+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    Join Date
    Apr 2012
    Location
    Northern Virginia
    Posts
    142

    Default Strength of Different Woods for Book Shelves

    I am researching building a floor-to-ceiling book unit (about 140 linear feet) for my book collection. This was excerpted for a TOH short arricle and I surprised that ordinary pine hold more weight than plywood (3 feet) for the same amount of sagging.
    __________________________________
    1. Solid wood: Hardwoods make the strongest and stiffest shelves, but they are more costly than plywood or MDF. Softwoods are weaker and cost less than hardwood boards of the same size.

    2. Hardwood plywood: These strong 4x8-foot sheets have minimal defects. Available in a wide range of face veneers suitable for paint or clear finishes.

    3. MDF (medium-density fiberboard): The most affordable alternative. Not as stiff as solid wood or plywood, but won't cup, warp, or splinter. Takes paint beautifully. Use special MDF fasteners for best anchoring strength.

    Strength Comparison: The amount of weight a 3-foot 1x12 shelf can hold without sagging more than inch:
    Oak: 313 lb.
    Pine: 200 lb.
    Plywood: 129 lb.
    MDF: 87 lb.
    ____________________________________________

    I have many books that are 13 x 10 (about 800 pages) or 11 x8 type (250-400 pages) so sagging is an issue.

    Solid woods like oak, cherry, etc. are out-of-the question - - I was thinking about plywood veneer, but , as a first project, taking on buying wood from a specialty place, splinter-free cutting, finishing, etc, appear very intimating.

    Thus, I was looking at plain plywood (trimmed w/ solid edges) etc., and paint finish (standard white). The paint could cover up knots, etc., and I wouldn't spend a lifetime of weekends on it.

    But then, the article listed pine shelves as holding more weight than plywood ??

  2. #2
    Join Date
    Aug 2007
    Posts
    6,616

    Default Re: Strength of Different Woods for Book Shelves

    What you use will depend on how you use it and the length of span. Two things that should never be used, IMHO, are MDF and particle board, including PB core veneered panels. MDF and PB do not have enough resistance to bending unless it spans no more than 24" to 32", even then I wouldn't use it.

    Plywood is acceptable and commonly used for shelving because it is less expensive than solid wood, and you can more easily make any depth shelf you want. The more plys, the stronger the plywood.

    Pine is perfectly suitable for shelving, as are other soft wood types, what you choose here will depend on the look and finish you're going for. The worst thing about pine is the amount of sap in it that hampers staining and finishing.

    The easiest way to increase the strength of any shelf is to put a nosing on it, which is typically 3/4" x 1-1/2" x shelf length. Make sure you account for the width of the nosing in your total shelf width or you'll have shelves that are deeper than your cabinet.

    When building shelving cabinets, the best rule of thumb is to not exceed 36" in width on the shelves, no matter what type of material you're using, this is about the maximum width you can go without the risk of sagging shelves. If you're going to load the shelves completely with books, use shorter lengths, if you're going to have lots of decorations and open shelf space, then you can go slightly longer.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  3. #3
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,622

    Default Re: Strength of Different Woods for Book Shelves

    For paint able shelves I would recommend poplar over pine.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  4. #4
    Join Date
    Aug 2007
    Location
    Portland, Oregon, formerly of Chicago
    Posts
    1,611

    Default Re: Strength of Different Woods for Book Shelves

    Most urban areas have lumberyards which cater to woodworkers. They will stock lumber and plywoods which the typical "big box"store or even lumberyard will carry. They are often set up to do some preliminary millwork. Unless you have a nice woodworking shop at home, it is kind of difficult to rip down plywood to suitable shelving sizes. Such lumber yards are also a good source of free advice, which is not always the case at the big box store.

  5. #5
    Join Date
    Apr 2012
    Location
    Northern Virginia
    Posts
    142

    Default Re: Strength of Different Woods for Book Shelves

    Quote Originally Posted by ordjen View Post
    Most urban areas have lumberyards which cater to woodworkers. They will stock lumber and plywoods which the typical "big box"store or even lumberyard will carry. They are often set up to do some preliminary millwork. Unless you have a nice woodworking shop at home, it is kind of difficult to rip down plywood to suitable shelving sizes. Such lumber yards are also a good source of free advice, which is not always the case at the big box store.
    (1) My idea was to use the thickest Plywood (3/4", actual 5/8" ??) for the panel frame.
    My first idea was also to use same Plywood (3/4", actual 5/8") for shelves, and nosing/trim to cover the ply layers, all around. BUT the article seems to say Pine or another solid soft wood (like Poplar) has less sagging than Plywood. Any opinion ??

