Circular table lamination, too difficult?

[Ryan Brucks]

Hey guys,

I am about to start on a large circular table project. The table will be in my porch and I plan to drop down the floor in the porch around 8", so the table can be very low to the ground, japanese style. It will be a "kotatsu" table. Around 5' in diameter. The center (maybe 24" diameter), will be an exposed circle (for the heater), and I will either put a round sheet of glass or some kind of blanket in the center to cover the heating element (my wife will help decide that later). But it means there is no true "center" for this table. It's more of a giant ring.


Now this is my idea on construction. It might be too difficult, so I'd like to get other opinions before I attempt it.

I want to build the entire top out of thin laminated sections, such that there is no straight grain on the table. I want all of the grain running circular around the table. I have done a small amount of bending before, but not even close to this scale. I am trying to evoke the feeling of a giant 5' tree cut in half basically.

Woods of choice are likely maple and cherry, with some layers of teak on the inside and outside.

So I have a few questions

1) Is something like this feasible for someone with moderate skill?

2) If I do it, I think joining the ends of the laminate strips will be the hardest part. Ie, I need to calculate the exact circumfrence for each laminate layer. Even if I got it perfect... would shrinkage/warping destroy this?


3) I would probably need to make tons of MDF clamping aids, cutting the inside to various radii, so that I can manage to get a perfect glue up without 5000 clamps. Do I have the right idea here?


4) assuming 90% of the top is maple, how thin would my laminated strips have to be? 1/8 or can they be bigger on the outer edges?



So with the challenges involved in clamping something this massive, combined with the difficulty in butting up bent sections together, combined with the sheer number of glue up sessions invovled (I am thinking 2-3 weeks of gluing up, since I only get a few hours at night time) I can see why there are not a lot of tables like this out there. Maybe there's a reason.... but I swear I've seen things made like this before, just on a smaller scale.


Just for fun here's a desk I made for my wife last week. Uses the same mix of maple/cherry/teak that my wife and I think worked out really well.

This photo is pre-finish obviously. 1st coat of waterlox is curing now and it really made the teak edges look sweet.
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[Jeff Duncan]

That's a heck of an undertaking and quite possibly the most difficult way I can imagine of accomplishing what your after. Certainly at the very least you'll want to experiment with some smaller laminations before undertaking this project. Also you don't have where your located listed so I would question if there are environmental concerns, (ie. Florida w/ super high humidity, New England with wide variations seasonally etc etc.), before choosing the type of wood. As well is it going to have exposure to the elements?

If it were indoors I'd recommend doing it in sections...kinda like a pie sliced up, rather than a lamination. Much easier to fabricate and will look good. You'll have a lot of things to work out to make this work, one how to get all the layers glued up in one shot. Another being how to scarf joint all your ends....you don't want butt joints between the pieces. Not that difficult with the right setup, but again, you need to get all these worked out ahead of time.

good luck,
jeffD

[Ryan Brucks]

Doh, I just added that I am in Raleigh NC.

Yes, humidity is a pretty big issue here. Thanks for reminding me. And the porch where the table will go is indeed outdoors.

I like your idea to build it in pie chunks. Assuming you mean I would still do smaller laminations to get the desired bend within each pie chunk. But that sounds muuuuuch easier to manage (imagining trying to glue a circular ring with a perfect end to end joint seems impossible now that I think on it).


I am not sure I have ever done "scarf joints", but it looks just like a simplified lock miter type joint. I used half lap joints on my last table (the pic above), which I guess are technically considered a scarf. Then there are the simple angled end types.

Is a finger joint considered a scarf joint? I am guessing not since all the joints I see when I google scarf joints appear to try to maximize long grain glue area (not so much with a finger joint).

I have a shaper, so it looks like the kind of thing where I could make the pie sections a bit oversized, then cut to size and run them across the shaper.

[Ryan Brucks]

more detail: the porch is well covered, has glass windows, roof, and even heating. but there is no cooling. So rain is not an issue, but wide humidity swings are a big one.

