CARBON FIBER
makezine.com/09/primer
C
2. Cut the mandrel to size, making sure that it’s
very straight along its length, so it will slide out
of the hardened composite after curing. You can
ensure a straight edge by cutting the MDF using
a fence on either a table saw or band saw (Figure
C). Then use a router with a ¼" round-over bit to
replicate the fillets (rounded edges) along the
D sides of the iPod (Figure D).
E
3. In order to form the bottom of the case cleanly,
the mandrel needs to have a slight flange for the
carbon fibers to wrap around. Create this flange
by marking its location 1" from the bottom of the
mandrel, then cutting a 1" deep groove around the
mandrel with a band saw (Figure E). Trim off the
excess on the flange with the band saw by using a
F block to hold it squarely in place (Figure F).
4. Wrap tape over the mandrel if necessary, to build
it up to the desired dimensions (Figure G). Be careful to keep out any wrinkles or bubbles.
G
5. Create a removable sheath for the mandrel by
wrapping it with either polyethylene sheeting taped
to itself, or with clear packing tape (Figure H). I cre-
H ated a tight, removable sheathing by wrapping the
packing tape around the mandrel sticky side up, and
then wrapping it again sticky side down (Figure I).
Fig. C: Cut the mandrel.
Fig. D: Replicate the
fillets with a router.
Fig. E: Flange cuts.
Fig. F: Vertical flange cuts.
Fig. G: Blue tape wrap.
Fig. H: Clear tape wrap.
Fig. I: The finished plug.
Fig. J: Clamp blocks.
I
Fig. K: Insert marking.
. Cut 2 clamping blocks out of MDF scrap, making
them the same dimensions as the mandrel, without
the extra 1" of length. Cover the blocks with packing
tape to keep them from adhering to the composite
during cure (Figure J).
MAKE THE BELT CLIP
1. If you’re adding the belt clip to your case, mark and
drill two 1" diameter holes on one of the clamping
blocks, in the location and spacing that you want
for the clip’s screw mounts.
J
2. Mark and drill holes in the mandrel at locations
that match the ones drilled in the clamping block
(Figure K). These are pilot holes for the set screws
that hold the T-nuts during layup and cure, so make
K them slightly smaller than the screws’ diameter.
3. Tighten the set screws into the mandrel so
they are exposed at least ¼" above the surface
(Figure L).
168 Make: Volume 09
