Hi guys,

Sorry i know i am never here that much, i need to be more.

I have a project on going where i need to epoxy aluminum tube over
some carbon fiber tubing. It's going to get tons of stress so it needs
to be really strong bond. My questions are. . . . .

What epoxy should i use? The CF tube is already made and i will make
it as rough as i can (been laminated see) so i'll probs sand it back
to the rought carbon fiber cloth. I think thats a good idea right?

Also the space between the CF tube to the ID of the aluminum tube, how
much space should i leave for 1, to get the amazing bond between both.
2, to get a good amount of epoxy in there.

I will use a canular on a syringe to injecet the epoxy to get it right
in there is my plan for putting the epoxy in place.

Any adivce what ever i will take, i really need your expertses here.

The aluminum tube that goes the CF tube is a good length which will
help with the bond and reduce flex etc etc but it's bonding them which
is my problem.

Thanks for anyhting you can offer here

Pete

Hi Pete,

I would first investigate this, If I remember right then carbon fiber
and Aluminum do not mix without a inhibitor, Carbon fiber corrodes
aluminum when they are in contact with each other.

take care

Frank De Brouwer

On 19 Jan, 10:04, REBEL  wrote:
> Hi Pete,
>
> I would first investigate this, If I remember right then carbon fiber
> and Aluminum do not mix without a inhibitor, Carbon fiber corrodes
> aluminum when they are in contact with each other.
>
> take care
>
> Frank De Brouwer

They'd be the epoxy between both, no direct contact at all

Not good enough. You will need a layer of .5~75 oz glass veil at a minimum 
on the carbon face. Ideally you should also use a dielectric primer on the 
aluminum prior to bonding to prevent galvanic corrosion. This is how we make 
carbon skin, aluminum honeycomb core structures. Carbon and aluminum have a 
significant anodic potential and just separating them with a bonding layer 
of epoxy is insufficient as the epoxy will permeate moisture, completing the 
circuit so to speak. It's a battery in other words.



Anthony J. Cesaroni

President/CEO

Cesaroni Technology/Cesaroni Aerospace

http://www.cesaronitech.com/

(941) 360-3100 x101 Sarasota

(905) 887-2370 x222 Toronto

 wrote in message 
news:f4bba741-6927-4df8-824f-706b429e7f35@f10g2000hsf.googlegroups.com...
> On 19 Jan, 10:04, REBEL  wrote:
>> Hi Pete,
>>
>> I would first investigate this, If I remember right then carbon fiber
>> and Aluminum do not mix without a inhibitor, Carbon fiber corrodes
>> aluminum when they are in contact with each other.
>>
>> take care
>>
>> Frank De Brouwer
>
> They'd be the epoxy between both, no direct contact at all
>

BTW, an optimum bond-line for structural epoxy is typically between .007"~.014". 
Anything else outside of that range usually has properties of diminishing 
returns.



Anthony J. Cesaroni

President/CEO

Cesaroni Technology/Cesaroni Aerospace

http://www.cesaronitech.com/

(941) 360-3100 x101 Sarasota

(905) 887-2370 x222 Toronto





"Anthony Cesaroni"  wrote in message 
news:4793b71b$0$18452$4c368faf@roadrunner.com...
> Not good enough. You will need a layer of .5~75 oz glass veil at a minimum 
> on the carbon face. Ideally you should also use a dielectric primer on the 
> aluminum prior to bonding to prevent galvanic corrosion. This is how we 
> make carbon skin, aluminum honeycomb core structures. Carbon and aluminum 
> have a significant anodic potential and just separating them with a 
> bonding layer of epoxy is insufficient as the epoxy will permeate 
> moisture, completing the circuit so to speak. It's a battery in other 
> words.
>
>
>
> Anthony J. Cesaroni
>
> President/CEO
>
> Cesaroni Technology/Cesaroni Aerospace
>
> http://www.cesaronitech.com/
>
> (941) 360-3100 x101 Sarasota
>
> (905) 887-2370 x222 Toronto
>
>  wrote in message 
> news:f4bba741-6927-4df8-824f-706b429e7f35@f10g2000hsf.googlegroups.com...
>> On 19 Jan, 10:04, REBEL  wrote:
>>> Hi Pete,
>>>
>>> I would first investigate this, If I remember right then carbon fiber
>>> and Aluminum do not mix without a inhibitor, Carbon fiber corrodes
>>> aluminum when they are in contact with each other.
>>>
>>> take care
>>>
>>> Frank De Brouwer
>>
>> They'd be the epoxy between both, no direct contact at all
>>
>
>
>

