Saturday, January 2, 2010

Just because I could, Part II

In my previous entry, I described how I made the mold/working pattern for a composite carbon fiber bobbin lace lamp shade for my Composites semester project. In this installment, I will describe how I actually worked with the carbon fiber to make the lace.

First of all, I’m sure some people are wondering what carbon fiber is. (I’m pretty safe in that assumption, because some people have asked me, “So, what is carbon fiber, anyway?”) Carbon fiber is used for a lot of high-end uses where strength and low weight are necessary. New planes being built by Boeing and Airbus right now are being made largely from carbon fiber—the Boeing 787 has been in the news lately. Carbon fiber is made by taking another material with high carbon content and basically burning off whatever isn’t carbon. Sounds kind of weird, but it works. So you end up with long, continuous strands of solid carbon. This can then be woven into fabric or used in filament winding (where the fiber is wrapped directly around a mandrel to make the part). If I had followed my original plan to make laptop sleeve, I would have used carbon fiber cloth or prepreg (cloth impregnated with activated resin so you don’t have to add it when you are making the part). But for my bobbin lace, I took advantage of the fact that the lab had several spools of fiber for filament winding available.
At 44” long, this would be the longest piece of lace I’d ever made. Also, as you can see in the preceding picture, the fiber (which is made from many individual strands) is much wider than the thread I am accustomed to working with. So I needed a special set of bobbins to accommodate this unusual material. I got some craft dowels, cut them to three inch lengths, drilled holes in the end, and glued in long nails.
Now, winding bobbins is always my least favorite part of making lace, and these were awful to wind. I took the bag of bobbins and the spool of fiber over to the machine shop, where I could be available to assist students working on projects for the class for which I am a lab assistant. Not surprisingly, everyone looked at me oddly and asked what on earth I was doing. I got that a lot in the course of this project! I miscalculated how many pairs of bobbins I would need, and wound several more than necessary. That turned out to be a good thing.

Finally, I was ready to start the lace. I placed a couple of clamps on the worktable in the composites lab, and laid a piece of release paper across them, to make a cradle to hold the mold/pillow/whatever you want to call it. I also got a box of toothpicks and rubbed a wax mold release into a few handfuls of them. The toothpicks would be the pins for the lacemaking. As usual, I hung the pairs of bobbins on in a diagonal. Honeycomb is a very easy ground to work, which is one reason I chose it for this project. It also can cover quite a bit of area rather quickly, which is another reason. Now, I had originally thought I would apply the resin to the fibers a few inches at a time while working the lace. Quite sensibly, I revised my plan and placed all the fiber for the whole thing before adding the mess of resin. As I mentioned in my previous entry, I have not worked on a bolster-type pillow before. I found that it actually wasn’t much harder than the other pillows I’ve worked with. The only real problem was that the strands of fiber kept getting caught in the heads of the nails on the bobbins, which got annoying. But it worked.
In the preceding picture, you can see the bobbins hanging on the pillow. The edges were worked as simple plaits, and I hung the edge pairs off the sides to keep them out of the way when I wasn’t using them. This only took nine pairs. This next picture is taken from the back, which is why the bobbins aren’t visible. Here you can see the worked lace, and how the whole thing is bristling with toothpicks!
As I worked, I found that I was starting to run out of fiber on some bobbins. I was prepared for this eventuality, though! As I mentioned earlier, I’d wound too many bobbins. So I had some prepared to add in to take over for those that were running out. However, I did it in a different way than usual. I took advantage of the fact that I was making a composite material: I had a little bottle of super glue ready. As a bobbin ran low, I would hang a fresh one nearby, then glue the fibers together. As soon as the glue was dry, I just cut the new fiber above the patch and the old one below. Not a way you would want to replace threads in regular lace, but a method that works well enough when the whole thing is going to be saturated with resin soon anyway! I ended up having to replace almost all the bobbins in the piece at one point or another. When I finished working the lace around the side, I finished off in the same way, by just gluing the fibers to the start of the lace.

Next, I turned the mold so the top was up and stuck toothpicks in all the points I had previously marked and plaited a center circle. I cut a long fresh strand of fiber off the spool, glued one end to the plaited edge at the starting point, and placed it along the marked path, pulling against the toothpicks to make the design. At the edge and center circle, I used a crochet hook to loop the long fiber around the plaits, and did the same at certain intersection points in the design. I placed the fiber along the entire top pattern twice.
Finally, I mixed up some room-temperature epoxy using a hardener that would give me a one-hour working time and 24 hour cure. I used a cheap paint brush to apply the epoxy first to all the lace on the side, then to the top. I paid particular attention to the plaited portions, since they were denser than the others, and I wanted to make sure they got enough resin to be fully wetted out. Then I just had to leave it all overnight and hope I would be able to get it off the mold the next day.


Happy Hound Creative said...

WoW!! I am so amazed!! This is wonderful. Thanks for sharing!

Giggles said...

Exciting! I can't wait for the finish.