Bad day yesterday – turning the patterns into moulds
The task was to lay a coupling coat on top of the gel coat on the patterns, the coupling coat comprises special resin that adheres well to the gel coat and has a layer of fine 100g glass chopped strand mat stippled into it. The fine mat apparently has less of a tendency to show through to the gel coat and acts as a bonder for the later 4 layers of 350g heavier glass chopped strand mat that provides ultimately the rigidity for the mould.
I decided to progress further with those patterns that had not evidenced too much blistering on the second gel coat just to see whether I could get away with it.
With the kitchen scissors, I cut the 100g mat into shapes that would wrap around each individual pattern allowing at least 25 mm surplus around the edge. The coupling resin was measured 100ml and mixed with the catalyst 3ml and the chosen patterns were wetted and the 100g mat laid on the top. I started with the sprocket cover and could not get the 100g mat to follow the contours, it kept moving and you could see the air gap as a white instead of resin coloured finish, I moved on to the ignitech enclosure and had a bit more success but still the white patches remained. All this took too long and as I moved onto the inner ring for the headlamp the remaining mixed-up resin (about 60ml) in the marmalade jar went solid. I quickly detached all cut shapes of 100g mat from the other patterns.
The white patches mean that the gel coat will be separated and unsupported by the coupling coat. I will have to finish these 3 moulds, separate them from the patterns and re-make them. In future the 100g mat will be cut to shapes that fit the intricacies of the pattern, rather than trying to be forced to follow the contours under the pressure of the stippling brush