[Steve Kohn]

I really like the idea on how this would look when done. If done correctly that is. Have you considered doing this as a spiral lamination? Start with a circular ring, maybe even a piece of steel pipe, in the middlle. Spiral your sections of wood around the middle clamping from the middle out to the "loose or free" end. You can stop anywhere in the process to change wood species, etc. It might work!

[Chris Padilla]

Some off-the-cuff thoughts.

Sounds really cool but a ton..and I mean a TON...of work. But, sounds like fun and would be unique. If you have time, you could probably build the whole thing with off-cuts and narrow boards resawn thin.

1/8" strips should bend very nicely starting at 24" diameter. You can rig up a jig on a stationary belt/disc sander (if you have one or mock something up with whatever kind of sanders you have available) that would allow you to create the very acute angles needed for a scarf joint. Sanding is the best way to get that joint crisp and clean.

I think if you start with a 24" disc of plywood or MDF, you could then start to built up ring upon ring upon ring as you wrap millions and millions (kidding) of 1/8" strips around it. Use a strap/band clamp with cauls and cork. If you're meticulous with the width of the strips (say 2"?) and use cauls that keep the strips inline (even with top/bottom of the table), you should have minimal work at the end as you go to flatten it. If you can find someone with a wide-belt sander, he could become your best friend but I don't think I've heard of any larger than 50".

One thing you'll want is a good glue. I'd say skip the PVAs on this one (white, yellow) and go for the plastic resin types (check joewoodworker.com for valuable info here). You want something that dries rock hard and that is very waterproof since this sucker will be outdoors more or less.

I look forward to you creating a thread on this project!!

[Ryan Brucks]

Thanks for the feedback and ideas, guys.

Helps to hear more seasoned wood workers confirm what a challenge it would be. Part of me wants to simplify the design because I can see the vast amount of extra work involved... but on the other hand I do this for a hobby and for me part of the enjoyment is learning to tackle new problems, and I already barely sleep so why not do a whole bunch of extra work :)

I like the spiral lamination idea. That could be really neat as well, but I am not sure it would give the look I am after in terms of the trim rings. Wonder how difficult it would be to stop the spiral, use a big circle routing jig (ie, some scrap piece o wood) to route the spiral to a circle, then do just one layer of non-spiral trim, then go back to the spiral design. Might be a good way to mix tecniques? Kinda like the thought of that, and also the pie-chuck construction idea.

Not sure why, but I have always been one of those people who is literally bothered if I see something I don't understand how to do myself. Maybe that's why I've done everything from making acrylic fish tanks to LED projectors to furniture projects :)


Chris I like your little jab about millions of strips :D yea thats kind of how I feel when I try to imagine how many... ok real talk... for 24" of table radius, thats 192 srips 1/8" wide. Yikes. But I wonder if I could increase to 3/16 or even 1/4 near the outer edges? Those would have a a bend radius of 30".

Thanks again.

[Brian Kent]

Here is a clamping technique I learned last summer. A piece of ply or mdf is a combination drawing board, assembly table and clamp holder. The clamps are oval circles of wood, made by using a hole maker on the drill press at an angle to the wood.

Here are some pictures. If anything looks helpful I'll share more. I just wrote a long post with the details and then accidentally deleted it.

The clamps are just screwed to the table and can be re-set as many times as you need.

Brian

[Chris Padilla]

Yes, you could increase the thickness as the bend radius increases.

Let's see, your first strip of 1/8" maple would need to be about 76" to wrap around a 24" disc.

The radius increases 1/8" for each layer and so the length of strip increases about 3/4"+ per strip assuming 1/8" the whole way.

In reality that radius would increase a bit more than 1/8" due to the glue but added up over 192 strips, it will show up so that you likely would need a few less that 192 strips but then you could go to thicker as the radius increase. I'm not sure where that would happen in the radius, however.

Fun stuff to figure out!!

