is bolted to the deck; it weighs a LOT more than a bench made out of cedar or redwood.

  6. #6
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    Ipe and Cumaru are both very heavy. Most of the other hardwood decking choices are about the same weight as oak. Ipe is expensive compared to most of the other choices simply because it's the one that people have heard of. I made my deck out of tigerwood (which is about half the cost) and other than turning gray you wouldn't know that it's close to 15 years old now.

  7. #7
    Join Date
    May 2009
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    Quote Originally Posted by Brian Bumpers View Post
    Bernie

    I have built quite a few chairs, chaise lounges and tables from poly lumber. It is easy to work with but there are several things I have learned via a bit of trial and error. First, unless you buy the structural rated material it is very flexible so you will need to plan accordingly. As far as I know, including talking to the mfg, you will not have any success with glue. I have used ca glue to hold plugs in screw holes but that’s it.
    All joints will need to be mechanically fastened with screws or bolts. I have had good luck using my domino with shop made plastic dominos.
    One surprise I learned the hard way is if you rip a board long ways, both parts will curve a bit. If you can design with existing profiles life is a bit more predictable.
    Poly lumber will shrink and grow lengthwise with temperature but not very much across. Just the opposite of wood.
    I hope this helps. Let me know if I can help.
    Thank you for the information. Fifteen years ago I build a half dozen flower boxes on the new deck with bench slats in between. Product was called Rhino but like the early Trex it has its problems as a deck material. Mainly that it swelled and filled the quarter inch gap between the boards. And definitely shrunk and expanded along its length. Any span longer than three feet had to have support to keep from sagging. I did use some construction adhesive with the boxes but it did not hold together well over the years. Surely there must be some adhesive that bonds well to this material.?
    You say that you used plastic Dominos but with what adhesive? And what is structural rated material? Thanks

  8. #8
    Join Date
    Nov 2003
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    Central North Carolina
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    There is a full thickness product available now called "Star Board" that was created for the marine industry. It is available in many colors and are not affected by the outdoors or Sun. The color goes completely through the material. It machines almost like hardwoods, but when using a router I find that the bit tends to be a little more "grabby", kind of like when cutting Ash, so climb cuts are especially dangerous if you are not expecting this to happen.

    I volunteer in the shop of a local Science Museum, and they have begun using Star Board instead of Baltic Birch plywood covered with laminate, for most of their exhibit construction. It's quite Grafitti Proof and deep scratches don't show as much because the color remains the same all the way through it. There is now a special glue that works well with it, but initially we were mostly using impact screws or pocket holes and screws to assemble it. We now use less screws and the glue, with the screws just holding it together "until the glue dries". Star Board is more rigid than HDPE and much like Baltic Birch of the same thickness. (It makes great cutting boards too).

    A Google Search for "Star Board" will bring up information about it, as well as sources for it. The suppliers will mostly be located in areas near the Marine industries.

    Charley

  9. #9
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    Jan 2008
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    1.5 hrs north of San Francisco, CA
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    MDO plywood is pretty weather resistant. It's designed I believe, for signs. I used it unfinished for a temporary gate for about tree years, and surface and edges held up amazingly well (remained flat and no delamination) through all seasons (no winter snow, but plenty of summer sun).

    It's ugly raw, but is great for paint. Nice smooth surface.

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