Jabiru J450, Руководство конструктора, Страница: 16 / 343

Jabiru J450 Constructors Manual
General>Composite standard procedures
Tuesday, April 6, 2010 16 of 343
Composite general
Glassing procedure
Any lay-up of glass fibre cloth should follow this general procedure: make a mix of resin and
brush a coat of resin onto the entire area to be glassed, then lay the first piece of cloth on and
carefully brush it into place, adding small amounts of resin to the brush as required to wet the
cloth, until the resin has completely saturated the cloth: the cloth seems to change colour
slightly from a silvery white to a colour close to that of the surrounding surface when it is
saturated with resin.
Once the first layer of cloth has been successfully brushed on, apply the second layer and
brush that on in the same manner, adding small amounts of resin as required to wet the cloth.
Repeat for as many layers of cloth as the task requires.
Peel cloth
Peel cloth is supplied in the bags of glass fibre cloth in the kit. The intended use for this peel
cloth is to brush it onto the top of a layed-up area of glass fibre cloth.
The peel cloth will smooth out the finished surface by allowing the resin to level off across
the weave of the glass fibre cloth and provide a good surface for painting preparation.
Trimming edges of glass fibre cloth
There are two times for trimming edges, these are before curing while the epoxy is 'tacky'
(approximately 2 to 4 hours after mixing) and when the structure is fully cured.
Various tools are used for trimming edges but for thin or 'tacky' lay-ups a sharp utility knife
may be used. Thicker cured edges may require a jigsaw and a rough file to trim. A heat gun
may be used to soften cured edges so that a utility knife can trim them.
Inspection and evaluation
Each lay-up will require an inspection and evaluation after curing.
Inspect for soft or wet patches after a reasonable time for curing has been allowed, as such
wet or soft areas may indicated an improperly mixed batch of epoxy.
Care must be taken to check that areas have actually been bonded together and that there are
no air gaps or bubbles between the layers of glass, especially in curves/radii.
Removing screws
Self-tapping screws are used to hold parts in place while epoxy is curing but once the epoxy
has cured it can be difficult to remove the screws.
Use your soldering iron to heat the head of the screw and the composite around the screw will
soften allowing the screw to be removed easily.
This is also a handy trick to use if any bushes are not perfectly in line and need a slight adjust.
Clecoes
Clecoes are used to hold hinges while they are being flocked into place prior to riveting and
so they must be free of oil and grease that could contaminate the surface to be bonded, and
they will inevitably get flock onto them during the bonding or flocking process.
To prevent these problems, keep your Clecoe fasteners stored in a sealed tin of Acetone to
ensure that they remain clean and ready for use – the Acetone will dry off them in seconds.