Anyone Work With Carbon Fibre?

[Bibbs]

I've got to mount a spoiler to a CF boot lid and have a few questions.

1. What's the best way to drill CF to put the bolts through?

2. What's the best method to re-inforce the CF so it'll no bend/snap/flex.

Cheers,

B.

[Caz SR]

Ben - does Al work with CF at all, or is it just fibre glass?

[Bibbs]

He knows a lot about FG. But no so much about CF ..

And it looks like that's what I'll be using to re-inforce the CF (with steel brackets).

[PaulT]

1. What's the best way to drill CF to put the bolts through?

That sounds tricky. The wing rigger on my sculling boat is all carbon and the drilled sections have metal inserts bonded above, below and through the holes to prevent the carbon surface delaminating I guess.

It occurs to me that you would probably stick the metal on first then drill the whole lot in one hit.

Is it not possible to glue the spoiler, or join the legs with a plate and glue that?

2. What's the best method to re-inforce the CF so it'll no bend/snap/flex.

Bond a foam core or honeycomb to a reasonable area of the underside and then another layer of carbon. I guess that would stiffen things up enough without adding the weight of metal struts.

Paul.

[Bibbs]

Cheers paul .. it's the whole de-lamination and then cracks and stresses that I'm worried about.

And it's a proper spoiler, so I don't want the boot flexing as then there would be no point it having one ;)

[jaxx]

CF is very abrasive, so youll need a good drill bit, a TiCN one should get through ok and stay relatively sharp as not to 'chatter' the material

we use diamond tipped ones at work and even they dont last long

for reinforcing, i would say metal back plates to bolt though, and seal them on with araldite! ive seen similar constructions on some assemblys we do

[PaulT]

And it's a proper spoiler, so I don't want the boot flexing as then there would be no point it having one ;)

Is it a twin skin with a core or just a thin sheet of CF?

Paul.

[kingdeacon]

what size drill bit you after? I use solid carbide drills every day at work that cost around £70-£80 just for 1 10mm drill bit, could send you one in the post for postage cost if you like

[Bibbs]

Jaxx, cheers man - just need to know what I need for next weekend (Nur is comming up too quick)

Paul, think it's just CF laquer and paint.

King Decon, I'll drop you a PM when I know the size of the bolts. MANY thanks for the offer!

[jaxx]

i was going to recommend solid carbide drill bus as said, they are a bit expensive, and shatter if you drop them!

[earpl]

i've done a fair bit ben, best way is to mark it out and use a dremmel type rotory tool (cheep ones about 20quid but must be 240V not rechargable) using sharp pointed engraving tool, slowly let it grind through the carbon and then work the hole from the inside out using various grinding bits in the set (nothing too rough though as large bits will shoot off). wear safety specs cause the bits (if they do come off) come off fast.... and a dust mask is also advisable cause its very dusty, black horrible stuff........

[PaulT]

Paul, think it's just CF laquer and paint.

In that picture I've posted above you can see the wing bolts through a carbon deck section. That deck is just three layers of prepreg carbon plus lacquer.

What the guy did to get those holes in the deck (they are custom measured, so I had to be there to say I want them there :) ) was to drill the deck first and then screw and glue in a hollow bolt and nut. So there is pressure from the top and bottom lips on the carbon to stay in place.

These holes are the main attachment point for the wing rigger and because of the leverage the load on those is quite high. I have never seen one give, though, and I have been sculling this make of boat for ten years.

Probably your best best is to try and track down some of those hollow bolts as they will reinforce the area around the hole. I guess you will still need to think about strengthening the structure as a whole too, though, as presumably it has been made as light as feasible.

Paul.

[Bibbs]

After speaking to my Mechanic (Alan ;)) we are thinking a few steel strips to form a skeleton under the boot from the hinges and boot lock.

Then well drill through the carbon and mount the bolts to the skeleton.

I've a dremel ;) but will look at the Carbide option too. Just need to work a way of stopping the holes from stressing as Paul suggests they might.

[jaxx]

the skeleton idea sounds the best method mate

[earpl]

seriously i tried drilling with a hs tc drill + it just chipped the laquer + you cant centerpunch CF so you likely to wander with the drill + scratch it :)

[Bibbs]

the skeleton idea sounds the best method mate

Yeah, as it actually looks liek the spoiler will be more than "all show" so I don't want it just deforming the bootlid and not actually putting any pressure where it's needed.

seriously i tried drilling with a hs tc drill + it just chipped the laquer + you cant centerpunch CF so you likely to wander with the drill + scratch it :)

So out with the etching tools then

[jaxx]

i take it youve got a CF boot and rather monsterous wing then ben :D

[Bibbs]

i take it youve got a CF boot and rather monsterous wing then ben :D

[jaxx]

hmmmmm carbon and GT wiiiiiiiiiiiiiiiiinnnngggs

[Bibbs]

It's the last little touches before Nur .. the car is losing a lot of weight (a 23kg exhaust is now a 5kg exhaust) and I think I need something to stop the bum breaking traction.

It's so subtle compared to the MR2 .. honest.

[jaxx]

and the mr2 was as subtle as a breeze block to the face

i like your style

[Bibbs]

I think the MR2 is subtle .. if it was any other colour it'd have been well OTT, but black you can get away with SO much.

I'm worried about taking the s2k on the track though. I've got to find an abandoded carpark soon and go for a shakedown test.

[LORD_ED]

I've got to find an abandoded carpark soon and go for a shakedown test.

chavtastic ben :D

[Caz SR]

The old airstrip at Farnborough might be an idea...

[Bibbs]

I've got to find an abandoded carpark soon and go for a shakedown test.

chavtastic ben :D

Well the last test, a Bomex scoop came of the car at speed and almost hit Alan :D