[LakeSurfer]

Scroll down for the DIY or read if your interested in my biased opinions on this technique.

OK, Lamborghini apparently, a few years ago "invented" a new type of carbon fiber that they call "Forged carbon". You can see this carbon in non structural parts like spoilers and interior bits of the new models. I believe this is a marking gimmick so they can cut costs. When Boeing started to build full carbon aircraft the price of carbon went up drastically and companies like Lamborghini felt the pain. Lamborghini predominantly uses prepreg carbon. Prepreg carbon is a carbon cloth that is pre saturated with a slow curing resin. The resin typically requires very high heat and an autoclave to cure. aside from this, you need the man power and time to place the carbon in the molds, line up the weaves and ensure that the carbon is tight in every corner and cure of the mold. very time consuming and easy to screw up. I believe they would mostly use this same process for non structural parts as well or at least a modified version of it. if the weave ends up crooked or you can see gaps or it doesn't align with an adjacent panel then it is junk, unless you paint it and hide your mistakes. Enter "forged Carbon". Forged carbon is basically small cut up chunks of fabric. picture taking a roll of yarn and cutting the strand into 1/2 inch or so pieces. if a manufacturer produces a bad roll of the woven cloth then they could essentially chop it up to make "forged carbon". any scraps that they have left over can be chopped up into forged carbon as well. this eliminates soooo much waste. the "forged carbon" is made in the prepreg form as well and comes in sheets. because the orientation of the forged stuff is super random you can overlay them and overlap them as necessary. and because the fibers are so short you can get them to contour more difficult shapes with a ton less man power. to make the parts they have a male and female mold in a press, throw in some "forged carbon" at any orientation, press it and apply a little heat, trim it, drill it and your down. They can pop out parts like nothing.

As a side note I was using this technique years before Lambo thought of it. if I had a non structural part that had a damaged corner or a miss drilled hole, i would cut up the carbon, mix a little resin and vacuum bag the part. and the boating industry practiced this with fiberglass years before I was born.

anyway, onto the DIY.

the part I made is a small under tray piece that sits under the front left bumper cover on my E93 M3. The part gets beat up from scrapping driveways and potholes and has lost the flat bottom due to damage.



some of the sides had been eaten away and holes wallowed out.



the first step is to make the part whole again. i used cardboard and hot glue to rebuild the missing pieces.



glued in some pieces for a little added strength.



do your best to fit the part back into position on the car to ensure you got the shape and fitment correct. Or redesign it as needed.

the carbon is going to overlay on the top of the part so the next step is to cover the part with packaging tape. this will ensure the resin does not stick to the part.



for added piece of mind i sprayed a little PVA on the packaging tape. This is for simplicity an alcohol/vinyl mixture that when the alcohol to evaporates it leaves a vinyl film on the part for better separation.



next i took my carbon cloth and chopped it up into random small chunks. try not to mix it or play with it to much as the fibers will start to separate and become a stringy mess like a dust ball in the corner of your kitchen, only bigger.



mix your resin, i'm using an epoxy resin but you could use fiberglass and polyester to save money and time. polyester resin will cure in less than 1 hour and the epoxy i use takes almost 24 hours to fully cure. paint a thin layer of resin onto your part to give the carbon something to stick to. use some throw away chip brushes and cut off about a inch of the bristles. gently sprinkle the carbon onto the part and drip a little resin on top. take the chip brush and stipple the carbon onto the part. this will help keep the carbon where you put it and ensure full saturation. don't brush the carbon on the part. it will look ugly but you've got a lot of sanding work to do so don't worry.



when it is fully cured separate your new part from the old sacrificial OEM part. because we built the part on the outside of the OEM, technically it will be slightly larger in all dimensions. this is not a big deal for this part because there is a lot of wiggle room and the extra dimensions are almost negligible. To help the part fit more like OEM its important to get the mating surfaces the same thickness as the OEM. use the same technique on the inside of the part to bulk up any areas that need it and add some carbon to the higher stress points.

sand surfaces flat, fill pinholes and low sports the same way we built the part with the copped carbon and resin. when it cures and you sand it, you will not notice a difference. Trim edges, drill holes and check fitment.

you can sand it with anything from 80 grit to 320 or whatever you have. the scratches will be hidden with the next step.

when you have it flat and pretty as possible, mix up some resin and paint it on the new part, the carbon will pop out and look amazing. to get rid of bubbles use a hair dryer, this will help them rise and pop at the surface. when it cures sand it flat again and repeat if needed. if you have pin holes, clean the dust out and use a toothpick to drop resin into them.

one last sand to make it flat but you should be able to use 1500 grit or so by now. work it up to 3000 if you like the shiny carbon look, (i Prefer a matte finish) and then polish and buff just like you would with paint.

The finished part fits great on my car but could use a lot more polishing and finish work, however, I plan to incorporate these parts into the splitter in the next year or less and you really can see it because its mostly under the car.







There are many ways to make parts and many better ways. Most of the time better ways with better outcomes take time and tooling. I have the tooling so time is a problem. This to me is the fastest, sloppiest way to make forged carbon that with a little more hand work can result in flawless beautiful forged carbon.

weight savings = probably none.
strength = about the same as aluminum of same thickness.
time involved = maybe 4 hours or actual hand time, several days of waiting for resin to cure.

DIY and DON'T BUY!

let me know if you have any questions or if you i could improve on my sloppy technique.

-Mark

[Blueeyesredpanda]

can't see a single pic

[SlimE92]

[LakeSurfer]

Originally Posted by Blueeyesredpanda

can't see a single pic

Interesting. They show up on my laptop but not in the app.

