HOMEWhats
important
to me
Indoor
DuctedFan
Learjet31A
Outdoor
EDF depron
Learjet
What is
DEPRON???
Depron
moulding
Hot S-400
PIBROS
My other
homebuild
R.C.Aircraft
 klik hier voor
de nederlandse tekst. |
The problem with depron is, that it
does not behave like an ordinairy sheet of plastic that
you can vacu-form. It will immediately go out of shape
when it is heated. It will warp, get thicker, more
brittle, and shrink its length and width. All this is due
to the fact that there are countless isolated, gas-filled
cells in it. When you heat depron, the heated gas wants
to expand desperately. As soon as the base material
becomes soft enough this expanding will immediately begin,
with all those unwanted side effects. Thats why you must
enclose the depron on all sides, when you heat it.
The general idea is
to shape, wrap, form, a sheet of depron, by hand around a
heated wooden core or mould. In fact I cold-crush the
depron to shape (without cracking it).Then to wrap clear
tape tight around the whole outside (this forces the
depron to follow the shape of the mould, and prevents it
to increase in thickness in the oven). After this the
whole thing must go in the (kitchen)-oven, followed by a
cooling off period outside the oven. This controlled
heating and cooling fixes the shape of the mould into the
depron, and restores the original strength of the depron,
that was partially lost when cold-shaping it.
An other problem is that
deprons ability to change its shape is much more limited
than normal "vacu-formable" plastics. Because
of this I had to split the lear fuselage into 5 sections
and glue these sections together.
A few important hints:
-Use an elecric oven with a good thermostat and indirect
heating with air circulation.
-Heat the wooden mould in the oven for 20-30 minutes at
90 deg.C (194 deg.F.)
-Heat the taped depron-and-mould for 15 minutes at 80-90
deg.C (176-194deg.F.) in the oven.
-Cool off outside the oven for at least one hour.
-Glue depron with (clear) polyurethane glue. if this glue
cures too slow, mix it
with a little water
 |
| These
are the moulds used to shape the fuselage of the indoor learjet |