Hi guys
This discussion has got me wondering about different types of foams. I was
advised to use the 24KG/M3 polystyrene foam nine years ago when I started
building and it has served me well so far. I am now getting ready to build
the outer wings in which there will be aluminuim fuel tanks. Although the
tanks will be ally, I just can't bring myself to build the wings out of
polystyrene foam. The last thing I need is to develop a weep from a hose
clamp or something and have the wing turn into an aerodynamically shaped
jelly.
The only polyurethane foam I have seen is the stuff used in the thermal
insulation business. It can be purchased in sheet form of various
thicknesses or as a two-pack that is mixed and poured into whatever needs to
be insulated. The sheet is very light and ridgid and sands very very easily.
When sanded, it forms very fine dust and produces a very good product. What
concerns me is the fact that the surface of the product seems to always be
shedding this "powder". I would imagine that the surface would seperate
quite easily from the glass even if a micro slurry is squeegied into it. It
also has the tendency to crush and not "give" when pressed by a fingertip
whereas the polystyrene has a certain amount of "spring" in it and will
return to its original shape--within reason.
My question is this: Is this polyurethane foam the same animal that you guys
over there are using.
P.S Mark J, I tried to look at the sight you refrenced regarding your wing
tanks but all I get is the top pic showing all the necessary tools & equip
needed for the job?? (http://www.krnet.org/wingtank/ )Also, how did you
secure the tanks to the spars?
Sorry for taking up so much bandwidth.
Dene Collett
KR2S-RT builder
Port Elizabeth
South Africa
mailto: dene.coll...@telkomsa.net
P.S: checkout www.whisperaircraft.com
