A question about drilling/riveting carbon fiber stock

[pipsqueaker]

We're considering using some 1x1 carbon fiber stock this year, and we were wondering how exactly you would join pieces together. With aluminum stock we'd just drill some eighth-inch holes and gusset things together, but we've never worked with carbon fiber so we're not sure how it holds up to the stresses of riveting, drilling, etc. compared to aluminum

[s1900ahon]

Originally Posted by pipsqueaker

We're considering using some 1x1 carbon fiber stock this year, and we were wondering how exactly you would join pieces together. With aluminum stock we'd just drill some eighth-inch holes and gusset things together, but we've never worked with carbon fiber so we're not sure how it holds up to the stresses of riveting, drilling, etc. compared to aluminum

Safety first. Carbon fiber dust is a slew of short sharp nasties that you do not want to breath in. Use appropriate personal protective equipment.

Carbon fiber is not difficult to drill, but it does wear tools quickly. You might start with this tutorial. It gets tricky if the layup includes Kevlar.

You can rivet it, but I'd use washers on the mushroom end if it is against CF. It gets tricky if the carbon has a honeycomb core.

[Jon Stratis]

Originally Posted by s1900ahon

Safety first. Carbon fiber dust is a slew of short sharp nasties that you do not want to breath in. Use appropriate personal protective equipment.

I want to echo this. Please consider that, at competition, you will NOT be allowed to do any machining of carbon fiber - no cutting, no drilling, no sanding, etc. The facilities we compete in aren't equipped to do so safely, and even if your team has proper personal protective equipment, your neighbors will not.

[timytamy]

Originally Posted by s1900ahon

Safety first. Carbon fiber dust is a slew of short sharp nasties that you do not want to breath in. Use appropriate personal protective equipment.

I too would like to echo this.

In addition to the dust, when cutting it is possible to end up with edges that will give you splinters, these are not pleasant and are often harder to spot and extract.

As for designing with carbon fibre, you want to get good at epoxy. A well designed carbon fibre structure will usually involve understanding the forces it takes and working out how to glue it together effectively.

The key thing is that you can't really treat carbon fibre like metal. It's much more susceptible to concentrated local stress, which is why gluing and wrapping are generally preferred to bolts and rivets.

[dominik.daners]

From what I have learnt in the RC hobby, carbon fiber in tube format is usually attached using clamps (usually made of aluminium), and people avoid drilling holes in the stuff due to the above mentioned reasons, as well as creating a weak fracture spot.
As for cutting the stuff, a dust mask and thick gloves is a bare minimum, and many people also use duct/gaffers tape around the cutting area to help trap the fibres, and to get a cleaner cut. If you want to overkill, feel free to do it underwater or in a glovebox, but keep any cuts to a minimum, and DONT file the stuff.