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Jonatan F 06-08-10 09:36 AM

Thinking of building a Aluminiumbike
I'm a determined diy-guy even though I haven't yet done a frame on my own! I've been longing for it but haven't gotten the skills. Anyway, now I've found a friend who have teached me how to weld and he also have a mma-welder (you could weld aluminium with mma, right?). So, i thought, why not do a alu-bike when I can! I want a roadracer but just have an old reynolds531-bike from like 80th.

I was thinking about building the frame up from square alu-pipes (mostly because it's easier to find and weld) and then attach a carboon fork and use a donnorbike for parts. (crashed roadracer or something).

Does anyone have any experience in such stuff?

Is there anything important to think of when you build it, alu aint as resistent as steel and i suppose I'll need some extra strong parts at the right place...

Anyway, this is what i want it to be like when it's done:

Even though I don't have a laser-cutter but i suppose i could drill some holes and then leave it a bit heavier than hes, I mean, some kilo doesn't mater for me being used to steel.

thanks in advantage for answers.

Jonatan F 06-08-10 09:37 AM

I browse the pic from the link too

ftwelder 06-09-10 05:17 AM

Hi, square tube has little torsional strength without the perforations so you would not want to do what has been done in the image.

Frames are made from two different types of aluminum. (1) self hardening/7005 (2) must be heat treated /6061. The easiest and most practical way is to use a Easton 7005 kit. This has all the materials you will need to construct a frame. After welding (with special alloy wire) you will need to heat the frame for several hours (pizza oven) to properly harden it. If you choose to use 6061 you will need to the related parts like bottom bracket shell etc. and then solution harden the whole frame at a very high temperature. You can use recycled materials but aluminum is extremely difficult to weld and parts become contaminated with oil and paint making matters far worse. I am not sure what a MMA welder is but you must use a tungsten electrode shielded with argon gas. Wire fed machines won't work and will ruin your materials.

It's very difficult to produce an safe and ridable aluminum frame. Some would say no matter what you do you will still be better off with a 531 frame.

Jonatan F 06-09-10 03:45 PM

Um.. That sucks! I was thinking of just buying some spare tubes of aluminium, cut up a old roadframe and weld it all together to get a awesome bike for low cost but it seams like my dream won't come true! :(
Well, I'll stick to the idea of building a oldschool tt-frame instead... whenever I'll get skills to do that...

And mma is some kind of very strong velding, with electrods (word?) screwed on to a handle... Can't describe this in English really... Here's a pic anyway...

rodar y rodar 06-09-10 06:39 PM

Ah- yes, we usually all that "stick" welding, technically known in English (at least in the US) as shielded metal arc welding. I know there are electrodes for aluminum for that process, but I can`t imagine using them on anything as thin as bicycle frames.

But don`t give up if you really want to build your own road racer- you just need to go about it a different way. The reason that most hobbyist builders use steel is that it`s so easy to work with. And gas brazing is much more common than welding for limited production bicycles, again because it`s so much simpler than welding. If you want to get exotic, you might look into carbon fiber bulding. I know very little about it, but there are a few home builders using different methods for that now.

Jonatan F 06-10-10 01:45 AM

The idea was to build a badass belgian-blue bike for roadracing without putting some 100 dollars into it.. Carbon would be nice but I think I'll need some kind of press for that... Maybe bamboo.. :)

ftwelder 06-10-10 03:11 AM

I am sure you could find some steel frame parts/random tube in local shops. I could send you some junk but shipping would be prohibitive.

those types of welders won't work on thin material or aluminum.

Jonatan F 06-10-10 07:56 AM

I suppose the aluminium-look (fat tubes and such) would be freaking too heavy if you made 'em in steel?
I'll stick with oldschool steel I suppose :)

Edit: And you mean like, buy a couple of steeltubes (gaspipe) weld it together (or braze?) and then see if I want to invest? Cuz' I don't think there are lugs and such at my local shops...

Jonatan F 06-10-10 01:27 PM

Cuz' there is no other way of building such a bike? Carbon is expensive, glasfiber too... Steel is to heavy... Tree... to difficult!

NoReg 06-10-10 04:02 PM

There really isn`t much in the way of cheap frames. It gets expensive fast as a hobby, even if you are willing to build low tech bikes, with garage materials, and expedient methods.

rodar y rodar 06-10-10 08:36 PM

Building your own is going to cost more than buying a prebuilt frame no matter how you slice it.

I don`t knowhow "fat" you want, but that`s possible. Oversized steel tubes are considerably bigger than traditional steel tubes and there are lugs easilly available for OS tubing. If you wanted fatter than that, straight wall cromolly is inexpensive, heavier than butted bike tubes (maybe too heavy for racing, but certainly not too heavy to make a useable bike), and easy to work with as long as you don`t mind getting away from lugged construction. In the US, it`s easy to order and shipping isn`t too bad, but I don`t know what your situation is. It`s probably available in Europe also.

I don`t think anybody here buys lugs from a local shop either, so you aren`t missing much by not haveing them at your local shop. Everything needs to be orfered and shipped.

Jonatan F 06-11-10 03:42 AM

Hum, then I suppose I'll get a second handed bike instead and maybe rebuild it like I want it (groups, bars, wheels and so on)
But someday I'll build a own frame, just not a racing one! :) Maybe a mtb...

Jonatan F 06-12-10 01:40 AM

Wnat about mig-weld a frame?

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