This tank mould has been WAY more work than I expected but it's finally pretty much done! I have been working on it a lot and you'd never know just by looking at it.. Let's just say I have a new appreciation for custom made composite parts.
So in last post I had pretty much constructed the plug(/form) and it just needed finishing. As it turned out the 'finishing' was probably the majority of the work. Every time I sanded it I thought it'd be the last time and then I sanded through into the fibreglass underneath and had to chop out a chunk and fill it back in with bog and sand again, or else I would find a bubble where the fibreglass was not bonded to the foam underneath it so I would have to cut the whole region out and fill it with bog and sand it again.
Anyway..
After a lot of sanding and filling I was getting pretty close. I threw down a guide coat with cheap rattle can paint:
And sanded it down with a sanding block to get rid of the high points:
You can see there were still some low areas (where the black paint is still on the part) so it got more filling and sanding until I was happy enough with it and hit it with an epoxy primer I had left over from my last cafe racer project. I used this paint because I thought it would be a nice high build which would help me fill in a few smaller holes and hollows:
I blocked this down again got it even flatter and smoother.
Next I had to extend the bottom edge of the plug to allow me to build the mould out beyond the edge of the part. I made this flange by gluing strips of EVA foam onto the base of the plug using Ados F2. This then got covered with polyester resin so that the clearcoat would stick to it (not really sure if this was necessary)
Then a couple thick layers clearcoat:
The clearcoat had my signature look - orange peel, fish eyes, and runs - so it needed some scraping with a razor blade (after leaving it for a day rugged up with an oil heater in the garage) and then more sanding and polishing. I went a bit overboard with the polishing, sanding up to 2000 grit then a cutting compound and then a finishing polish. This made for a great result but it didn't really transfer that well to the mould (I think because of the PVA mould release)
Here's a short video I made for my instagram of the final polish:
https://youtu.be/xdq7ZuSPdyQ
The fish eyes and gaps around the foam flange were filled with plasticine and modelling clay and shaved down with a razor blade:
Finally it got 6 coats of mould release wax and PVA before starting the mould.
Here's a timelapse I made of me making the mould. About 12 hours work condensed into a nice three minute video, I hope you enjoy
https://youtu.be/c7sliT8tXnk
Getting the PVA to have a glassy smooth finish without any runs was a nightmare. I have done it before but never with a part this big. I tried spraying on the PVA with my paint gun and thinned it down with alcohol - both bad ideas.
Eventually after many redos I got something good enough.
After the PVA I painted on the tooling gelcoat:
Then laid about 2 layers of 100gsm woven glass:
The next day I filleted the central flange with bog (using polyester resin means the bog should stick good) and laid more glass over it.
I started with some 200gsm offcuts, then about 1.5sqm of chop strand which was about one and a half layers, and then a full layer of 200gsm as a top layer to cover up the nasty chop strand.
It came out pretty good
bolted together and trimmed:
I missed my original deadline - DGR 2016 - so I guess my new deadline is DGR 2017. Still a ton more to do and I have been inspired to put in a lot more effort into the details after I get this bodywork done. I am thinking I will strip the frame and do something special with it and get the engine casings polished up and a few things like that. Probably won't be finishing this any time soon...
And one more thing, I got contacted about a month ago by photographer Johny Cook ( https://www.facebook.com/JohnyCookPhotography/ ) who asked if I wanted to take the bike out for a photoshoot in the ranges out west of Auckland. I was stoked with the shots he got, this is how the bike is looking right now. Totally excited to get this thing finished now and shoot it again properly with that awful red tank gone!!
If you're still reading find me on instagram @max_betteridge_design
https://www.instagram.com/max_betteridge_design/
And check out the build on my website:
http://www.maxbetteridgedesign.com/building-the-ducati-cafe-racer