Replies

1. 
   robkelly | Aug 29, 2004 12:23am | #1

   I use a damp, almost wet, cloth whenever I can. No problems, except sometimes it raises the grain a bit, but I'm going to sand anyhow. 2 or 3 boards is a matter of taste. The wider the board, the more likely it is to cup, depending on the grain. On a 48" top, I'd use a clamp 2" from each end, and 3 more in the middle equally spaced. Use pipe clamps, alternate top and bottom. Put wax paper under the clamp where the glue line is to avoid staining. Lay a straightedge across the top, and drive little wood wedges under the pipes to make things flat if necessary. Use wood strips to protect the edges from the clamps, not plastic or rubber, because those will move when you use the wedges.

2. 
   nikkiwood | Aug 29, 2004 12:47am | #2

   As Rob mentioned, boards this wide (12" or 18") are almost inevitably going to give you problems with cupping -- unless the stock is very old, and has had time to stabilize.

   The more conventional approach would be to use boards that are 5-6" wide.

   There is a difference of opinion on how best to deal with glue squeeze out. Some believe you should allow the glue to set up (until it's rubbery, but not hard), and scrape it off. You have to time this pretty closely, and there is sometimes a risk that the scraper can tear out the grain here and there.

   Others, like Rob, will use a wet cloth to scrub each of the glue lines. The risk here is that you won't remove every bit of the glue; if you leave even a slight residual film of glue, as you point out, it can soak into the grain and cause problems in the finishing process.

   I generally use the wet rag method, but I am always careful to rinse the glue from the rag frequently, and keep scrubbing until I am satisfied that I have removed every vestige of the glue.

   As far as clamping is concerned, I would say a 24" space between clamps is not good -- better to set your clamps somewhere between 6-10" apart.

   I assume you know that the mating surfaces of the boards must be perfect. You should not rely on the clamps to close any spaces. That's what jointers are for.

   Also, I assume you know how important it is to rig the clamp assembly so the table top is absolutely flat once the clamps are tightened up. This is usually done with cauls, or as Rob suggested, alternating the clamps (one on the bottom of the table top, the next on the top).

1. 
   BG | Aug 29, 2004 01:06am | #3

   Wendy1,

   I use a sharpened five-in-one tool or chisel to take up the squeeze out...gets into the corners nicely and the wood is nice and clean.....for me, its much easier than the wet rag.  I also use spring clamps on the board ends before I tighten down on the clamps...this also helps. 

1. 
   wendy1 | Aug 29, 2004 02:11am | #4

   Hi,

   Now that I've decided how many boards I'm going to use for the table top and the type of clamps. I have one more question.

   How much glue is necessary for a tight joint? My friend seems to think a lot is necessary.  Once you see the glue beginning to squeeze through the joints that means the clamps are tight enough I assume.

   Wendy

1. 
   BG | Aug 29, 2004 02:37am | #5

   Wendy1,

   I recently changed my process for gluing up boards.  Now I butter up one side pretty good using a squeeze bottle and pop-sicle stick...looking for a nice even bead the entire length on the top side. If I'm gluing up plywood I put glue on both sides.

   One of the issues with pipe clamps is you can go too tight....the bead should do it.  

   However, I did a box with 45 degree miters and just two bands of white tape about 1/2" wide and that made a nice tight strong joint...so maybe less is better with regard to pressure

   Edited 8/28/2004 7:39 pm ET by BG

2. 
   bobJackson | Aug 29, 2004 02:48am | #6

   Hi Wendy....  I just take my glue bottle and lay out a thin stripe of glue from the slot in the bottle tip on one of the two boards to be joined in the glue joint .I put the glue right down the middle. I then place the two boards in position on my clamps and slide one board by the other and push a bit. This places and smears glue on the other board. If I have used the correct amount of glue, I will see a little bit bead up on top. If I have too much I will see glue running out the bottom and top. Try a couple pieces of scrap, and you will quickly see how much is needed. A lot of glue means a lot of cleanup. When you slide the board you create suction. At times you can even forgo the clamp if you are careful. I dont do this on multiple or anything nice.  You can stand the boards on edge on your clanps and apply glue, then lay them down in the clamps,swipe by and tighten. I lay newsprint on my bench and a strip on my pipe clamp to prevent black stain from getting on my wood. I will scrape the glue beads after they dry say an hour. The paper comes off when you sand.. Good luck on your table    Bob

