So, I managed to get the wet-lay done last night. It took a couple of hours and about 4 litres of resin. The stuff I was using was simple non Lloyds approved resin from Leeds Fibreglass Supplies which worked well. I mixed it at 2% catalyst and in 2L batches. It only started to gel-off right at the end of the tub, which was a success. Also, the resin was pink not blue, and turned gray as the catalyst started to activate.
The part came out of the mould in about 90 minutes which was a fair fight. I’m really glad I used PVA again because it’s water soluble. You just get a thin wedge in (I used a plastic bog-spreader) and spray some water down. It slowly starts the separation and all is well. Keeping forth the birth metaphor, you can see the birthing remains stuck to the part. PVA is like a skin (rather than EasyLease which is a chemical barrier).
Here’s a nice shot down the top of the tunnel, or chute, or birth canal, if it were. What you can’t see is the quality of the surface finish. It’s actually quite shiny but there’s little sunlight to reflect off it (cloudy overcast day).
It’s not all perfect though – no matter how much resin I poured on and how manic I got with the bubble-buster (i.e. special wet-lay roller) I just couldn’t sort some of the white patches and it’s come through the mould. There’s the odd bubble between the layers (which I will live with – this is the master buck, not the part) but there’s also some dry patches of glass on the face.
Next steps are to dress the surface issues and then seal for a part … can’t wait.
- Making a master part from the failed mould was the right thing to do. Not only am I confident I have a good part but it was a step forward after the frustrations of the mould not working due to bad mould material choices.
- Thoroughly wet through the first layer. Don’t get resin on most of it and then try and catch up later. If I’d done this, even though I may still have had bubbles, I wouldn’t have had dry spots.
- Filleting wax is great.
- I rushed this a bit because I was concerned resin would be gelling off. Not so.
- 2% catalyst was right for this part in these temparatures. I was working with “winter catalyst” which is more aggressive.
- Laying large (300mm) strips down the side into the middle with lots of overhang into space means the glass is balanced on top of the part and doesn’t fall down into the mould. Once set, the overhang can be cut off and reused in smaller bits.
- Having lots of supplies (i.e. spare glass and resin) means you’re not fretting about running out (which I did last time) which meant rushing.
- Styrene stinks, and gets through the brick-work from the garage into the house. I need to think about what to do here.