In general, when determining a new piece, there are always sequels to past projects to be considered, perhaps doing a mirror image or multiplying the form. Then there are the many paper pieces I have already constructed, awaiting a paper-to-wood conversion. When I want to take a totally new tack, however, it's time to play - sometimes with blocks, or staring at shadows, or making random marks on paper. I have to consider whether there is a function (such as a lamp or table) which demands certain parameters and then an added concern is the requirements of the chosen material (paper, wood, photographs, x-ray film, plaster or Mylar).
This time I decided to make a wooden sculpture based on a previously made paper piece. Before cutting the wood though I had to consider how feasible the translation would be by visualization, making of models and many calculations as angles and other dimensions would need to be slightly altered. As it began to be clear what the finished piece would look like and my calculations indicated the number and size of the wooden pieces needed, it was time to look for suitable wood.
Even though hemlock is my preferred choice, there are still the variables of straightness (avoiding boards bent either left to right or top to bottom), location of knots and other blemishes (splits, grain tears and stains - even staples and other embedded dangers), color, hardness (even within one type of wood), grain direction and annular ring thickness. Having ascertained that enough suitable boards are available, I review the project. Sometimes a piece can be made larger by economical cutting. Sometimes it has to be smaller because of flaws in the wood. It is wise, I find, to allow a generous margin.
When the wood is selected, the milling begins. Firstly I trim the unredeemable knots, bark and flaws. I then select boards who's color and grain match. I pass the boards multiple times through the planer until suitable thickness and smoothness is obtained. I usually add one or two extra boards at this stage to allow for errors.
I mark any remaining faults on the boards with a pencil. I also mark the boards so that after they are straightened with the table-saw I can see where each piece lay in the original board. This allows me to place similar boards side-by-side in the finished work. These precautions allow me to remove boards neighbouring a recalcitrant piece since they might also have a potential to bend.
Now all the pieces are of the same length, though of varying widths. It's time to get the first straight edge. Each piece is trimmed as little as possible, but, of course, all nicked corner edges, rough sawn edges and splits must be dealt with. Each trimmed edge is placed against the saw-fence to make sure that the trimming has rendered it straight. By this time, all the wood pieces have one straight edge.
If I begin cutting the widths at this stage, I would be left with scrap that is one-side rough, so I rotate all the piles of rectangles so that the freshly trimmed, and hopefully straight, edge will line up against the fence as I trim the other side. After running every piece through the table-saw again, I am left with a pile of largely sound, rectangular pieces of uniform length. As I cut the required widths, I find I have to repeat trimmings of pieces that have slightly warped. Since I usually make a sculpture from uniformly shaped pieces, I test cut a piece at this stage. If a piece is needed of an irregular shape, I deal with it first.
At this stage, I rip the large rectangular boards into three or even four pieces. Since the cutting releases tensional forces that might warp the wood, it's important not to use a convexed edge as a guide. The many boards I had started with have by now become a surprisingly small pile of fairly regular rectangular boards. I usually let the wood sit for a few days at this stage to allow it to do any warping it might do as it dries.
The next job is to get one straight edge. The straightest, or most concave edge is placed so it will slide against the tablesaw's fence. The concave section in the middle is shimmed with masking tape or cardstock, so that when pushing it up against the fence, it can't deform, only to spring back after the pressure is released. (warping the freshly cut edge). After moving the fence a bit more than the most warped piece was found to deviate from straight (and figuring that is admittedly a bit of a crapshoot), the straight or shimmed edges are placed against the fence and all the pieces are trimmed. The less perfect side, possibly already straight, possibly a bit convex, is trimmed off straight, after which the newly trimmed edge is checked for further warping. If the piece has warped, it is removed from the pile.
The piles are rotated 180° and, after being sure that all the just-cut edges have remained straight, the second sides are all trimmed straight. Next, the worst end is butted up against a stop and the good ends are trimmed as little as practical. If any pieces are too short, they are trimmed anyway and set aside. After one end is trimmed on all pieces, then the shortest piece is used as a guide for moving the stop sufficiently such that each piece will have its other end trimmed square. Sometimes, even at this stage, a further ripping trim is necessary to remove slivers or developed warps.
All the piles are now laid out flat with pieces laid side by side to be inspected in order to reject any remaining flawed pieces. I decide the best orientation of the pieces at this stage before I make a final diagonal cutting that produces the triangular wedges I finally assemble. Sometimes I only get one good small piece from a large piece.
Before I continue, I check the maths - the total number of pieces required and the angles. Before cutting though, a carrying jig has to be made that, using tape and a hinged pressure handle, would hold each piece securely against the pressure of the sawblade as the rectangular piece of wood is cut into two angled-in-two-dimensions pieces. With the jig ready, the sawblade set at 10° and each piece set to be cut as a 4° wedge, the distance to set the fence back from the blade was calculated and a test piece was taped to the jig, trapped by the hinged handle and cut. Perfect! The tape was removed releasing the first test piece and the cutoff piece was reversed, placed in the jig and run through the saw trimming it to exactly the same size. A few more test pieces (mainly to determine the best way of placing the 90° sides to keep them from getting confused with the 80° sides), checking for straight edges and fit between pieces and I was ready to cut all the rectangular boards into doubly-angled wedges.
