Talk Composites - The Forum for Advanced Composites

MTB carbon frame

http://www.talkcomposites.com/Topic29238.aspx

By KostasBiz - 9/3/2018 3:38:38 PM

Hello just came here to this forum . My name is Kostas and i would like to share with you my ambition to make a CF bike frame .
I will? present my thoughts in order to give me some feedback thus to avoid mistakes .
I designed a bike frame in Solidworks and i plan to 3d print the design in HIPS (a plastic similar to ABS that is disolvable by d-limonene).

The plan is to wrap the 3d-printed core with CF then vacuum bag it and then dissolve the core in d-limonene. After that to place the three main parts on a jig for best alignment tack it with some resin and then wrap the joins with some extra CF .In theory everything looks good but in real applications i face a lot of issues.
here are some initial tries

cut  and  ready  for wet layup

core  ready for wrapping ,i have used 2layers of 322gr -11.3oz unidirectional , some ud tape , and outside a braided sock ,total  1500gr-53oz of CF and about 135gr-4.8oz of resin.
cover the vacuum bag with an electric blanket since my ambient temperature was 21C -70F

result looked promising but...

please feel free to comment suggest ,
do you believe that the final assembly of the individual parts glued and wraped with CF would produce a  strong enough bond for a bike frame?
By Kirill Tulin - 12/14/2019 1:16:13 AM

 
KOSTAS - 9/3/2018 5:21:50 PM
 
oekmont - 9/3/2018 4:07:39 PM
Your work looks promising. Wrapping and bagging such parts is not that easy.
Your mistake however was to underestimate the forces the bag applys on your cores. To get the dimensions of the wishbones right you might close the open end with a bar. As you are using sleeves, the bar has to be detachable. Additionally, when bagging, you should give some extra bag in between the wishbone, so the bag doesn't create as much force in the first place.

You are on a very promising road. a bit of practice here and there, and a well made jig to bond everything together, and you will get a very nice frame.


Thank you Oekmont
After wrapping i will set a holder between legs and spare some extra bag around the whole part in order to share tensions. Thank you for the encouragement i was a bit discouraged by my results . but i will try again   . I will post my next results Smile I hope soon .

Hi Kostas! I curious with what results did you end up on your project? Did you reach dimensional stability?