| Preparation of
Composites For Bonding |
| |
| In all bonding and
coating operations, surface |
| preparation is a key
operation. GRP and carbon fibre |
| are notoriously
difficult to bond due to the presence of |
| resinous material on
the normally smooth surface. |
| Grease or dust also
compromises effective adhesion. |
| |
| The Vapormatt process
utilises water and fine abrasive |
| in suspension,
delivered by a slurry pump and |
| accelerated by
compressed air to a process nozzle |
| which is directed
manually over the surface. The action |
| of the slurry scours
the surface leaving a thoroughly |
| clean and lightly
abraded result. The water can be |
| heated and mild
detergent added to ensure grease and |
| oils are removed. |
| |
| The ratio between water
pressure and air pressure in the |
| process nozzle is
variable to allow a "water buffer" to be |
| maintained between the
abrasive particles and |
| processes
surface. |
| |
| This water buffer has
several effects: |
| |
 Lubricates
the action of the media. |
| |
| Eliminates
static build up. |
| |
| Washes the
surface continually during processing. |
| |
| Prevent
impregnation of hard abrasive particles into the soft resin
surface. |
| |
| Prevents
fibre damage. |
| |
| Until the Vapormatt
process was used, manufacturers |
| used a combination of
peel ply and hand abrading using |
| wet and dry abrasive
papers. The latter leaves an |
| uneven surface and the
part still needs to be chemically |
| cleaned to remove
surface contamination. |
