More about TIG welding......

[SPOKE]

Since there are some pretty tight spaces to weld on bike frames what ceramic cup diameter should I use? Any reason to use a larger or smaller diameter cup for certain areas to be welded?
What about tungsten diameter? 1/16".....3/32" diameter. One size to weld the main triangle and another size for dropouts?
Thanks in advance for your info and knowledge.
Cheers.....Bill

[John Winston]

depending on a whole lots of stuff.......but in a nutshell.......... steel & aluminum with normal bicycle tube walls, I use 1/16 tungsten (aluminum 3/32 tungsten), gas lens (not the large lens) and a #8 nozzle. Seems to be good for about 99.99999% all my bike welding. Occasionally I need to change things around.

In practice, a larger cup allows you to stick the tungsten out farther to reach those tight spaces while keeping gas coverage acceptable.

Tungsten size depends on how many amps you are running, among other things.

of course, there are many ways to 'skin the cat', this works for me.

[SPOKE]

Thanks so much for the info. Shielding gas is a new dimension for me to consider. Is there some "rules of thumb" to go by regarding how far you can extend the tungsten electoode vs cup diameter?

[Rody]

There is a lot of good base info on the web...one of such is the Miller Welding site.

A rule of thumb...

The inside diameter of the gas cup
should be at least three times the
tungsten diameter to provide ade-
quate shielding gas coverage. (For
example, if tungsten is 1/16 in.
diameter, gas cup should be a
minimum of 3/16 in. diameter.
Tungsten extension is the distance
the tungsten extends out gas cup of
torch.
The tungsten extension should be
no greater than the inside diameter
of the gas cup

Download the rest of the manual here: www.millerwelds.com/pdf/gtawbook.pdf

That being said...guidelines are just that. There are sooo many little tips, tricks, and mods that are necessary for welding thin walled bicycle tubing that only experience (or one on one instruction) can teach.

Good luck,

rody

[mjbabcock]

There is a wealth of knowledge on search.bikelist.org and on the mtbr framebuilding forum. People like Don Ferris and Carl Strong put it all out there for us to try to copy.

[SPOKE]

You guys are the absolute BEST!