Neutral Flame

[grdev]

I thought I understood the neutral flame, but now I'm not so sure.  I went to remove a brace I had tacked in and to my surprise it came out with a snap, like a dry twig breaking. I couldn't touch it with a file. I went back to reading about  brittle welds, and you have a carbon  flame that is very easy to get..  I think I have it right now, my welds are not as pretty, but I can't tear apart my sample welds, and  the biggest surprise to me was I could now file my welds, they didn't ruin my file.

It has probably been gone over a hundred times, but maybe some of you a lot more knowledgeable about gas welding and what the flames should look like can explain again for guys like me that aren't to sure.

[rockiedog2]

the inner cone is sposed to be clean edged but not hard edged.  set it with too much acetylene then watch it as you gradually decrease the acetylene you will see the acetylene whisker disappear from the inner cone. that's where we're sposed to set it. right there where it disappears. if you continue to gradually reduce the acetylene the inner cone will go hard edged, that's O2 rich and the condition we want to avoid. I run just a bare whisker of acetylene on mine to be sure it's not O2 rich.
there is room for error in what i'm trying to say and your interpretation of what i'm trying to say...if in doubt best to get somebody competent to help be sure youre doing it right.
i'm no expert by any means and was taught by an old timer way back...so if anybody with more knowledge knows diff by all means say so. but that has worked well for me for a buncha welding.

[Dan_]

the inner cone is sposed to be clean edged but not hard I run just a bare whisker of acetylene on mine to be sure it's not O2 rich. there is room for error in what i'm trying to say

I have had it explained to me by describing it as a "blur"...  

You could say it goes from full feather, to whisker, to blur, to neutral, and then to hard edged...  

Put just a little blur on the tip of the inner cone.  

Try to get in the habit of checking every few minutes to see that the cone is just a little out of focus on the tip.

[Justin]

Sounds like you did it right. That's why tacs are so useful. Strength multiplies in the joint as it is welded.

 If you bairly increase the o2 to keep the blue flame in the inner cone, you had it.
Be sure to buff tubing with emery cloth and wipe with a cleaner before final weld!