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markovwgti

Repairing CF Helmet

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So unfortunately my helmet came off my head with all my video equip on yesterday...it is a tonfly feugo pro...the back of it is pretty cracked up but it might just be repairable...what would you guys use to repair it...some type of bondo...sanding it down and then painting it? is it possible?

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what would you guys use to repair it...some type of bondo...sanding it down and then painting it? is it possible?



That sounds more like a cosmetic repair. I'd be more concerned about the structural integrity. You might want to look into some sort of fiberglass or carbon fiber repair.

Maybe trim the rough/splintered edges of the cracks, and use some gaffers tape to hold the shell in the correct shape on the outside, then lay the repair material on the inside of the helmet. Build it up until it seems strong, and then address the outside. You could sand and bondo for looks, or re-inforce the repair by laying some material on the outside as well. It might not finish up as 'pretty' but it would be strong.

First, go with Spot's idea. You might get yourself a steep discount on a replacement, or maybe they'll throw you a lid they have sitting around the factory just because they feel sorry for you. I know that L and B replaced dozens of Pro Tracks lost due to riser strikes when moutned on the outside of a helmet. They didn't have to, but they did.

I understand that your cameras might be hurting pretty bad, but borrow one and post some pics of the carnage.

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Not one single thing was savlageable...actually sorry just the battery from my xsi...The back of the helmet

I dropped it off at a buddies house...hes been repairing helmets and doing airbrushing on them...he said itll cost about 250 to fix it and then black and red paint job on it would make it come to about 400...i already ordered a solar convertor side....now after this happened i definitely want a back up helmet and i dont really wanna let go of this thing...it was my first work helmet!

So i lost a Sony pc1000, Brand newish Canon XSI, Tokina 10-17mm lens, cookie box....

Bite switch stayed in my mouth as the helmet ripped off my head....it was my last chance i was waiting for my teeth to get ripped out of my mouth...

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I wouldn't try it that way.

You might have a cosmetic solution but structurally it is seems worthless.

Carbon fiber relies on the fibers for it's strength. If it is cracked you have lost the strength on that location.

I've once repaired an old cracked Glass fiber helmet for a buddy by sanding down the paint and applying a set of large CF patches on top of them

You 'll have to apply patches that are large enough to transfer the forces applied to the helmet.
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So here's the deal with repairing your helmet. Wherever you see the delamination (white cloudy area on the helmet, looks like yours goes from the very back edge of the flat mount on top, to around the sides, I'd say right up to the edge of your freefly man sticker, and around and equal distance to the other side and then about to mid level of the helmet at the back.)
You're going to need to completely cut that out, but VERY carefully. You need to cut it out and then find a way to brace the piece you've removed. You're going to use it to as a temporary mold to pour plaster or two part pourable foam into. Once you've made the mold of the damaged part, you then need to use it to recreate a new piece to put back in.
Now the fun part, you have to go around the entire perimeter of both the NEW part and the EXISTING helmet edges. Very carefully sand a 16:1 feathered edge on both, but make sure it's opposing from helmet to new piece. What you want is a very nice gradual feather that will allow the most surface area of the composite layers to meet. Once you have this edge you can then begin to bond the two together. You'll want to run two layer of CF in the inside, and feather to match existing structure, and then run two layer of CF outside, also blending into existing structure. The best way to build the patch though is to keep it two layers less than the helmets layer count, this way you can apply two wet layup patches directly butting into the helmet, and then carry on with two more inside and out as described above. This will give you the most strength.
If you need some really detailed pics, let me know and I'll send some from the last aircraft repair I did. It was on a Slingsby firefly wing, and it took a week but it is as strong as factory. B| It's not a helmet, but the exact same rules apply for any type of composite repair. The most important thing is to get a good feather edge for bonding to. You'll also need to decide if you're going to use an epoxy based resin, or a polyester.
I prefer epoxy as it's easier to use and provides greater strength, but some like polyester because it still provides enough strength for a helmet and is cheaper, but it does not resist UV very well. Do some research and decide what you'd like to use if you want to do the repair.

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A friend of mine recently cracked the frame on her carbon fiber road bike, because of the manner the incident happened the manufacture wouldn't warranty the bike. The local bike shop sent the frame off to a guy locally that repairs surf boards who was able to repair it. Perhaps you have someone locally that could take a look at it for you. Good luck, sorry about your lid.

Chuck Bryan

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You'll also need to decide if you're going to use an epoxy based resin, or a polyester.
I prefer epoxy as it's easier to use and provides greater strength, but some like polyester because it still provides enough strength for a helmet and is cheaper, but it does not resist UV very well. Do some research and decide what you'd like to use if you want to do the repair.



Isn't your choice of epoxy or polyester based on what the helmet is made out of? I thought one didn't stick well to the other.
"For you see, an airplane is an airplane. A landing area is a landing area. But a dropzone... a dropzone is the people."

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Fixed Will post before and after photos in a few minutes

The paint design looks off centered but its not...its the shape of the helmet that throws it off a little bit...other then that in person its fucken fantastic for a helmet that came off my head at 5k...Thanks alot jeremy and Jmac for fixing it :)

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That is correct,

Epoxy will stick to both poly and epoxy substrate, and poly will stick to itself, but not so well to epoxy. This is why I told OP to do some investigation to decide which would work best for him. Most of the larger helmet manufacturers are passing off that they have these great carbon fiber helmets, but then use polyester resin to provide the bond. This is sort of going out the back door to try and cut production costs, but to be honest, if they used epoxy then the helmets would be even more costly, but would stand up to abuse better. It's really not important in the grand scheme of things though.;)

Also have to add that the repair looks good.

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