Replies

1. 
   Piffin | Jan 31, 2004 01:47am | #1

   Wendell,

   Hi. This can be done but often is not attempted. One reson is that it is not too hard to end up with a hundred dollars worth of labour invested into saving a hundred dollar unit.

   There are a few ways to do it and it depends a little on your skill level but assuming that cost is part of the equation, I would probably opt away from more plywood to making up some mini joists to glue up under these panels. I would shape pieces of wood such as poplar or pine with a slight crown up by planning them. This would offset the current sag down.then I would use Titebond glue of possibly Gorrilla Glue and clamps to secure the pieces to the panel whiole the glue sets up.

   Probably 1x2 @ 8-12" OC layout

   .

   Welcome to the

   Taunton University of Knowledge

   FHB Campus at Breaktime.

   where

   Excellence is its own reward!

2. 
   locobis1 | Jan 31, 2004 02:03am | #2

   Dear Wendell,

   I think it is time to bid your two units goodbye and replace them with something more substantial.  If you consider your initial investment and the number of years you have had them, you will probably find that you have gotten your money's worth from them.  If they are still in relatively good condition, donate them to charity, take a modest credit for your tax return and go find something new.  No doubt your needs have changed since you originally bought them and you could use some additional new features. 

   Jim

1. 
   JohnSprung | Jan 31, 2004 02:36am | #4

   I'd second the motion to scrap and replace these things.  But what I've done for the plywood shelves on my roll-around (4' wide) is to use angle iron from old bed frames to strengthen the exposed front edge.  Bolt it to the underside with the other flange facing up, and it creates a small lip to keep stuff from falling off when moved.  This is very sturdy, but strictly a shop item by way of appearance.

   -- J.S.

1. 
   DaveRicheson | Jan 31, 2004 03:46am | #5

   Use a modification of piffens idea, but you only need a front and rear under shelf rail on somthing that size. Use a piece of hardwood like oak,maple hickory, etc., not poplar. A 3/4 x1 1/2" rail clamped and glued to the shelf  front and back edge. Use TiteBond yellow glue. Drill pilot holes for a couple of screws from the bottom of the rail to the bottom of the top. Glue, clamp, and screw them on. Do not remove the clamps for at least 24 hours. You are good to go for another ten years. Cost about $10.00 if you alredy own the clamps (minimum of 4 each side).

   Dave

1. 
   wbatespg | Feb 02, 2004 09:39pm | #6

   Thanks for all of the suggestions!

   I think I will try the hardwood rails front and back, clamped, glued and screwed.  I did want to give the "Gorilla Glue" a try, anyway.  Will regular wood screws hold in the particleboard (pre-drilled and countersunk through the hardwood, of course) or do I need special ones?

   Thanks again,

   Wendell

1. 
   Mongo | Feb 02, 2004 10:25pm | #7

   If you;re going to do the hardwood rail deal, consider rabbeting the back/top of the rail to receive the front edge of the shelf. 3/4" shelf? Make a 3/4" by 1/4" or so rabbet in the back of the rail.

   The two edges of the rabbet will capture the shelf, provide more glueing surface, and provide more overal resistance to sag than a face rail that is simply face glued and screwed.

   I like the angle iron idea.

   I'm doing a built-in set of wall shelves for books. Heavy load with a large span. Shelves are planned to be 2" thick, with 1" square steel stock sandwiched between two skins of half-inch sheet goods. A 2" face piece, rabetted top and bottom to capture the upper and lower skins of the shelf, so it'll hide the steel as well as cover the edges of the sheetgoods.

2. 
   Dan019 | Feb 03, 2004 06:55pm | #8

   In woodworking this is called “Curb Furniture” as its final resting place is out on the curb for the trashman to take. It will never be cherished as an antique and passed along to future generations.

   That being said, do like Mongo suggested and cut the rabbet. Another way to get the rabbet is to cut ¾” x ¾” strip and glue it to the bottom of your ¾” x 1 1/2” strip effectively making a ¾” deep rabbet. The ¾” x 1 ½” strip is where your strength will be coming from. Also, you need to be gluing to wood (particle board) surface, not to a glued on laminate strip. Remove your shelf and rip it down to 26 ¼” instead of 27” (25 ½” if you do this to the back, also) and glue your rail(s) on. You can use biscuits or not. A different solution for the back is to glue and nail a plywood back on. It will also add the strength plus it will keep the box from racking out of square. The important thing is that you expose the wood (particle board) surface for gluing and not glue to the laminate. The more exposed surface the better.

   Any mechanical fasteners used are really only good for holding everything in place until the yellow glue sets, the fasteners won’t add much strength in particle board but the yellow glue is incredibly strong. If a joint breaks, it won’t break at the glueline.

   If you use gorilla glue you’ll need to mist the particle board with water first because water is what makes the glue react and expand. Also, it’s very messy, so wait for the glue to fully dry then scrap off the excess.

   Dan019

3. 
   wbatespg | Feb 05, 2004 11:58pm | #9

   Thanks for the info!  I must not have been clear in my earlier post, but the rabbet idea is not a viable option, since one unit already has a non-structural "trim strip" across the front edge, and the other has a laminate edge across the front.  What I planned to do was to use some scrape 3/4" red oak flooring, laid flat, underneath both the front and back edges, and perhaps one in the middle, parallel to them.

3. 
   AdamB | Jan 31, 2004 02:11am | #3

   for what it's worth, I've done this before.

   Flip the TV cart upside down on a table

   3/4" plywood glued to the bottom and clamp it down hard (your trying to remove the sag) after you get the sag out and its all clamped down real good, then screw the 3/4 ply into the bottom, use a lot of screws.  let it dry overnight like this and ..... done.

   you could use drywall screws (LOL) but the heads will rip off.

   Use the gold general construction screws. 1 1/4" should word just fine.