3. 
   AlanTurner | Aug 30, 2004 06:56pm | #7

   Wendy,

   The number of clamps turns on the number and widths of boards. Each clamp will put pressure on the edge like a fan pattern, at 90 degrees (45 deg. on each side of the centerline). Thus, you will need fewer clamps for wide boards, and more for narrower boards.

   In terms of glue clean up, I don’t believe in wiping, ever, on this type of glue up. Wetting the glue, even carefully and with a clean rag, runs the risk of the glue filling the grain, and the staining process will show you where this happened, too late in time to properly or easily fix. Instead, let it dry, some or more, and take after it with a scraper with a coarse hook. Just takes a second.

   Alan

   http://www.alanturnerfurnituremaker.com

1. 
   Elcoholic | Aug 31, 2004 07:03am | #8

   Consider the zone of force for clamps is 60* and space them accordingly.  I use plenty of glue and wipe or let it dry.  I never sit around watching the glue dry to that magical rubbery state.  One of the advantages of Bessey K Body or Gross PC parallel bar clamps is that they don't deflect and transfer that torque into your panel, hence the need to alternate pipe clamps above and below.  Also the straight handles limit how much torque you can put on the joint helping one from starving the joint.  Get some as soon as you can.  That said , they're expensive compared to pipe clamps so we all have to use pipe clamps too.  I have the Pony clamp pads on all of mine.  I also chopped several sticks of 1" Sch 125 PVC pipe into 2" lengths and put 2 on each pipe.  No more black pipe stains.  No matter what type of clamps I'm using I use enough pressure to pull things together and then I back them off and snug them up about a 1/4 turn.  If it counts, you always have time for a dry run!

   John O'Connell - JKO Handcrafted Woodworking

   The more things change ...

   We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized.  I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.

   Petronious Arbiter, 210 BC

   Edited 8/31/2004 12:05 am ET by ELCOHOLIC

1. 
   AlanTurner | Aug 31, 2004 04:22pm | #9

   John,

   I would not disagree that 60 degrees as the zone of force (nice turn of phrase) is a safer rule of thuumb. As to the deflection of the Besseys, I don't agree. I think there is some, although not as much as many other clamps.

   I have 3 pairs of sticks, about 1" wide, and about 2" wide, dead flat and strainght. One narrow edge of one pair I cover with packing tape to avoid glue sticking; two faces of the other 2 pair are covered also. Put a pair on the bench, lay out your stock for glue up, and slide 2 clamps under the stock and tilt upright. The height of the boards needs to be about 1/4 to 1/2" taller than the height of the bar to the bench, so that the bar does not touch the stock, even if there is a bit of deflection in the bar. The other 2 pairs are for the top and bottom of the edges, with tape on the flat side. This way you can register the edges into the same plane with only light clamp pressure at the joints. After the two bar clamps are snugged up, and the edges are alighned in the same plane, add bar clamps as needed for the pressure. These later bar clamps need not be of bessey quality.

   Once you are set up for this operation, it is very efficient. One pair of the sticks doubles as my winding sticks.Alan

   http://www.alanturnerfurnituremaker.com

   Edited 8/31/2004 1:11 pm ET by s4s

2. 
   lwj2 | Sep 05, 2004 08:34pm | #10

   Thanks, John. Wish I'd thought of using oversized PVC years ago.

   I'll be heading to Lowes tomorrow to get a couple of sticks.

   Leon Jester, Roanoke VA