After cutting enough wedges for the base, I had to determine how many 80° spares to cut. As such spares often never find another use, I didn't want any more than necessary, but at all costs wanted to avoid the (impossible to do accurately) need to end up cutting replacement pieces after the jig, fence and blade had been moved for the second part of the process. This ends up being an entirely subjective decision based on what the wood looks like, whether it looks reliable or whether it might contain faults or it develop a warp over the next few days etc. On the other hand I was already thinking of a new sculpture and whether there might be enough offcuts from this one to make it.
In this particular piece I had to decide whether to put a transition piece between the base and the rest of the work. I compared it with the original paper form, I made a paper model, and I worked out the math. The paper model decided me, so I phoned my mathematician friend, Roger Servranckx, who came over and confirmed there was no need for a transition piece.
I cut the replacement spares and toyed with an idea for the next sculpture. I then cut the 84° pieces and some spares for them too. I temporarily taped the wedges together that would form the base, and also joined the pieces for the top. Everything was going well until I lifted the top section. Gripping the apex, the perimeter lifted off the table and I could at once see I had made a mistake. The upper cone that I had intended to be nearly flat with edge angles of 84° turned out to be a cone of about 73°. By rechecking the math, I saw I should have made the pieces with 88° sides. But what to do?
I could recut the remaining rectangular pieces or I could try remilling more good rectangular boards. I could recut the 84° top pieces to the required 88°. I took a second look. Although it was different from what I had intended, it had the potential of being an interesting form. Considering the time and material that would be used up in making the correction I opted for the ``chance'' new form.
Breathing a sigh of relief, I started in on assembling the wedges. In theory using the right glue, it should be possible to tape all the 29 pieces tightly together like so many pieces of pie. They should be secure enough so that after covering all the edges in glue, the wedges could be wrapped in a cone shape and held there against the tension of the masking tape until the glue was dry. In practice, however, what happens is that there is never enough time. Lubricated by the wet glue, the wedges slip and move. Glue gets squeezed out often leaving the joint dry and the table, your hands, clothes and, most important, the sculpture, a disgusting mess. Unfortunately I had taped the whole 29 wedges.
I cut the cone into three sections and prepared glue spreaders (trying to avoid splinters). I used soda straws for pushing along the glued line. The straws gather most of the excess glue inside them. Paper strips stretched the masking tape to make room for the glue. I then started to glue. I covered the edges and let them dry out a little before hand-holding the 10 wedges together for 20 minutes. I had used too much glue and , in fact ended up using a load of paper towel. It was only after I had glued together the remaining two bunches that I saw another mistake! The hand-held pressure had caused the bundles to bend in the middle and the edges which should join one bunch to another unfortunately showed a gap in their mid-section. I made a planning jig and rejointed the five offending edges. The cone formed up perfectly.
Determining not to repeat the mistake with the top of the sculpture, I taped an uncut, straight, rectangular board on each side of similar bundles of eight or more wedges. This distributed the clamping pressure and being taped on, protected the edges from inadvertent glue. Using less glue and having more straws available, the job was much less messy. The edges of the sections to be joined were still not straight, but after much sanding and many trial fittings eventually I glued together the last set of thirds. I retired for the day.
The next morning, to my dismay I could see that the edge that would join the base to the top was not straight. How to smooth this edge right up to its apex? I, after much searching, ripped a piece of oak off a cupboard door I had stashed in the basement and fastened strips of sand-paper to each side. Moving very carefully back and forward it took ten-minutes (I had spent three hours looking for a solution though). With the edges of the upper and lower cones protected, I sanded the whole piece, first with 60 grit paper on a belt sander and then by hand using 60 grit aluminum oxide on the flat side of a rubber sanding block. I used the curved side for doing the inside of the base. This was fine for the lower inside portion, To get to the apex inside, I wrapped more 60 grit paper around a bit of 1/2 inch water pipe insulation wrapped around a 1/2 inch dowel. For the last little bit I switched to a 3/8 inch dowel.
The whole sanding was repeated with 100 grit paper and again with 150 grit. When all was smooth, I did a final taping gluing the top and bottom cones together. Next day a few hours sanding finished the project. I rested a day or two and then I wrote up the whole process, did the quarterly GST, the yearly income tax, prepared slides for duping to send to galleries, worked on a mailing list, brochure and poster for an upcoming show - all things I had neglected sadly while working on Enwrapped. I was ready for the next project, a sculpture more closely matching the original paper piece that had started all this.