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boompole reparation (glueing carbon fibre)


Sprotnik
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Hi you all.

I have a VDB boompole (carbon fibre) and it is around 10 years old, it is not new but it was working perfectly until...

one of the inner thread (the one glued to the fibre tube, not the one that you hold with the hand to tight or loose for adjust the boompole extension) got unstick, so I can´t tight one of the boompole sections.

How can I fix it?

I think that glueing carbon fibre with metal should need some kind of special glue, I´m afraid to use any glue that will damage the boompole.

I would appreciate any advice or experience

 

thanks and regards

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1 hour ago, Sprotnik said:

I was searching in internet finding nothing.

Thanks!!!

Hello, if you have a hobby store near you, buy "thin" cyanoacralate. I have broken lots of carbon fiber, some on accident, some on purpose for testing. CF will wick cyanoacralate (super glue) and make it very strong, but, it will no longer have the flexibility it had prior to the cyanoacralate. Can you send me a properly exposed picture of your damage, I may be able to walk you through this.

I am editing this, here is a link to the CA that you would probably need.

http://www.ebay.com/itm/Hobbylinc-INSTA-CURE-Super-Thin-Cyanoacrylate-1-2oz-CA-Super-Glue-101-/272223405060?hash=item3f61c78404:g:WWQAAOSwubRXHi8J

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2 minutes ago, Wandering Ear said:

Ambient recommends using high temp epoxy for fixing their poles.  Regular epoxy can become soft if used for long periods in the sun.

I would like Ambient to tell us how to use epoxy without vacuum bagging. If Ambient instructions included vacuum bagging,  I might go along with that. 

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thank you all for your help.

here is a picture about what happened to my boompole

 

20160702_203007.jpg

 

as you can see, I have to glue the metal thread to the segment of carbon fibre. there´s nothing broken in the pole, just the thread is unsticked to the tube

 

 

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1 hour ago, Sprotnik said:

thank you all for your help.

here is a picture about what happened to my boompole

 

20160702_203007.jpg

 

as you can see, I have to glue the metal thread to the segment of carbon fibre. there´s nothing broken in the pole, just the thread is unsticked to the tube

 

 

Oh, I see. I was thinking you had cracked CF. Well this is a horse of a different color. 

First, if you stick your finger in the hole, does carbon fiber dust get on your finger? BE CAREFUL around carbon fiber. Don't let it poke you. Just feel inside and tell me if you get CF dust on your finger, or if it is "slicky".

Also, will your problem let you easily separate the 2 parts that need to be one?

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well, there´s  a little bit of dust inside, but I think it´s just dust from the 10 years of shooting in location (the age of the boompole) and it is not CF dust.

is not easy to separate the two parts, the metal thread is embraced strongly by the CF tube but it´s not strong enough, cause when you operate the boom the wheight of the shootgun microphone makes it rotate, and you can´t boom properly following the characters.

so, it will be hard to remove it by hand cause it´s strongly embrace, but it is not strongly enough to work with it as it is right now.

I think I will have to remove it (somehow) and glue the metal thread to the CF tube, but I´m afraid to damage the CF with a glue chemically active with the CF.

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5 hours ago, Sprotnik said:

well, there´s  a little bit of dust inside, but I think it´s just dust from the 10 years of shooting in location (the age of the boompole) and it is not CF dust.

is not easy to separate the two parts, the metal thread is embraced strongly by the CF tube but it´s not strong enough, cause when you operate the boom the wheight of the shootgun microphone makes it rotate, and you can´t boom properly following the characters.

so, it will be hard to remove it by hand cause it´s strongly embrace, but it is not strongly enough to work with it as it is right now.

I think I will have to remove it (somehow) and glue the metal thread to the CF tube, but I´m afraid to damage the CF with a glue chemically active with the CF.

You are good at drawing references, so can you draw a line thru the part that is moving versus the part where it goes? So I can be clear. Thank you.

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Hi

sorry, I´m not english native and the explanation can be a little confusing...

the part that is moving is the metal one that I have been calling "the thread" (don´t know if it is the better word fot that), a piece of "the thread" (around an inch) gets inside the CF tube and it is where it is glued from factory and it is where I have the problem

20160702_203007.jpg

 

thanks for helping Martin

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2 hours ago, Sprotnik said:

Hi

sorry, I´m not english native and the explanation can be a little confusing...

the part that is moving is the metal one that I have been calling "the thread" (don´t know if it is the better word fot that), a piece of "the thread" (around an inch) gets inside the CF tube and it is where it is glued from factory and it is where I have the problem

20160702_203007.jpg

 

thanks for helping Martin

Your English is fine. So, to make sure I have this right. Below the red line, is the part that is slipping. You need to prevent the part above the red line from rotating inside the part below the red line. The reason I had asked about the CF dust, is because if the CF is still resin impregnated (and slippery) , then the metal, which won't want to glue to the carbon fiber anyway, will have a very hard time staying glued to the CF. If you can pull the part out, then you could scar, NOT sand, the inside of the CF. If you sand the interior of the CF tube, you will make the tube inside diameter larger, making the slipping worse. Also, CAUTION, when you scrape, grind, sand or otherwise remove particulate from CF there is a HUGE DANGER. When you grind aluminum, steel or just about anything else, the particles that are ground off and fall on the floor, or bench or whatever is below the part being ground. When you grind or sand CF it floats around in the air waiting for you to inhale it. Trust me on this one. So, wear a mask, or at least an old t-shirt, and consider doing this with either a vacuum cleaner attached, or do it outside, but still wear a mask.

