Composite decal opinion

[PRIVATEER]

Ok guys...I know the general rule is to put a gloss overcoat on cf decals,but what about cf that has weathered?

I tried a flat finish over 3 different SMS decals to see how it would look. Try to imagine a "C" class car cf monocoque, after a few laps,would it lose its gloss? I know its a motorcycle fender,but how would this look on the exposed parts of the car?



Let me know what you think about using this method on parts that would weather.

[JTRACING]

looks good to me,
i watched the F1 race today, and they showed the new Carbon fiber helmet in bare cf, and it had a flat finish like that

[joeyko2000]

i think adding a smoke layer would look good too~

[mikemechanic]

Bottom left stuff looks good, the top part just looks like a band-aid bandage.

[willimo]

The reason CF is shiny is because it's carbon fiber, which is a woven sort of fabric, which is coated and permeated with a composite resin (this is from what I understand). So, while the resin layer may get worn during a race and not be as shiny, I don't imagine it would be and duller than semigloss. The surface may be pitted and worn, so not beautifully shiny, but there will still be a very thin layer of clear resin over the CF, which would still show. Do some more experiments, compare them to photos, and most importantly, ask people that know more than me.

[Vric]

Originally Posted by willimo

The reason CF is shiny is because it's carbon fiber, which is a woven sort of fabric, which is coated and permeated with a composite resin (this is from what I understand). So, while the resin layer may get worn during a race and not be as shiny, I don't imagine it would be and duller than semigloss. The surface may be pitted and worn, so not beautifully shiny, but there will still be a very thin layer of clear resin over the CF, which would still show. Do some more experiments, compare them to photos, and most importantly, ask people that know more than me.

[bvia]

From "someone who knows more about CF than those two...or me!"

"Carbon fiber has many guises.

"Straight or unidirectional tows" look like brushed (black) stainless
steel. Stongest but only in the direction of the tow. It is harder to work and takes more careful engineering than woven layups.

"Plain weave" has a weave pattern similar to a basket or a shirt. It
has good drape during manufacture, but the crimp (the change in fiber
direction due to the over-under weaving process) causes it to (a) weight more and (b) be less strong. The strength, however, is now distributed along two axis. Strength along the bias is more limited.

"Twill weave" lies between unidirectional and plain weave. It is harder
to drape cleanly over molds than plain weave, but because it has less
crimp it is lighter and stronger. Twill patterns have a zig-zag or herringbone sort of pattern.

All carbon fiber is black black black - BUT - it is also reflective.
The satin sheen is due to the light reflecting off the [thousands?
millions?] individual micro-extrusions of fiber being held in matrix by epoxy. The weave style is made very visible by this reflection/refraction.

Carbon fiber can be finished smooth or left rough. The smooth finish is
made by extra coats of resin which adds to the weight but not significantly to the strength. Smooth is aero, so that's why the racers do it. But typically undersides are rough with obvious weave texture. I think I read where Attridge laminated some tissue paper on specific surfaces of "The McLaren" to get that correct "unfinished" texture.

The smooth finish can be anywhere from almost matte to high gloss and
anywhere in between.

Another variable is the size of the individual tows that make up a
weave pattern. Fat tows (fewer weaves per centimeter) result in less crimp (good), higher carbon-to-resin ratios (good), less weight, but are more bidirectional in strength and harder to work. Large areas usually will have fewer tows per centimeter where smaller and complex areas (e.g. suspension struts) will have a higher number of smaller tows per centimeter. Decals come in various sizes and Scale Motorsports offers scales (1:43, 1:24, 1:20, 1:12) which should really be labeled small, medium, large medium, and large. It can be entirely correct to use three different sizes for various applications on a model.

Carbon fiber is frequently woven with other materials, the most
frequently Kevlar(tm) or high modulus fiberglass. Glass is mostly a cost-cutting measure so it doesn't show up much in race cars. Kevlar, however, has very different characteristics than carbon and is used for specific areas.

Kevlar's color is close to #CCCC00 and imparts a golden or bronze sheen
to carbon/kevlar composites depending on the ration of Kevlar to carbon. Kevlar is not quite as strong as carbon in tensile strength and it weights slightly more. But it is MUCH stronger off-axis and MUCH less brittle. This makes it ideal for impact areas such as helmets and F1 side pods. Where carbon tends to shatter and splinter, Kevlar tends to deform, dent and stretch.
--Scott Truesdell"

So there ya' go...yes and no is the answer...;-)>

hth,

Bill

[RallyRaider]

Yeah there is no hard and fast rule about CF, every piece is different because it is all hand made. When Mclaren first started using CF for their "black chassis" the surface was very rough. I recall seeing pictures of a recent F1 Ferrari where you could clearly see the weave pattern even through the glossy red paint - so much for smooth aerodynamics!

As far as weathing goes it would be damaged, scuffed, dirtied, maybe even chipped the same as any other gloss surface.

[bvia]

Originally Posted by RallyRaider

Yeah there is no hard and fast rule about CF, every piece is different because it is all hand made. When Mclaren first started using CF for their "black chassis" the surface was very rough. I recall seeing pictures of a recent F1 Ferrari where you could clearly see the weave pattern even through the glossy red paint - so much for smooth aerodynamics!

As far as weathing goes it would be damaged, scuffed, dirtied, maybe even chipped the same as any other gloss surface.

You said it about the McLarens! They were rough. Also the Mazda 767-787's were the same way.

Almost ANY CF car body will experience what is known as "telegraphing" or the weave being visible underneath and through the paint, simply because primer and glossy smoooth paint weigh more than just a thin coat of pigment/paint. From the Ferrari F1's to the "street" F40's...Telegraphing is visible in the Rossa Corsa.

Also the dimpled effect of the "tow" keeps the boundry layer attached to the cars body...at least in the F1's case.

Ain't race car modeling fun?!?!?...;-)>

Bill (NOT that Bil)