Legs for a midcentury bench

[Aaron Liebling]

I'm making a slatted midcentury bench for my sister-in-law's birthday. I'm not sure what to do for legs. I really like the curved (laminated?) legs from Joe's bench:

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How are these generally done?

Alternately, I considered going with some McCobb-style midcentury bench legs. I have the wood, but unfortunately not the lathe to turn my own. I can buy them premade, but only in maple, cherry, white oak or walnut. The bench is iroko and will be outside (covered patio).

Anyone in the SF By Area willing to turn some legs for me if I provide the wood? I'd happily pay a reasonable amount for the effort.

[Jim Becker]

A leg construction like that would likely be a bent lamination...many thin layers glued together, clamped in a form to provide the curved profile.

[Alan Lightstone]

I was going to jump in and make the same suggestion that Jim did. That's a really nice looking bench. I would try to duplicate the legs. I think you'll be very happy you did.

[Aaron Liebling]

Seems like it's time for me to learn to do bent lamination. Any good guides or references?

Also, do I need any special tools or can I simply cut, glue and clamp the laminated sheets?

Finally, the wood is iroko - Can I cut thin sheets of it? I'm worried about splintery texture. Should i consider a different wood for the legs (maybe with a veneer). Again, this is an outside bench, so weather resistance is important.

Thanks for the feedback - always nice to try something new and this is the perfect project for it!

[Russell Hayes]

Pretty easy to turn McCobb style legs on your table saw with a jig. Search Youtube.

[Mark Rainey]

Seems like it's time for me to learn to do bent lamination. Any good guides or references?

Also, do I need any special tools or can I simply cut, glue and clamp the laminated sheets?

Finally, the wood is iroko - Can I cut thin sheets of it? I'm worried about splintery texture. Should i consider a different wood for the legs (maybe with a veneer). Again, this is an outside bench, so weather resistance is important.

Thanks for the feedback - always nice to try something new and this is the perfect project for it!

Forum members should be able to guide you through the bent laminations for this project. Drawer the legs out on paper. Create a template on poster board or 1/8 inch plywood, then trace that on some particle board or MDF. Saw that out. You can create a form by connecting the two particle board pieces with hardwood blocks. Cover with bendable plywood. You are going to have to see how thin you have to resaw the iroko to get it to bend at that radius. Probably no thicker than 1/8 inch and perhaps thinner. I have done many bent laminations. Michael Fortune has good information in Fine Woodworking. Let us know if you need further information.

[Jamie Buxton]

I would make those curved legs as bent laminations. I'd make a bending form to establish the curve. I'd make a custom vacuum bag wide enough and long enough to hold the laminates. The bending form would be outside the bag. The bending form establishes the curve, and the vacuum bag squeezes the laminates together while the glue cures. The laminates have to be thin enough to bend around your curve. I haven't bent-laminated iroko, but my guess is that the laminates would be less than .1" thick. I use a bandsaw to cut those laminates. I'd use epoxy for the glue-up. It doesn't creep. It has a long open time, so you have plenty of time to get the glue spread, laminates stacked and inserted in the bag, and the vacuum sucked down -- all before the glue starts to harden. I use West Systems 105.

So.. my process wants you to have a bandsaw to cut the veneers, and a vacuum veneer press with a custom bag. You might find arranging for those turned legs to be easier and/or less expensive.

[Aaron Liebling]

I'm leaning towards cutting veneer for laminate on my table saw (wasteful but I have the stock for this one off) and trying the glue up without vacuum (lots of clamps).

I've found a number of videos and guides online that make this seem reasonable.

I'll let everyone know my results!

[Aaron Liebling]

Body of the bench is about ready, so finally getting ready to tackle the laminate legs.

What glue do people recommend for this given that the bench will be outdoors (albeit under a roof and in Los Angeles)?

Also, thickness of the leg and veneer? I was thinking six layers 1/8" thick for a total thickness of 3/4".

I assume I should be cutting the veneer a bit thicker and planning/sanding to final thickness? Can I tape the strips to a substrate and run them through the planer?

[Jim Becker]

For outdoor (even though covered) I'd use TB-III or polyurethane glue (Gorilla or other brand). Since this is a lamination, the polyurethane glue might be better since it has a much longer open time than TB-III. There are also some other glues that are specific for laminations including exposed.

[Jamie Buxton]

Body of the bench is about ready, so finally getting ready to tackle the laminate legs.

What glue do people recommend for this given that the bench will be outdoors (albeit under a roof and in Los Angeles)?

