Week 5 – More Doors

The guts of the doors were completed last week and this week I wanted to try and get the veneered skins on the doors.  Todd led me to a plank of curly birch in the wood room that had an awesome bubbly lava lamp like character to it.  I thought this would be great for the inside.  I also thought that it would be great to use an often overlooked wood.

I unfortunately did not take any pictures of the process used prepare the veneers from a plank of wood, but suffice it to say that you slice off some rather thin (3/32” thick) slices of wood as wide as the plank (8” – 10”), plane/sand the slices smooth and thin enough to bend around the forms, and finally glue the slices together edgewise to form a sheet large enough to cover the inside face or outside face of the door.

Veneers applied to curved door panels

I made the rather bold assumption that gluing the veneers onto the substrates would go as smoothly as gluing up the plywood substrates.  This did not turn out to be the case.   The vacuum press was not quite able to pull the veneers tight against the substrate at the very edge of the door.  After some discussion and conjecture with the instructors we modified the glue up with some additional cauls to put extra pressure on the edges of the door, but even then the second door also had a few gaps between the substrate and the veneer.  If you look closely in the photo below you can see a thin gap between the outer veneer and the edge band.

Gap between veneer and door substrate

“It’s not a mistake until you can’t fix it” – Jim Budlong

It took about a day, but using a Zona saw and every other thin kerf saw I could find in the tool cabinet I was able to slice down about half an inch between the veneer and the substrate to remove the glue which had hardened within the gap and allow the veneer to be pressed tight against the substrate with a small amount of force.  I worked some glue into the tiny joint and applied as many clamps as I could along the length of the gap.  After the glue had set and the joint was cleaned up again the gaps were gone and no one was the wiser.

Plane shavings of repaired door veneers

Week 4 – Doors

Version 1 of the Mediastinum mockupThis was a challenging but great week in the project.  Not much happened in terms of woodworking but some major design decisions occurred.  The original mockup of the project had a set of swiveling drawers at the top of the cabinet and two doors at the bottom.  There was much debate about to keep the grain patterns properly aligned between the door and the drawer and how much effort and risk that involved.  There was also debate about how to keep the curvature of the door and the drawer consistent, as there could be slight changes in the shape of the door fronts versus the drawer fronts over time as the drawer fronts would be captured by the drawer sides and completely unable to change while the doors might change.  I seemed to have two options.  Option 1 requires me to perfectly align the exterior veneers of the doors and drawers during each glue up with little trimming or waste along with a lot of luck that the doors and drawers would maintain consistent shapes as they were being constructed.  Option 2 would expose the partition used to support the drawers and use it to provide a transition between the drawers and doors that I could use to hide any disruption in the grain pattern or disguise any difference in the shape of the doors and drawers.  Neither of these options was appealing to me.  I didn’t want to rely on good luck for the success of the project and no matter how I mocked up the divider between the top drawer area and the bottom door area I could not stop the project from looking like a layer cake or ice cream cone.  While lamenting my conundrum with the ever helpful and wise Todd Sorenson, he me if I had considered just having two doors and get rid of the drawers all together, then I would not have any of these problems.  I thought for a minute and decided I would rather trade these problem in for a new and different set of problems.  The swing-out drawers are gone!

Version 2 of Mediastinum mockup

With that monumental design change out of the way, I was ready to start making two doors.  I decided where I wanted the doors to break from the cabinet and cut the curved plywood cores that I made last week.  I glued the curved sycamore edge bands to the top and bottom of the door cores and trimmed those flush.  I then glued straight sycamore edge bands to the front and back edges of the door cores and trimmed those flush as well.  I spent the next day squaring up the doors so that the faces ran plumb and the orientation of the curve was true and identical on both doors.

Door cores with edge captured edge bands

Week 3 – Cores and Choices

Skinning the bending form in the vacuum pressLast week I finished making the form that I would use to create the curved panels for the carcass of the cabinet.  The next step is to create a curved substrate that I will eventually veneer with the woods that I choose for the project.  The substrate is create by gluing together four layers of bending poplar or wiggle board.  The bending poplar is a special plywood about 1/8 thick that is very flexible in one axis but stiff in the other.  The reason that a plywood is used as the substrate is that it will not expand and contract like a solid wood substrate.  This means the door is unlikely to change shape or size as the weather changes.

Creating a plywood substrate on the bending formCreating the substrate is straight forward.  Cut a few sheets of bending poplar to size.  Cover them with glue.  Set them on the bending form and place them into a vacuum bag.  Suck all the air out of the bag and let the weight of the world press the layers against the form to create the desired shape.

Once the glue has cured I slide the plywood core off of the form.  I will need to cover the edges of the new plywood with something pretty so that the plywood does not show when you look at the top/bottom edge or side edges of the doors.  Creating curved edge bands from narrow strips of wood on the bending formThese are called edge bands and they can be straight pieces of solid wood glued to the vertical edges of the door panels, or they can be curved pieces of wood glued to the top and bottom curved edges of the door.  To make the curved edge bands I use a similar process but instead of bending poplar I use thin and narrow strips of solid wood and bend them around the form.  If you look closely at the photo you can see the top and bottom edge bands at the far edges of the form.  I had to use a clamp in order to get a little bit of help bending the last few inches of the edge band to meet the form.  Those clamps are foreshadowing of a learning opportunity I will experience next week.