[Steve Jenkins]

Chris hit a couple of the main points. use a band clamp and a disk or edge sander to create the scarfed ends for the joint. It is simply a really long taper. On a piece 1/8 thick the taper may be about 1-1/2-2". I have edgebanded round tops with this method and it isn't too bad. The thickness of your strips can certainly get thicker as you increase the radius. Just test to see. I like to make mine thin enough that I can pull them into place without too much effort. When you glue it up do one strip at a time. It will be quite a project but should look pretty cool. The closest I have come to something like that is when I ripped 3/4" baltic birch ply into 1-1/8" strips then turned them on edge and glued them back together for a 42x74" top.
Have fun

[Chris Padilla]

Ah, yes, Steve is right. You'll need to add an inch or two to the length for a good scarf joint. I think the scarf joint will be the toughest part in getting that "just so" such that you don't create a bump but believe me, you'll be damn good at them by the time the project is done! :D

[Ryan Brucks]

Thanks guys.
Brian, that is a pretty smart little clamping setup. Just turn the ovals a bit like gibs... love it.

Steve, I think I am over thinking what you wrote, but this confused me a tiny bit: "use a band clamp and a disk or edge sander to create the scarfed ends for the joint"

Now sounds to me that the band clamp is what I would use for the actual glue up... but I am wondering if you are suggesting some use of the band clamp with a sander, to somehow make the scarf cuts? Or maybe you meant two different processes there...

I don't have a belt or disc sander (always gotten by without em). If I do the pie-chunk construction, I would probably try cutting the scarfs on the tablesaw, maybe using an angled sled to get an angle greater than 45... or if I just do complete circular rings (or the same for spiral lamination), then I would probbaly cut the scarfs on the miter saw.


But then again, for the pie-chunk method, why would scarf joints be any better than tounge and groove, or biscuits for that matter?
Thanks again

[Graham Wintersgill]

Some strip build canoe builders use staples to hold the planks in place. Would certainly work for the thinner strips and the holes would all be hidden. For doing lots of repeatable scarf joints it may be worth build something similar to http://www.woodenwidget.com/scarf.htm

Regards

[Ben Hatcher]

When I first read this, I thought huge waste of time. Now I'm starting to like the idea. I have no idea if it will hold up to the elements, but man will it be cool that first year!

The scarf joint would be used to connect the ends of each strip together to make a complete ring. The end of each piece would have a long taper to it, say 2-3" long going from 1/8" to 0" with each end having the opposite taper. When the ends are clamped together, the edge is nice and flush.

No, if doing a pie wedge, you wouldn't need them.

As for rings/spiral, I doubt that on a table this large you'd notice the difference between the two without some careful inspection. The spiral would probably be a little faster and easier especially if you use Grahm's idea of using a stapler to hold the laminations in place as you wrap them. Otherwise, you'd be looking at doing them all one at a time, glue, wrap, clamp, wait. Rinse and repeat.

You can use a router trammel and a flush trim bit to trim the table back to round should you start to wander. This is likely to happen sooner or later unless you scarf joints are very nearly perfect every time. Good luck. Take pictures and post your project. This one is certainly one I'd rather read about than repeat;)

[John Coloccia]

Here is a clamping technique I learned last summer. A piece of ply or mdf is a combination drawing board, assembly table and clamp holder. The clamps are oval circles of wood, made by using a hole maker on the drill press at an angle to the wood.

Here are some pictures. If anything looks helpful I'll share more. I just wrote a long post with the details and then accidentally deleted it.

The clamps are just screwed to the table and can be re-set as many times as you need.

Brian

Not to be a wise guy or anything, but I think you can accomplish the same thing by using round stock (like a dowel) and just drilling the hole off center. That's what I do for that kind of clamp, anyhow :)

[Michael Peet]

"We choose to [do these things], not because they are easy, but because they are hard."

I like the concept a lot, Ryan. It will be an interesting and unique piece, should you succeed. I agree with Ben that a spiral will not be noticeable - not at that size. I also like the idea of some kind of mechanical fastener to button down the end of each strip.

