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As title.... I intend to build a GRP hardtop for a roadster, with the shape similar to a soft top. Intention being to use it in the Winter. Wanting to keep the weight as low as possible, and a good enough finish to paint (probably matt black paint).
"a roadster"... as in, a z3? If so, should be able to buy all the clips and fixings for the hard top which they made for the car. Shouldnt be too hard to make a thin metal frame which connects all the bits, and then cardboard, parcel tape and grp to connect them. Same with an MX5, and with the price of those hard tops, I wouldnt be surprised if someone has done that a few times already.
I wondered if something like the lightyear fastback top might be a good starting point, if you can find one (or something like it) on this side of the world (light-year are aussie-based). https://www.miataturbo.net/build-threads-57/carbon-fibre-time-attack-twins-48089/page28/
I've seen it done using a timber frame and 1/4" plywood clad with black vinyl. You could glass over the wood and then paint it, depends on what finish you want.
Thanks for your comments lucky. With your experience of GRP, do you consider a horizontal flat panel of the roof with a total of 1200 gsm chopped strand mat would sag over time? If so, maybe adding 5mm nidaplast honeycomb reinforcement and 450 mm layer under may stop it sagging? roughly 1m x 0.8m panel? I'll be grateful for your opinion.
The Tribute guys could probably take a splash mould of the existing hood and then lay up a basic shape for you. Reinforce it with f/g rope as required.
I'm no GRP expert, best to talk to a laminator for their opinion.
I've tried one of the suppliers to get some guidance - my first thought was to use some coremat in the rooftop to minimise the likelihood of it sagging. the supplier suggested Nidaplast (a honeycomb reinforcement) as it will be lighter than coremat. I used 12mm Nidaplast when I built my caravan, but 5mm will be the one for the hardtop. I don't know any laminators..... maybe they would be reluctant to give their info? But I have a plan. The better weather in Spring may see a start on this, as I plan to do it before I paint the car (in case of spillage!)
Try asking Chris or Dan at Tribute or Gary at Formosa. There's a lot of info on youtube too. There aren't any big secrets , sounds like you are pretty familiar with the stuff having built a caravan ! A small hard top should be quite straight forward.
Try asking Chris or Dan at Tribute or Gary at Formosa. There's a lot of info on youtube too. There aren't any big secrets , sounds like you are pretty familiar with the stuff having built a caravan ! A small hard top should be quite straight forward.
I agree, but it's always useful to get advice from others - there are small things I could do differently if I was to build another caravan, and that may be useful info for someone else similarly. In fact I'd like to build another (of a different design) if only I could sell the one I've got! I do enjoy playing with GRP
I’ve had the thought of using the existing hood, wrapped in cling film and tinfoil, to create an original mold. Then make a more structured part from that.
Thanks for that. I planned to use foam board, but now have a fiendish plan to save effort (because I'm lazy). I'll report back with my result (should be by Summer)
I once saw a JC Midge with a hard top that looked just like a soft top. It was only when the owner tapped on it that you knew it was fibreglass and not canvas. Good luck.