If you have been following along and any of this is making sense, you are probably wondering exactly what type of solid wood I have in the vacuum press for those curved edge bands.  You would be correct in the assumption that I have made some final wood selections for the project.

Close up of douglas fir grain
Douglas Fir

Swamp Ash close up
Swamp Ash

I spent a good part of week 3 in the wood room and the back room at The Krenov School looking at various planks.  Pear was suggested by one instructor and the thought of a nice even creamy texture and tone was very appealing.  Old growth Douglas Fir was the suggestion of another instructor and the thought of the tight grain accentuating the curves of the cabinet was also very appealing.  There was a plank of Curly Eucalyptus that is absolutely stunning but probably a little too crazy for the outside of the cabinet.  I have a plank of Eastern Swamp Ash that I picked up in Michigan while driving across the country this summer.

Spalted Sycamore

Suddenly and not unexpectedly I was trapped in plank purgatory overwhelmed by the endless options for the cabinet that I might build.  Late in the week as I was rummaging around my workbench I came across a stack of Spalted Sycamore veneers that I had cut on the last day of school last year with fantasies of some summer project. They had quite a bit of vertical character like the Douglas Fir that would show off the curve of the cabinet and they had a whole bunch of crazy drippy graphics like the Curly Eucalyptus.  I thought they looked great and I had plenty of them.

Mahogany

The Spalted Sycamore looked great on the carcass but was not an option for the top of the cabinet.  I wanted something rich and homogenous and complemented the colors in the Sycamore.  Back to the wood room and more digging.  Another day in plank purgatory and in another bout of frustration I rummaged around my workbench and came across a piece of mahogany that I had used last year to test various finishes.  I held that up to the Sycamore and BAM!, that looked pretty darn good.

At this point I could not discern if the beauty of Spalted Sycamore and Mahogany combination was due to serendipity or exhaustion.  I decided I would head to Kinkos over the weekend and do some digital printing so that I could hotrod my mockup next week.

 

Mockup with digitally printed wood grain from Kinkos

Week 2 – Forms

This year I am going to try and postpone as many decisions and plans as long as I possibly can in the project.  Last year I spent a lot of time thinking about the construction process and planning too far into the future.

Unlike a solid wood project where I need to select your wood before I can start, a veneered project allows me to postpone this decision because the core of each panel in the project is constructed of plywood and glue.  A not so nice thing about veneered projects is that you spend a few weeks creating the wood that is used as a substrate for the project.

The starting point for this project is the creation of a master template on which almost all the curved panels in the project will be based.  First I created a template of the outside shape of the project on the bandsaw and cleaned it up with a spokeshave.  I then decided that I would split the project down the center so that I would have a set of left panels and right panels.  Each side of the project would consist of the door and a back panel.  I don't know exactly how big my door will be at this point, but that does not matter since I do know that the shape of the door and back panel will match the master template.

Master template of bending form for cabinet door panelsI picked one side of the master template (let's say it was the left side) and decided that this would now be the shape of both sides.  I made a copy of the left side of the master template plus about 2 inches of the curves into the right side, because I needed to be certain that the edges of the panels would transition smoothly across the left/right boundary.  I decided that my doors would be a little over a 1/2 inch thick, there might be up to a 1/8 overhang of the top (but it really doesn't matter because I can always make the top a bigger version of the master template and nobody will be the wiser), I guessed that my bending form might me skinned with two layers of bending ply, and thus I decided that the ribs for my bending form should be 3/4 inch smaller than the master profile of the cabinet.  So, I took my master template to the shaper table and proceeded to create a copy that was exactly 3/4 smaller than the master.

Assembling the ribs of the bending formI then proceeded to make identical copies of the the master template from 3/4 inch MDF.  Each copy had three index holes that I used to align the template as well as align each copy with the next.  I had originally planned to have a  1 1/2 inch gap between each rib but was convinced by the instructors that their experiences with that large of a gap did not result in a smooth form.  I decided to go with a 3/4 rib and 3/4 inch gap and assembled 21 copies of the rib together to make the skeleton of the form.

Bending form skeleton with handles I was also advised to put some handles on this monster so that I could get it in and out of the vacuum bag more easily.  I added some handles and attached the ribs to a base and had a bending form ready to be skinned.  The final step in the process was to wrap the ribs in a skin of bending ply.  I spent a few hours doing dry runs and figuring out how to apply a skin, how to load the huge form into the vacuum bag, how to orient the bag and platen, how to seal the bag, and how to maneuver the excess material of the bag as the air was being sucked out.  I then mixed up a batch of Unibond 800, smeared it onto the ribs, popped a couple staples into the skin to hold it in place, and loaded the entire form into the press.

Skinning the bending form in the vacuum press