Carbon fibre is extremely hazardous when it comes to
sanding and will cause respiratory problems if
dust mask is not used.
The dust will also settle on
every thing in the surrounding area. Use an old vacuum
cleaner (with an inline separator) and hold it against the
area been sanded.
Carbon fibre dust is also
conductive and can get into electrical equipment and short it out.
Preferably use air tools and don't let the dust get into places you may
There is also the problem of handling the edges of
tubes that have been made from carbon, the fibres
themselves in the skin causing blistering
of the skin.
The same caution should be taken with
all fibrous materials.
E Glass 163g - Used for everything, cheap and
easy to use.
Use 85g for a smoother finish.
Avoid it. It won't wet
down easily and causes fury edges
when sanded, cut or drilled.
Most expensive of the three, brittle and
most glues will
peal off or separate.
Don't use it if transmitters are to be housed inside.
You can get rolls of pre made mixes of different fibres.
My favourite combination for HPR is:
For making tubes:- Glass, carbon, then glass again.
For fins:- Glass, carbon, light ply in middle,
West Systems 2 part epoxy has fast or slow
Use the fast drying only in very cold conditions or on small jobs.
Use disposable plastic drink cups to mix the resin
scrap paper to place the cup on during
If its hot weather mix half a cup at a time
otherwise it will get
hot and melt the cup before
you have finished.
Left over epoxy will boil in the cup in hot
weather, have a old
tin can to dump it in or
have a second use for any leftover epoxy.
(Paper weights, fin fillets etc.) Don't rush the job by adding heaps of epoxy.
Massage each new layer of
glass so that any excess epoxy
from the previous
into the new layer.
The fiberglass ends will however get a bit messy and
dry, so you will need to
a bit of extra
and work it in with your fingers.
Creating fiberglass tubes
Making fiberglass tubes is a bit of an art.
Like cooking it
needs preparation, time,
and can get messy.
1 First, find a PVC pipe longer than the size you need and
of a suitable diameter for your design, this becomes your
Mandrel. (Avoid Aluminium tubing unless absolutely necessary.)
2. Polish the mandrel and remove any high spots caused
by scratches etc.
3. The mandrel needs to be turned during the fibre glassing
operation so shove a dowel through the middle of your mandrel
and support the ends with a table, saw bench etc.
One end of dowel will have to be fixed otherwise the whole
job will fall onto the floor when you least expect it.
4. Wrap the tube with "Glad Bake" paper.
The direction you wrap the mandrel is important as the glass
has to be wound in the same direction.
5. Start from LH side of mandrel and hold the starting wrap
with a strong elastic band ( tape wont stick unless wound
around fully) and carefully do a spiral wrap keeping a even
amount of overlap all the way along.
When the end of
mandrel is reached hold it with another elastic band.
6. Go back to start of wrap and recheck that the Glad
Bake is tight on the mandrel with no exposed sections
of mandrel (except at end of wrap) and no large creases.
A few notes before continuing instructions.
Don't wrap the glass over ends of tube or
over the rubber bands/tape.
Don't let the glass get dirty or touch the floor.
Put old news paper on the floor as you will
get resin drops.
Test wrap the fiberglass first to see how
long a length of glass
you need. Or hang
the roll from ceiling as a continuous feed and have an old pair
scissors handy to cut it.
Surgical gloves for small jobs.
bigger jobs as epoxy
through thin gloves eventually.
Your gloved hands will get completely covered
with epoxy so make
sure everything is
ready and nearby as you will not be
reuse the gloves if they have
to be removed.
Things like scissors will get covered
with epoxy so have
thinners nearby to drop them in.
|Wrapping the glass and applying the Epoxy
7. Mix the epoxy and run a bead of it along the mandrel.
8. Quickly drop the starting edge of glass on top. This part can
be the most difficult on big jobs especially if the class is pre cut,
so be carefully it doesn't drop onto the floor and pick up any dirt.
9. Make sure the glass is added in the same direction the Glade
Bake was. If it goes on in the opposite direction the glade bake
will bunch up underneath and you will need to start again.
10. Gradually add some epoxy on the dry parts of the Glass and
work it in using fingers and palm, but don't twist the glass too
much as it will get bubbles.
Removing the glass tube from mandrel
Its hard to give accurate guidance for making fiberglass tubes
as methods have to be modified slightly for tube size, drying time
and type & condition of mandrel.
Warning: Use heavy garden gloves or similar when handling the
tube otherwise you will get glass splinters.
11. Remove any tape or elastic bands. Remove any excess
Glade Bake so that you can grip the mandrel.
12. If you used a aluminium tube or are making a very long
tube, remove the tube just as the glass sets (stickiness has just
disappeared but is still soft).
Tubes will (should) slide off mandrel easy if you slide it
off from the side the Glad Bake wrap was started.
14. If the glass tube stops sliding don't force it, sometimes the
Glade bake folds up underneath. try reversing the direction or
spinning the tube on the mandrel as you reverse it.
15. The Glade Bake will come out easy after it has been
removed from mandrel.
* Try using "Shrink tape" straight after laying the glass then poke
it with heaps of holes before hitting it with a heat gun. This will
remove some excess epoxy.
* If you make the tubes late in the afternoon when day is still
warm, remove the tube in the early morning when the tube is
cold - it comes of easier.
Light but strong fins can be made by using "Light Ply"
between E glass.
For strong fins without using E glass - Try aircraft ply.
The fins in the picture has thin 3ply wood, 2 carbon, 2 Kevlar,
2 E glass
layers each side just to see the result. - wont be using
got furry fin tips. But they wont break :-)
These were made for a rocket that takes "N" size motors.