Gluing thin panels

Re: Gluing thin panels

JL

Question - why glue up thin panels?

For drawer bottoms and for carcass backs - I usually use plywood.

Wood movement is wood movement - aren't thin panels going to move as much as thicker panels?

Re: Gluing thin panels

Don Stephan

No question plywood is more efficient and economical than solid wood for drawer bottoms, but one can question whether the obvious grain pattern of plywood is appropriate in an otherwise solid wood piece with obviously hand made dovetails. Plywood is neither right nor wrong, except esthetically, in my opinion. So it would depend on one's relative importance of the look.

Regarding wood movement, if the grain runs parallel to the drawer front, seasonal wood movement will occur at the back of the drawer. A slotted screw hole through the drawer bottom, and/or use of wire brads, have seemed able to accommodate seasonal movement of many drawer bottoms over the years.

Re: Gluing thin panels

Jack Guzman from Maine

Jl, I'm not speaking for Bill but in my case,I agree plywood is more efficient but for certain pieces I much prefer using solid wood. There are many manufactured products more efficient than wood but I like working with wood. I like using the processes needed before technology made them unnecessary. ---Jack

Re: Gluing thin panels

Brian Holcombe

I use solid wood. I agree with Bill on gluing technique. If you use quarter sawn material it will not move as much.

Re: Gluing thin panels

John McGaw

Yeah. I can't figure why anyone would think that gluing thin wood would be more difficult than any other unless, maybe, it was some sort of mass production problem. When I first made attempts at woodworking in Alaska I did a lot of small stuff using thin exotics with little thought as to how garish the results might be. Making a stationery box with a lid of birdseye maple, ebony, and purple heart would not be unusual for me at the time. I did glueups of 1/4" stock using my few clamps (you show more clamps in your picture than I owned at the time) and weight. In this case the weights were dumbbells (smooth ends well waxed beforehand) placed strategically across the joints. I never had any uneven results.

Re: A Luthier's Trick

Hank Knight

I learned a trick from a luthier friend for gluing thin panels. 3M makes a stretchy painters tape for the automotive industry. It's light green in color and it's used for pin striping and other applications where the tape must conform to curved surfaces. When gluing up panels from thin stock (like gluing up guitar backs and sound boards), joint the mating edges well. Put them flat on the workbench with the mating edges together and apply 8" - 10" strips of 3M tape perpendicular to the joint about 4" apart, stretching the tape and you apply it. Then apply one strip of tape the entire length of the joint. Flip the assembly over and fold the pieces back like closing a book to expose the mating edges. Apply glue sparingly to the joint. Open the "book" and lay it flat on the bench, tape side down. Apply tape to the new side in the same manner as you did to the other side, stretching the perpendicular pieces as you apply them. Place a weight on the panel to keep it flat. When the glue cures, remove there tape and scrape off any squeeze out. The stretched tape provides enough "clamping" pressure to keep the joint together. It works like a charm and doesn't deform the panel like clamps are prone to do.

Re: Gluing thin panels

Barry Irby

My friend, back when he was alive, made reproduction furniture. He called the people that made the pieces he was reproducing "The Old People". According to him, The Old People would have planed that joint with hand planes, rubbed it with hide glue and leaned a couple of stick against the wall and leaned the panel against them.

Re: Gluing thin panels

Sgian Dubh

Barry, your friend was right. Back in the 70s and early 80s when I used to do quite a bit of antique restoration or repair that's pretty much the same technique I used employing hot hide glue - straighten the edges warming them if necessary, slather on glue, rub the edges together, lean the panel against the wall, go for a cup of tea and a smoke (or get on with the next job) depending on how vigilant the boss was at the time, or not, ha ha. Slainte.

Re: Gluing thin panels

Joe in a Cleveland suburb

"The recent Fine Woodworking has an article describing a needlessly complicated way to glue thin panels. "

They have to fill the pages with something...

Re: Gluing thin panels

TM Stock

For really thin stuff, such as the usual 1/8" to 3/16" stock that luthiers work with for plates, even opposing clamps will not work that well for maintaining a flat panel, so a combination of the tape method and the wedged 'Cumpiano' method (from Cumpiano & Natelson's 'Guitarmaking') is used.

- Joint and dry-clamp the panel show face up into a fixture made with some 3/4" ply, a 3/4" fence screwed to one edge, and the wedge/wedge blocks seen in the photo on the other edge...a fixture 8" wider than the work and a few inches longer works well.

- Tape across the joint with 3M 1" wide stepping tape every 4-5 inches, then cover the joint along its length with some low tack masking tape to keep glue from dripping through.

- Remove the wedges, then flip the panel around face-down, use a couple small blocks to open the joint (which is now nicely hinged with tape), glue with hot hide glue in a 2 ounce poly squeeze bottle, pull the blocks to close the joint, then place a 5 lb weight on the panel face to keep things from buckling while the side wedges are inserted and lightly tensioned. Use a dead blow hammer to tap the jointed edges into alignment if needed.

- Clamp the pressure beam over the joint(s) and add wedges as shown. Set the side wedges.

- Some copier paper sliced into 2" wide strips both under and over the joint will prevent squeeze out from gluing the work to the fixture.

question

Bill Tindall, E.Tn.

The method you describe, or a variant of it, is necessary for the thin material approaching the thickness of veneer, or veneer. But the FWW article was using a similar technique and a roll of tape to glue a 1/4" panel, a thickness that is easily, and less expensively, assembled with clamps.

For 1/16" homemade veneer I just use tape on one side. How

I have a question on the 2nd to last paragraph. What is the advantage of the wedges over simply applying a clamped stick over the joint.

Re: Gluing thin panels

Don Stephan

For repeated glue-ups of the same number of pieces into the same finish sized panel, the illustrated clamping method looks very interesting. Thanks for sharing.

Instrument makers may encounter such repeat situations, and a chest with several drawers the same width may offer enough repetition to justify making such a fixture. But for the occasional drawer width, a rub joint using hot hide glue is extremely efficient.

Re: question

TM Stock

1/4" panels are usually stiff enough so that buckling is not a big issue. Many luthiers just use tape (as I do for alignment), but I've repaired hundreds of failed edge joints on instruments, and there is a strong correlation between glue line thickness and cohesive failures, so getting glue line pressure up to a reasonable level - whether with wedges or clamps - is something that I think pays off.

The individual wedges do a better job of handing uneven thicknessing on the panels - if the stock is already uniformly thicknessed, a clamping bar would work provided it has the usual gentle rocker to apply even pressure.

thanks , makes sense

Bill Tindall, E.Tn.

The wood glues we typically use are not gap fillers. All that water in hide glue winds up as bubbles when a thick glue line dries, and bubbles don't hold much.

Re: Gluing thin panels

TM Stock

A single 4' x 2' piece of ply would handle just about anything up to 46" x 18" - just move the wedge blocks where needed (I use 1-1/4" deck screws). I think thicker stuff - the 1/4" and up stuff - is better done with clamps.