Monsterbike 2013-11-26 Getting its carbon skin on the positive mould.

Working with positive moulds is quick, but ...not so easy. Anyway ...waw ...what a view. I will love to drive this black beast.

Monsterbike 2013-11-26 Getting its carbon skin on the positive mould.

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Maybe I'm confused about terms, although 'positive mould' seems clear enough. It's what also gets called "the Buck" or the "Male". Later you'll take female moulds off it, and these will be used to make the actual body sections?

In which case, why are you using expensive, way over-spec. CF cloth to cover it? The practice in England is to make the buck out of pretty much anything to hand, chicken wire (mesh) plywood, etc., covered with automotive bodyfiller (cheap polyester/clay mix). The (production) Voyager buck was bodyfiller over PU foam for instance. Once the female moulds are done the buck is usually scrap, being fragile and heavy. A lighter, more robust, one-piece, GRP male can be taken out of the female mould (before the panel breaks and flanges are added), if needed.

I kinda suspect that this is the actual bodywork? That would explain the CF, although my supplier (Matrix Mouldings in Bristol) suggests that epoxy/glass is the best cost/effective option, with the cost of CF making it a high-end option where ultimate strength trumps everything else. Most of the strength/weight imnprovement avaiable in GRP comes from using Epoxy resin (they tell me). Part of the problem with CF is it's very unfriendly collapse state - splinters basically.

Go on, tell us more!

Re: Puzzled

Royce, indeed ...the CF is the outerskin of the bodywork. I just made this Monsterbike to show off a bit. ;) I need to promote my firm a bit, don't i.

As i never knew if there would be any interest in my work i planned to make a single prototype and safe on money by not making female moulds. I hope to catch attention with my design. If it works fine, i plan to make negative moulds, but ...i would redo the shaping a bit to my new experiences with this prototype.

All i can say now is that i might have done a bad decision by making no female moulds ...even for a single prototype. The body will not be as good as it could. And i need to work now with a body that is vertical. Not easy to place reinforcements when the work goes vertical. In a female mould which lays horizontal all is much easier. Anyway ...a good lesson learned.


I think it makes complete sense to do one-offs as you are. It's exactly what I'm doing and for the same reasons, to save money and time on a prototype. If it works you can always take female moulds off it.

I'm impressed by the CF surface layup. It's a challenge to get a perfect, clean layup with a transparent resin!

The (French) Sicomin epoxy resin I use doesn't run off vertical surfaces, It's stickly enough to layup onto an underside surface with no risk of peel, no liquid phase during cure. It is transparent but I do all the surface finishing in an lightweight (epoxy/glass bubble mix) filler, so the glass layup is not visible.