How to Finish our Carbon Fiber Nosecone?

I'm fishing for opinions on how to finish our carbon fiber nosecone. It was built for us by Dan at Python Rocketry and I have to say that we are very happy with it!

The nosecone is very well shaped and smooth overall, but the weave of the twill is still somewhat apparent. We would like to use a clear filler if possible, as the visual depth of the carbon fiber composite is really cool.

One possibility would be to use Aeropoxy laminating resin (we have a quart on its way). Would this be a good idea? Does anyone know how clear it cures? Is there another resin that might be easier to use/finish? We would be giving it a final clear coat after sanding.

Another possibility would be to build up several coats of automotive clear coat, sand, and then apply a final coat.

The last resort option would be using body filler and paint. While this could possibly be the easiest route, we would lose the look of the carbon fiber, which would be a shame.

What would you do?

Thanks in advance for any replies!

RocketFeller said:

One possibility would be to use Aeropoxy laminating resin

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That is what I use for the same application and it works well and stays clear enough. It actually has a clear yellow finish but over the carbon you will not notice. Mix up a batch, brush it on well, let it sit for 10 min then just wipe it off with a cloth that you will throw away and does not leave fibers. This will leave you with a nice finish one that you can reapply as required, and it will add minimal weight if that is of concern.

Keep in mind it the rocket is expected to hit high Mach 2.5 and up for any length of time the finish will erode.

That's quite a cone. You'll have to post the rest of the rocket at some point!

An easy way to finish carbon fiber is just to take aeropoxy, wipe it on and then wipe it off. The effect of that is shown on pages 54 and 55 in the link below. This works well if the carbon is sanded smooth to start with. You can build up uneven areas with aeropoxy, to a point, but if there is some unevenness, then it would be better to sand down rather than to build up. But the Aeropoxy wipe is pretty easy and it works. After wiping it on, the idea is to wipe almost all of it off so it literally feels dry (so that there is no drag from the epoxy on the cloth). I use a cotton cloth that doesn't seem to have much lint. This can be done a second time if desired, and if the surface is smooth to start with, you won't need clear coat.

Jim

https://www.raketenmodellbau.org/repository/archive/167792?view=true

mpitfield said:

That is what I use for the same application and it works well and stays clear enough. It actually has a clear yellow finish but over the carbon you will not notice. Mix up a batch, brush it on well, let it sit for 10 min then just wipe it off with a cloth that you will throw away and does not leave fibers. This will leave you with a nice finish one that you can reapply as required, and it will add minimal weight if that is of concern.

Keep in mind it the rocket is expected to hit high Mach 2.5 and up for any length of time the finish will erode.

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Thanks for the reply!

This rocket is actually going to be a low-and-slow upscale of the Binder Design Dragonfly. It should stay under 2/3 Mach, probably more like 500 fps.

It sounds simple enough but I do have a few questions, if you don't mind:

The wipe after 10 minutes is to remove excess resin and possibly drips?
I imagine you would sand it with finer grit between coats?
How bad does Aeropoxy smell? (I'm working with students)
Do you use disposable brushes or, if not, what do you clean up with?

JimJarvis50 said:

That's quite a cone. You'll have to post the rest of the rocket at some point!

An easy way to finish carbon fiber is just to take aeropoxy, wipe it on and then wipe it off. The effect of that is shown on pages 54 and 55 in the link below. This works well if the carbon is sanded smooth to start with. You can build up uneven areas with aeropoxy, to a point, but if there is some unevenness, then it would be better to sand down rather than to build up. But the Aeropoxy wipe is pretty easy and it works. After wiping it on, the idea is to wipe almost all of it off so it literally feels dry (so that there is no drag from the epoxy on the cloth). I use a cotton cloth that doesn't seem to have much lint. This can be done a second time if desired, and if the surface is smooth to start with, you won't need clear coat.

Jim

https://www.raketenmodellbau.org/repository/archive/167792?view=true

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Thanks! I was replying to mpitfield's reply and didn't see yours - you answered a couple of my questions already. We will definitely be sanding down , but I was afraid it would fuzz out if we get into the twill too much.

Do you apply it with a rag or a brush?