You may be able to flatten the final product with a handplane. That's how I would try it. If that doesn't work, you might try to build some kind of router sled contraption to skim the surface.

Mike

[ian maybury]

I'm guessing the risk with an unusual construction is that discs generally have a habit of twisting if you get circumferential stresses locked in.

A laminated spiral by placing the long grain circumferentially/in a circle might avoid problems, as might pie slices with the grain running tangentially. I'd be wary of running the grain radially in a pie slice type layout.

Scarf joints on laminations could be tough in that very minor differences in thickness of the strip or the glue film would make a significant difference to the required length of each lamination, so accurately placing the scarf could be tough. Easier if it could be done in situ, but how?

Harder to see how more than one lamination can be done at a time without stuff coming loose/getting out of position/gaps opening....

ian

[Ryan Brucks]

" I agree with Ben that a spiral will not be noticeable - not at that size. I also like the idea of some kind of mechanical fastener to button down the end of each strip.

You may be able to flatten the final product with a handplane. That's how I would try it. If that doesn't work, you might try to build some kind of router sled contraption to skim the surface.

Mike


Thanks. I agree that the spiral construction would not be very noticeable...

When I said I was worried about it, I should have clarified what I meant. I intend to have a few thin (1/4") strips of cherry or teak by themselves, one probably 6" from the inside, another from the outside. I only meant that I was concerned that these trim layers be circles, not part of the spiral. you would notice the ends not matching up on a single dark trim strip.

This way, I'd only need perfectly matched scarves on the trim layers, and the majority of the strips are just spiral strips, so length can be whatever(as long as scarf angles match).

That's why I was thinking of using massive router trammel, WITHOUT an edge bearing, from the center of the table, to kill the spiral, and turn the outside into a circle, just for the accent layer (or trim layer, w/e). Then I would do one strip of trim as a complete circle, then resume the spiral again, until the next trim layer. I will probably use my block plane to get the layers close to level, then smooth with a smoothing plane. I did this on the last desk and the block plane worked out really well to flush the trim (much nicer than a router for some stuff).

In terms of scarves, I like that hand plane sled that was posted. I actually do not have a powered hand plane. I do however have a sliding table saw.

A few weeks ago I made a parallel ripping jig inspired by Paul Cresti. It works better than I could have imagined. I actually used it to make the tapered legs on the desk I just finished. The cuts were so smooth I could barely tell the tapered sawn faces from the flat jointed faces (I know this because I forgot to mark, and it was really hard to figure out which faces were tapers, haha, good problem to have imo, but I will mark better next time).

Assuming that that little flat ledge at the end of the scarves is not important, I can cut scarves without those ledges with this jig very easily:

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[Ryan Brucks]

one other thing I would probably do to make the trim layers easier:

maybe purposefully make the trim layer a foot short, then glue it up.

Then I'd have a foot section left, and it would be small enough that I could cut the strip a bit large, visually check it, and make final final adjustments on the spot, rather than trying to get one long circumfrence perfect with glue to account for yada yada...

feels like the plan in my head is becoming doable.

[Peter Quinn]

When I first read this, I thought huge waste of time. Now I'm starting to like the idea......

I feel the same way, but it strikes me as the most exciting waste of time I can imagine. Fantastic idea. I like everything about this. Its pure man versus materials, an expression of your will to express a vision or visual and control the materials. Have you ever seen a giant reel of edge band tape on an edge bander and just wanted to take a hair dryer to it and make it one big solid mass?

I have little to add in terms of technical production, but I feel like with some type of sub structure perhaps hidden below you could keep the thing flat. And if you use epoxy or resorcinol, it will last in any environment. I can't wait to see the pics.!

[Dick Brown]

Just a crazy thought: Cut a circle out of MDF size of the outside, work from the outside in, staple as you go after the first few rings and butt joint the ends of each ring. As the strip will have tension when bent, and if the butt joint is a tight fit, it would need very little to no clamping. Strip could be put in, clamped on the start end, pushed tight, marked and trimmed to proper length for a tight fit and the last end slid down into place. Told you it was a crazy thought! By the way, it just might work.

