Est. 1998 — 28 years of woodworking knowledge
OT Repairing Carbon Fiber Question
Barry Irby
I have a Honda Walk behind Lawn mower with a carbon fiber deck.
Yesterday I noticed a crack in the side of the blade housing with a piece of debris sticking out of it. I cleaned out the debris by prying the crack open a little and shoved it back into position.
So, what can I glue it with? How to reinforce this?
Re: OT Repairing Carbon Fiber Question
Philip Duffy
Well, this is an interesting challenge! You could try CA glue, Gorilla, epoxy or, as a last resort, rivet a piece of sheet metal across the broken area and then stand back, way back, to see what happens! P.
Re: OT Repairing Carbon Fiber Question
Ralph Lipeles
I would epoxy a fiberglass patch along the length of the crack. The strip should be about 3" wide. Lightly sand the area where the patch will go. Brush some epoxy on the deck, lay the fiberglass on the brushed epoxy and then saturate the fiberglass patch material with more brushed epoxy. After the epoxy sets I would probably put a secong patch strip on top of the first one. If the underside of the deck is accessible, the second patch should go on the underside rather then oon top of the first one.
Re: OT Repairing Carbon Fiber Question
john in lutz
If this is what Honda calls a Nexite deck they come with a limited lifetime warranty. Go to Honda.com and search for Nexite and you will find the warranty information.
Re: OT Repairing Carbon Fiber Question
Dick Coers
The warranty option is best, but will likely require an invoice. That’s always a problem with my filing system. I would suggest using a resin compared to epoxy. It might also benefit to drill a small hole at the end of the crack to prevent further propagation before bringing in resin and cloth. Edit; Definitely paint the repair as many resins get brittle with ultraviolet exposure.
I called Honda.....
Barry Irby
Home Depot gave me the number, but it was for the credit card division. Hunted up a number on the interweb. Finally got through. First two tries the line was busy. Remember that? They seemed surprised it broke and said to take it to a real dealer/service center. I called them and they were slightly buffaloed by the break but said to bring it in. And so I shall. They said some of the decks are made of Nexite and some are Zenoid (sp?). None of them had a clue as to what glue, if any, might work.
Guess I will have to pull out my ancient John Deere with the magnesium deck to finish the season.
Metalic duct tape
Re: OT Repairing Carbon Fiber Question
William Duffield
I agree with Ralph and Dick: Reduce stress to stop the crack from propagating, sand, epoxy, fiberglass, more epoxy, and paint.
Re: OT Repairing Carbon Fiber Question *LINK*
Bob Entwisle in NJ
How about a carbon fiber repair kit?
I've no experience with this, but it would seem like one should repair fiberglass with fiberglass and carbon fiber with carbon fiber, my 2¢...
Bob in NJ
Carbon Fiber Repair Kit
Took it to a repair shop....
Barry Irby
It might have a limited lifetime warranty. I hauled it in. Left it for evaluation. The shop told me, as I was about to drive away, they charge $43.50 for the evaluation even if they don't do anything.
They also spotted a second hole in the deck. Now that changes things. Can't say it would be worth the effort to try any sort of repair. This mower is about seven years old and has been lightly used and kept indoors. Not much good to say about whatever that deck is.
Incidentally, It is not carbon fiber.
Marketing a warranty *LINK*
Dick Coers
The word warranty seems to mean less and less. Road hazard warranty on my Costco tires cost me $58 to replace a tire destroyed in a pothole. A Stanley ribbon hose with limited lifetime warranty spilt about a foot from the end. If I shipped it to them, they would evaluate it. So if I spend $15 shipping, I MIGHT get a replacement $39 hose. I'm getting the feeling all those lifetime warranties were best described in the movie Tommy Boy while discussing guarantees.
https://www.youtube.com/watch?v=ALQNFusg_m0
Re: OT Repairing Carbon Fiber Question
William Duffield
Rhetorical question: Are we engineers or landscapers? 
From an abstract point of view, it makes sense to repair carbon fiber with carbon fiber, because, for equivalent strength, thickness, and other physical parameters, carbon would provide similar and probably better performance properties. That would also apply to the particular epoxy resin and hardener chosen. It would be important if you were building for example an America's Cup yacht (Reference Australia One off San Diego in 1995). 
https://www.youtube.com/watch?time_continue=159&v=8Yau9A7XDHs
But I think it is a moot point for a repair to a seven year old lawnmower deck. Use whatever leftovers you have laying around from a previous project. If you don't have any, purchase whatever is cheapest and at the closest supplier. Fiberglass cloth is cheaper than carbon fiber cloth. Fiberglass felt is cheaper yet. There is lots of difference in price among epoxy resins, and probably even more between them and polyester resins.
The builder of the boat explains the failure in the first comment to the YouTube video. (It wasn't the carbon fiber.)
Re: OT Repairing Carbon Fiber Question
Don Goodwin
If the Honda engine is still good, can you take the engine off of the mower with the bad deck and mount it on the old metal mower deck? I did something similar about 35 years ago.
When I bought my first house in the early 1980's, my parents gave me their old push mower (purchased in the late 1950's). I used it for awhile until I got tired of fighting the 30-year old (at the time) 2-cycle engine and bought a newer push mower at a garage sale. I used that mower until the deck gave out and then took the engine and mounted it to the old 1950's frame. I used that mower for several years until my girlfriend (future wife) made replacing it with an actual store-bought brand new mower a condition of marriage. She has made me actually purchase new stuff over the years instead of cobbling something together.
