Ken and I are now like a well oiled machine. A carbon sandwich panel making machine. Yesterday we finished side B of our first panel containing seat parts, and BOTH sides of the next panel which consists of the bulkheads. We have a pretty good system down, and so far the panels are coming out great – very flat, hard, smooth and strong. The photo above shows the two panels sitting on my warm water heated floor in our TV room. Since winter seems to be hanging in there in Calgary, it isn’t warm enough in the garage for these panels to fully cure.
Following is the step by step process for making a carbon fiber sandwich panel:
1. The above photo shows two patterns for our next panel running almost the full length of the table – something like 26 feet long. I believe these are the two main side panels of the hull.
2. The first step is to roll out poly for the vacuum bag. The plastic is folded on the left hand side and will envelope the entire panel after it is fully whetted out to form a sealed vacuum bag.
3. The next step is to place the Corecell foam core down on the table and bond the individual sheets of Corecel together.
I use a pre-mixed epoxy/micro balloons fairing compound, then place flat boards and weights over each join so that it stays flat.
More photos after Monday’s work!
David Tangye on April 26, 2009
Excellent info. I would love to know the full process, having never done it. Carbon fibre laminates were just appearing 'in my day' in the late '70s. In step 1, how are the moulds made, and what from? Then they are set aside til later? Step 2 is just joining core slab ends, no laminating yet, no carbon fibre yet?
danfmccarthy on April 27, 2009
Just in regard the HPV project, I was just commenting to my wife a couple of weeks ago, "I see all these "How It's Made" and such programs showing how carbon fiber structures are made. But how/where does the actual carbon fiber come from?" I've seen processes for making nanotubes. But nothing for how you get from soot-powdered graphite-whatever into strands of "carbon" to make into sheets for laying up or strands for spinning. Any info on that Greg?
biff on April 28, 2009
Wikipedia has a good description of how carbon fiber was first created, and how it is created now. Under the history of carbon fiber on this page
http://en.wikipedia.org/wiki/Carbon_fiber
danfmccarthy on May 1, 2009
Aah! I tracked the answer about how carbon (or graphite) fibers are made down through the links. No problem talking about how the early fibers were made. But the manufacturing of current high quality fibers is all hidden behind what is termed "trade secrets." They mention starting with "oil pitch," and then the curtain is drawn. That's information that is too valuable to patent. I guess we won't be seeing that on "How It's Made" for a few decades, if ever.
This is similar to the manufacturing of photographic film. I was taught about this quite a few years back. It was explained that to make the emulsions more sensitive there were some techniques so old everyone knew them. But most of what Kodak, Fuji, etc. did was tightly held trade secrets. It was commonly known that why the techniques worked frequently wasn't understood. Not surprising since exposing a grain in a film emulsion is a quantum mechanical effect. And "weaving" carbon atoms together also involves working with atoms/molecules at that same level.