[streetpro]

I cant see them either (mobile/desktop)...

[LakeSurfer]

Sorry guys, i had the pics set to private for some reason.

-Mark

[Philip451]

End result looks REALLY cool. Thanks for sharing.

[IllSic_Design]

Thanks for the DIY, was waiting for the pics to be included so I could get an even better idea of the process. I definitely will be trying out some forged carbon on my car in the near future

[LakeSurfer]

Originally Posted by IllSic_Design

Thanks for the DIY, was waiting for the pics to be included so I could get an even better idea of the process. I definitely will be trying out some forged carbon on my car in the near future

There are definitely better ways to do what I did. But this way is probably the cheapest and quickest. building molds and vacuum bagging would produce even more eye catching results.

If you haven't work with this material before I would suggest using polyester resin with regular fiberglass cloth. for starters its 1/4 of the cost and you can find black fiberglass that will give you a similar look. Also if you're new to composites there is potential for a lot of waste and "screw ups". When you figure out what and how your gonna attack something then splurge for the epoxy and carbon. and be prepared for another learning curve. carbon fiber is super slippery and will get messy real quick.

good luck and if you have any questions let me know. im pretty nerdy about this stuff.

-Mark

[WhatDoIPutHere]

Bumping this thread, How hard would it be for someone to coat an unpainted polyurethane lip? I have no experience with this whatsoever.

[Tambohamilton]

Lambo are charging money for CSM (chopped strand mat) parts! Genius. As you said, OP, boaters have been using the stuff in glass form for many years.

I do like that it's consuming what would otherwise be waste though, to make functional (though not amazingly structural) parts. My dad only ever buys 'reject CSM' for his boat repairs; it's regular CSM that has defects in the 'weave'. Most often the defect is that it's thicker at one side of the roll, and thinner at the other...not much of a hassle to work around for repairs!

Nice DIY on making parts too

[LakeSurfer]

Originally Posted by WhatDoIPutHere

Bumping this thread, How hard would it be for someone to coat an unpainted polyurethane lip? I have no experience with this whatsoever.

Raw poly is pretty tricky to get epoxy/carbon to stick to, however, if you can have it primed first, you'll have much better luck getting it to mechanically bond.

Or...

Lay a few layers of the carbon on the part, let it cure and in theory you'll be able to separate the carbon from the poly leaving you to do the finish work on the carbon part.

It's not all that difficult, sometimes it just takes a little trial and error. Whenever I start a new project I always learn something new.

Give it a shoot.

[LakeSurfer]

Originally Posted by Tambohamilton

Lambo are charging money for CSM (chopped strand mat) parts! Genius. As you said, OP, boaters have been using the stuff in glass form for many years.

I do like that it's consuming what would otherwise be waste though, to make functional (though not amazingly structural) parts. My dad only ever buys 'reject CSM' for his boat repairs; it's regular CSM that has defects in the 'weave'. Most often the defect is that it's thicker at one side of the roll, and thinner at the other...not much of a hassle to work around for repairs!

Nice DIY on making parts too

Lol! It's crazy right?

Some places sell "defective l" carbon as well. Most cases it's just an odd width roll or something stupid like that.

I have already picked up plans to build a boat but that's a little ways down the road.

[WhatDoIPutHere]

Originally Posted by LakeSurfer

Raw poly is pretty tricky to get epoxy/carbon to stick to, however, if you can have it primed first, you'll have much better luck getting it to mechanically bond.

Or...

Lay a few layers of the carbon on the part, let it cure and in theory you'll be able to separate the carbon from the poly leaving you to do the finish work on the carbon part.

It's not all that difficult, sometimes it just takes a little trial and error. Whenever I start a new project I always learn something new.

Give it a shoot.

I see, thanks for the info! I'm surprised there's not more people doing this, it looks great and is really different (which I like ) do you know if 1/8 vs 1/4" chopped carbon fiber would make a big difference on the look?

[Tambohamilton]

Originally Posted by LakeSurfer

Lol! It's crazy right?

Some places sell "defective l" carbon as well. Most cases it's just an odd width roll or something stupid like that.

I have already picked up plans to build a boat but that's a little ways down the road.

Nice, I'll look out for that

[LakeSurfer]

Originally Posted by WhatDoIPutHere

I see, thanks for the info! I'm surprised there's not more people doing this, it looks great and is really different (which I like ) do you know if 1/8 vs 1/4" chopped carbon fiber would make a big difference on the look?

I think it's preference on the 1/8 or 1/4 inch chopped carbon. Not a huge difference between the two but the 1/4 will stand out a little more than the 1/8. I think the 1/8 looks fantastic up close but less attractive the further away you get. I do like the more subtleness of the 1/8.

[bluewater328]

I see a few people doing this. My only question is that, when you use it like this, do you lose a lot of strength it has woven since you are now relying on the resin bond vs the resupported matte weave?

[LakeSurfer]

Originally Posted by bluewater328

I see a few people doing this. My only question is that, when you use it like this, do you lose a lot of strength it has woven since you are now relying on the resin bond vs the resupported matte weave?

Absolutely, forged carbon is not nearly as strong as just about any weave lbs for lbs. Lamborghini tried forged carbon structural parts a long time ago but failed. This is why we only see it on cosmetic parts. A work around is to lay carbon fiber woven cloth first and build up a few layers and then the chopped/forged carbon on top.

However it's still pretty strong. The part I made has smash the concrete a few times and hit a parking block and only has scratches.