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The mkiv Supra Owners Club

carbon Fibre Replacement dash


Guest trackday addict
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Im afraid I dont have any pics of a dash as I've never done one. The part that is visible doesnt look hard, but I havent a clue what the back of the dash is like where it fixes to the chassis.

 

I have a pic of a front splitter/understray assembly for a race car (cant remember what model of car) thats shows the non-shiny rough CF finish but it doesnt really do it justice as it was taken on a camera phone plus the composite has some dust on it.

 

Basically, when making a composite under vacuum you have numerous layers that you use to both hold the CF in place whilst still allowing resin to be 'sucked' out under vacuum. One of those layers is peel ply, which you rip off the final product leaving a rough surface ready for paint/lacquer. You can see the weave fine but instead of a smooth shiny surface, you have a rough dull surface.

 

That Ridox one looks the nuts and if you can get one of them it would be alot cheaper buying one than getting one made over here (as you'd need to get mold made also)....unless you had a GB which would share the cost of the mold.

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I think its gonna have to the mold route unfortunately, I've contacted John...hopefully he still uses the same email address, but I think it will be way out my price range for my interior budget, never know

 

Orido's turnaround is very slow, and I gather that was a custom part,

 

It does look really good though!

http://www.envyperformance.com/picasa/RSR/images/dsc00220.jpg

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I'd imagine the mold would be quite costly as it would require a lot of work on it to give a super smooth surface like the one shown as the supra dash isnt that smooth (atleast mine isnt lol).

 

I have found a pic of the dull cf splitter/undertray I mentioned above - have attached it but like I said the picture isnt that great Im afraid.

cf.jpg

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What methods are used to make the mould

 

Making a mold isnt that hard though it can be messy and expensive depending upon the type of mold you want to make.

 

Basically you take the part you want to mold (in this case the dash) and prepare it for molding by:

 

:: Blocking off any holes on the surfaces you will be molding (aluminium foil tape is great for this)

:: Wax it several times to reduce the chance of the gelcoat sticking to the surface

:: Apply a release agent like PVA to aid the release of the part from the mold.

 

Now you choose what type of mold to make. You can use Polyester or Epoxy based products. Polyester is cheap and cheerful whereas Epoxy is generally more expensive.

 

When making a CF composite you should ideally use an epoxy resin as opposed to a polyester based one as epoxy resins tend to have higher structural properties.

 

There is nothing stopping you creating a polyester based mold to create epoxy based composites as long as your using an epoxy resin that cures at room temp (therefore not requiring any high temp curing).

 

However, if your going to be making a CF composite from a resin that requires a high temp to cure you'll want an epoxy based mold. This 'matching' of resin types will ensure the mold and composite expand/contract at the same rate when cured in an oven at high temp (note you can make you own oven from kingspan insulation material - you dont need a proper autoclave).

 

Polyester

Basically:

 

:: apply an even layer of gel coat and leave to tack off

:: apply a 2nd layer of gel coat which is a different colour to the previous one and leave to tack off

:: wet out the mold with a polyester resin and use chop strand mat to build up the mold (5 layers of 2oz should do) ...wetting out each layer of CSM as you go

:: roll each layer to remove any air bubbles in the mold.

 

Here's a vid pretty much showing the process of building a mold with CSM: http://www.youtube.com/watch?v=DEa5_WHQZo0&feature=related

 

Note: He is spraying his gelcoat and PVA release agent on, you can however brush the gelcoat on and use a cloth to apply a thin even layer of PVA release agent. He also doesnt mix gelcoat colours.

 

The 2 layer alternate gel-coat approach is handy when you come to flat the mold. Lets assume the 1st layer is blue and the 2nd layer is white - as your flatting the mold, if you see white gel you know you are through the 1st layer of gelcoat and could be close to going through to the actual glass fibre beneath (best avoided!)...so think of it as a warning system :)

 

Epoxy

There are numerous epoxy tooling systems available, each one has its own process for making molds. The process is similar to the polyester process above (gelcoat, then resin and material), except the tooling system may only allow 1 layer of gelcoat (varies depending upon what your using).

 

I use one called Polydur, which Im pretty sure is the same tooling system as the one used by the laminators in the 'carbon supra' thread on here not that long ago, but its bl**dy expensive (you have to buy a minimum x amount of materials). Applying it is like paper mache, fun but smelly :)

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Thanks for that, how long do you reckon it would take and cost of materials e.t.c, just trying to get a rough idea of how much a mould would be

 

Another question for ya, you see the weave in that RS-R Dash, it looks nice and aesthetic, but then you see a lot of weaves that are almost little squares in comparison,

 

What is the stronger weave?

Is the aesthetic one more expensive, or is more to do with the resin they use?

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With regards to costs, hard to say if your buying the materials yourself as different suppliers vary from cost and minimum order requirements. It may be an idea for you to find a local'ish composites company and buy the required materials from them unless you have a nearby composites supplier you can call into and have a look at the various bits and bobs they stock (plus you can chat to them and they'll give you advice on what to use).

 

Timewise I'd say a week to make the mould and fettle it ready for producing a composite from.

 

If you where to get a mold made by someone, expect to be paying over £500 for a polyester based one, and more than that for an epoxy based one (depending on what epoxy tooling system they use). I'd expect the mold to consist of several pieces that are flanged so you can bolt it together 'as one' when making a composite from it.

 

With regards to the weave. CF comes in various weights and twills (the lattice pattern), its a case of finding one that is pleasing to your eye (generally the denser the weave - the more it costs). This website shows several types of CF weight and twill pattern, click on the pic for bigger versions.

 

With regards to strength, the denser the weave the strong it should be (ie: 5k has more fibres than 3k, hence it should be stronger). Bear in mind that CF is only structurally strong in the direction of the weave. When you make a CF composite you would use several layers of CF, rotating the direction 45 degrees between layers to increase overall structural strength. The type of resin you use also effects the strength too (some resins have more structural properties than others).

 

Something else I havent mentioned upto now is UV stabiliser, something you need to add to non-UV-stable resins to stop them going 'milky' when exposed to sunlight for a while (not required for making the mold - just the composites). There are UV stable resins available but they are pricey and usually have to be bought in rather large amounts.

 

The cheapest way you could do this is to make a polyester based mold and create a polyester based CF composite (wet lay method). The polyester composite wont be as strong as an epoxy based one, but I'd have thought it would be up to the job of being a dash. The next option (at more cost) would be to use wet-lay with vacuum (no oven required), then your into F1 territory using pre-impregnated CF material and autoclaves (at extreme cost).

 

When using the wet-lay method (without vaccum) you may need to use some chop strand mat to lie on the carbon to hold it down as CF will try to lift when you want it to bend around something or on uneven surfaces (this adds to the weight of the final composite).

 

If your main reason for a CF dash is to save weight - go epoxy and use wet-lay with vacuum and a home made oven.

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