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rcs_888

R34 Sports Sedan Build

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Go with what Soric specify in their data sheet. I actually meant 550g per m2 per mm thickness, so that's about right. But I couldn't remember exact numbers, it's been awhile since I used Coremat. 1kg per m2 for 2mm thick Coremat seems right.

 

Resin ratio for wet layup of woven, unidirectional or stitched (double bias is a stitched material) is 1:1. So for a 400g DB, you will need 400g of resin per square metre per layer. 

 

Your layup schedule sounds good. Make sure you add an extra couple layers of the double bias in the areas where the bodywork is going to be mounted to spread those loads. Also if you are going to use bonnet pins, leave the core out of those areas and do extra double bias. Cores don't like compressive loads, so better to make those areas solid fibreglass.

 

Happy to help man, that's what forums are for! Looking forward to seeing you nail this layup, then later I'll talk you into redoing it in carbon 😉

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31 minutes ago, Unzipped Composites said:

Go with what Soric specify in their data sheet. I actually meant 550g per m2 per mm thickness, so that's about right. But I couldn't remember exact numbers, it's been awhile since I used Coremat. 1kg per m2 for 2mm thick Coremat seems right.

 

Resin ratio for wet layup of woven, unidirectional or stitched (double bias is a stitched material) is 1:1. So for a 400g DB, you will need 400g of resin per square metre per layer. 

 

Your layup schedule sounds good. Make sure you add an extra couple layers of the double bias in the areas where the bodywork is going to be mounted to spread those loads. Also if you are going to use bonnet pins, leave the core out of those areas and do extra double bias. Cores don't like compressive loads, so better to make those areas solid fibreglass.

 

Happy to help man, that's what forums are for! Looking forward to seeing you nail this layup, then later I'll talk you into redoing it in carbon 😉

Carbon is the eventual dream and i was checking out your website the other night and thinking that oneday i might have to fly over and do one the the workshops ;) Do you think this current mould would work for carbon? the surface finish is far from mint and my plan was just to wet sand it but unfortunatey the Gelcoat is too thin :( so im guessing that im going to need to do the wax styrene to build it back up to sand it out. 

Whats your thoughts on a rough cost to do it in carbon would you use similar layup layers? just wanting to try and maybe get my head around it and maybe start stockpiling some gear to be able to do it

 

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Yeh unfortunately you'll never get a great surface finish using PVA release agent. It forms it's own surface, and even sprayed, it will get bits of dust in it and not lay down flat etc. It has it's uses, but I use it very rarely these days. Semi-permanent chemical release agents are the way to go.

 

There's no reason your current mould can't work for carbon. The biggest issue would be whether you have used a polyester or vinyl ester tooling gelcoat, as you would want to use epoxy to make your carbon component and epoxy isn't compatible with polyester, it will stick to it. If you've used polyester, then to use your current mould you would need to spray PVA release agent in order to build up a nice thick film with absolutely no fish eyes or porosity where the epoxy can come into direct contact with the mould surface. 

 

For that reason, I wouldn't bother trying to sort out the surface finish on your current mould. I assume you'll be painting the fibreglass bodywork, in which case that will sort out the finish on that, and if you do end up using it for carbon then you'll have to use PVA anyway and then clear coating the carbon will be the best way to get a decent surface finish on that.

 

In all honesty though, I wouldn't bother with trying to wet-lay carbon. You really need vacuum to get good consolidation and get full advantage of the strength to weight, and if you've got the equipment for vacuum then you may as well be infusing to really get a perfect result straight from the mould. To infuse, your current mould may be a bit troublesome. The flanges are quite small, so you will struggle to position your consumables and get a good seal, which is critical. Really need a 5" flange for infusion. Then with infusion as I mentioned above, you can get a perfect surface finish straight from the mould - so then you would want your mould surface to be vinyl ester and have the surface finish you want so that you can use a chemical release agent.

 

Carbon layup could be quite a bit lighter than the fibreglass layup. On the bonnet section I would do a single layer of 200g twill, a 2mm core, and then another layer of the 200g twill. The fenders and front bumper sections don't need the core, they could be a single layer of 200g and a single layer of 450g and that would be plenty strong enough. Extra reinforcement around the mounting points again and you're dusted. With infusion, you should be able to get the total weight of the entire front end down to about 4-5kg. 

 

If you get the chance, definitely come over for one of my courses. It's a great 4 days, bunch of fun, you'll learn way more than anyone can handle, and it's worth it just for the lunches 😉 haha seriously though, if you're interested let me know. For my interstate guys I try to do 4 days in a row rather than splitting it over two weekends. You lose a bit of the course content because there isn't enough time to post cure the moulds you make to use them with pre-preg, so I have to supply some moulds for that part of it, but it saves you spending a week over here. 

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