Fill center of carbon bar with epoxy

[TilmanHH]

Hi,
how do you fill the center (let's say 10cm) of a carbon bar with epoxy? I filled in a stopper from one side (wood) and filled in the epoxy from the other side. Was a mess because the stopper let through some epoxy.

How did you do it? What did you use as a stopper?

[evan]

Pipe insulation foam. Packed tight enough will be even airtight.

But I stopped with this because eventually you wear through the bar eating away your depower cord or even break the bar when you grind through the carbon.

[TilmanHH]

At least this time I´ll be smarter and try first with water if it let´s fluid through, before I fill in epoxy;)

"could break": I ordered 3mm diameter this time. Even 2mm seemed bombproof to me after 10 sessions.

"you wear through the bar eating away your depower cord ": Indeed. I use a tube now.

[merl]

Or you could avoid the issue completely

[evan]

Indeed. I use a tube now.

Sharp carbon likes to eat polyurethane tubes in particular n)

[wavy navy]

Sharp carbon likes to eat polyurethane tubes in particular n)

Why? I thought it's a matter of how you sand the surface (how rough the surface is)?

[evan]

It roughs itself back up after a few sessions and eventually you grind through the bar itself making the edges of the carbon razor sharp. Went through multiple pu covered depower cord a year with bare carbon and i did my best to keep it smooth with rounded edges.

Now with a plastic insert I am still on the first cord after a year. Changing the insert is way less work than making a new cord and sanding the bar.

[Herman]

I to have cut through a carbon bar. Also, I have had to take off almost razor sharp edges created in both stainless steel and alloy bar inserts. The burrs and cut were created by raw dyneema, I don't use pu tube on center lines. It was from fairly heavy duty TT riding.

[alpaia]

I rolled biax fberglass with colored epoxy up to nearly the inner diameter of the tube so it could squeeze in
prepared 2 plugs of styrofoam and pvc tubes of equal length so that total length = bar length + 2cm
pushed the rolled up fiber in the center btw the plugs of foam and pvc tubes
compressed the lot with a strong clamp
The biax then expands as it is compressed in length
adds a lot more structural strength than pooring in epoxy and relying only on outiside tube only that is weakened by the hole

[merl]

I rolled biax fberglass with colored epoxy up to nearly the inner diameter of the tube so it could squeeze in
prepared 2 plugs of styrofoam and pvc tubes of equal length so that total length = bar length + 2cm
pushed the rolled up fiber in the center btw the plugs of foam and pvc tubes
compressed the lot with a strong clamp
The biax then expands as it is compressed in length
adds a lot more structural strength than pooring in epoxy and relying only on outiside tube only that is weakened by the hole

This sounds interesting, but a bit too hard to understand... Do you have any pictures?