    (2) For finishing, I'm thinking Paint, and if done well, would look good as a "library." (I will ask separately, how to do a Paint finish on Plywood.)

    (3) Because I will load completely with many full height books (9-13" high), I would keep the shelf span to no more than 30" wide (my wife thinks it will still sag noticeably, because she's accustomed to mass produced MDF book cases).

    (4) I just have a mid-line table saw, and would need a lumberyard to have 4x8 Plywood cut in half for me - - I'm thinking I can then handle (by myself with a roller stand) 2x8 sheets and get to 1x8 with a fine cut blade ?? From 1x8 boards, I would get the panel frames and shelves.

    My skill level is novice, but a reasonable furniture refinisher quoted $3,000 for veneer plywood (details unknown), and while it's fair, it's beyond my tolerance. I've already spent $2,900 on Rak (modern) aluminum shelfing for the same books in a previous house which I can't reuse in my curent traditional house.

  6. #6
    Join Date
    Aug 2007
    Posts
    6,616

    Default Re: Strength of Different Woods for Book Shelves

    Quote Originally Posted by t_manero View Post
    (1) My idea was to use the thickest Plywood (3/4", actual 5/8" ??) for the panel frame.
    My first idea was also to use same Plywood (3/4", actual 5/8") for shelves, and nosing/trim to cover the ply layers, all around. BUT the article seems to say Pine or another solid soft wood (like Poplar) has less sagging than Plywood. Any opinion ??

    In an effort to make more money (under the guise of better material utilization), the manufacturers now measure plywood in 1/32 increments. What used to be 3/4 is now 23/32, the 5/8 equivalent is 19/32. You will definitely want to use the thicker material for the shelving for maximum strength. Also, the more plies, the stronger, more resistant to sag the material will be. 3/4" is typically 5 plies to 7 plies, though you can get more in some materials.

    For your cabinet walls, it will depend on how you construct them what you'll need to use. If you are building multiple individual cabinets and screwing them together, then thinner material will suffice. If you share one panel as the wall for two cabinets, then use the thicker material.


    (2) For finishing, I'm thinking Paint, and if done well, would look good as a "library." (I will ask separately, how to do a Paint finish on Plywood.)

    Painted cabinetry can work, but, choose your paint wisely, as today's latex and alkyds are not as hard as they once were and may not stand up to the use and abuse of book weight and scuffing.

    As for painting plywood, you'll paint it like you would just about any other surface, you'll sand it to your desired smoothness, prime it, then apply your top coats. You'll get your best finish from a spray gun.

    (3) Because I will load completely with many full height books (9-13" high), I would keep the shelf span to no more than 30" wide (my wife thinks it will still sag noticeably, because she's accustomed to mass produced MDF book cases).

    Definitely stay away from MDF and particle board materials for the shelves, that just isn't going to hold up. You will be able to get away with plywood, as long as you stick with 3/4" and put a good nosing on the front of it. You can increase the shelf strength by making box shelves, basically two pieces of plywood with spacers in between to make a thicker shelf. With this style you more than double your strength because you're dividing the load between two layers of plywood. With a shelf of this nature, you could actually get away with using a thinner plywood.

    I also agree with you decision to keep the shelf lengths down to 30". One thing to consider with shelf lengths, though, is the total length of the unit you will be building. For a 10' long wall, you will have four equal 30" sections, but if that wall is any longer, say 11', then you have to increase the shelf length to 33" to have even sized shelves and no weirdness at one end or the other. If your overall length is a little less than 10', then of course, your shelf lengths will be a touch less to remain aesthetically pleasing.


    (4) I just have a mid-line table saw, and would need a lumberyard to have 4x8 Plywood cut in half for me - - I'm thinking I can then handle (by myself with a roller stand) 2x8 sheets and get to 1x8 with a fine cut blade ?? From 1x8 boards, I would get the panel frames and shelves.