[Ryan Brucks]

I like the way you think, Dick. Sounds like it would make the assembly itself a tad easier if nothing else.

I am also envisioning building an inner ring of MDF too... then to "clamp" the rings to the already glued layers, I could use simple scraps of wood with mitered ends, and just wedge those scraps. Then every few layers I need to trim the scraps down a bit so they still fit. Kind of like how countertop installers will wedge some scraps to force the countertop down under cabinets...

only thing that would be harder with that method, is if I was using the spiral lamination technique. I can't see how I'd be able to route the inside of the circle effectively to make a circle for the trim. But it probably just hasn't occured to me yet.

Also yes there will definitely need to be an entire substrate. I was planning on using MDF for a substrate anyways since that is apparently recommended when using a kotatsu heater. So I am not worried about what the bottom looks like. I dont know if the table will have an envelope around the bottom parimeter or not yet. Since it is going to be very low to the ground I think it might just get in the way.


"Have you ever seen a giant reel of edge band tape on an edge bander and just wanted to take a hair dryer to it and make it one big solid mass?"

haha... I've never seen the stuff on an actual bander but I've seen the rolls and yes I did think something like that :)

[Mike Henderson]

I did a much thinner version of what you are planning and did it in a spiral. It took a long time because I laid up one layer at a time. I made a form out of MDF and covered it with packing tape. Then took the first layer (actually two layers) and glued them up, using a band clamp to keep them tight against the form. I scarfed the ends before doing the glue up. Once that was set, I cleaned up the outside and laid in the second (actually the third) layer, aligning the scarf joint. Just kept doing that day by day until I got the thickness I wanted - but much thinner than what you want to do. My goal was to not show that the border was multiple layers, but to make it look like a single piece of wood. So someone who knew wood would wonder how I got that circular border.

To my great surprise, the border fit on (around) the center work that I had previously built, with no gaps.

Mike

[Dell Littlefield]

I agree it would not be noticeable if you built it in a spiral because your scarf joints would be in almost random patterns. Maybe you could scarf one end, glue up, then use the router on a trammel to scarf the other end of the installed layer. This would also keep it round. Sure would be tedious though. If you can get air dried lumber, you may be able to fudge a little on thickness because it bends better than kiln dried. You could use staples as clamps but you couldn't layer over them. Many canoe builders use 18 guage nails with a short section of thin wood or plastic tubing under the head of the nail to hold the strip to the form.

[Jeff Duncan]

OK so when I suggested at the beginning an alternative glue-up using pie shaped pieces I meant solid wood pieces, not laminations. Making the laminations that way would not provide anything beneficial that I can think of. However gluing up the solid pie shaped pieces would be worlds easier than what your thinking of trying. May not be the look you want, but they do look good and can be done fairly easily by someone with moderate skill.

If you just want to do it for the look of the laminated rings then that's a different story. The biggest concern when you start laminating multiple layers is getting sufficient clamping. If your only trying to do a couple layers at a time then it's probably managable, however if your going to try to glue up the whole top in one shot I see a disaster in the making. Trying to get more than a couple layers glued up and clamped sufficiently while everything wants to slide around a bit is a challenge. Then add in the scarf joints and your begging for trouble. Even if you use an outside form you still have to clamp, the spring of the laminations will not be enough force. This is why I suggest a trial run first. These clamp ups require a LOT of clamps and even then are hard to get a smooth curve. There's a tendency for the wood to want to pull away a bit between the clamps.