It is a monster of a nosecone, a 12.75" 5:1 ogive. The rocket is going to be an upscale of the Binder Design Dragonfly. The body tube is actually shorter than the nose, as you can see. The fins will be 10.85" x 23" elliptical fins. I am picking up the carbon fiber laminate for the fins on President's Day, and then we have to figure out exactly how to build them...

I will definitely be posting updates as it comes together. We are working on it one day a week, so it has been slow. We're planning to fly in late June, so it definitely will be done by then!

Fwiw, I would be honored to have Jim Jarvis compliment on a carbon fiber rocket, I've followed some of his work and 'how-to' vids, and it's -amazing-.

I really have to build one some day, CF is just absolutely gorgeous when it's all polished!


I am sooo envious of this rocket, it looks to be a masterpiece! The fact that it's monstrously large doesn't hurt either lol

RocketFeller said:

Thanks! I was replying to mpitfield's reply and didn't see yours - you answered a couple of my questions already. We will definitely be sanding down , but I was afraid it would fuzz out if we get into the twill too much.

Do you apply it with a rag or a brush?

It is a monster of a nosecone, a 12.75" 5:1 ogive. The rocket is going to be an upscale of the Binder Design Dragonfly. The body tube is actually shorter than the nose, as you can see. The fins will be 10.85" x 23" elliptical fins. I am picking up the carbon fiber laminate for the fins on President's Day, and then we have to figure out exactly how to build them...

I will definitely be posting updates as it comes together. We are working on it one day a week, so it has been slow. We're planning to fly in late June, so it definitely will be done by then!

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It shouldn't fuzz. I apply with a rag. The idea is to put on as little epoxy as possible - just enough to get the surface wet - because you have to wipe off everything you put on. More is not better. This is like using rubbing stain on wood if you are familiar with that.

You will want to be using the Aeropoxy 2032 resin and 3660 hardener. If you have some other form of Aeropoxy, then you'll need a different plan. The Aeropoxy doesn't smell too bad, but you'll want ventilation. If you are not familiar with safety precautions for using epoxy, the do a little research on the risks. You'll want to use nitrile gloves at a minimum. The cleanup procedure is to not need to clean up.

Jim

JimJarvis50 said:

It shouldn't fuzz. I apply with a rag. The idea is to put on as little epoxy as possible - just enough to get the surface wet - because you have to wipe off everything you put on. More is not better. This is like using rubbing stain on wood if you are familiar with that.

You will want to be using the Aeropoxy 2032 resin and 3660 hardener. If you have some other form of Aeropoxy, then you'll need a different plan. The Aeropoxy doesn't smell too bad, but you'll want ventilation. If you are not familiar with safety precautions for using epoxy, the do a little research on the risks. You'll want to use nitrile gloves at a minimum. The cleanup procedure is to not need to clean up.

Jim

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Thanks for the help, Jim.

That helps to think of staining wood. Do you wait a few minutes, or basically wet and wipe as you go?

We will definitely be working with plenty of ventilation, we will be using a shop with the roll-up door open and a fan while applying. I do have experience using hobby store epoxy (for rockets) and polyester resin (for boats), so I totally understand what you mean about cleanup!

The Aeropoxy is from Giant Leap and is sold as "laminating resin". It is supposed to arrive Friday, so I will check then.

McKailas Dad said:

Fwiw, I would be honored to have Jim Jarvis compliment on a carbon fiber rocket, I've followed some of his work and 'how-to' vids, and it's -amazing-.

I really have to build one some day, CF is just absolutely gorgeous when it's all polished!


I am sooo envious of this rocket, it looks to be a masterpiece! The fact that it's monstrously large doesn't hurt either lol

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Absolutely an honor!

I am still in awe of the thing. The biggest rocket we've built previous to this was a fiberglass rocket built from Giant Leap components and a 6:1 ogive, about twelve pounds...

We have been really fortunate to have had some amazing support from our component manufacturers. I have also received a lot of guidance from Mike Fisher, who will be supplying the motor. People here at The Rocketry Forum have also been incredibly helpful, it would be hard to do this without you guys!

RocketFeller said:

Thanks for the help, Jim.

That helps to think of staining wood. Do you wait a few minutes, or basically wet and wipe as you go?

We will definitely be working with plenty of ventilation, we will be using a shop with the roll-up door open and a fan while applying. I do have experience using hobby store epoxy (for rockets) and polyester resin (for boats), so I totally understand what you mean about cleanup!

