Replies

1. 
   UncleDunc | Dec 26, 2003 12:00am | #1

   I vote for the glue. If 100 pounds will flatten it out, then you can reduce the tensile load on the glue to less than one PSI by installing five battens each 3/4" wide. Use Roo Glue, designed for melamine. I would probably use screws as well, just because I'm neurotic, but if you use enough battens and they're deep enough to provide the required stiffness, the glue should work fine.

   If you do use screws, the fiddly bit is to drill the clearance holes in your battens so the screws only stick out 1/2 to 5/8". Predrill all the holes in the battens and the table so you can start all the screws at the same time and then tighten them down in a pattern, like torqueing head bolts, so that no one screw is ever loaded enough to pull out. Be sure to use a depth stop when drilling the melamine, even if it's just a piece of masking tape wrapped around the drill.

2. 
   KMcColly | Dec 26, 2003 05:14am | #2

   I'm with Uncle Dunc.  Use a 3/4" straight router bit and strip just the melamine off the back down the center.   If the edges are covered with laminate rip that off.  Then I would use plain old PVA (Titebond or similar) to glue 2 1/2 x 3/4" oak down the center, and glue 1 x 4" oak around the perimeter.  Use clamps to hold it until it is set and screw it to the table top from the oak side about every 6-8".  Should solve your problem.

   Ken

1. 
   Jeff | Dec 26, 2003 03:47pm | #3

   Ken & Uncle Dunc

   Yeah, I've been leaning toward the glue & screw method from below.

   Was worried about the holding power of the screws in the MDF substrate.

   Also, was worried about the Melamine holding power.

   Can't seem to find the Roo glue in any of my catalogs.

   Probably the router method is best.

   Thank you

   Jeff

1. 
   jako17 | Dec 26, 2003 05:03pm | #4

   Titebond make melamine glue.Why not drill through from the top, countersink the screws deep and fill the holes with bondo.I can't see why it should bother you

2. 
   UncleDunc | Dec 26, 2003 07:07pm | #6

   I Googled for "roo glue" and found several online sources. Here's a list of distributors. Doesn't look like it's wildly popular in your part of the country.

   http://www.rooglue.com/roostore.html

1. 
   Jeff | Dec 27, 2003 03:28pm | #7

   Hi all

   Yes, I realize that I may need to adjust a bit for straightness.

   Yes, I can screw thru the top, but would like to avoid that if possible (call me a perfectionist or nut, whatever).

   Anyone know how strong the Melamine surface is attached?

   Thanks for the suggestions everyone.

   Jeff

1. 
   USANigel | Dec 27, 2003 05:12pm | #8

   Just the job for pocket screws. Lowes has a kreg kit for $20+ screws and this you can use to install the screws from underneath. I would add 4-5 battens and make them out of 1x6. Install with the flattening weight in place.

2. 
   Jeff | Dec 28, 2003 03:56am | #9

   Hi all again

   Was pointed out to me and I think that this is ba particle board base not MDF.

   I never gave it a thought.

   I guess this changes things.

   Any thoughts?

   Jeff

3. 
   UncleDunc | Dec 28, 2003 04:34am | #10

   I still think glued on battens will work if the battens are stiff enough and you use enough of them. Spread the load over a large enough area and there will not be enough pull in any one place to separate the battens from the outer surface of the melamine nor to separate the inner surface of the melamine from the particle board core. The only trick will be keeping it all flat while the glue cures.

3. 
   Manchild | Dec 26, 2003 06:02pm | #5

   After you're done gluing and screwing there's no way of being sure it is going to be flat.

   You might want to approach it in a two step way.

   1. Glue and screw to the melemine to bring it close to flat and establish a good bond.

   2. Screw on another layer without glue to dial it in. If you get it close on the first one the second should be minimal and you can adjust it for any movement or spring back.

   I would put the 100# in the middle of the table while you're doing it also.

4. 
   DavidCockey | Dec 28, 2003 05:32pm | #11

   Be careful of formica on one side and bare wood strips on the other side. You may be creating a humidity gauge which bows down when the humidity is higher than when you add the strips, and bows up with the humidity is lower. The wood strips will expand and contract with humidity changes - perhaps not much lengthwise but still enough to bow the table it the humidity changes are large enough.

