Putting t nut in carbon fiber stock

[Jabot]

What's the best tool used to make hole in stock?

 

[jcheng]

use a spade drill bit.

 

[Jabot]

Thanks, this doesn't mess carbon fiber up

 

[2010Ruger]

I use a counterbore bit for fiberglass and it leaves a really clean hole. No experience with carbon fiber though.
Snappy Tools 1/4 Inch x 3/4 Inch 3-Flute Flat Bottom Counterbore with TiN coated twist drill #34816 https://www.amazon.com/dp/B01MF8TZAU/ref=cm_sw_r_cp_api_glc_fabc_Ha7ZFbAE9JR71?_encoding=UTF8&psc=1

 

[jcheng]

Thanks, this doesn't mess carbon fiber up

I usually put painters tape on the carbon fiber portion before drilling to prevent splintering when you drill the hole through it.

 

[bonifacio]

I usually put painters tape on the carbon fiber portion before drilling to prevent splintering when you drill the hole through it.

Definitely go with painter's tape.

 

[Jackalope]

Would go with a forstner bit. Leaves a nice flat bottom hole and they’re much nicer to use than a spade.

 

[308pirate]

Thanks, this doesn't mess carbon fiber up

Don't see why it should. Just like fiberglass.

 

[Jabot]

Put t nut in last night. Friend had a forster bit works awesome, very clean and easy. Used painters tape over initial drill hole. 10 minutes and done

 

[elwarpo]

You should recoat the resin matrix around the hole. Epoxy glue us best, but crazy glue or even nail polush will work.

 

[bonifacio]

Don't see why it should. Just like fiberglass.

Are they clear coated?

 

[elwarpo]

Don't see why it should. Just like fiberglass.

Carbon fiber uses an polymer matrix (often epoxy) to bind the carbon fibers. In effect the carbon fibers reinforce the polymer matrix increasing it's strength (tensile strength and deformation resistance...). When you drill into you interupt the matrix, which can cause point weakness. Carbon fiber also can be affected by crack propagating, when a crack starts and keeps moving through the piece. Unlike fiberglass which is sheets of glass fiber glued together using unsaturated polyester resins.

 

[Jabot]

Carbon fiber uses an polymer matrix (often epoxy) to bind the carbon fibers. In effect the carbon fibers reinforce the polymer matrix increasing it's strength (tensile strength and deformation resistance...). When you drill into you interupt the matrix, which can cause point weakness. Carbon fiber also can be affected by crack propagating, when a crack starts and keeps moving through the piece. Unlike fiberglass which is sheets of glass fiber glued together using unsaturated polyester resins.

Good info thanks

 

[308pirate]

Carbon fiber uses an polymer matrix (often epoxy) to bind the carbon fibers. In effect the carbon fibers reinforce the polymer matrix increasing it's strength (tensile strength and deformation resistance...). When you drill into you interupt the matrix, which can cause point weakness. Carbon fiber also can be affected by crack propagating, when a crack starts and keeps moving through the piece. Unlike fiberglass which is sheets of glass fiber glued together using unsaturated polyester resins.

Metals are more my speed but........are there not carbon fiber laminates made from resin-impregnated (either pre-preg or impregnated during layup) woven carbon fiber cloth?

Not sure how the resin (epoxy vs polyester) controls crack propagation.

 

[elwarpo]

Metals are more my speed but........are there not carbon fiber laminates made from resin-impregnated (either pre-preg or impregnated during layup) woven carbon fiber cloth?

Not sure how the resin (epoxy vs polyester) controls crack propagation.

Here is an article on crack propagation and ways to help prevent it. Crack propagation article
To sum it up... Once a stress level in the epoxy matrix is reached the resin matrix cracks, this crack them moves between sheets of carbon fiber. This is due to the a prominent stick-slip behavior of viscoelastic epoxies. The unstable fracture behavior is very dangerous for application and use of epoxy / carbon fiber composites. Drilling may or may not reach the stress level where a crack may start. Once started, every time stress above the strength of the matrix is applied, the crack increases and eventually you have delamination of the layers. This is why I suggested using a resin on the hole area.

 

[308pirate]

Here is an article on crack propagation and ways to help prevent it. Crack propagation article
To sum it up... Once a stress level in the epoxy matrix is reached the resin matrix cracks, this crack them moves between sheets of carbon fiber. This is due to the a prominent stick-slip behavior of viscoelastic epoxies. The unstable fracture behavior is very dangerous for application and use of epoxy / carbon fiber composites. Drilling may or may not reach the stress level where a crack may start. Once started, every time stress above the strength of the matrix is applied, the crack increases and eventually you have delamination of the layers. This is why I suggested using a resin on the hole area.

Linky no worky

Interested in learning more

 

[elwarpo]

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