Big Ash Roubo Build Thread

[Jason Dean]

I've been planning a slab top Roubo build for awhile. Initial posts will document my progress so far. I expect progress to be slow based on available time. Comments, criticisms, and suggestions are most welcome and highly valued. I am learning as I go along.

This was my lumber stack at our last house just after it had been sawn:

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The top two slabs are 6" thick, 9 feet long, and were about 23 inches in total width.

After one year, a cross-town move, and a third child, I got to a point where I had a free spot to work and could no longer balance my enthusiasm against the moisture content of the lumber.

Starting with the top, I planed each piece until the joint looked good to my eye. Several days past before I again had the free time to glue the slab. 192 gram strength hide glue was used for the glue-up. Working alone, I quickly applied the hide glue from a warmed squeeze bottle and hoisted the behemoth slabs into place.

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I found (too late) during the process that the slabs had gone into wind during the time between planing and glue-up (perhaps due to their moisture content). Despite my best efforts to clamp it out, there was a large gap present on the underside of the bench top which I reasoned shouldn't bother me because I would never see it. Fast forward a few days and this gap opened up at the end:
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This gave me a good reason to go back and fix the gap that would have bugged me every time I looked at it. You can see a steamer in the upper right of photo. That was my first approach; it was marginally successful on the ends of the bench but could not overcome the thermal mass of the slab toward the middle.

So I cut it apart:

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With the help of my two assistants Porter and Cable (circ saw) I cut as deeply as I could from both sides and sawed out the rest with my 4 PPI rip saw. It was a lot of work.

Lessons learned so far:


Ash is heavy
50F is pretty cold to apply hide glue to large heavy timbers and also position them by yourself, mostly because of Lesson #1
I need an overhead hoist
If something looks wrong, it probably is wrong.


At this point, I have the top planed again and glued-up once more.

More pictures to follow.

[Malcolm Schweizer]

Wow. That is going to be a really nice bench.

[Noah Magnuson]

Don't feel bad, I had to rip my 2-piece sycamore top apart after the slow set epoxy failed 3 weeks in. Good ol' yellow glue did the trick the second time. I think I lost 10 lbs building that bench. Can't wait to see this one go together.

[Andy Nichols]

Will make a great bench, but dit not know it was 50 deg in OH....

my lesson learned, when you know how you should fix a problem, go ahead and fix it, it pays in the long run.

Know that cutting it apart was a pain, but you'll be glad you did....

Andy

[Bradley Gray]

That should make an immovable bench - just don't hurt your back building it.

Sounds like your wood is still too wet. The old rule is a year an inch for air drying.

You might consider a mechanical joint such as bolts rather than wait for air drying.

[Jason Dean]

Will make a great bench, but dit not know it was 50 deg in OH....

my lesson learned, when you know how you should fix a problem, go ahead and fix it, it pays in the long run.

Know that cutting it apart was a pain, but you'll be glad you did....

Andy

Andy, I made my first glue attempt in late April. Between work trips and auto maintenance projects its taken me this long to get the joint back in shape for gluing.

[Stew Denton]

Hi Jason,

My first thoughts were the same as Bradley offered above. It looked like the top is too wet. When lumber dries it shrinks, and it shrinks at the ends first. That may be why the glue pulled apart at the ends.

The big problem with that is that the next step in the shrinking at the ends more rapidly than the center, is the ends starting to develop splits, and if it dries rapidly enough, the splits can become extremely severe.

To solve that you need to slow the drying out of the end grain, and force the lumber to dry evenly out the sides and faces of the lumber. To do that you have to coat the ends of the lumber with a moisture blocking material. There are paints made for that exact purpose. I use a 50/50 mixture of paraffin wax and bees wax, because I do not have any of the special paint. I hope to get some of that special paint sooner rather than later. Once you get the ends sealed you then need to wait it out. As Bradley pointed out above for it to air dry adequately is to wait one year for each inch of thickness before you use it. You also have to stack it with stickers so that air can get to all sides of each stick of lumber in the stack.

If you already knew the above, my apology for repeating what you already knew. However, if you have wet lumber and were not aware of this, then there is not time to loose, get the ends sealed before you have severe splits, there literally is no time to loose.

Stew

[Jason Dean]

Bradley,

The wood is most definitely still wet. I sprung the glue joint a bit and had much better squeeze out the second time around. My fingers are crossed that it is going to stay together with butterflies and cabinet connectors as a back-up plan. If things really go pear-shaped I might even run some threaded-rod through it.

