Matt Vandart Posted February 7, 2011 Report Share Posted February 7, 2011 I'm amazed that the bond between the flanges and carbon fibre bit are strong enough to cope with the forces in the rear wheel. Laquer the cf Glue for the win! I would have said the forces in the carbon part of the flange are more likely going outwards/inwards axially myself, rather than torsionally, which as stated, is handled by the spokes and the invisible hand of GOD. I'd stay well away from any modern airliners if I were you then! We use a 3M adhesive called 9323 B/A on our Formula Student program to bond our wishbones, now THAT is an adhesive! This is good shit. Crisps anyone? I will not at all be surprised if bike frames are being glued together some time soon. The potential benefit is very high especially in trials, xc and road. Quote Link to comment Share on other sites More sharing options...
aener Posted February 7, 2011 Report Share Posted February 7, 2011 I will not at all be surprised if bike frames are being glued together some time soon. The potential benefit is very high especially in trials, xc and road. Would be super cool if it could be melted with a blowtorch or something, too Cracked downtube: melt glue at welds, buy replacement, glue it in! Hehe. Quote Link to comment Share on other sites More sharing options...
Matt Vandart Posted February 7, 2011 Report Share Posted February 7, 2011 Would be super cool if it could be melted with a blowtorch or something, too Cracked downtube: melt glue at welds, buy replacement, glue it in! Hehe. Exacally! Quote Link to comment Share on other sites More sharing options...
ben.g Posted February 7, 2011 Report Share Posted February 7, 2011 brilliant bit of engineering Adam! I won't take offense to that given what a few people who I know who work at British Aerospace have said i love that...but i am a BAE boy Quote Link to comment Share on other sites More sharing options...
LukasMcNeal Posted February 7, 2011 Report Share Posted February 7, 2011 i love that...but i am a BAE boy Please tell your company how much I dislike the 146 then please! On another note nice hubbage! Quote Link to comment Share on other sites More sharing options...
ogre Posted February 7, 2011 Report Share Posted February 7, 2011 any idea what the lightest rear disc hub set up you can get is without hacking it appart? Quote Link to comment Share on other sites More sharing options...
Christophe' Posted February 7, 2011 Report Share Posted February 7, 2011 so , how much does an echo splined cog (assuming its a cro mo jobbie?) weight in the same size as yours adam? Quote Link to comment Share on other sites More sharing options...
Shaun H Posted February 7, 2011 Report Share Posted February 7, 2011 I will not at all be surprised if bike frames are being glued together some time soon. The potential benefit is very high especially in trials, xc and road. They already are man, aluminium forks with steel steerers have been bonded together for about 2 decades now, the dropouts on carbon forks are bonded in (and the steerer if it's alloy), as they are on frames plus there's a good few frames about which have aluminium "junctions" bonded to carbon tubing. Plus anything involving carbon fibre is technically held together by glue (the resin matrix) I've got a few things I want to try with the spare pre-preg we get from making our chassis, if I get the time to do them I'll post them up. Quote Link to comment Share on other sites More sharing options...
Rob Leech Posted February 8, 2011 Report Share Posted February 8, 2011 They already are man, aluminium forks with steel steerers have been bonded together for about 2 decades now, the dropouts on carbon forks are bonded in (and the steerer if it's alloy), as they are on frames plus there's a good few frames about which have aluminium "junctions" bonded to carbon tubing. Plus anything involving carbon fibre is technically held together by glue (the resin matrix) I've got a few things I want to try with the spare pre-preg we get from making our chassis, if I get the time to do them I'll post them up. I'm sure that quite a few carbon frames are built up in sections then bonded together, watched a company on 'How its made' making frames and the headtube, downtube, chain/seat stays were all individual parts that had been made to slot together. Quite a good watch - http://videos.howstuffworks.com/science-channel/36382-how-its-made-carbon-fiber-bike-frames-video.htm Josh. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 9, 2011 Author Report Share Posted February 9, 2011 Awesome video, makes me really want a CNC machine Hub on the bike in case anyone is interested... I know the guys on OTN were keen to see it! Quote Link to comment Share on other sites More sharing options...
craigjames Posted February 9, 2011 Report Share Posted February 9, 2011 Looks smart Adam, i'm guessing it's to late to use some form of clear gel coat to make it look uber shiny pimp? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 9, 2011 Author Report Share Posted February 9, 2011 Could probably do it but might make a mess! Not keen on the super shiny look for CF though or I would have moulded the sleeve 'inside out' (if that makes sense). Quote Link to comment Share on other sites More sharing options...
