Rear Fender Moulds. Stagea Update (Patreon)

Following on from the last update, I finished the polishing on the plugs and added the flanges for mould making. Went around all the edges with filleting wax to round over any sharp corners or overhangs.

After applying 5 layers each of TR-900 Mould Sealer and TR-910FD Mould Release Agent, the gelcoat was sprayed on. I find spraying is best with moulds as I've had some trouble in the past with brushed gelcoat being a bit too thick in the corners, resulting in shrink back that totally ruined the mould surface. Tooling gelcoat is quite pricey so I like to screw up with it as little as possible.Gelcoat is by far the trickiest step in fiberglassing. It's the most unforgiving and even if the application goes well you can still get wrinkling from the following layers. In the video I showed that I actually had some trouble with this batch setting too quickly. It turns out that was caused by the MEKP catalyst I used not being the right blend. I restocked and found that they now provide this gelcoat with a slightly less reactive MEKP so even when mixed at the lowest rate of about 1.5% like I did with this batch, it should be a bit more chill.After gelcoat had a few hours to cure I did the skin coat which for me is 1 layer of 30 GSM surface tissue followed by a layer of 225 GSM chopped strand. I think I might double up my 30 GSM layer in future as I think I am still seeing some faint signs of print through showing up in some of my older moulds.Because I wasn't sure about the plastic underneath these plugs, (this was my first time using 3D printed parts and I didn't know if the heat from fiberglassing would warp them) I decided instead of just hitting it with 4 layers of 450 GSM with the tooling resin, I broke the layup up into 2 passes, 2 layers of 450 GSM with standard polyester resin, let that cure, and then 2 layers of 450 GSM with the tooling resin on that. In the next update I'll be finishing off the second part of the main mould and then removing them both and polishing them up to make them ready to make the final fiberglass parts from.Because I still have to shape the sideskirts though I will be leaving the plugs on the car so that any sanding only messes up the plugs and not the new fiberglass pieces.