Lastly I think I would go with a sander for the scarf joints. Laminations of 1/8" are thin enough to make life very difficult trying to cut them on a table saw. You may have to sandwich them between a backer to prevent any movement which would ruin the joint. If you have an edge sander or a disc sander you can make a simple jig to get quick, easy, uniform scarfs for all your pieces.

good luck,
jeffD

[Floyd Mah]

I may be in the minority (actually I am, as an Asian American), but if you are intending to build a Japanese style table, why don't you consider what a Japanese craftsman would do? In my opinion, you would be attempting to force straight pieces of wood into a circular pattern, when those forms already exist naturally. Why not purchase a cross-section of a tree and use that? If the diameter that you desire is unobtainable, cut slices and make a rosette type of design. You could even incorporate a spoked design to pull your wedges together. I think it would be an infinitely more interesting design and more attractive than reorienting the wood into what is basically a cross-section of a roll of paper.

[Ryan Brucks]

That is a really cool idea actually.

I never thought about it realistically, since I thought getting a 5' diameter slice was basically impossible (but I am pretty in experienced at buying rough wood, although when I was I teen I regularly had to cut down trees for firewood, heh).

When you meantion doing it like a rosette... I assume you mean kind of like Brian Kent posted on the 1st page, but for the center? To be honest that has always been my fallback plan... try to pick out some nice pieces that have a large curvey grain, and just try and orient the chunks to maintain the circle around the parimeter. I know that is certainly doable... Is that kind of what you mean using a cross section that is a little too small? I am just wondering, if its "a little too small", what advantage would starting with a real cross section piece give me? I cant think of one. In fact I think it might look weird since the radius of the anual rings would be too small. I think it might look like a circle was pinched slightly into a star shape. I might be better off faking it with picked out face grain (if that makes sense).

But I appreciate your pulled back perspective on this.

[Floyd Mah]

I don't know what's available in your area. I remember when I watched "The Last of the Mohicans" that it was filmed in South Carolina in some very old forests. Maybe there is a source there for large burls. In California, near Santa Cruz, there's a town Felton, where you can get redwood burls. In fact, I still have one under my bed that I'll have to turn into something soon. My wife's been complaining about it for years. Anyway, take a look at this website (http://www.redwoodburl.com/countertops.htm) to get an idea of what they have.

When I mentioned rosette, I was thinking of lobes that would appropriate to the size and type of wood you had access to.

[Chris Padilla]

Sweet wood porn there, Floyd! Wow! I'll have to stop by when I'm up there.

[Steve Jenkins]

Thanks guys.
Steve, I think I am over thinking what you wrote, but this confused me a tiny bit: "use a band clamp and a disk or edge sander to create the scarfed ends for the joint"

Now sounds to me that the band clamp is what I would use for the actual glue up... but I am wondering if you are suggesting some use of the band clamp with a sander, to somehow make the scarf cuts? Or maybe you meant two different processes there...

Thanks again

Yes. band clamp for clamping and sander for scarf joint. If you don't have a disc or edge sander a handheld beltsander layed on its side and clamped down will work if you have one of those.

[Sam Murdoch]

Lots of great advice above - I chime in with a few ¢ worth of ideas too. I love the idea and agree that it will be a lot of work - absolutely worth it though. I propose - glue up a few strips, 3 maybe 6 each day. Use epoxy. Butt joint the strips Do a dry lay up. Saw each strip to length. Epoxy and brad one end of the strip to your core - pull tight and nail or staple the other end. Lay up the next strip with the butt joint being away from the last perhaps on the opposite side of the circle. Brad the ends. Glue up the next in sequence. Add a few layer of shrink wrap around the assembly of the day and then clamp all tightly with a band clamp. The butt joints could be 45° but I think square and tight would be easier and just as effective. Scarf joints are too problematic in stock this thin.

Each day start by cleaning up your previous glue up (or not) then continue another batch of alternating butt joint laminates. When you remove from the core - at the end of your glue ups you will have a few little brads or staple tip sticking through but those can be filed down or pulled through if you have used headless pins.

Finally, I propose using ash and/or mahogany for this project as both of these woods will bend nicely while allowing a slightly thicker stock. Cull pieces from your stock as you dry fit. If you get some edge set as you are wrapping a piece - that is one that should be discarded.

This could be a truly beautiful and unique table :).

Sam