[abbys7]

hi im new to this site, ive got a small job to do my wifes bike frame snapped on the seat pole, i believe its alloy.
im looking at getting a tig welder so that i can weld it back together, the welders ive looked at are only dc inverter mma combi tig/arc was looking at the clarke 131 tig/arc welder
most welding is steel my question is is this machine ok to weld the alloy? 2 inch diameter weld
any help and advice appreciated
thanks mike

[jpence38]

As long as it's a steel alloy you will be ok.

[joseph.mowery]

Is the bike frame a Moly alloy?

[kermdawg]

I thought most bike frames were alluminum :/

[Otto Nobedder]

Here's showing my age--

My Schwinn had a steel frame.

Any bicycle worth repairing today is either aluminum or carbon-fiber. Carbon fiber is probably the easier to repair. The Al alloys in today's bikes are generally hard for the home-shop welder to handle. There's preheat, post weld cooling, possibly normalizing to consider. These are extremely thin wall tubes, requiring back-purge and possibly cooling blocks. This repair is not for the beginner, unless you've already replaced the bike and have nothing to lose.

Steve

[delraydella]

Aren't most bike frames fusion welded now?

[ogorir]

I dunno. the old steel schwinns were furnace brazed, all the joints at the same time.

to the OP, just go buy a new seat post. they're not that expensive. it's really not worth the trouble.

[Otto Nobedder]

Aren't most bike frames fusion welded now?

Since fusion is the goal of all welding processes, I'm not sure what you mean. I assume you're referring to a particular process, like sonic, laser, or friction stir?

Steve

[delraydella]

Aren't most bike frames fusion welded now?

Since fusion is the goal of all welding processes, I'm not sure what you mean. I assume you're referring to a particular process, like sonic, laser, or friction stir?

Steve

The process where the tube ends are flame heated to the melting point and then fused by pressing them together.

[Otto Nobedder]

Aren't most bike frames fusion welded now?

Since fusion is the goal of all welding processes, I'm not sure what you mean. I assume you're referring to a particular process, like sonic, laser, or friction stir?

Steve

The process where the tube ends are flame heated to the melting point and then fused by pressing them together.

-
Ah, gotcha. The modern equivalent of forge welding.
With Al, I would guess induction heating in an O2-free environment would be required, but the process would be essentially the same.

This doesn't preclude a TIG repair, but that would depend on the alloy, as some are virtually unweldable by conventional means.

I seem to recall an episode of "How it's Made" that featured bicycles built from 6061-T6, which is weldable, but requires some sort of PWHT to achieve full strength. I've been welding a long time, and I'd have to do some research before attempting the repair the OP asked about, which is why I said it's not for the beginner, unless there's nothing to lose. (If there's nothing to lose, it would be a valuable learning experience going through the research and attempting the fix.)

Steve

[Benson]

If it is 6061-T6, you're gonna play hell. You'll need a helium-argon mix and then a way to preheat the aluminum prior to welding. Otherwise you'll get mega porosity.