Now, this is a job for an epoxy, not cyanoacralate. Probably. Cyanoacralate, will not adhere to the metal very well. So, now, you need an epoxy. But what epoxy? I have no idea what is available in Espana. Whatever you use, you need to test it first. 

To be continued. I am afraid all of that typing will disappear.

 

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Ok, so. Once you find the epoxy. Your are going to have to test it. I'm guessing you don't have any spare CF lying around that you could test with. If you do, let me know. So, when you mix epoxy, you need to have very equal amounts. Or you just get a wet mess. Now, you need to make a practice batch. So thoroughly mix equal parts of your 2 part epoxy, about 25mm in diameter for each part. I use a razor blade to make sure that every bit is mixed. Mix this on a non porous substance that is oven safe. Now that you have it mixed, let it dry for the amount of time indicated. Generally speaking, the longer it takes to dry, the better. Ok, after it has dried, stick it on an oven safe container. Pizza pan etc and place in a preheated oven for 10 minutes at 60C. If you pull it out and it looks good, still hard, not cracked, it might be ok to use. It would nice if you could glue something together and then cook it.

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Now, if it were me. If I could separate the 2 pieces, I would use a bore gauge and measure the inside diameter of the CF, checking several spots for uniformity. Then, I would use a dial caliper to measure the outside diameter of the metal tube. Now, since we know the metal doesn't want to stick to the CF, we need to find something that will stick to the metal, and that will subsequently then stick to the CF. So, if we have have the clearance available,

This is where Kevlar (or Vectran, we will get to that in a minute) thread comes in. If you wrap the Kevlar thread tightly around the metal tube, until the entire metal section is wrapped in Kevlar, you then apply the thin CA I mentioned earlier. You have to hold both ends of the thread tight. Let this dry. You should not be able to move the Kevlar thread at all at this point. It should be at one with the metal. You can use Vectran too. It comes in a thread that is more like tiny tape. Picture teeny tiny threaded gaffer tape, but a lot stronger, with an extreme abillity to take heat. So, now that it is VERY dry, you slide the 2 parts back together. This should be a very tight fit. If it isn't,  let me know, but it should be. Now, you have already scratched the surface of the CF so the CA can sink in. Me personally, I would now use thin CA, as discussed earlier. As long as the fit is very tight, we could talk tolerances if you had the tools to measure, but I'm guessing you don't.  So, very tight. Now, slide the parts together. Once they are fully inserted, you let the thin CA run down the inside of the tube, between the Kevlar and the CA. Kevlar/Vectran will stick together to the CF like metal welding. You will likely never get those parts apart again without cutting them apart.

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Thanks a lot for your detaliled explanation, I'm reading it carefully and I think I will have to search in my area for some components you mention, epoxi will be easy but I'm not sure about the kevlar or vectran...

Just for being sure I'm not missing something: what is the CA you are saying?

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CA= Cyanoacralate. Most people refer to this as Super Glue, which is a low quality brand of Cyanoacralate. Be careful if you go the epoxy route, if it says it will only handle just slightly hotter than what YOU can handle, it won't work. If you visit your local hobby Shop, they can probably sell you the thin CA. Check back with me if you want before you start. We can go thru what you bought and make sure. I looked on Ebay, I was amazed there is no surplus Vectran for sale. At least I could not find it there.

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ok, martin.

removing the metal part from the tube wont be easy by hand, it´s strongly embraced and it´s pretty thin, so I think it would be easy to twist it, spoiling the mechanism. I´ll have to be very careful removing it (to apply the glue) and putting it back cause, although it rotates, it´s very tight.

I´ll do a research in the hobby shops looking for vectran, kevlar or epoxies "heat proof". I guess the way to go depends on the materials I will find in the store.

I´ll write you back then, I´m sure I´ll need some advices with this products.

thanks again.

regards

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3 hours ago, Sprotnik said:

ok, martin.

removing the metal part from the tube wont be easy by hand, it´s strongly embraced and it´s pretty thin, so I think it would be easy to twist it, spoiling the mechanism. I´ll have to be very careful removing it (to apply the glue) and putting it back cause, although it rotates, it´s very tight.

I´ll do a research in the hobby shops looking for vectran, kevlar or epoxies "heat proof". I guess the way to go depends on the materials I will find in the store.

I´ll write you back then, I´m sure I´ll need some advices with this products.

thanks again.

regards

Sprotnik, yes, that is a decision to make. Do you epoxy the unit in place, not taking it out, taking the chance that it fails again? Or, do you remove the piece from the CF, risking destroying the part that now holds it together? You can't go the CA route without pulling it apart. You have to use the epoxy if you fix it without removal.

If it were me, I am fairly sure I would remove it, and fix it via the Kevlar/Vectran route. I just don't know your abilities. Also, I have access to more parts and pieces than you do. If, for instance, I removed it and it took a large amount of CF with it, I would just CA more CF back into it and carry on. And your very welcome. You can learn a lot about CF from testing it, breaking it, repairing it and my least favorite thing to do to it, burning it. 

Regards, 

  

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