    Ordjen is correct, woodworking suppliers will cut panels down for you, but don't count on their cuts to be accurate. Always have an extra set of hands to help you with larger, bulkier pieces. If you don't have help, then build yourself saw horses or benches/tables that are the same height as your saw to carry the piece stably, then all you have to do is guide it through the saw. When I built my shop, all my tables and equipment are at the same height specifically for this reason.

    My skill level is novice, but a reasonable furniture refinisher quoted $3,000 for veneer plywood (details unknown), and while it's fair, it's beyond my tolerance. I've already spent $2,900 on Rak (modern) aluminum shelfing for the same books in a previous house which I can't reuse in my curent traditional house.
    Bookcases and shelving are some of the easiest things in the world to build. As long as you keep your construction techniques simple, you'll have no problem. For instance, instead of bothering with rabbet joints on the cabinets, just use butt joints. Glue all joints and either nail if the panel will be visible, or screw if it will be hidden. Always predrill and countersink screws.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  7. #7
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,622

    Default Re: Strength of Different Woods for Book Shelves

    Rather than using a table saw to cut sheet goods consider a circular saw and a saw guide. http://www.popularmechanics.com/home/reviews/4283497 Just click on "skip ad"

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  8. #8
    Join Date
    Aug 2007
    Location
    Portland, Oregon, formerly of Chicago
    Posts
    1,611

    Default Re: Strength of Different Woods for Book Shelves

    t_Manero,

    When painting your new cabinets/shelves, do use a good oil enamel undercoater. An enamel undercoater has more "build" and will fill in the grain of the wood well. Avoid water based primers, as water raises the grain of the wood. After dry, it can be sanded very smooth, keavubg a fub=ne dust which must be removed.

    Avoid latex/acrylic paints. These do not dry to a hard, non-gummy finish. Remember, you are putting heavy books and/or knick-knacks on them. They will tend to stick to an acrylic paint.

    Spruce is correct, a sprayed finish will be superior to a brushed finish, but a very good finish can be obtained with a quality oil paint. Unfortunately, the "big box" stores have very little oil paint. You would be better advised to go to regular paint store for such paints.

    If you have spray equipment, there is also the possibility of spraying lacquers, either water based or solvent based. Lacquers have their own dedicated primers. Oil can also be sprayed.

    You don't want acrylic paints because of their inherent poor qualities, but they also don't spray well with conventional or HVLP sprayers.

    Wood or plywood of birch or popular will take paint much better than a pine or fir. Their grian is much tighter and more even. Pine or fir will show the grain pattern, even under several coats of paint.
    Also, the harder the wood surface, the less prone it is to denting and chipping.

  9. #9
    Join Date
    Apr 2012
    Location
    Northern Virginia
    Posts
    142

    Default Re: Strength of Different Woods for Book Shelves

    All, thank you for all the suggestions; they were something I didn't consider . . . A follow-on question:

    I assume Painting is easier & faster than a Stain finish -- is this strue ??
    I am required to unpack 75 boxes of books, and need to do it within my remaining lifetime and need to select the faster method.

    The 1/32" spec thickness of Plywood now make sense to me as I didn't see it with other types of wood -- it's like 1.5 quart of ice cream as the new 1/2 gallon container.

    Using cutting guides instead of a table saw looks to be an excellent alternative to make 8-feet long cuts.

    Thanks.

  10. #10
    Join Date
    Aug 2007
    Posts
    612

    Default Re: Strength of Different Woods for Book Shelves

    Regarding the sheet goods long cuts, if you already have a table saw and like me, don't have the circ saw cutting guide, just get close with your rough hand saw cut and then get the final cut with the table saw. It is a lot easier to handle the "close to shelf width" planks on the TS than the full plywood sheet! Although... I am the first to say any new project deserves a new tooyl, so the cutting guide would qualify!!

    I recently made a set of built in shelves for books and a free standing bookshelf and in both instances used 3/4" hardwood ply with a hardwood nose. The built in had wider shelves than I usually like so I put a piece of the nosing as a ledger under the back of the shelf for extra support. I used stain and shellac for the finish rather than paint. The ply and hardwood nose took the stain pretty evenly. I like shellac because of the finish look compared with poly & the quick dry time.

Posting Permissions

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