Welding Tips and Tricks

I heard on the "cheats" podcast a short discussion that motorsports guys like the purple welds on stainless. But I had also heard that a nice silver is a good color for a stainless tig weld. I have also seen some respected drag race chassis builders describe the same purple coloring for 4130 when tigging a chassis. They indicated that's how you know you got the temperature right.

I would like to see a video or hear a discussion about weld coloring - is there something we should be shooting for to indicate that we have the proper settings when welding 4130, Stainless, mild steel?

Thanks for all the great information....

gmcconn1 wrote:I heard on the "cheats" podcast a short discussion that motorsports guys like the purple welds on stainless. But I had also heard that a nice silver is a good color for a stainless tig weld. I have also seen some respected drag race chassis builders describe the same purple coloring for 4130 when tigging a chassis. They indicated that's how you know you got the temperature right.

I would like to see a video or hear a discussion about weld coloring - is there something we should be shooting for to indicate that we have the proper settings when welding 4130, Stainless, mild steel?

Thanks for all the great information....

Video aside, color on stainless welds is actually an indication of contamination (from a lack of shielding), although not necessarily a sign of a bad weld, now with titanium that's a different story.

I agree with Richard,

There's a lot of mythology and misinformation about weld color. The resulting end color is a factor of residual temperature (affected in part by material thickness, and in part by heat input) and gas coverage. If you have very broad gas coverage, you will get a better color for a given heat level. Many of those straw-colored to nearly silver welds you see on weldporn are done with large cups. Others are done very quickly to minimize heat input. Which is the better weld? Only destructive testing will tell... Bend tests and cut-and-etch, neither of which you can do on a finished part for your customer.

The simple fact is, if the color will brush off and not leave dark lines at the edges of the weld, you haven't "cooked" it. This is true for steels and stainless.

And yes, Titanium is a different animal.

Steve S

Otto Nobedder wrote:I agree with Richard,

There's a lot of mythology and misinformation about weld color. The resulting end color is a factor of residual temperature (affected in part by material thickness, and in part by heat input) and gas coverage. If you have very broad gas coverage, you will get a better color for a given heat level. Many of those straw-colored to nearly silver welds you see on weldporn are done with large cups. Others are done very quickly to minimize heat input. Which is the better weld? Only destructive testing will tell... Bend tests and cut-and-etch, neither of which you can do on a finished part for your customer.

The simple fact is, if the color will brush off and not leave dark lines at the edges of the weld, you haven't "cooked" it. This is true for steels and stainless.

And yes, Titanium is a different animal.

Steve S

Yea, that's what I meant well stated Steve

LtBadd wrote:

gmcconn1 wrote:I heard on the "cheats" podcast a short discussion that motorsports guys like the purple welds on stainless. But I had also heard that a nice silver is a good color for a stainless tig weld. I have also seen some respected drag race chassis builders describe the same purple coloring for 4130 when tigging a chassis. They indicated that's how you know you got the temperature right.

I would like to see a video or hear a discussion about weld coloring - is there something we should be shooting for to indicate that we have the proper settings when welding 4130, Stainless, mild steel?

Thanks for all the great information....

Video aside, color on stainless welds is actually an indication of contamination (from a lack of shielding), although not necessarily a sign of a bad weld, now with titanium that's a different story.

I agree with you. I have heard that color in the weld ( stainless steel ) shows that an oxide layer has been formed which may probably affect the corrosion resistance.

And 4130 chromolly is a different animal again. Higher heats and interpass temps are allowable. Jody mentioned Chromolly airframes being welded with oxy/acet.