Joining slabs

[Maximus]

I'm interested to hear your experiences in joining slabs: positive and negative experiences.

I'm about to do it seriously for the first time.  I've done simple glue-ups before, and seen my dad do a few, but now I'm embarking on a series of projects to remodel our home.  Counters, tables, an island or two, shelves and bookcases...  Our home, which is new to us, is a sheetrock nightmare in need of serious timber love.

We mill quite a lot of doug fir and red alder, but use it mostly for outdoor projects.  Now we're going indoors, so drying, joinery, and finishing are all in play.

We have many 2" red alder and doug fir slabs that have been air drying in our barn for about 18 months, stickered and stacked.  We're about 75% relative humidity here in the Puget Sound, so I expect our moisture content is sitting in the mid-teens.  Next step, we're bringing about 10 of those slabs indoors to further SLOWLY dry near (not too close) to our wood stove.  Thence we're going to finish the drying in a dehumidifier-based kiln in our garage.  Shooting for 9% moisture content, then the games begin.

My dad was a builder and I'm an average hack, so I'm not asking about joinery in general, and certainly not "fine woodworking".  I very specifically am focused on making solid table/countertops from joined 2" slabs.  We appreciate a few knots, dents, and other relatively harmless imperfections.

Our plan, once dried, is to circular-saw the slabs down to 8", 10", or 12" lumber.  The width will ultimately depend on the joiner/surfacer solution we choose (and do not yet possess).  I'm thinking the Grizzly combo 12" joiner/surfacer, https://www.grizzly.com/products/grizzly-12-combo-planer-jointer-with-helical-cutterhead/g0959?gad_source=1&gclid=Cj0KCQiAwP6sBhDAARIsAPfK_wYQpcvKEkyiyD3aCOzzt1a5HDFQsWWddS595hZN327vDJfHJorCoo0aAlKQEALw_wcB.

Then, with the lumber squared, I was planning to use biscuit joinery with 40" Bessey parallel clamps (just purchased on a great Rockler sale) for the glue-up.

My dad, rest his awesome soul, never used any of these methods.  Everything he built was from left-over lumber, no biscuits, no stinking joiners or planers...all by hand.  While I admire him infinitely, I don't want to spend any extra second in my spartan garage shop that I could otherwise spend in our garden.  I want to, and will enjoy, making good stuff, but my focus remains growing things.  I recognize the tempt of "fine woodworking" and am looking away.

We have slabs up to about 26".  Does a 12" joiner/surfacer make sense?  Biscuit joinery vs. dowels/dominoes?  Drying in a garage dehumidifier kiln?  An alternative is just joining wider slabs (no joiner/surfacer mumbo-jumbo), then finishing the surface with some combo of hand-surfacers, planers, sand paper, etc.  I can only mill slabs up to about 26", so for any surface larger than that, it's joinery.  "Live edge" is not important to us.

[Crusarius]

Joining can be accomplished alot of different ways. One of the ways I have used in the past is to place the two edges tight together then run the track saw down the seam touching both pieces. It may not be a jointed joint but by cutting both at the same time you get a matched edge.

[doc henderson]

I call that Kerfing.  It does not have to be straight but might as well be.   A little wave will complement the other.  The splines and dominoes and biscuits just keep the edges aligned so they do not squirm around during clamping when the glue is more of a lubricant, than bonding agent.  the more the slide the bigger the edges that have to be sanded down.  at some width, you will exceed a 12-inch jointer/surfacer.  that is why you joint them flat, then plane them parallel, then glue up and do not let them slide.  If you can find a guy with a cnc router, they can surface a big slab, and it may be smoother than a planer or drum sander.  my buddy just bought a 5 x 10 foot one, but it was 52K.

[doc henderson]

when kerfing, you have to clamp both slabs, so they do not move.  you cannot clamp them side to side, or it will pinch the blade, and the kerf behind you will come together and you no longer have a nice tight joint to glue.  I used this on a miter joint.  the first is a maple stump table flattened with a router sled.  the second group is a miter on spalted sycamore, and the miter was tightened up with Kerfing.  I used a straight edge to guide my circular saw.



 

 

 

 

 

 

 

[Maximus]

I like the kerfing idea, will consider that option as I progress and start fixturing.  I've never had or operated a jointer, so if the edges look mismatched, I'll probably try kerfing.

That dang L-bar makes me thirsty.  Beautiful!

[Larry]

I put together live edge slabs frequently.  My preferred glue edge is made on the jointer as it is quick and accurate.  I have glued together slabs that were too big/heavy to joint so I have used the kerf method but always with a router.

