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PostPosted: Fri May 10, 2013 7:41 pm 
Old School Hero

Joined: Sat Jan 12, 2013 11:40 pm
Posts: 154
Location: loughborough, leicestershire
Hi guys - looking for a broken (or crappy pile of junk that never deserves to be ridden again :roll: ) bike for a project.

For all those interested by the phrase "interesting project" the parts Will be used in a Carbon bike project that I'm intending on doing over the summer- there will be a build thread put up if there is enough interest. :?:

The only specifics if has to fit are:
- Intact 1 1/18 headtube (not to fussed on length but 12-14cm would be ideal)
- Intact English threaded MTB size BB (68mm I think?)
- Intact Normal style dropouts (Not vertical...)
- Not at all fussed on material.(anything from steel, alu, ti, carbon, would do- but ideally not magnesium :lol: )

:shock: THIS WILL BE CHOPPED UP :shock: - so if it has any sentimental or monetary value then I suggest you look away :wink:

A bonus would be Disc mounts, but not necessary as can add that easily

I can pay postage + a bit of beer money, but I can collect if very near loughborough (within 5-10 miles of LE11 as have no car at uni), or within 10 miles of OX7 (oxfordshire)

If you want to chop yourselves (can be fun - trust me :P ) to make posting cheaper/easier I would be happy to add a bit of money for time/effort (not necessary though)

NOW SORTED :P


Last edited by oliverracing on Thu May 16, 2013 3:54 pm, edited 1 time in total.

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PostPosted: Thu May 16, 2013 11:25 am 
Old School Hero

Joined: Fri Aug 19, 2011 3:23 pm
Posts: 234
Erm are you planning on bonding bits into a carbon frame?????

If so, time to get reading up on galvanic corrosion!!!

Don't want to teach gran to suck eggs but if you want any advice I used to work at the company that manufactured olympic frames and have a few connections within the industry on the composites side of things.

I'm also developing a composite frame at the moment too but we can't exchange too much info on that!!

John


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PostPosted: Thu May 16, 2013 11:43 am 
Old School Hero

Joined: Sat Jan 12, 2013 11:40 pm
Posts: 154
Location: loughborough, leicestershire
Yep, but had read about galvanic corrosion, the aluminum parts I have obtained are only really going to be used as liners, (head tube and bb shell) and not as lugs/ or whole sections, the rear dropouts have a lot of material on the so will be able to get a decent bond on them.

I had heard it can be stopped by using a thin layer of fibreglass between the alu and carbon :?:

This bike has now been 2 or 3 years in the planning (now have about 150 A3 pages of designs ideas :roll: )

If I run into any issues I may just pop you a message, if that's ok with you? :D


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PostPosted: Thu May 16, 2013 12:22 pm 
Old School Hero

Joined: Fri Aug 19, 2011 3:23 pm
Posts: 234
Any contact between the carbon and al/mg/common steel can lead to galvanic corrosion if not protected. Ti is OK in that respect.

Yep, a veil of glass etc will help prevent the GC.

Surface area is, kind of, irrelevant to bond strength and it plateaus anyway so bigger and bigger isn't always best. Surface prep is vitally important!!!

Sounds like a lot of planning!! Have you done any CAE/FEA?

BTW you can get off the shelf al/ti head tubes, BB shells dropouts etc.

Any probs, give a shout, and ill hopefully be able to help.

All the best with your idea!!

John


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PostPosted: Thu May 16, 2013 1:52 pm 
Old School Hero

Joined: Sat Jan 12, 2013 11:40 pm
Posts: 154
Location: loughborough, leicestershire
Are you sure Ti is 100% ok? I had previously read somewhere that it still corrodes, just to a much lower factor so still benefits from a protective layer.

yeah - currently doing an engineering degree so have worked with FEA on this, but have decided to go for strength over weight on this first build (aiming at ~ 1350-1400g where FEA suggested I could in theory get down to sub 1150g , but I have now lost the files for that so will go and make the frame and test it (either to destruction or till I fancy something else) :shock: - )

I had looked into off the shelf parts, but I was practically donated a frame, and as this is going for a really low budget (I already have Carbon fibre fabric (many different weaves/types :wink: ) from a project I did last year) I have decided to cut it up and see how it goes from there!

I will put up a build thread when this finally gets under way (not till mid june as got exams at the moment)


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PostPosted: Thu May 16, 2013 2:23 pm 
Old School Hero

Joined: Fri Aug 19, 2011 3:23 pm
Posts: 234
6Al series Ti alloys, Nickel-based superalloy and 'some' stainless steels are excellent in the galvanic respect but 6Al/4V Ti should be fine without an isolation layer. Then there is the CTE match to consider, which is also excellent with 6/4 as it is the closest to CFRP.

On my design I am not chasing weight either as I want to develop a freeride type of frame. Long term it could convert to a light XC type affair through material substitution as it is essentially a modular design. I'm also going to be trialling some materials that have never been used to manufacture a bike frame!! This, for obvious reasons, I cannot discuss!

It sounds like you are well on the way. Perhaps when you graduate you should apply for a job at our place, The AMRC in Sheffield!

John


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PostPosted: Thu May 16, 2013 2:46 pm 
Old School Hero

Joined: Sat Jan 12, 2013 11:40 pm
Posts: 154
Location: loughborough, leicestershire
Ah ok, for this I'll stick to my aluminum method for this frame, and should it work then I will start to really chase the grams! I intend to use this for XC/trail riding so I guess a few extra grams is ok as long as it's strong!

Graduation feels a long way off (I'm a first year at the moment), but to be honest I ideally want to get into F1 and the more data analysis side of engineering, and to keep this as fun/interesting/productive hobby.


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