School me on aluminum welding

[gcappy]

I am starting a project and need some information. I have an 05 Cannondale super-v with the carbon swing arm and headshock fork. I want to turn this into a super-v fat bike. I am thinking of building a new aluminum swing arm and retrofitting the headshock with new aluminum legs. Questions:

1) Will I have to heat treat the new swing arm and the modified fork?
2) Should I make the swing arm out of plate or tubing?
3) Should I use a new wide fat bike fork for the legs or create legs from tubing?

thanks
Gcappy

[GrayJay]

Ambitious project. A few similar transformations have been made, see;
http://forums.mtbr.com/fat-bikes/pro...al-714699.html and for custom headshock Bob Brown Cycles, Custom framebuilding in St. Paul, MN

Any time you weld 6xxx series aluminum it does need to be heat treated, otherwise it looses a lot of strength and will likely fail on a vital bike frame part. Unless you are skilled with TIG welding and knowledgeable with working aluminum, this does not sound like a good first time project to tackle.

I would suggest that doing all your fabrication work from steel rather than aluminum is much more realistic. See the above headshock link where he re-built a fork with steel legs. For the rear end, investigate to see if there is anyway to widen the swingarm and/or bushings so that a 170mm width hub can be used. Hacking apart and re-bonding carbon parts is likely going to be much easier than working with aluminum.

[gcappy]

The welding is no problem. I just don't know anything about heat treating. I thought about using steel but I have this very light frame with full suspension and want it to stay light. I will check the links.

thanks
Gcappy

[einreb]

from what I understand, 7005 is the 'easiest' to heat treat with a pretty simple schedule. I plan on trying that with my powder coating oven setup once i get around to actually putting a frame together with AL (just tubes, not suspension bits).

6061 involves quenching and some rather specific processes that are a bit more difficult.

This may be relevant to your interests...

http://www.eastoncycling.com/bike/wp...-7005_6061.pdf