assistance with first carbon fiber project.

General Composites Discussions Composites Talk
#1

Hello to all,

I am looking to start my first carbon fiber project. I want to make a carbon fiber plate/brace that will bolt onto a aluminum chassis for a rc nitro truck. Please see attached chassis photo, the red box is where i want to add the brace, which is directly under where the engine mounts.
The reason for adding the brace is to reduce/prevent the chassis from flexing.

I have used fiberglass in the past on different projects but have yet to make anything out of carbon fiber, so this will be my first attempt.

From reading around the froums, i was thinking about using the west system epoxy resin and hardener which i can pick up locally.

I am completely lost on which type of carbon fiber cloth/sheet I should use for this application.

Any input would be appreciated, thank you.

#2

Rc truck? Is that like a quad or a toy truck? From the picture it looks to be a flat area. Would you just put a sheet of carbon and bolt it on with bolts and nuts?

West system is ok but expensive for what it is. I’ve never infused with it but used it on overlays while ago. It sucks basically because the TG isn’t very high so if structural integrity is in the equation and heat is s factor I would stay way from west system.

#3

I guess you can call it a toy if you like, its a nitro remote control truck. I attached a pick of it put together to give you a better idea.

Appreciate the input on the west system, what would you recommend i use instead of it? And yes my plan is to bolt it to the chassis

thanks again

#4

Well you have a bunch of options since there’s a good amount of ways to make a flat panel. Without any tools really and expense other than some plexiglass and resin and fabric you could do a flat panel and cut to shape.

If you want to infuse you’ll need other equipment, and if you do wet layup bagging you’ll need other stuff too.

It kind of depends. I would recommend researching each technique. Your technique will most likely reveal which epoxy may suit you best.

For this application west system would be fine though.

#5

A flat panel should be no problems. You could even do it without vacuum by laying up your carbon between two plates of metal and then clamping them down. After it cures, just cut the piece to shape and drill.

Should be a great starter project. I’m thinking just about any fabric would be fine for you. Plain weave would work great. Whatever you can get your hands on that is not too expensive.

#6

If it’s just the one off project I’d just buy a 2mm piece of carbon sheet

Not worth buying the epoxy , carbon , wax , gloves , this an that , list goes on

But if it’s got a curve or some bends etc , then you don’t have a choice

#7

Appreciate all the input,

I think i need to do some more reading prior to purchasing anything, i am sure more questions will come up along the way.

Thanks again

#8

i finally purchased a few things after talking with someone from Solarcomposites.
-3k 2X2 TW 270GSM, 640Ksi, Carbon Fiber
-AdTech 820 Resin & Hardener

Their recommendation was to add some kind of strips in both directions, to give the carbon fiber some curves/valleys which will make it stiffer compared to a flat piece. I was thinking of picking up either some balsa, basswood, or poplar wood strips which ever i can find locally and use those to create the valleys ect…
I attached a photo that someone else posted of a CF brace they made and added some dotted green lines just to show how i plan on placing the strips.
Although the photo is of the same chassis that i have, this person bent the two arms that stick out which is where the servo is mounted so that it is level with the part of the chassis where the engine is mounted (photo with the #2), I want to first try and make this brace with out bending those since I will need to make other changes up top to the brake and throttle linkage.
So what i am working with is shown in the top left image (photo with the #1) where those tabs (yellow arrow) are lower than the area where the engine mounts (red arrow)
one thing i am not sure about is how thick those strips should be, i found square strips online as small as 3/32" not sure if that is big enough to see a benefit but i think it will be hard to fit strips that are much bigger than that.

So my plan was to first cover that area in painters tape and add 1 or 2 layers of fiberglass, because i read that the CF can corrode the aluminum if it has direct contact with it. Next i would make the cutouts that i need on the fiberglass and mark or maybe even drill the holes that i need. Followed by gluing the wood strips as shown in the attached photo and add the CF on top of that.

Any input, suggestions, things to look out for would be appreciated
Thanks again

#9

Came across these cf rods that come in many small sizes can this be used instead of the wood strips? Link below
http://www.acpsales.com/OnlineStore.php?cat=4924

#10

No comment = perfect plan?

Sent from my SM-T810 using Tapatalk

#11

give it a go and take pics :smiley:

#12

I would guess that a flat laminate stack would be plenty strong for that application. 5 to 6 layers of 5.6oz carbon fiber, or even S glass. Having a carbon fiber or fiberglass tubing laminated into the part would decrease flex, but not knowing the load or stress the part will see, it’s difficult to say if it would even be necessary.

Carbon fiber will corrode aluminium over time unless the aluminum surface is treated, anodized or similar. This is generally a concern if the aluminium is cast, molded, or epoxied directly into the cf part itself.

#13

No need at all for strips/reinforcement. Use the flat plate as mentioned, design in CAD/paper and transfer to a vector file and have it waterjet cut from a flat sheet, ideally a purchased flat sheet, this will be strongest. You can also make your own if you like.

Carbon will make it stiffer, but not more resistant to impact, it will shatter if you hit a bigger rock or something.

#14

appreciate all the replies, not exactly sure what some of these items are that have been mentioned so i will have to read up on them…ex…“flat laminate stack”.

i started with the fiberglass, made it larger than it will end up being, i figured i can just trim it down as needed. I am trying to use as many of the existing screw holes as possible. link to photo https://flic.kr/s/aHskE6SZ6g

Green circle= existing screw/bolt
red circle= new bolt to be added
red box area= is just to cover a cutout not so much for support
blue box area= is directly under the engine mount.

I should have some progress/updates this weekend along with more questions i am sure.

thanks again

#15

Some updated photo’s
https://flic.kr/s/aHskE6SZ6g

I used a honeycomb foam mat from ACP in the center. I was not expecting the finish to come out matte black, not sure if that is normal or if i did something wrong, not a big deal since the brace goes under the chassis. The white lines are from the edges of the rip stop nylon that i used to cover it while it cured.

For the bolts that i will use to mount the brace to the chassis do they need to be a special material in order to prevent them from corroding?

I will most likely make another one since this was my first attempt. I would really love to eventually make the entire chassis out of CF, i may also pick up a vacuum bagging starter kit.

thanks again