r/CarbonFiber

My first go at making my own C.F. parts ( metal guy here 😅 ) a few pinhole and voids but this was vacuum bagged with a home vac and clothes bag. Turned out not so bad for a 1st..

The disc is C.F. , the blades are aluminium and glued in place with PU structural adhesive, as well as riveted with alu rivets. Each weights about 650g. Built exactly the same way Lancia did in the late 80's early 90's with the Gr.A integrale.

Yeti sb 115 it’s right at the seat post, like below it near the rear shock as u can see the curve in the bottom right 2023 model got it in 10/28/23
, and I have been riding and racing it pretty hard since then.

I think I have a good idea of how to make this, but I was just wondering if anybody had a better idea. I’m pretty sure you’re just stack a bunch of Carbon sheets together and you vacuum seal it down.

One of the less obvious reasons is the composite structure itself.

The interesting part is that composites allow engineers to tune stiffness and vibration behaviour directionally, simply by changing fiber orientation, laminate stacking or local reinforcements.

Two drone arms can look almost identical externally, yet behave very differently once airborne.

A frame with a laminate focused mostly on axial stiffness may react differently to propeller-induced vibration than one designed with more off-axis reinforcement. The result can affect: flight stability, sensor accuracy, camera vibrations, control response, autonomous navigation performance.

This becomes especially noticeable with HD mapping payloads, LiDAR systems, thermal cameras and high zoom optics

A lot of the engineering is basically invisible. The external geometry may stay the same, while the real tuning happens inside the laminate architecture itself. That’s also why in UAV engineering, manufacturing quality matters much more than you might expect. Small differences in fiber alignment, bonding or compaction can completely change the dynamic behaviour of the aircraft.

I made small test parts of carbon fiber details, two layers of carbon fiber on a mold, then applied epoxy with brush on it till it was all wet, and then covered with nylon fabric and breather on top and in the vacuum bag for 24 hours. What could be a reason they are so weak and flexible? Thank you.

First time repairing carbon on a bike frame. I used two layers each with an overlap of 1/2 inches (I think this was screw up 1).

I used heat shrink tape but it did not compress nearly enough to do anything, so I wrapped an inner tube around the repair area and waited 24 hours. The epoxy seems to have cured but there are significant wrinkles in the sheets I added. I should have asked here before trying to sand/correct the valleys but I assume the answer will be the same… do I need to resand down to the original carbon and do it again?

48 hours in, and my resin is still tacky/soft on some areas of the roof, annoyingly this is the 2nd attempt to get the top layer looking right, the first attempt ended up with some cloudy looking patches in the resin which were visible under bright light (I think these were sanding marks which the following coats of resin didn't fill in properly)

I've had a heater under it since I put the first coat of resin on, but it's still not curing, I'm gonna leave it cooking overnight in the hope it goes off, but it not looking good.

Is there anything I can do to help it along?I don't want to risk sanding yet it in case it does the same thing as last time.

Resin is easy composites EL2, with a 50/50 mix of fast and slow hardener, I'm pretty sure it was well mixed (I did each cup for 5 minutes, scraping the sides/bottom and stirrer as I went

Hello,

Is wax enough of a mold release for making epoxy/CF or Polyester CF infused parts on a mould that's finished with polished polyurethane paint ? Or will the resin attack the wax and stick to the paint ?

I used wax and PVA before, but it leaves streaks, I can't get it on the mold as a nice even and shiny coating ( the PVA )

Also, could anyone recommend a nice tissue fixative spray to me so my weave doesn't distort when cutting/handling?

And as well, a tack adhesive to stick the tissue to the mould prior to bagging and infusion that is compatible with epoxy / polyester resin and won't leave colors or residues on the finished product ?

Stuff available in the EU if possible

I tought this was unidirectional carbon until it broke, i didnt know it was unidirectional fiberglass. Anyways how does one how about making it black? I can sand it and add some epoxy no problem but is that black just pigment added to the epoxy ?

Hi folks! I’m brand new in the carbon fiber world. I just bought a brand new carbon miata part and something seems off with the gelcoat. As you can see in the pictures, some parts of the piece in question have haziness in them while other parts of the piece are crystal-clear.

From what you can see, what could cause this haziness? Humidity trap in the gelcoat? Gelcoat too thick at certain places? Other suggestion?

I cannot return the part to carbon miata.. what can I do to correct these defects?

Thanks in advance!

I bought this wheelset used today and found this weird streak on it. The surface is as flat as the rest of the wheel and there is no difference in knocking sound. So I'm confused if it is resin, bc it doesnt seem to be a crack. I checked the inside of the wheel and there is no sign of damage at all

Seller seemed trustworthy and said he checked for cracks, the packaging from the shipping was really secure.

Is it cosmetic and safe to ride or should i contact the seller for a refund?

Appreciate the help

I have a "dry" carbon fiber hardtop for my car. The inside of the top is unfinished. I just noticed this splitting with some strands showing (I don't know much about carbon fiber so no idea what the correct terminology is).

Should I be worried about these spreading? Or anything I can do to prevent it from continuing? I've had it on for about 2 years but just noticed these because of the lighting.

Thanks

The metal parts were not the goal of the patent.

There were some things i wanted to do but the rest of the team did not.

I wanted to use a premade cad file for the outside of the gear.

I also wanted to use a vaccuum bag earlier, they insisted we did another a wet lay

Overall, it was a success and we delivered the prototype on time

Landlord hit my wing with a rock while mowing (rock was still sitting on the wing) and I'm not sure what my repair options would be. I know I can go through insurance and that would only cost my deductible but I would like options before I jump to one conclusion.

recently picked up a new car, it came with these aftermarket carbon side skirts but they are all scratched up and broken from the previous owner.
this feels like a dumb question but would end up saving me a lot of money so is this fixable? i have no experience with carbon or know anyone that does.
any info would help me a lot.
(i don’t really care to fix the carbon on the bottom/back of the skirt were no one will see it, only care about the scratches really