Questions on finishing carbon fiber.

[Scurvy092]

I just acquired a new knife that has 3d machined cf handles. for the most part they are smooth (but not polished like most cf) but in one area it is quite rough. I can feel the weave.

Is this something I can do? How do you guys finish your carbon fiber?

I hope this is the appropriate section but if not, please move (maybe to maintenance and tinkering?).

Thanks guys!

 

[mitsaru]

If the resin is thin you can try over casting more resin and then polish that area, I have used the clear epoxy resin to add thickness and make the 3d look people are after. I have done this on carbon fiber pieces we laid for a rally car, we would paint our pieces but the tuner guys liked the look so we would put extra resin on theirs and then polish. If the resin is thick enough you can just sand and polish.

 

[Scurvy092]

Thanks for the reply.

Here is the cf in question.

This is the smoother side, you can see the milling marks:

This is the rough side:

My guess is the machine bit was getting towards the end of it's useful life when they did this one.

Is this something I can fix? Would it be possible to knock it down with some extremely fine sandpaper and the add a thin layer of resin and polish?

Thanks!

 

[Patrickknives]

You need to be careful, you will change the pattern slightly when you start to sand into the fabric. I would start with 1000 grit and sand over a bucket of water. CF is easy to sand and it does not take much. Keep an eye on the surface to see if you are cutting into the fibers, with 1000 you should be ok. If you want a better finish you can jump right to 2000 or 2500, I don't mess with any grits in between.

 

[Scurvy092]

You need to be careful, you will change the pattern slightly when you start to sand into the fabric. I would start with 1000 grit and sand over a bucket of water. CF is easy to sand and it does not take much. Keep an eye on the surface to see if you are cutting into the fibers, with 1000 you should be ok. If you want a better finish you can jump right to 2000 or 2500, I don't mess with any grits in between.

View attachment 377543

Do you think if I just made a few passes going with the machining grain, it would just smooth it out a little. I don't really want to polish as much as I just want the two sides to feel the same.

 

[Patrickknives]

I don't see an issue, use lots of water, make a couple of passes and see what you have. 1000 will not remove much but works pretty good at getting stray fibers without removing more resin.