The Aeropoxy is from Giant Leap and is sold as "laminating resin". It is supposed to arrive Friday, so I will check then.

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I don't know of any particular reason to wait. For a cone that large, I'd do section at a time, maybe a square foot, and then move on. Don't make more than 50 grams of epoxy at a time or it will just kick before you use it. Sounds like you're getting the right epoxy.

Jim

Dan,
When sanding carbon, or fiberglass, be sure everyone is wearing good masks. You don't want that carbon dust in your lungs. I also use a filtered fan a few feet away to help clear the dust out of the air.

pythonrock said:

Dan,
When sanding carbon, or fiberglass, be sure everyone is wearing good masks. You don't want that carbon dust in your lungs. I also use a filtered fan a few feet away to help clear the dust out of the air.

View attachment 281474

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Definitely! The kids will be swaddled in protective equipment throughout the process.

By the way, everybody that has seen the nosecone has been thoroughly impressed. Thank you very much!

Is there any way you could spray the epoxy top coat(s) on? Seems like you would better, more even coverage that way.

sooner.boomer said:

Is there any way you could spray the epoxy top coat(s) on? Seems like you would better, more even coverage that way.

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I would think in order for epoxy to be sprayed, it would have to be thinned dramatically, and likely not possible. I know of an Old Skool way to heat up paint (about 140deg) to thin it to spray, but that would be ill advised to do to epoxy.

JimJarvis50 said:

You will want to be using the Aeropoxy 2032 resin and 3660 hardener. If you have some other form of Aeropoxy, then you'll need a different plan.

Jim

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The Aeropoxy showed up today and it is indeed the 2032/3660 resin/hardener.
Thanks!

sooner.boomer said:

Is there any way you could spray the epoxy top coat(s) on? Seems like you would better, more even coverage that way.

Click to expand...

McKailas Dad said:

I would think in order for epoxy to be sprayed, it would have to be thinned dramatically, and likely not possible. I know of an Old Skool way to heat up paint (about 140deg) to thin it to spray, but that would be ill advised to do to epoxy.

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I was thinking that if the final coat doesn't look glossy enough we could sand it with 400+ grit and then have it sprayed with an automotive clear-coat.

The tip is wooden (under the cf) with a small aluminum point. We may spray the top three or four inches and then fade the color back for another foot. The tip is not exactly "beautiful" carbon fiber, so this will look pretty nice. We may even do some flames in the fade-out...

I would like to add something about the tip not being beautiful. Dan at Python Rocketry had told me that the lay-up was all by hand and that we might want to paint it. When it came we wiped it down with some water to get a look at it and I have to say that it is way too pretty to paint. The last few inches where it all comes together at the tip is the only thing that I would considering covering up, and I think it will add a nice look.

Nooo!

To me, painting carbon fiber would be like painting a DeLorean

I have yet to own either, but still, IMO way to purdy to cover up.

I've never used the 'Future' floor polish/cleaner, but would it work in this case?

McKailas Dad said:

Nooo!

To me, painting carbon fiber would be like painting a DeLorean

I have yet to own either, but still, IMO way to purdy to cover up.

I've never used the 'Future' floor polish/cleaner, but would it work in this case?

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I agree 100%! We're only looking at painting the top few inches of a six foot tall nosecone.

I have used Future before, but I want a little more durable finish. If the Aeropoxy has a decent gloss to it we will leave it at that, except for the tip. The original plan was to paint the nose with some of the carbon fiber showing. Now we are reversing that to leave most of it bare and only paint a little. The body and fins will be bare except for decals.

sooner.boomer said:

Is there any way you could spray the epoxy top coat(s) on? Seems like you would better, more even coverage that way.

Click to expand...

There are finishing epoxys that can be sprayed. There are reducers available for them that thin them enough to spray through an airbrush.

RocketFeller said:

I agree 100%! We're only looking at painting the top few inches of a six foot tall nosecone.

I have used Future before, but I want a little more durable finish. If the Aeropoxy has a decent gloss to it we will leave it at that, except for the tip. The original plan was to paint the nose with some of the carbon fiber showing. Now we are reversing that to leave most of it bare and only paint a little. The body and fins will be bare except for decals.

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After you wipe your PR2032 on and off (wax on wax off :wink you should be satisfied with the finish, if not you can always give it another wipe.