Replies

1. 
   dtraversi | Jan 03, 2007 02:53am | #1

   Hi GrampaH-
   The problem as I see it is ... you need long, and thin, and perfect- no room for any error on a table-

   I may be mis-reading the situation but this might work.

   1/8" veneers are not to thin to edge join prior to the veneer process.
   3-4 at a time-clamps every 6-10 inches and some mass to keep the whole thing flat
   (I use bricks wrapped in duct tape)

   one you have 3-4 sub pieces- edge glue the entire panel
   scrape the glue and THEN veneer to the MDF substate.

   You might also try a slower setting glue Plastic resin gives 20+ minutes of work time and you can avoid the hurry hurry hurry associated with yellow glue veneer jobs.

   Disclaimer! I have never tried the exact thing I've suggested- I have done plenty of veneer work though and think it might serve your purpose- I look forward to see what others suggest.

   Cheers,
   daveT

2. 
   cadiddlehopper | Jan 03, 2007 03:25am | #2

   GrandpaH,

   I did something similar using thick veneer.

   I veneered MDF strips on both sides at the same time, clamped them side-by-side to several hardwood planks as if they were to be glued together edge-to-edge except spaced 3/8-inch apart, then ran a router down a straight edge between them planing facing edges simultaneously with a straight 1/2-inch bit. This router cut must be done in one pass only. Any irregularity on one face will be mirrored on the other for a perfect joint. To align the glue joint I cut a series of biscuit slots opposite each other. The biscuits were custom-made hardwood which fit the slots closely, not standard biscuits. My slots were narrower also. The veneer faces aligned well enough that sanding was adequate to level the surfaces. The entire joint was glued, not the biscuits.

   It is imperative that each strip be veneered on both faces and at the same time while held dead flat. I used an inexpensive veneer on the back. My fingers are crossed on that, but all seems copacetic after more than a year. Good luck and patience!

   Cadiddlehopper

1. 
   grandpah | Jan 05, 2007 04:03am | #5

   Cadiddlehopper,  Thank you very much for the suggestion.  I have a router and making one pass between two adjoining pieces is a very practical way to skin the cat.  I will try it.  Thanks GrandpaH

3. 
   JeffHeath | Jan 03, 2007 03:28am | #3

   Do you own a router.  If so, you can use it, with a flush trimming bit, to joint the veneers by sandwiching them between mdf, and flush trimming.  Ask if you need a clarification on the procedure.  It sounds as though your main problem is working with stock which is not flat and square.  If you can't get it that way with your jointer, than this procedure should help.

   Jeff

4. 
   Rich14 | Jan 03, 2007 03:55am | #4

   Grandpa,

   You MUST veneer the table both front and back to produce a "balanced" structure. There is no getting around this requirement. Otherwise the table top will warp and twist as the glue dries and with relative humidity changes, as a natural consequence of the structure you're creating.

   I am trying to picture how you cut the veneer strips from the original stock to get 3" wide strips. Was the original stock straight on the two surfaces that now represent the edges of the veneer strips? Are the edges straight before you try to glue up?

   If the edges are not straight, they MUST be straightened. The best way would be to use a "carrier board" which has a perfect straight edge, riding against the saw's rip fence, to which they are clamped, so that a strip's non-straight edge is carried through the blade. Once one edge is thus "jointed", you probably could just run the veneer strip through the saw, using its new straight edge against the rip fence. But it might be better to clamp the strips to the carrier board to joint BOTH edges.

   I assume the blade you used left a "gluing surface" on the sheets of veneer? Saw blades don't really prepare wood for gluing like planing or a joiner does. If the strips don't have at least one smooth gluing surface, the veneer will NOT stay down. If so, you will need to run them through a planer, just for one surface. Many planers cannot thickness plane 1/8" or less. I have put a board of 3/4" particle board or MDF on the bed of a planer to allow it to plane very thin material.

   I do not think you can accomplish this job by laying the strips down in a bed of wet glue. The need to control the forces and movement are enormous. I would think one would need industrial hydraulic presses to do this.

   Gluing standard "thin" veneer (which is what the furniture industry developed to get rid of the nightmare you are engineering) can be done by coating the veneer and substrate with white or yellow PVA glue and letting it completely dry. Then the veneer is ironed down with an ordinary clothes iron as dry PVA glue is reactivated by heat. I don't know if you can get enough heat through 1/8" wood. White PVA activates at a much lower temp than yellow, so that would be the one to use in this situation.

   Here's another method. It uses hot hide glue, the most wonderful glue in existence.

   Lay down a bed of glue, about 4" wide, along one long edge of the MDF. Make sure the glue completely goes off the long edge and the 2 short edges.

   Lay a veneer strip into the warm glue, keeping one long edge slightly overlapping the MDF, and the 2 ends of the strip overhanging the short edges. Working quickly, slide the strip lengthwise back and forth slightly and roll the strip down with a wooden veneer roller. Sliding wood pieces against each other with hot hide glue is all the "clamping pressure" you need. But usually such pieces are stiff lumber and the force is easily transmitted all along the gluing surface. That won't happen with 1/8" strips, hence the addition of the roller for downward pressure.

   The first piece will grab and in not much more than a few minutes, will be immobile. Wait until it is really firm.

   Lay down anoth srip of glue, wider than the next strip. The small amount of cooled glue already on the MDF will re-activate with the new hot application. Bed the next strip, butting the edge against the first strip, forcing hot glue to ooze up and out between the mating edges as you press the second strip firmly against the first. (The veneer's edges MUST be square to the surface). It will be messy. Don't worry about the excess glue. You will need to drive veneer pins into the 2nd piece to hold it close against the first.

   Working this way, you will be able to veener to the opposite long side. Then veneer the back. Then trim the overhang from the four edges.

   A LOT easier said than done, but the technique will work. But if you haven't used hot hide glue, you'll need to practice on a smaller scale first. It's messy, but works beautifully, and was the only way French craftsman had to accomplish essentially what you're trying.

   It can be done, but you HAVE to prepare your veneer, and when you're done, you'll fully appreciate why veneer comes in very thin sheets! The type of veneering you're trying is best left for small objects like jewelry boxes!

   Let us know what happens!

   Rich

1. 
   grandpah | Jan 05, 2007 04:13am | #6

   Rich,  Thank you very much for the many suggestions in your post.  I've learned several things that I've already used.  This is in addition to the mistakes I made in the workshop -- what fun.  If I can't salvage the table top that I've glued up, atleast there are stories to tell. 

   The Brazilian cherry was cut on my Rockwell table saw from salvaged flooring.  Yes, I got cupping within 24 hours -- so I veneered the backside and clamped the entire slab for a couple days.  I removed the clamps tonight to find a reasonable (salvageable) tabletop.  Thanks again.  GrandpaH 

2. 
   grandpah | Jan 05, 2007 04:22am | #7

   Rich -- I'll learn more about hot glue. Thanks GrandpaH