Also, thickness of the leg and veneer? I was thinking six layers 1/8" thick for a total thickness of 3/4".

I assume I should be cutting the veneer a bit thicker and planning/sanding to final thickness? Can I tape the strips to a substrate and run them through the planer?

Epoxy. It doesn't creep, which is important for bent lamination. It is also pretty water resistant. I use West Systems 105, but there are others.

I betcha that 1/8" thick wood will not bend around the curve in the pic. The laminates will likely have to be thinner than that. Experiment with the thickness before you cut all the laminates.

[Mark Rainey]

Like Jim I like Titebond 3. You can count on 20 to 25 minutes of open time. It will be fine outside. This is in pouring rain and is in it's second season outside. No glue failure.

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I believe you are going to need more than 6 laminations, probably 8 like I have. You will have to experiment to see what your laminated thickness has to be because you have a pretty tight curve there. Perhaps 3/32". Try that and see if they crack on you or bend. Go slow. You have to cut them fat, at least 1/8". To thin them, try the Boggs vacuum box which I explain here (https://sawmillcreek.org/showthread.php?286743-boggs-vacuum-box&highlight=). Keep us posted...it looks to be a great project. Let us know if you need more help.

[Aaron Liebling]

I like the idea of epoxy. A nice long open time, too.

I was thinking that re: 1/8".

Assuming I had to go thinner, what's a good process for flattening them? At that point I assume the planer cannot be used.

[Aaron Liebling]

Ooh..thanks Mark! The vacuum box looks just the ticket!

I'm always building one thing to build another...

[Mark Rainey]

Ooh..thanks Mark! The vacuum box looks just the ticket!

I'm always building one thing to build another...

You are welcome Aaron. Another concern would be using a table saw to resaw to that thickness. I have a bandsaw and do my resawing on that. I understand that there are safety issues with resawing on a table saw, but i have no experience in this area. Has anyone resawed 1/8 inch or thinner laminates safely on a table saw? Perhaps there are fellow creekers in your area with a monster bandsaw that can give you 3/32" laminates almost glue ready for a reasonable fee?

[Aaron Liebling]

I'm planning on cutting on the left side of the blade (away from the fence) off a wide board. It's wasteful, but I'll cut thick and plane to the desired thinness.

There's no safety issue that I know of with cutting veneer from the non-fence side of a TS...you just need an additional guide to help keep a consistent thickness.

[Jim Becker]

I like the idea of epoxy. A nice long open time, too.

I was thinking that re: 1/8".

Assuming I had to go thinner, what's a good process for flattening them? At that point I assume the planer cannot be used.

Drum sander...you are correct that in most cases, a thickness planer isn't going to be the tool of choice when you need to go really thin...catches and ripping apart is a common issue with the thickness planer on really thin material.

[Rod Sheridan]

You are welcome Aaron. Another concern would be using a table saw to resaw to that thickness. I have a bandsaw and do my resawing on that. I understand that there are safety issues with resawing on a table saw, but i have no experience in this area. Has anyone resawed 1/8 inch or thinner laminates safely on a table saw? Perhaps there are fellow creekers in your area with a monster bandsaw that can give you 3/32" laminates almost glue ready for a reasonable fee?

Solid material should be ripped with a short fence that ends just beyond the start of the blade, allowing pieces the freedom to move without becoming trapped between the fence and the blade.

A short fence can be as simple as a piece of MDF attached to the machine fence…..Rod.

[Aaron Liebling]

So I have my form built and I ran some tests with the largest possible radius corners that looked good. It looks like my final thickness for the laminated strips will have to be 1/32". Any thicker and they broke.

Given this, it would be nice to lose some overall thickness on the legsGiven the strength of bent laminations for a purpose like this, what should I be looking for as a minimum total thickness? I was planning on 1", but that requires 64 total strips and a lot of cutting and gluing! Could I safely go with 3/4"? Width will be ~3".

[Mark Rainey]

I do not know the answer to your question. Any structural engineers out there? I have not done laminations of 1/32". I am impressed. What is your method for getting uniform laminates that thin? Mark

[Aaron Liebling]

I cut a few on the table saw and got a nice consistent 1/32" after sanding..that said, it was VERY wasteful of wood 91/8" kerf). I found a local millwork that will re-saw and sand them for me. It's not super cheap, but it's cheaper than buying a bandsaw and much cheaper than moving to a bigger shop which I'd need to fit the bandsaw in!

They'll only promise 3/32", so I'm going to reword my form with slightly gentler curves that should work for that thickness.

