Carbon Damage

[DaveG28]

Whilst inspecting a carbon plate have noticed a White line dining from the edge of one of the holes in it, it's only visible one side but looks like a slight delimitation, is this likely to mean the plate is damaged and weakened in that area?

[SlowOne]

It could be a couple of things...

Something in the resin, in which case not a problem.
A piece of the CF thread, in which case just remove it with a knife, and seal the area over with superglue to prevent moisture getting in, or more thread getting out.

CF is damaged as soon as the resin cracks. This is usually identified by a bulge in the plate if the damage is internal, or an obvious crack that extend to the fibres. A small bruise in the top surface is usually OK, providing you re-enforce that area with a clamp that spreads the load - a nut and bolt with a large diameter washer is a fix I've used before with success.

De-lamination around a hole will usually manifest itself as a crack in the edge of the hole. Use a magnifying glass to look. Always clean around the hole with motor spray to get rid of any dirt that might be hiding the crack. If you can remove the crack by enlarging the hole, until you get back to 'solid' resin, then that will also fix the problem. You don't say what the hole is for, but if it's a screw hole providing location, or a countersink, that repair is not going to work!!

Depending on what the CF part is, and what load it is carrying, you can glue it back together. Get some really thin superglue, run along the crack, and then clamp the part in a vice. Leave for 24 hours. I've used this to repair 12th chassis and they've lasted for ages! Don't forget to smear grease on the vice jaws to prevent you have to race the car with a vice attached!! :lol:

CF is pretty tough stuff, and always a bit over-engineered for our usage. Providing you can get the part back to some solid resin (remove the crack in other words) and the part is flat and true, you'll usually save it. Always seal edges with superglue after repair, as this will give an immediate indication if the problem returns - the superglue cracks are easier to see than cracks in the CF.

HTH :)