Three ways to make sure the slabs align and are flat.  Biscuits, Domino's, and clamping cauls.  Domino's work a little better on live edge slabs because they are wonky to clamp.

Yesterdays glue up, two book matched slabs.  I haven't pulled the clamps yet.



About twice the number of clamps that I normally use but the live edge was making the clamps scoot around.  The joint is good enough that it will clean up with a ROS.   



I laid the slabs on two cauls in case I needed to make the slabs flat while putting them together.  I didn't have to use cauls for this one.  I just took a pic to show how to use them if needed.  They have packing tape to keep glue from sticking.

Lots of little tricks that I didn't cover.

[Ianab]

What I've done to join two slabs is joint them on my slab surfacer rig. Just clamp then in place vertically (mine is an old sawmill frame, so about 5ft vertical adjust). I figure if it will joint a 6 ft x 2 ft board, it will joint the 2" edge just as
well. So surface the 2 faces to be joined. Cut some slots for some small splines to help with alignment, then glue them together.

It's just a work philosophy of mine, that if the work piece is too heavy, then move the tool. Log to big to move? Move the sawmill to it. Board too big to plane / joint? Move a router on rails over the board. Either way you cut a straight edge.

[doc henderson]

OK Larry, what are the rest of your tricks and secrets?     you make it all look easy.   

[doc henderson]

i also want to thank @tule peak timber the wizard of crap for all his help on that bar top!

[doc henderson]

I just got a 12-inch jointer and 24-inch planer but will still have bigger stuff and you can only afford so much especially if you rarely use it.  and bigger takes more space and power.  It is good to have friends with more tools than .. well you know.  We probably all fit that category.

[Maximus]

that is why you joint them flat, then plane them parallel, then glue up and do not let them slide. 

Thanks Doc, that was my impression of an elegant, repeatable, glue-up process.  Seems I need a biscuit joiner, 12" combo jointer/planer, and a dozen or so bar/parallel/panel clamps.  I can use those tools for a hundred other things later, but for now, they'll serve as an initial handhold to start climbing the glue-up learning curve.

[Maximus]

I put together live edge slabs frequently.  My preferred glue edge is made on the jointer as it is quick and accurate.  I have glued together slabs that were too big/heavy to joint so I have used the kerf method but always with a router.

Lots of little tricks that I didn't cover.

Thank you Larry!  I appreciate your insights, especially enlightening me on the caul-"or"-biscuit choice.  I was vaguely assuming both together were better, but that seems, per your posting, overkill.

But I'm left wondering, what drives your choice of, say, joining just two large slabs vs. joining 5 smaller slabs (like 8" wide, as they're much easier to process)?  I do not intend to go for any live-edge effects, at least not for now.

And I stand with Doc:  It would be a pleasure to hear some of your other secrets!

[Maximus]

What I've done to join two slabs is joint them on my slab surfacer rig. Just clamp then in place vertically (mine is an old sawmill frame, so about 5ft vertical adjust). I figure if it will joint a 6 ft x 2 ft board, it will joint the 2" edge just as
well. So surface the 2 faces to be joined. Cut some slots for some small splines to help with alignment, then glue them together.

It's just a work philosophy of mine, that if the work piece is too heavy, then move the tool. Log to big to move? Move the sawmill to it. Board too big to plane / joint? Move a router on rails over the board. Either way you cut a straight edge.

Nice!  I value elegance, which is pretty much never the same as perfection.

So on that point, you mentioned "joining two slabs", but not sawing slabs into more bite-sized chunks (say, 10"), that can then be jointed/surfaced, then glued-up.  That's where I'm aiming, I think.  I can cut 30" slabs, I just can't imagine trying to work with such heavy monsters!  In your experience, assuming 2" thick, would you prefer working with 8, 10, or 12" members?  Or just stick to 2 larger slabs?

[doc henderson]

If you want it to look like a large intact slab, stick with bigger and fewer.  If you do not mind some joints that make it apparent that it is glued up, fine.  It should all dry first cause otherwise, all your flattening is for naught.

[Maximus]

If you want it to look like a large intact slab, stick with bigger and fewer.  If you do not mind some joints that make it apparent that it is glued up, fine.  It should all dry first cause otherwise, all your flattening is for naught.

Yup!  Thanks for that reminder.  My wife and I are bringing the slabs in today to nestle by the fire for a month or so.

Speaking of learning curves, I sealed the ends of all of our logs, but not the slabs!  Many have small splits at the ends already, and on the alders, those splits are quite large.  Any sense in sealing them now, or has the cow already escaped the barn?