   Use an oil based paint, varnish, shellac or epoxy to seal the  wood strips, or use metal angles instead. Don't use latex paint as it's relatively permeable to water vapor.

5. 
   jackiechan | Dec 30, 2003 10:15am | #12

   Jeff,

   Loading the table with 100+ lbs of weight and then attaching battens to it will be awkward and may not give you the flat top you're looking for.  The weights would have to be distributed perfectly so that the top is flat in every direction.  There is a good chance that you will create a new warp or bow using this method.

   A more precise and easier plan of action would be to remove the table, and flip it upside down on a perfectly flat surface - then clamping it down on all sides thus pulling it flat to the table.  This would allow you to attach battens without them being under any stress or tension. 

   The best battens for your table (besides thick wooden ones) is some beefy angle iron attached with sheet metal screws - lots of them!  Using numerous screws will distribute the load put upon them, thus avoiding pull-out.

   If you have any questions, please feel free to ask!

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

1. 
   Jeff | Dec 30, 2003 04:20pm | #13

   Hi Dan

   Long time no see.

   Actually, I kind of had to wait a few weeks on this.

   I put the outfeed table back in place and an trying to finish up some work I needed to get out right away.

   I cheated a little.  I put on three pieces of straight oak under the table to flatten it while I'm using it.

   Looks kind of funny with all the clamps on either side, holding the pieces in place.

   Since the table can slide sideways between the saws, I just shift it to clear the clamps for long cuts.

   I'm thinking of just cutting the pieces (5/4 by 3") to proper size and making them perminant with screws and glue.

   Short of finding a place to mail order the Roo glue, I'm thinking of just using epoxy to glue to the Melimine surface.

   I would assume the epoxy should hold to it as well as the Roo glue.

   Do you know have any experience with it?

   I use epoxy all the time for repairs, but never glue ups of any sort.

   I was also thinking the epoxy would improve the screw holding in the particle substrate.

   Jeff

1. 
   jackiechan | Jan 01, 2004 07:30am | #14

   Jeff,

   Western Tool Supply carries Roo Glue (16 oz. and 1 gallon bottles). http://www.westerntool.com/cat_detail.asp?fromSearch=&searchType=&keywords=roo+glue&productID=ROO+CLEAR%2D16

   Gluing the melamine with epoxy will work, but will be more effective if you scuff sand the surface prior to gluing.  (Just make sure to remove all of the sanding dust.) 

   I'm in favor of screwing hardwood braces to the underside of the table to straighten it out.  If you do this, give the wood a few good coats of poly', or Watco oil on all sides before mounting them - this will help to keep them more stable as the seasons change.  To avoid screw pull-out in the table surface, drill numerous pocket holes in the wood brace on both sides - the angled screw will give you more surface area purchase, and the multiple screws will help to disperse the pull forces.  Just be aware how deeply the screws are being imbedded - you don't want a raised bump under the tables surface!

   You might also consider using connector bolts (see below.  It would mean drilling through the table top, but the bolt heads can be mounted flush to the surface.View Image

   If you have any thoughts/questions, please feel free to ask!Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

1. 
   Jeff | Jan 01, 2004 04:12pm | #15

   Thanks Dan

   I guess I have been somewhat against just drilling thru the top.

   I must say, after 20 years without a hole in it, I kind of hate doing it.

   It was one of my better ideas (and projects) from years ago.

   I'm using the top now, while I finish up some work.

   This gives me the time to get the glue and hopefully in about a week I'll finish up the top and be onto other things.

   Thanks for the help.

   Jeff

1. 
   jackiechan | Jan 02, 2004 06:57am | #16

   Jeff,

   Have you considered using a truss rod(s) to bring the table top back to flat?  Cleats could be screwed to the outside bottom edges of the table, and then either threaded rod with locking nuts or a turnbuckle style truss rod could be used.  The rods could be concealed with low profile wooden box covers, that could be removed for any rod adjustments needed. 

   This would work, and you wouldn't have to drill through the table top.Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

2. 
   Jeff | Jan 02, 2004 04:55pm | #17

   Dan

   I must admit, I never gave that idea any thought.

   Let me think about it and look at the way I have things set up.

   Jeff