[Jason Dean]

Hi Jason,

My first thoughts were the same as Bradley offered above. It looked like the top is too wet. When lumber dries it shrinks, and it shrinks at the ends first. That may be why the glue pulled apart at the ends.

The big problem with that is that the next step in the shrinking at the ends more rapidly than the center, is the ends starting to develop splits, and if it dries rapidly enough, the splits can become extremely severe.

To solve that you need to slow the drying out of the end grain, and force the lumber to dry evenly out the sides and faces of the lumber. To do that you have to coat the ends of the lumber with a moisture blocking material. There are paints made for that exact purpose. I use a 50/50 mixture of paraffin wax and bees wax, because I do not have any of the special paint. I hope to get some of that special paint sooner rather than later. Once you get the ends sealed you then need to wait it out. As Bradley pointed out above for it to air dry adequately is to wait one year for each inch of thickness before you use it. You also have to stack it with stickers so that air can get to all sides of each stick of lumber in the stack.

If you already knew the above, my apology for repeating what you already knew. However, if you have wet lumber and were not aware of this, then there is not time to loose, get the ends sealed before you have severe splits, there literally is no time to loose.

Stew

Stew,

To paraphrase Confucius, its one thing to read about something and quite another to have several hundred pounds of it cracking in your garage. Which is to say I "knew" but now I am experiencing it first hand.

I sealed the ends when it was first cut 12 months ago with a 50/50 mix of mineral spirits and paraffin. But the moisture gradient in the wood changes and needs to be re-balanced every time I plane the wood or cut it to length.

My logic may be flawed, but to my mind the splitting is aesthetic so long as I retain the ability to flatten the top and the splits don't all the way through any of the pieces.

[Stew Denton]

Jason,

If you end up running all thread through it, as you mention, responding to Bradley, you may still be just fine. I hope that is the case, or if you end up using the glue, it still might be OK.

However, I would leave the paraffin/mineral oil mix in place on the ends even while your build is underway. I might even renew it at some point to maximize the benefit. That way it will continue to dry slowly through the sides and faces, and hopefully minimize any tendency to crack. By renewing the wax you help prevent cracking, but by using the all thread you can also continue the build so that you can use the bench. You can also snug up the top by tightening the all thread a bit as the lumber dries and shrinks.

At any rate, I wish you well on the build. Keep us in the loop. So far the build looks great, and the lumber is fantastic. (As you probably have easily figured, most of us SMC readers are really keen to follow bench builds.)

Just my 2 bits.

Stew

[Pat Barry]

Bradley,

The wood is most definitely still wet. I sprung the glue joint a bit and had much better squeeze out the second time around. My fingers are crossed that it is going to stay together with butterflies and cabinet connectors as a back-up plan. If things really go pear-shaped I might even run some threaded-rod through it.
I hope it holds together this time! Question, why use the hide glue vs Titebond?
Comment, when I laminated my Ash bench top (made from 2 1/4 inch wide by 3/4 inch thick Ash strips), I used about every clamp I had to get that thing stuck together - 8 pipe clamps, another 8 Jorgenson bar clamps and a few quick release clamps (to keep the pieces lined up vertically) and I only added maybe 4 strips at a time. Point is, I could actually close up the joints and get nice squeeze-out along the entire length of the joints top and bottom. I can't imagine trying to spring a joint for slabs as massive as yours. How many clamps did you use to pull your two top pieces together with that spring joint?

[Brian Holcombe]

Seal the end grain. I use anchor seal on green wood and it works beautifully. I think it is asking for trouble to just let it crack.

[Jason Dean]

Pat,

After I fussed with the way it fit together, I ended up with only 4 clamps, one F-clamp at each end across the end grain and two half-inch pipe clamps in the middle to close up the slight gap I had sprung.

I picked the hide glue mainly because I had heard/read good things about it (strong, self-clamping, won't cause wood to swell) and wanted to give it a try. That and the winter temperatures in my garage ruined my PVA glue.

[Mike Baker 2]

Ash is probably my favorite wood. That is a gorgeous bench.

