Wadders
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| posted on 17/2/06 at 02:45 PM |
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carbon fibre moulding question
How do folks produce items in cf or fibreglass for that matter,which are cosmetically smooth and shiny on both sides. For example seats or throttle
body trumpets where both sides are on show.
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bernie955
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| posted on 17/2/06 at 02:55 PM |
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Most shiny CF parts have been clearcoated. A proper vacuum bagged piece should look dull (minimal amount of resin - vacuum bagging forces excess resin
from the part). Cosmetic CF will be clearcoated to make it look nice.
I've also seen cosmetic parts that are fibreglass with a layer of CF on top to make them look like CF.
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Wadders
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| posted on 17/2/06 at 03:11 PM |
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Using the vaccum bagging method, is it possible to use a male mould and still get a decent finish on the last layer of cloth?
Cor this is hard to explain!, reason i'm asking is i need to make my rear arches wider to cover new wheels (approx 2" So i wondered if
instead of widening the arches by cutting and inserting a 2" strip down the middle. Then using them to make female moulds, can i simply lay up
on top and get a
good finish. In the past iv'e made stuff by making a female mould, but the inside of the finished product is always rough.
thats weird, that smiley fella shouldn't be there.
Originally posted by bernie955
Most shiny CF parts have been clearcoated. A proper vacuum bagged piece should look dull (minimal amount of resin - vacuum bagging forces excess resin
from the part). Cosmetic CF will be clearcoated to make it look nice.
I've also seen cosmetic parts that are fibreglass with a layer of CF on top to make them look like CF.
[Edited on 17/2/06 by Wadders]
[Edited on 17/2/06 by Wadders]
[Edited on 17/2/06 by Wadders]
[Edited on 17/2/06 by Wadders]
[Edited on 17/2/06 by Wadders]
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nitram38
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| posted on 17/2/06 at 03:31 PM |
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Most fibreglass panels that are shiny both sides are made seperately and then bonded together.
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balidey
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| posted on 17/2/06 at 03:40 PM |
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grp panels needing a good finish both sides can be made in one of several ways. Here are the two i know most about
1. RTM, resin transfer moulding, a closed mould process, the fibres are laid in dry and pre-mixed resin is injected under low pressure. (very
expensive tooling costs due to the high forces)
2. A new process called RTM Lite, this is very similar to vac bagging, but instead of a bag a thin (one or two layers should be enough) grp inner
mould gives the finish on the inner face. Again the mat is put in dry and the vacuum draws in the pre-mixed resin. Pressure is provided by the
atmosphere, so the outer mould needs to be strong, similar to and RTM mould, so again quite expensive, but half the price of RTM tooling. And no
expensive injection machine is needed
These two processes are fantastic, give very good repeatable results, very clean, but are only really cost effective if doing a production run.
So your best best would be to cover the back face with a good clear gel coat and sand smooth after.
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bernie955
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| posted on 17/2/06 at 03:41 PM |
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You could do it my sandwiching the CF between two moulds. You'd have to make plugs that were smooth on both sides to make your moulds, which is
a lot of work. Your plug would also have to be the right thickness. Best bet is to have it shiny on the outside and spray some bitumen/sound deadener
underneath to stop any cracks from stones etc.
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kendo
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| posted on 17/2/06 at 04:21 PM |
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CRFP Mods
I have attached a 6 step guide to how to modify your wheel arch. Take care to scarfe the joint well and ensure the w'arch and sub-master have
release agent on the moulded surfaces. Also make sure you have exactly the same cloth and carefully match the weave up or it will look dreadful.
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tul214
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| posted on 17/2/06 at 04:43 PM |
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See here, may be some use?
http://www.swtoc.co.uk/articles.php?ID=3
1.6 Raw Super6 sold
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andyb64
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| posted on 17/2/06 at 08:48 PM |
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There is quite a bit of info on the Beardmore Bros website about moulding panels in Carbon Fibre
www.beardmorebros.co.uk
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JoelP
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| posted on 17/2/06 at 09:22 PM |
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A good friend of mine makes GRP and c/f effect stuff for a living. From talking to him, the easiest way to get a smooth finish without a mould is to
just sand it smooth and paint it.
If you want any stuff copying or replacing, or making with a plastic vacuum former, gimme a shout and i'll ask him.
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tigris
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| posted on 17/2/06 at 11:25 PM |
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male mould
use a perforated release film-not a fabric type, this leaves the surface very smooth. wet sand to desired shine, then clearcoat.
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Wadders
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| posted on 18/2/06 at 08:18 PM |
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Thanks for all the input, really appreciated, although i'm still struggling to understand a few things. Found this site which has helped some.
http://www.mci.i12.com/carbon/hugger.htm
still not sure how when using the lost foam technique, you end up with a smooth finish, do you have to flat and laquer it?
as well as extending the arches, i would like to make a rear valance to fit under the back end (similar to the one westfield sell) i'm hoping
to mould this using foam,and then cover it in cf, thoughtsand advice please.
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tigris
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| posted on 27/2/06 at 07:12 PM |
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the carbon will be as smooth as the surface you mould from, the foam will be a mess to sand away, but you can use chemical. Try electrical tape on the
surface if you a going for a quick mould
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