glueing screw rivit back into metron 5d - glue advise?

Discuss light weight issues concerning road bikes & parts.
MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

Hey

Superman here just saw that the rivet holding the outfront computer mount on my metron 5d poppet out on one side. A idiot (... me) must have done what i always do - overtighten the mount screw forcing the rivet to push out.

well.... any advise on glue for glueing the rivetback into the carbon-hole of the handlebar?

What works well bonding metal to carbon? Superglue experience has not been super (high strengh på to brittle)
Heard about something like Araldite Epoxy.

Thanks...

by Weenie


MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

hm - no one?

Well - Found out that 3m Scotch-Weld DP460 should work + get a new rivnut and make a homemade expander tool.

Just thought of asking the local bike shop if they have any rivnuts (are the same as for bottle bosses)

But i must say that i am dissapointed in the design of the rivnut mounting. there is about 7mm of CF laminate. WWWAAAYYYY to thick to make rivnuts secure :evil:
The expantion area is like 5mm high, so the rivnut only hangs on with its nails.

Hate half-assed solutions...

eric01
Posts: 666
Joined: Mon Feb 06, 2006 1:06 am

by eric01

Do you have pics? Might help folks to visualize.

Epoxy in general is strong stuff and should be fine for a computer mount. But it’ll be impossible to adjust if you don’t get it right the first time because it is strong
Specialized Tarmac Sworks SL6, Moots Compact, Carl Strong Titanium

MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

True :)
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MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

what looks like cracks BTW, are not cracks. the are finish scars. a little piece of supperficial carbon came out together with the rivnut.

joeyb1000
Posts: 241
Joined: Thu Mar 03, 2016 8:37 pm

by joeyb1000

I suggest a new rivnut. For glue: permatex plastic weld.

MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

joeyb1000 wrote:
Sun Jan 26, 2020 12:29 pm
I suggest a new rivnut. For glue: permatex plastic weld.
Thanks for the suggestion

jfranci3
Posts: 879
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Yeah, you need epoxy that sticks to epoxy and you need to sand that spot down. I"d do the rivnut and the expoxy. The rivnut to better take the canalevered vibrations and the epoxy to hold the rivnut in place while you tighten it. Sand the hole a bit, put epoxy on the rivnut, then insert the rivenut.

MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

jfranci3 wrote:
Sun Jan 26, 2020 5:31 pm
Yeah, you need epoxy that sticks to epoxy and you need to sand that spot down. I"d do the rivnut and the expoxy. The rivnut to better take the canalevered vibrations and the epoxy to hold the rivnut in place while you tighten it. Sand the hole a bit, put epoxy on the rivnut, then insert the rivenut.
thanks.

c60rider
Posts: 526
Joined: Mon Feb 27, 2017 11:12 pm

by c60rider

The best stuff I've found that seems to stick anything to anything else, indoors, outdoors, in all weathers is CT1. Amazing stuff and always my go to whenever something needs to be glued in easily and not come apart

alcatraz
Posts: 2664
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

That rivnut shows no sign of compression. They forgot to finish installing it didn't they?

Image

MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

alcatraz wrote:
Mon Jan 27, 2020 2:03 am
That rivnut shows no sign of compression. They forgot to finish installing it didn't they?

Image
Bad design. The laminate is thicker than the compression zone of the rivnut. But it seems that the old rivnut had only traces of adhesive

Butcher
Shop Owner
Posts: 1021
Joined: Sun Jan 03, 2010 4:58 am

by Butcher

That rivnut was compressed but the nut does not appear to be the proper thickness. The nut also looks like it was not flush when it was compressed. If you look at the top of the nut, it's fatter than further down. Because of that, the hole is probably compromised too.

If you elect to use another rivnut, get one made to install on thicker material. Buy/borrow the proper rivnut tool. Buy a couple nuts so you can practice and feel how much tension it takes to fully compress the nut. With aluminum nuts, you do not want to pull out the threads when you compress the nut. Maybe a bit of epoxy may help too.

MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

Butcher wrote:
Mon Jan 27, 2020 5:03 pm
That rivnut was compressed but the nut does not appear to be the proper thickness. The nut also looks like it was not flush when it was compressed. If you look at the top of the nut, it's fatter than further down. Because of that, the hole is probably compromised too.

If you elect to use another rivnut, get one made to install on thicker material. Buy/borrow the proper rivnut tool. Buy a couple nuts so you can practice and feel how much tension it takes to fully compress the nut. With aluminum nuts, you do not want to pull out the threads when you compress the nut. Maybe a bit of epoxy may help too.
Thanks

by Weenie


MaxPower
Posts: 123
Joined: Fri Sep 20, 2019 9:30 pm

by MaxPower

Butcher wrote:
Mon Jan 27, 2020 5:03 pm
That rivnut was compressed but the nut does not appear to be the proper thickness. The nut also looks like it was not flush when it was compressed. If you look at the top of the nut, it's fatter than further down. Because of that, the hole is probably compromised too.

If you elect to use another rivnut, get one made to install on thicker material. Buy/borrow the proper rivnut tool. Buy a couple nuts so you can practice and feel how much tension it takes to fully compress the nut. With aluminum nuts, you do not want to pull out the threads when you compress the nut. Maybe a bit of epoxy may help too.
Already because of the not very tight fit of the rivnut (slight oversized hole) i think epoxy is the only longterm way to go. (rattling fit)

Think my approach will be sanding slightly to. Make top and inside smoother and removing any adhesive left overs, sanding the area with the superficial carbon damage smooth and clean with vacuum and denatured alcohol. Then putting epoxy (using 3M dp460, expensive bit should be super good for carbon/metal adhesion) on the rivnut, put in, compress slightly, let it cure for lile 2-3 days and pray.

I am afraid that rivnuts for that laminate thickness are going to be to tall for the wing shaped handlebar. Also being sensitive with the expansion tool, as i dont want delamination caused by excessive pressure om the carbon wall.

So in the end, i hope for the epoxy to hold that rivnut in place, as a normal expansion lip is not feasible on this handlebar design.

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