[William Fretwell]

I've used end sealer paint on Ash, it micro cracks after a few days so it's not so good. Candle wax melted and brushed on once a week for 3 weeks or so works well. I've even used duct tape over the ends to slow drying. Whatever the method make sure it works.
Fighting with drying wood will just raise your blood pressure. My bench top wood had been drying at least 8 years. My legs only 2 years and that ruined one leg.
If you really want to get frustrated try gluing two 7 foot finger joints in cherry. See if you can get the glue on and the joint together before the wood swells and you break off many of the fingers. Just had to laugh at myself; what was I thinking?

[Tom Trees]

That looks to be the makings of a solid bench Jason, nice and bright too
May it give you joy every time you enter the labyrinth ;)

Who else has used hot hide glue on their bench build?
I am curious as I'm contemplating the same, for the same reasons as the OP.
I would like my bench to last as long as my Baileys have without delaminating ...
How long has aliphatic resin glues been used for? .... don't think its around long enough to prove itself worthy yet. ???
Mine will be made up of lots of selected iroko door stiles laminated together, and I'm aiming for it to stay very flat, like my surface plate like composite top I am using now.
I hear that hide is more resistant to creep also, so those are my reasons.

Hoping I can get this done without heating the shop as it might cause things to move.
If it needs to be done, so be it.
Best of luck with your bench build
Tomas

[David Eisenhauer]

For those who have not had any hands-on exposure to hot hide glue, be aware of the fact that it can be a very sticky, messy operation if you do not watch how you handle the glue application. The glue works great, but you need to take more care in not making everything around your project (including yourself and your clothing) a sticky mess as compared to when using yellow glue.

[Hasin Haroon]

Should be an awesome bench Jason! I'll be following along as I plan on building a similar one (albeit in maple) soon.

[Jason Dean]

Progress Update- The slab planed out to just under 6 inches thick and 20 inches wide. It will be 96-ish inches long when I get the other end cut down.

One End Cut:
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Slight mishap (D-8 bit me, narrowly avoiding sutures):
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Grammercy Holdfasts grabbing well in the 6 inch top with no backside counterbore after abrading with 220 grit.

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[Brian Holcombe]

Nice, that is going to be sweeeet!

[David Eisenhauer]

it is hard to imagine a great big lump of wood that size. Heckuva benchtop.

[george wilson]

I bought a log and had it cut into 4 x6's,4x4's to make a future bench. I took the planks into the toolmaker's shop. Must have let it dry for at least 10 years. Beech is the WORST wood I have EVER seen for maintaining stability while drying!!

[Pat Barry]

How much does this bench top weigh?

[Matthew Hutchinson477]

Are you sure you meant to type "Big Ash" and not "Big-ass"?

Nice build. Thanks for sharing.

[Robert Engel]

Jason,

I think the knot caused that section of the glue line to open up because there are stresses around knots that cause it to move disproportionately to the surrounding fibers.

When timbers this size start moving, there is really nothing you can do to stop it. Even threaded rods will bend. I hope this doesn't continue as it will transmit through the entire project and cause you much aggravation.

To avoid this issue, many benchtops a glued up in laminations rather than using beams or slabs.

Also, 4" is plenty thick for a benchtop.

[Jason Dean]

Pat,

I'm not sure how much it weighs. If I assume it is "dry" @40lbs/cu ft it calculates to 266 lbs.

[Mike Baker 2]

Slight mishap (D-8 bit me, narrowly avoiding sutures):
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Ouch. This and my chisel incident reminds me I need a tetanus booster. Hope it heals fast.
The bench is looking fabulous!

[Malcolm Schweizer]

Grammercy Holdfasts grabbing well in the 6 inch top with no backside counterbore after abrading with 220 grit.

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That's good to know. Mine came out 5.25" and I bought one custom made Roubo holdfast, two Grammercy, and two Veritas ones with the brass knob to cinch them down. (The Roubo took OVER A YEAR for the guy to get around to, so I bought the Grammercy, and then of course a week later the Roubo came) I haven't yet drilled my holes, so we will see how they work. I had planned to back them up with a 1" forstner bit from underneath and drill up about an inch or so to shorten the hole.

Mine is a split top and each half is just over 12". I put one of them on the bathroom scale to weigh it; I am now buying a new bathroom scale. It crushed it. They are well over 100 pounds each. The entire bench should tip the scales at around 500 pounds. I'm already loving it. IT. DOES. NOT. MOVE. Solid!!! I have been using it for the past few months to catch up on projects and now am finally going to make the chops for it. I just clamp stuff down for the time being.

Good looking bench so far. Keep us posted.