Shaun H Posted February 10, 2011 Report Share Posted February 10, 2011 Could probably do it but might make a mess! Not keen on the super shiny look for CF though or I would have moulded the sleeve 'inside out' (if that makes sense). How would you have achieved ID tolerance with a female "mould/mandrel"? Also, did you use a room temperature curing resin system or do you have an appropriate oven? Trying to get hold of some cheap core material atm but its pricey wherever I look! Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 10, 2011 Author Report Share Posted February 10, 2011 Didn't 'plan' that route, but off the top of my head, probably would have used some braided tube (http://www.easycomposites.co.uk/carbon-fibre-reinforcement/carbon-fibre-braided-sleeve.aspx - wish I'd have used that actually!) then an old inner tube inflated through the inside to squeeze against the inside of tube with 22mm ID. It's room temp curing resin Edit: Now found this tube which is a fair bit cheaper than I'd seen before, again - if I'd know about that I probably would have used it instead!: http://www.easycomposites.co.uk/Products/carbon-fibre-tube-roll-wrapped-22-2mm.aspx Quote Link to comment Share on other sites More sharing options...
Shaun H Posted February 10, 2011 Report Share Posted February 10, 2011 Edit: Now found this tube which is a fair bit cheaper than I'd seen before, again - if I'd know about that I probably would have used it instead!: http://www.easycomposites.co.uk/Products/carbon-fibre-tube-roll-wrapped-22-2mm.aspx That's roll wrapped uni-directional though. Cheap (relatively) but rubbish in torsion, although it'd probably be strong enough for this application. Plus there's no sexy weave Quote Link to comment Share on other sites More sharing options...
dirt jumper jake Posted February 19, 2011 Report Share Posted February 19, 2011 Lush! what lathe do you have? i did city and guilds engineering at school on the lathes so quite like playing around on them are you gonna do a matching front? Quote Link to comment Share on other sites More sharing options...
dann2707 Posted February 19, 2011 Report Share Posted February 19, 2011 Lathes are awesome. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted March 2, 2011 Author Report Share Posted March 2, 2011 Lush! what lathe do you have? i did city and guilds engineering at school on the lathes so quite like playing around on them are you gonna do a matching front? Just a small Axminster one, not particularly good quality but does the job for small bits. Might do a front one if I get time... The hub has actually died to an extent - however nothing to do with the bits that people speculated might break! The fibreglass inner layer was too soft and deformed, so the hub started creaking and it was really annoying. The carbon was intact and the glue held well, but I had to destroy it to remove the flanges. Got another centre piece curing at the moment made of 100% carbon - braided sleeve and pressure tape - hoping my freezer will be cold enough to shrink the mandrel to release it... Quote Link to comment Share on other sites More sharing options...
forteh Posted March 3, 2011 Report Share Posted March 3, 2011 That sucks, at least you know what to do for the next one Mandrel is only copper pipe isnt it? Worst case, I guess you can always machine it out carefully, would lose a perfectly good mandrel though Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted March 3, 2011 Author Report Share Posted March 3, 2011 Hopefully..! The new mandrel is aluminium, which has a much larger coefficient of thermal expansion, I've heard of people 'freezing' the tube out so I'm gonna give it a go... If not - boring bar time as you said! Quote Link to comment Share on other sites More sharing options...
forteh Posted March 3, 2011 Report Share Posted March 3, 2011 Im not sure how the coefficient of expansion of carbon compares to aluminium. The only recent experience of thermal expansion I have is heating crankcases in the oven and freezing bearings, they just drop in where as cold you cant even hammer them in; of course thats taking extremes of 100°c aluminium and -5°c steel. If you can cap one end of the mandrel (assuming its tube), spray a load of plumbers freeze spray inside, all being well the aluminium will contract enough; maybe even try it with a warmed piece to begin with. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted March 3, 2011 Author Report Share Posted March 3, 2011 Didn't think of the freeze spray - cheers for that! Quote Link to comment Share on other sites More sharing options...
Joshtp Posted March 3, 2011 Report Share Posted March 3, 2011 put a pic of the finished full carbon sleeve up when your done.... this whole project is pretty awesome.... what I wouldn't do to have access to a lathe.... Quote Link to comment Share on other sites More sharing options...
Shaun H Posted March 4, 2011 Report Share Posted March 4, 2011 Im not sure how the coefficient of expansion of carbon compares to aluminium. Totally different. Carbon is used for the structures of satellites since it has an extremely low coeff of expansion, one side of the satellite can be at -273degC whilst the other is heated by the sun, yet there is barely any distortion. Adam I recommend getting a water based release agent, you can get spray bottle ones which are super easy to use. Quote Link to comment Share on other sites More sharing options...
forteh Posted March 4, 2011 Report Share Posted March 4, 2011 Totally different. Carbon is used for the structures of satellites since it has an extremely low coeff of expansion, one side of the satellite can be at -273degC whilst the other is heated by the sun, yet there is barely any distortion. Adam I recommend getting a water based release agent, you can get spray bottle ones which are super easy to use. Ah cool, usefull info to know Should make adams job a lot easier to get the mandrel out! Quote Link to comment Share on other sites More sharing options...
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