[Ron B.]

Can a carbon fiber panel be modified with epoxy and fiberglass cloth? Small change.

 

[flyboykelly]

in short yes. If your carbon fiber panel will be touching any aluminum surface there should be a layer of fiberglass between them.

 

[jsharkey]

Perhaps..

Cutting and reinforcing on the back with fiberglass might work. Otherwise although strong I suspect it will look ugly.

Jim Sharkey

 

[Transporter]

Carbon Fiber Panel Mod

Your post doesn't indicate whether this is a structural mod, but the short answer is yes, you can modify/repair a carbon fiber structure using epoxy and fiberglass cloth.

However, the appearance and strength will definitely not match the carbon fiber since the carbon fiber adds a tremendous amount of stiffness to the structure (and strength, based on the direction of the fibers).

Carbon fiber cloth is available from a number of sources in a variety of weaves (unidirectional, twill, etc.). As an example, see:
http://www.jamestowndistributors.co...=Fiberglass Supplies&categoryId=373&page=GRID

Depending on whether or not your mod will be visible (and need the strength), you might consider using carbon fiber, or a combination of carbon fiber and fiberglass cloth in your mod.

It's also possible to dye your epoxy using black pigment to create faux carbon fiber. Strictly an appearance option (and it won't match exactly...but can come close, depending on pigment and technique). For an article on adding pigments to epoxy see:
http://westsystem.com/ss/adding-pigments-to-epoxy/

Good luck,
Mike

 

[rleffler]

Can a carbon fiber panel be modified with epoxy and fiberglass cloth? Small change.

If you are talking about the Aerosport carbon fiber panel, the answer is yes. How you apply the fiberglass and epoxy may vary depending on what you are attempting to accomplish.

I'm also assuming that you're going to paint the panel, since the modication would be obvious using different materials.

I would recommend given Geoff a call to discuss the specifics. I'm curious, what are you going to modify?

bob

 

[RV7Guy]

More info

Need to know if you are going to fix the front that is visible or the back side that isn't. The panel was probably either laid up from a mold or vacuum bagged. It might be tough to recover the finish on the front.

I have a carbon panel in my 7 that was vacuum bagged. It is 3 layers of 45 degree biased CF and 2 layers of Fiberglass. It is an overlay over the modified original panel fastened with 6-32 stainless socket screws with aluminum anodized shoulder washers from the RC helicopter department.

Regarding the carbon to aluminum deal. This another one of those issues that someone came up with (like the zip ties sawing an engine mount in half) that nobody can show me any quantitative evidence that this is a real problem. In my case, my carbon panel is an overlay. The glass was used to gain thickness in the panel because it is many times cheaper than carbon.

If you are using carbon as an overlay that is fastened to a panel it is certainly not an issue. If you are really concerned, put a some UHMV tape on the aluminum and call it done.

I'm at work and Imageshack is blocked so I can't post a picture of my panel.

 

[flyingbeaver26]

in short yes. If your carbon fiber panel will be touching any aluminum surface there should be a layer of fiberglass between them.

Any explanation for this? Will the CF wear into the AL with vibration?

 

[rleffler]

Any explanation for this? Will the CF wear into the AL with vibration?

Carbon can cause a chemical reaction when expose to the aluminum over a period of time. This is why most folks are taught to use a sharpie instead of a pencial when marking parts.

The carbon fiber on the panel is embedded in epoxy, which I would think isolate the carbon from the aluminum inserts.

 

[RV7Guy]

Show me

Carbon can cause a chemical reaction when expose to the aluminum over a period of time. This is why most folks are taught to use a sharpie instead of a pencial when marking parts.

/QUOTE]

Hey Bob,

Not picking on you here, but this is the myth that has been perpetuated that no one can prove. It has been mentioned a few times on the Internet so it must have become fact. Probably started by gmcjetpilot Hope I didn't wake him

I spoke with an Aeronautical Engineer who works with Boeing Helicopter in Mesa. They use lots of composites. He's a RV6 owner and is building a 7. When confronted with this question, he stated that the next set of dinosaurs will be roaming the earth when a carbon to aluminum mating would become an issue in our planes.

As noted, it isn't raw carbon anyway.

 

[Ron B.]

Thanks for all the replies. I did call Geoff and it's OK to do my mod. I want to install rocker switches just like Geoff has, but I also want to install more on the co-pilot side. There isn't enough height so vola the mod. We will be painting the front and what's hidden shouldn't be too sitely.I wasn't planning on priming the alum. backing plate for the carbon fiber panel but probably changed my mind.

 

[Bob Kuykendall]

...this is the myth that has been perpetuated that no one can prove...

I have definitely seen it. It mostly happens when you lay carbon up directly on aluminum. It is a galvanic reaction between the carbon and the aluminum that causes the aluminum to corrode. It is especially nasty if the carbon/aluminum interface gets wet.

I haven't seen this reaction happen when bolting or riveting aluminum to cured carbon. The epoxy resin does tend to encapsulate the carbon and prevent the direct contact that results in the galvanic reaction. However, just to be on the safe side I generally include a thin glass laminate anywhere I am bonding in a metal part such as a bearing in a spot that is difficult to access or inspect.

Bob K.
www.hpaircraft.com/hp-24

 

[rleffler]

Thanks for all the replies. I did call Geoff and it's OK to do my mod. I want to install rocker switches just like Geoff has, but I also want to install more on the co-pilot side. There isn't enough height so vola the mod. We will be painting the front and what's hidden shouldn't be too sitely.I wasn't planning on priming the alum. backing plate for the carbon fiber panel but probably changed my mind.

Good luck with the mod! Be sure to send Geoff or I some photos so we can get them posted to his site.

bob

 

[dhammer]

I have definitely seen it. It mostly happens when you lay carbon up directly on aluminum. It is a galvanic reaction between the carbon and the aluminum that causes the aluminum to corrode. It is especially nasty if the carbon/aluminum interface gets wet.

I haven't seen this reaction happen when bolting or riveting aluminum to cured carbon. The epoxy resin does tend to encapsulate the carbon and prevent the direct contact that results in the galvanic reaction. However, just to be on the safe side I generally include a thin glass laminate anywhere I am bonding in a metal part such as a bearing in a spot that is difficult to access or inspect.

Bob K.
www.hpaircraft.com/hp-24

To add to that and FWIIW - The earlier Bombardier Challenger aircraft had a serious problem with carbon floorboards that were attached directly to the aluminum floor beams. Some corroded so bad they had to have beams replaced within the first few years of service. The fix, if within limits, was to treat the corrosion, paint the beams with epoxy paint, then apply a vinyl tape between, before the boards went back down.

Virtually all new larger corporate aircraft such as Gulfstreams and Challengers have carbon floorboards to save weight and are fitted with a barrier system so carbon can't touch the aluminum. They coat the beams with the epoxy paint also.

Don