[doc henderson]

not sure now as the crack stress will follow the path of least resistance (i.e. continue along the crack already started).  you could try to restrain it with a clamp until things stabilize.  If it is in the middle, you could try to kerf it with a router and glue back together.  Look at some of the slabs of @tule peak timber, and you will see why he is affectionately called the "wizard of crap".  he takes splinters and a few wood pieces and turns them into gold.  He is big on epoxy stabilization and sealing things up evenly to keep stuff from warping.  look at his gallery.

[doc henderson]

Max, we like pictures.  Help us help you!   :D :D  have you been able to master the pic upload feature?

Edit:  I just went to your gallery and now remember your great build.  send pics of the slabs if you can.

[Magicman]

If I wanted something without character defects, I would buy something artificial from the store.   

[Maximus]

If I wanted something without character defects, I would buy something artificial from the store.   

Amen, brother.  And thanks for turning us on to "Redbeard" here on Whidbey Island!  Just up the road from us!

[Maximus]

Max, we like pictures.  Help us help you!   :D :D  have you been able to master the pic upload feature?

Edit:  I just went to your gallery and now remember your great build.  send pics of the slabs if you can.

Yup, wilco.  We're starting to pull the slabs out after lunch, then we'll have to stare at them a while to decide what's next.

When I explained the functioning of a jointer/surfacer to my wife, she immediately said, "Huh.  Doesn't that mean you need double the space of the length of the board going in?"  I had not thought of that!

So keeping in mind garage kiln design, debarking for bugs, shortening to anticipated proper lengths, maybe narrowing some for use of the jointer...we've got a good deal of staring and head-scratching ahead of us today before we actually bring them into the house.  We'll be sure to upload pictures of both!  :D

[Ianab]

I can cut 30" slabs, I just can't imagine trying to work with such heavy monsters!  In your experience, assuming 2" thick, would you prefer working with 8, 10, or 12" members?  Or just stick to 2 larger slabs?

With my router jig I can joint and plane about 4ft wide x 16ft long, not that I've got any boards that big, but they will fit under the rig, so I can machine them. I'm not trying to wrestle them over a jointer or through a planer etc. The only time I would cut a wide board down would be if I need to remove cupping from it. Then sawing into 2 or 3 sections, jointing and regluing is an option.

The build I was talking about was gluing 2 x ~14" live edge slabs together to make a 28" top, about 12ft long.

[doc henderson]

So keeping in mind garage kiln design, debarking for bugs, shortening to anticipated proper lengths, maybe narrowing some for use of the jointer...we've got a good deal of staring and head-scratching ahead of us today before we actually bring them into the house.  We'll be sure to upload pictures of both!  :D



So if you mention bugs and scratching your head to an ED doc, all I can think of is head lice!   8)  :D :D :D

[Maximus]

These were the first things we cut with the mill in July 2022.  I was imagining at the time someday making some counters and tables.  Well. here. we. are. 

They've been stickered and stacked (under weight) since then in our barn.  At 80% relative humidity, they should be 16-17% moisture content.


















All slabs seemed to dry w/o any apparent warping.  The Doug firs were all fine, but the Red Alders almost all split at the ends, some significantly.





So now we're scratching our heads and wondering...  The table and island we can do later at our ease, but the remodel this summer kinda presses us to get some countertops in the assembly line this summer.  We've got 7 good fir slabs, 13"-20" wide, 10-1/2' long, plus another 15 Alder slabs, but those are almost all compromised at the ends (split).

Our indoor relative humidity is about 50%, so maybe 3 months indoors, near the wood stove, will be sufficient to get us close enough to work these slabs without kilning them?  I guess in about 2 months, we'll know.  If they're not below 10% by then, we'll assemble the kiln.

As for the countertops themselves, my wife has *ordered* me to make them 30" deep.  With approximately 30' of countertop to make (plans just now beginning to take shape), I guess I'll be using all the fir plus some of the alder.  We kinda like that, so we can do a comparison.

So there's the pics.  All thoughts, doubts, encouragement, and ridicule are welcome.

[Oth]

30" is too wide unless you are both exceptionally long armed folks. Assuming a 1" overhang your cabinets are going to be 29" deep. Typical drawer slides for a kitchen are 21" deep to fit in a 34" cabinet. If you're doing doors in your bases imagine all that space and then think about how much you're actually going to be able to access. For a peninsula or and island you can go wild with your width but there's a reason 25" is standard against a wall. Ergonomic and practical.

[21incher]

We find 30 inches is perfect  if you have limited counter area. I pulled my cabinets out 6 inches when we switched  to granite and we love the extra space. Had to build a custom backsplash for the stove and gad extra room for gas lines and plumbing. My counters are 31 1/2" and perfect for us even with short  arms.