Mdthbs

Background

I am working on a butcher block style countertop / tabletop, and am wondering how best to glue the wood together. The countertop is unfinished maple hardwood floor, with the tongue / groove cut off, flipped on its side. So, the final result will be about 1 3/4" thick, mostly quarter sawn, 3/4" width strips. The final countertop will be 7' long and 20" wide, with the wood running lengthwise.

(To clarify: I am calling it a tabletop / countertop, as I am not quite sure what to call it. It will be installed on top of a half-height wall between the kitchen and hallway, and will be used as extra counter space, a serving area, and a 'breakfast bar'. For extra support it will have three steel beams on the underside, with grooves for screws to allow for a bit of expansion across grain. The ends will be finished with a breadboard end joint, although that is outside the scope of this question.)

For illustrative purposes, this is somewhat how the tabletop will look. Each strip is 3/4" wide:

I plan on the glued-up tabletop being longer than 7', and then trimming to length.

I will be using Titebond 3.

Question

My question is how to do the glue-up in such a way as to eliminate any gaps where I glue the strips end-to-end in a given row. I am obviously going to be clamping width-wise (across the 20" side), but am not sure how to clamp each row length-wise (across the 7' side). I hope to do a handful of rows at a time (maybe 5 or so?), let them dry, then add more on.

Some Possibilities

Some possible answers I have come up with:

1. Make a clamping block that includes some sort of padding (styrofoam?) underneath a solid board, so that you can clamp 5-ish rows at a time without applying pressure only to the longest one. My concern here is that I don't think styrofoam would provide enough pressure.


2. Just push the rows together end-to-end while I am doing the side-to-side clamping, and rely on the side-to-side clamps to prevent any movement. I don't think that this will work, as glue-ups are always slippery.


3. Use a strip of rubber innertube that I use for guitar body glue-ups and individually wrap it around each row. This is the most promising approach so far, IMHO - the rubber strip is very long, and should have no problems wrapping around the length of it 4 - 5 times. My concern here is that I won't have time to get it wrapped up before the glue has started to set. I suppose that starting with just a couple of rows to make sure I have time will be the answer there.

Thanks in advance for any suggestions!

Cheers

My question is how to do the glue-up in such a way as to eliminate any gaps where I glue the strips end-to-end in a given row.

You don't need to worry overmuch about the tightness (or not) of these staggered end-grain joints as far as strength goes because they're essentially irrelevant in that regard. Occasionally these aren't even glued, without it seeming to undermine the glued-up panel in any way¹.

Really the only reason to be fussy about them being nice and tight is aesthetics, and just hammering on the ends before the clamps are fully tightened up could easily do enough — that's all that many builders do and it works fine in most cases, as we can see from the closeups of their assembled tops. And anywhere a small gap does remain it's one that's easily tackled with some basic filler work (can give a nearly invisible result with care).

However if you want some system that would guarantee these joints end up tight you could add a pocket screw to them, the screws acting as individual tiny clamps at each location. Depending on your preference these screws could be left in place or removed after the glue has dried (after which they serve no purpose). Note: if you don't own a commercial pocket-screw jig there's no need to buy one just for this project, see footnote 2 for options.

If you would prefer a clamping option for this long length and the strips of innertube prove unworkable you could use a 'Spanish windlass', basically a tourniquet, made from a long length of cord or rope and a piece of wood to wind it tight.

Obviously the end of every board within the field of the panel needs to be perfectly square regardless of what you do. If necessary shoot them square in a shooting board.

Also worth having a look at this old Question, How to join short boards to make a longer panel

¹ Which makes sense, the long-grain joints everywhere in the panel are at least as strong as the wood around them so there's abundant strength throughout.

² See Substitute for Pocket Hole Jig?

Don't worry about the end-to-end butt joints.

I think you mentioned the right answer in your question. Make sure that the ends are square, put some glue on them, then as you're gluing up the sides of the long boards, make sure to push the butt joints together firmly.

The butt joints don't have any structural significance (as long as they're staggered throughout the panel) and clamping pressure on the sides should be enough to hold them from slipping apart as the glue dries.

If you're worried about the boards slipping while the glue is wet, you can try adding some salt to the glue. It is just abrasive enough to prevent slipping and as far as I know, does not have an effect on the chemistry of the glue. Also, don't over-apply glue. The less excess glue in the joints, the less sliding around you'll have.

I'd glue up the individual pieces first. Use a dowel in the end to keep it aligned and add some strength to the end grain to end grain joint. Make sure you have good, clean ends. If you are making the cross cuts with a table saw, flip every other board top to bottom. This will cancel out any slight deviation from 90°. Once all of the pieces are glued to length, then glue them together as you would solid strips.

This allows you to redo any joints that are not tight (cut them off and re-glue), eliminate a clamping axis, and allow you to make sure all of the cross joints are arranged in a visual pleasing manner.

With the final table top being almost 2" thick, there should be plenty of structure to keep it together without needing the steel beam underneath.