Saturday, June 9, 2012

Bending with Seth Rolland

Last weekend I had the opportunity to take my first live woodworking class.  I belong to The Woodwhisperer Guild and Shannon Roger's The Hand Tool School and I've been to a few seminars, but this was two very full days at the Port Townsend School of Woodworking learning bending technique from Seth Rolland.  Seth is one of my favorite modern woodworking artists.  You can see some of his work at Seth Rolland Custom Furniture Design to understand why I was so excited to take this class.  In this post I will discuss the different methods we covered in the class.  There was a lot of information, so I will not go into great detail.  I encourage you to read all you can about bending and, if the opportunity arises to study with a professional, take it!

The school is located in beautiful Port Townsend, Washington where my brother spent time in the Coast Guard manning this lighthouse.

This was his view every day.

The town has a vibrant and very funky vibe.  Located in the rain shadow of the Olympic Mountain, it is lush, but only receives 18.75 inches of rainfall per year.  This was the view off the deck of the house we rented for several days.
On our first day of class some of us got to go the the local farmer's market, which although smaller than the local market here in Pasco, WA had much cooler fare to offer.  I had a Big Bob sandwich which had fresh salmon and egg among other things.  Delicious!  I also very much enjoyed that the town is extremely dog friendly.  Many people had their little and not so little buddies with them.

On the first day of the class we got the prerequisite safety talk, which is more a philosophy of mindfulness than anything else.  Because this class was focused on bending and only two days, Seth had all the material we would need for the two days already prepped and ready to go.  He did take us into the machine room to show us how he made regular and tapered laminate strips.  For any size that can be done on the tablesaw, he prefers to do them there, using a thin kerf blade.  For tapers, he will either use a sled that is equipped with toggle clamps to create the tapered laminate on the tablesaw or a simple sled that holds the laminate for use in a planer. I apologize that I didn't get photos of those particular items.  For laminates that are wider than the tablesaw's capacity, he suggests a bandsaw and a drum sander or planer using a sled to keep the thin strips from exploding as the force of the planer knives engage the work.

The first class session was bending laminates using forms.  I wish I'd had this class prior to building Gretchin's Cradle.  The form I built for the laminated legs was way too much material and going with a positive and negative form made the glue up much more difficult than it really needed to be.  Seth quickly shaped a half elliptical form in the machine shop, fared the curve and drilled some holes for clamping.  We then arranged the laminates according to the cabinet makers triangle Seth had placed on them earlier and got to rolling on the glue.  The other form was to show acute and concave bends, which take much more care to accomplish without blowout.

After lunch we got to tackle free form bending utilizing a vacuum press system.  This was a lot of fun!  We first stacked the laminates in the vacuum bag and drew a vacuum.  Then we moved the laminates into the form we wanted to create.  Once satisfied with the form, we had to create blocking to hold the form.  Then it was a matter of removing the laminates, applying glue, re-installing the laminates into the vacuum bag and getting everything back into position and clamped down.  That and a bit of clean up brought our first day to a close and we were off to have some beers and then some great Indian food with Tim Lawsen, the Executive Director of the school.

The second day of class we returned to the free form bend.  The vacuum bag was removed and we embarked on a complimentary free form bend using surgical tubing.  This is something I can't see myself ever doing on my own.  There is just too much going on for one person.  You need one or two people bending ahead while another feeds the tubing ahead of the person drawing it tight.  The results were still quite good.

While we were stretching tubing we had the steam generator going to heat the steam box.  Seth's generator was an old electric deep fryer with a trouble light dome caulked to the top.  It made copious amounts of steam, but chose this day to die.  After a bit of excitement with the local fire department we quickly got other steam boxes going.  A Twitterverse buddy of mine, Todd Butler (@Tbdi0629) had come to the class, along with his wife Elizabeth.  Together they run The Butler Did It Woodworks.  Todd had the Rockler steam generator and a PVC steam box with him.  Tim Lawsen had built the steam box outlined in the Veritas Steam-Bending Instruction Booklet.  We got those up and running and discovered that while the steam got to temperature in the PVC steam box, the box itself was dissipating, instead absorbing and holding the heat.  With a small modification, we connected Todd's steam generator to Seth's steam box.  Seth's steam box design seemed to do the best for holding heat and I liked that it was made to easily add sections for longer pieces.  The box is made from CDX plywood, has blocks on the bottom at angles to both support the bending pieces and allow for good steam movement.  All the edges are sealed with a heat resistant caulk and screwed together.  Simple weather stripping is used on the door and flanges to prevent too much steam escaping, although you need to allow some steam to escape, so that boards can be fully engulfed for even steaming.  Weep holes are place on the bottom to allow condensation to drain.

The basic principle of steam bending is that you are softening the natural occurring glue, called lignin, so the fibers of the wood can move past each other.  This shot of a failed bend shows the lignin between the fibers.
Once the lignin sets up again, minus a bit of spring back, you have a bend.  In this shot, you see we twisted a piece.

To do that we first bent the wood along one axis, then along the perpendicular axis to break all the lignin bonds.  Once done a clamp was affixed on the top and we twisted the piece.  You can see how the fiber slid past each other in this shot.













We also got instruction on hot pipe bending, which is used quite a bit in the luthier trade.  Be sure to not to use galvanized pipe, as the coating takes a long time to burn off and is not good for you.  You want the pipe hot enough to make drops of water dance, but not evaporate.
 Hotter than that and you'll too easily scorch your wood, cooler and it will take forever to relax the lignin.  In the following shots, you can see the set up of the propane torch and how high to set the flame.



Here are some shots from the class and a short, my apologies, poor video of us bending on the elliptical form.





While in Port Townsend I stopped at the local Rockler and picked up my steam generator.  I also have the basic bending hardware as well as the transition hardware on the way from Lee Valley Tools.  Soon I will finally build my outfeed/assembly/bending/router table on the back of the tablesaw.  I'll keep you posted, as always.

NOTE:
There was a in depth discussion on glues and why Seth uses the glue he does on laminates.  Urea Formaldehyde found in glue such as Unibond 800 and DAP Weldwood Plastic Resin Glue, which create a rigid glue bond, is classified as a carcinogen.  While there are some, like myself, who don't seem to be sensitive to formaldehyde, there are others, like my wife who are very sensitive to these type of environmental toxins.  A person's sensitivity can increase dramatically from prolonged exposure.  From discussions with Titebond, Seth had decided to primarily use Titebond II for glueing laminates.  If you do use a Urea Formaldehyde product in your shop, be sure to wear appropriate safety gear and try to limit your exposure time.  To learn more about Formaldehyde do some research.  Here are a couple links to articles I found:
http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde ; http://www.cdc.gov/nceh/ehhe/trailerstudy/pdfs/08_118152_Compendium%20for%20States.pdf


4 comments:

Mike Lingenfelter said...

Very cool you have made it over to PT and to take a class from Seth. I'm hoping to take class from Seth one of these days!

Mike

Vic Hubbard said...

Mike, it WAS VERY cool! Seth is a great guy. Very engaging as a teacher and had some really good design advice. If you get a chance to take one of his classes, I'd hop on it. He also teaches a week or two week long design intensive. I'd like to figure out how to go to one of those, too.

thelightheartedwoodworker.com said...

Great post Vic. The NYCwoodworkers guild did a seminar on bending this month and of course-I missed it! Now I am intrigued.
Chris

Vic Hubbard said...

Chris, as you might be able to discern from my one and only piece, so far (Gretchin's Cradle). I love curved pieces. I'm currently building my outfeed table for the TS to be a bending/assembly/outfeed/router table. It will house my veneer press system and bags, as well as my steam equipment.