Talk Composites - The Forum for Advanced Composites

Bike Frame Project Questions

http://www.talkcomposites.com/Topic11735.aspx

By FrameFudger - 6/9/2014 11:26:39 PM

Hi,

Got my tubes made, been using 100gsm hi-mod UD CF. next step is to jig them and epoxy the joints together and then fillet the joints, also need to epoxy carbon fibre to a titanium bottom bracket shell I am using...

Bottom bracket Shell

Will be wrapped in pre-preg UD CF. Want to make sure the bond between the titanium and CF is stronger than the just the pre-preg resin. So which epoxy to use?

Tube joining

Tubes will be mitred and then fit flush to each other. Once they have been glued I will then be wrapped further pre-preg UD CF around the joints, so the epoxy needs to be generally strong with a little flex, however will not be the only structural element taking force and load.

I was looking at the ET515 Epoxy Adhesive, but I am not sure if this is the most suitable?

http://www.easycomposites.co.uk/products/structural-adhesives/semi-flexible-15min-epoxy-adhesive.aspx

If not what would you suggest?

Joint filleting

Prior to wrapping the joints in further UD CF I need to fillet the joint so there are no sharp acute angles which could create a void after wrapping and curing.


Similar to this...

http://applemanbicycles.com/wp-content/uploads/2013/12/KoenFilletHTP1040089.jpg



What filler \ epoxy combination would you suggest, as this isn’t structural the lighter the better.

Look forward to your responses.


Cheers,

Andy


By f1rob - 7/20/2014 9:51:35 PM

If you wrap your bottom bracket have a cf ply on the ti you will have a lot better bond than u/d

Glue wise best choice would be a pre preg film glue fm87 would be perfect but depending on the glue you use for bonding you might want to go for a LTM so you don't compromise your glue with the cure temp

To do your radius try araldite 252 I doubt you will find lighter its a bit difficult to work with till you get use to but then its ok

Its used in F1 to fill the holes in chassis inserts where pockets are machined out to lighten them

Bonding the tubes if you want to go OTT you have Hysol 9394

myself I would use 3m 9323b/a