If not obvious from the title, this is going to be a long blog post. I first came up with the title and then wrote the blog and in the end, didn't separate it into parts...so while it's a fabrication, it's still a tip of the cap to what's coming.
And what's coming is a flurry of words and pictures that may or may not make sense. Which is kind of weird, because flat surfaces shouldn't be all that confusing...so what's going on here? The basic answer is: I can't use solid wood for the top. Solid wood moves; it expands and contracts with the seasons and my desk construction doesn't allow for movement. To accommodate the design, I have to apply veneer on top of a stable inner core. Often that core is plywood, but in this case, I've chosen the Swedish path...the path of the Swedes...that starts with a bunch of poplar sticks.
Magically, and with hardly a mouse scroll, I turn said sticks into this:
Poof! There's the top...done. But hey, that's not a very long blog post! And you're right...I went straight from appetizer to dessert. I've decided to give you a choice over the meat and potatoes portion, so if you have some time (who doesn't?) and an interest in alternative veneer constructions (who does?), then by all means, click the link, keep on reading and I'll keep it...educational.
You stayed with me, good for you! As a reward or punishment I'm going to do something different...a blog a la Memento. A pretty good movie with some original storytelling and Guy Pearce, but what it means for this post is that I'll be going backwards, peeling the layers, so to speak (no, actually literally), off my top until we get back to the poplar sticks. This could totally bomb...but whatever, let's try it!
First...or last, is gluing up the outer veneers, the final surfaces. Over such a large area, clamps do not work very well, so options are a hydraulic press (like in Terminator) or more realistically and still pretty cool...a vacuum bag! It's basically like this...but for woodworking.
Attached to a little motor, the bag, platen and top stayed sucked like this for around four hours. Given that this whole system was on top of the table saw, it basically knocked out use of the machine room for half a day. Fortunately, I picked the right time...Noah was off to work and I had an evening of no responsibilities and a good book. Here was the set up.
Before I brought all these separate pieces down to the machine room to apply the final veeners, this is what it looked like.
Ok...some explaining is necessary. First...yes, that is another layer of elm veneering, it's essentially a two layer Russian doll. I'll explain that later though.
What takes priority now are the three blocks attached to the sides. The front and back are elm and the ends are poplar, but regardless of the wood type, they are all captured edge bandings. Umm...what? Yeah, edge bandings, or bake-ins, if you care about non-technical CR terminology.
Their purpose: given that veneers only cover the top and bottom of a surface, you need to apply solid wood to all the edges in order to hide the composition of the inner core. As you'll see the front and back thicknesses when all is done, I had to use elm for those sides. The poplar ends however, will be hidden by the joinery between desktop and leg frame, so material choice doesn't matter.
Make sense? I did say it was going to be a tough one...but there's a chance for further crystallization below. Anways, after subtracting all four CEB's...we're now able to see the ends of the poplar sticks after a square cut on the cross-cut table saw.
This next picture will help in understanding the role of bake-in's...notice the front edge below? It's solid poplar...the side of one of the many sticks of the inner core. If I hadn't applied an elm edge banding to it, you'd see that non-matching white face while sitting at the desk. While potentially cool to mix-match different woods in a project, that's not what I wanted here.
Just a few days ago I was wondering where all my blue tape went...I guess this is my answer. The tape was not a poor man's clamping system...it was just the best way to prevent the veneers from slipping/shifting while moving it into the vacuum bag, round 2! Or 1. Bag pressure again works similar to this really sweet product. If you hunt or fish, you just have to get one.
So, why did I have to foodsave my desk top twice? Or, why did I need two layers of elm veneer on top and bottom? Well...it's basically for strength. The sticks, as you'll see in a moment, are not attached to one another, they are merely spaced evenly apart. For rigidity, they must all be bound together and the inner veneer serves that purpose. Once held together with glue, the core is stable and strong.
The poplar sticks were planed together at the same time guaranteeing an even thickness. The spacers are used to expand width but also ensure stability. If sticks were touching they'd move as one solid piece of wood (bad), but now separated, wood movement is eliminated.
And mercifully back to the beginning...
Phew! There you have it...a complicated process brought together with a needlessly arduous form of blog writing.
There's still one question left to answer though and that's...why did I go through this overwrought process of double veneering and poplar stick separating when plywood is a stable, satisfactory and ready-made product? Yeah, that's fair. Answers: 1.) As mentioned earlier, this is how they do veneered panels/surfaces in Sweden and I liked my time in Sweden, so there you go. 2.) I didn't want to buy a whole sheet of nice plywood...$$$ 3.) And the best reason...plywood comes in limited thicknesses and I wanted my top to be exactly 28 mm thick (yeah, I use metric, another thank you to Sweden), which means I had to thickness my core to exact dimensions. As you can't plane plywood, I was forced to make it myself.
Ultimately, it is time-intensive, but I'll take it as it worked great and the last element of my desk is nearly complete.
Next blog will be simple I promise...for all our sake's.