Lude Generation

Be careful skinning metals directly with carbon. If the carbon contacts the steel it causes pretty severe galvanic corrosion. Either prime the metal with a sealed epoxy primer and then skin or best or all use a blocker layer of fibreglass between the metal and carbon

Carbon corroding metals has been a massive problem in aerospace for years.

that makes it harder, cant skin under the skin cause the doors wont shut and the rubber allaround wont be any good would have to be a chemical barrier, although easy is just another expense do you happen to know why? is it the carbon as i have never come across this with fibre glass

It is the carbon, fibreglass doesn't do it.

I may not be 100% right as I am digging in the depths of my memory here

I think it is because for this type of corrosion to occur you need an anode and a cathode, Fibreglass is, as the name suggests, made from glass which is an insulator and as such cannot act as a cathode. Carbon however is a very good conductor and can therefore act as a cathode, the metal itself will act as the anode.

So carbon and metal = anode and cathode - corrosion, whereas glassfibre and metal = anode only = no corrosion.

The same process as dissimilar metal corrosion where two different type of metal in contact with each other will corrode.

I think.......................

As said before just use a layer of fibreglass between the metal and carbon. That's what boeing and airbus do.....

vti2003 wrote:
The same process as dissimilar metal corrosion where two different type of metal in contact with each other will corrode.

I think.......................

That bit is true from my days or restoring classic big Healy's with ally scuttles and steel wings. As for the rest of your post I will take your word for it!

If you look at the chart below it explains. The bigger the gap between the materials the more likely corrosion is. Mild steel is quite far on the right as is aluminium while graphite (Carbon) is on the far left. Big gap = big rust The new Boeing 787 has had to use loads of titanium for fittings instead of aluminium as the main fuselage is made entirely from carbon fibre. The chart shows why. Titanium is very close to graphite and will not corrode like ali, as well as expanding at a similar rate to carbon when heated.

So when you are delaing with carbon treat it as a metal for corrosion purposes.

i remember this now, yes you are correct. the skin will be sitting onto a layer of primer, still havnt made up my mind to either attach it (bonded together) or have it detachable, the problem there would be moisture,

yeah to prevent the moisture getting in it would have to be bonded could you use an epoxy primer

bonding would be easy, just key the primer, the skin has a resin undercoat, but i was thinking i could make them detachable then i could make more, just use silicone to stick them down, they would be held in place by the rubber seal, but bonding would prob be best.

heres some i stole off google

By littlefeller2010 at 2012-04-01

By littlefeller2010 at 2012-04-01