I should be able to get a total thickness of over 1" relatively easily - probably go for 12 laminations.

[Alan Schwabacher]

The other method that helps bent lamination to work with somewhat thicker pieces is to heat bend the stock before layup. You would need to check whether it works with the species you're using, but it's the way things like violins are made. Search for "hot pipe bending". You spritz the wood with a little water, then bend it in seconds around a heated pipe that quickly drives the water off, stopping to respritz before you char. You would put an approximate bend in each piece, then the clamping cauls just need to fine tune the curve and press it together, usually with less chance of breaking and less work for you in the glueup (though more overall).

[Tom Bender]

If you make the radius larger the bench will have more tendency to fall over. To counteract that you might make it wider across the bottom and make the curve more than 90 degrees, then make a sinuous vertical. While you are doing that, raise the bottom off the floor in the center so it sits better on an imperfect surface without any wobble. Actually it might be good to add some feet, either wood or rubber.

[Alan Lightstone]

Aaron:

I may be following you making a similar bench. I really like the design. You're getting some great suggestions from our experts here.

I'm really interested in how the Iroko turns out. I've never worked with that species. How/why did you choose it?

Also, what's your game plan for its finish? It would be a shame for that to turn grey outdoors.

[Aaron Liebling]

Great suggestions indeed!

I was already planning on adding some embedded rubber feet, as this will be sitting on concrete.

The iroko choice was a combination of:

1. Supposed to survive well outdoors
2. Nice color/texture for the piece
3. Was 25% off at the local mill when I was wood shopping

I've been super happy with it so far.

Regarding finish: this will be outdoor on a covered patio in L.A. and likely get some sun. Since it's my sister-in-law whom I visit regularly, I'm going to go with an easy oil finish and just reapply seasonally as needed. If this were going to be out of my sight, I'd consider something more protective. That said, even if you finish the pieces before constructing, it's going to need refinishing at some point and unless you can take it apart, oil seemed like the easiest path for that ongoing maintenance - more frequent, but easier.

Note: I had a local place (3 blocks away!) cut the laminations for the legs - I have 40 3.5"x60" strips just under 3/32" thick.

Unfortunately, I broke my ankle over the weekend, so things are on hold for a bit.

[Tom Bender]

Not sure if steam bending is effective on this wood but it may let you pre bend it some prior to glue up.

Never tried hot pipe method but that may be an option.

For the glue up your form will be critical and extensive. Maybe make a mockup of that. You will want a ton of clamping force to prevent those little gaps between laminations, especially if your stock does not have identical grain in each piece. A little quarter sawn next to some flat sawn will fight the bend more and open up a gap.

Good luck and get well soon.

[Alan Lightstone]

Not sure if steam bending is effective on this wood but it may let you pre bend it some prior to glue up.

Never tried hot pipe method but that may be an option.

For the glue up your form will be critical and extensive. Maybe make a mockup of that. You will want a ton of clamping force to prevent those little gaps between laminations, especially if your stock does not have identical grain in each piece. A little quarter sawn next to some flat sawn will fight the bend more and open up a gap.

Good luck and get well soon.

From my limited experience steam bending, I would also think that getting the four curved pieces the same after springback would be unlikely. But again, not an expert in that.

Get well soon. Sorry about your injury.

[Alan Lightstone]

Aaron:

Ever get back to this after your injury? If so, I'd love to see some pictures of it.

I like the design so much, I'm seriously thinking of starting on a similar bench soon. Not sure of wood choice. Sadly, SWMBO will likely make me paint it (sob...:(), so sapele or mahogany which would normally be my first choices will be pretty unnecessary.

[John TenEyck]

Did anyone mention using a support strap on the outside of the laminations to prevent them from breaking going around the form? That's pretty common practice for making tight bends, and it allows one to use thicker laminae. There is at least one article in FWW showing how it's done. Another method that should work is to make a narrow vacuum bag, slide in the glued pieces, pull a vacuum, and THEN mend it around the form. The bag acts like the support strap. I've used this approach on making curved door frame headers, but never on a radius that tight so I'm not sure it would work.

As for glue, NO to TB III. It's terrible in the sun and has low creep strength. Polyurethane, UF, or best of all, epoxy.

John

[Alan Lightstone]

I really don't want to steal Aaron's thread, but I'm definitely going ahead and building one of these. A number of modifications, of course, but I'm going to try doing it with bent lamination.

I'll start another thread. Still hoping Aaron is okay, and progressing with his table.