Hi,

Well i got the original aluminum part off and there was just a direct
carbon to aluminum bond with the epxoy nothing else. Looks at manny
other things like this and they are the same! So 0.17779999999999998
too 0.35559999999999997mm will do for the space between the carbon
fiber to the aluminum... (christ thats small not even 1mm)

Here is the next question then, what epoxy to use? It needs to be mega
mega mega strong!

You're into a low viscosity structural adhesive for that application. 3M 
DP-460 will get you up to around 4500 psi shear as long as you don't go much 
past 160 F. If heat is an issue then a single part epoxy such as Hysol 
9346.5 will get you well over 5000 psi and 300 F continuous. It comes frozen 
and you need to cure it at close to 300 F so if the TG on your CF laminating 
epoxy is less than that and it probably is, you're pooched. You will also 
have to center the two tubes accurately and close them out properly, then 
inject the resin at pressure at points around the perimeter. Part stability 
is critical. I've done that for composite/alloy pressure vessel close-outs 
and it's a PITA. Surface preparation is also critical.



I'm not sure why you are taking the approach you describe. There are 
stronger, lighter and simpler methods that accomplish the same thing. You 
may need to do some research and analysis to verify the structure you are 
proposing.



Have fun, just don't be disappointed.



Anthony J. Cesaroni

President/CEO

Cesaroni Technology/Cesaroni Aerospace

http://www.cesaronitech.com/

(941) 360-3100 x101 Sarasota

(905) 887-2370 x222 Toronto




 wrote in message 
news:30ea3e00-f55e-4dda-854e-15b6b9f39c2c@c4g2000hsg.googlegroups.com...
> Hi,
>
> Well i got the original aluminum part off and there was just a direct
> carbon to aluminum bond with the epxoy nothing else. Looks at manny
> other things like this and they are the same! So 0.17779999999999998
> too 0.35559999999999997mm will do for the space between the carbon
> fiber to the aluminum... (christ thats small not even 1mm)
>
> Here is the next question then, what epoxy to use? It needs to be mega
> mega mega strong!
>

And,

TNO and the Delft university developed GLARE (used in the A380) for
weight saving purposes based on aluminum and glassfiber in layers,
they are doing the same now with aluminum and carbon fiber for weight
saving and strengthening purposes, but it is not an easy process as
Anthony already discribed. For your purposes I would stick to a full
carbon fiber option with kevlar in layers in the fins for
strengthening and flutter resistance, and that is already overkill for
our purposes.

I will be in the UK from tomorrow up to the 13th of Feb for some sim
training in Bournemouth, so if any one is in the area for a beer, just
sms, call me or drop an e-mail.

Frank De Brouwer

On 23 Jan, 09:33, REBEL  wrote:
> And,
>
> TNO and the Delft university developed GLARE (used in the A380) for
> weight saving purposes based on aluminum and glassfiber in layers,
> they are doing the same now with aluminum and carbon fiber for weight
> saving and strengthening purposes, but it is not an easy process as
> Anthony already discribed. For your purposes I would stick to a full
> carbon fiber option with kevlar in layers in the fins for
> strengthening and flutter resistance, and that is already overkill for
> our purposes.
>
> I will be in the UK from tomorrow up to the 13th of Feb for some sim
> training in Bournemouth, so if any one is in the area for a beer, just
> sms, call me or drop an e-mail.
>
> Frank De Brouwer

Sorry guys this not for a rocket. it's a set of carbon fiber forks for
my trials MTB bike. The moves we do are very powerfull and high load.

I just need an amazing epoxy that will hold these togther!

I've a jig already to center the build whilst it cures and i inject
the epoxy