Getting nice colors on stainless pipes

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Hi everyone, i have tried searching up and down and still have no clue how people give stainless exhaust or pie cuts a nice blue or gold color but not at the welds?  I will try posting some links to show what i'm talking about. http://i02.i.aliimg.com/img/pb/374/0...p32_1_4653.JPG http://higherarcing.org/yahoo_site_a...212457_std.JPG http://higherarcing.org/yahoo_site_a...143543_std.JPGI'm pretty sure these were not done thermally but probably some kind of chemical like ferric oxide or something similar.  Does anyone know anything about this?
Reply:Stainless welds very often turn different colors. I think putting pieces in a temperature controlled furnace will give different colors. I know you can color steel in a furnace. Maybe if someone was really careful they could do it with a heat gun? I think it would be hard with a torch and flame to get it consistent.
Reply:@ OP - the image shown via your 3rd link is a Ti exhaust built by Chris at Unobtanium Welding.  He's a CAN wizard fabricator who builds really nice products.  Give him a call.  Surprised what you may learn."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:The exhaust pipes are titanium, stainless does not color like that. Titanium is very expensive and requires absolute gas coverage. The pipes turn blue and gold do to heat from the engine. The weld is silver because of good gas coverage.
Reply:You won't get stainless AS blue as the pics of titanium you have there. But you can still give it a 'burned' look. - http://www.8thcivic.com/forums/diy-h...ue-purple.htmlI don't know how specific your colouring requirements. But if you just want blue, and it has to be stainless steel, have a look into patinas. Most info on it probably jewelry related.It's a fab life.
Reply:flame or induction heatingWelding/Fab Pics: www.UtahWeld.com
Reply:are the blue parts on the titanium still corrosion resistant?
Reply:I can remember the exhaust pipes on old British Triumphs turning the coolest shades of blue.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:Originally Posted by kingneroare the blue parts on the titanium still corrosion resistant?
Reply:TITANIUM - past to present "Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:So am I the only one who looks at all that off- color stainless and worries about chromium depletion?Currently working as a Paralegal, but still interested in hobby welding.Miller Bobcat 225ntOne- Character Fractions: ¼ ½ ¾ ⅛ ⅜ ⅝ ⅞
Reply:engine heat will also turn them blue/gold.
Reply:Originally Posted by teh603So am I the only one who looks at all that off- color stainless and worries about chromium depletion?
Reply:Thanks for the vid link ManoKai. T'was a good watch.It's a fab life.
Reply:In the flashlight and knife collection world heat anodized titanium is very much desired.
Reply:The color is a different kind of rust. It will fade and dull quickly if not immediately protected from the atmosphere in stainless faster than titanium, but titanium will loose its brilliance. I have seen some people color hole parts blue in stainless. It must go from hot to cool relatively quick, with a catalyst. Air works, but gunsmiths have some more predictable chemicals. If you ever look at really old guns with the decorative hard casing color, you will notice is faded.Constant Current Weldor.
Reply:What Is Carbide Precipitation?"One of the biggest pitfalls to avoid is carbide precipitation.Carbide precipitation occurs when the chrome and carbon in the austenitic stainless steel are drawn out of the material and react to the atmosphere. It occurs between 800 and 1,400 degrees F (426 and 760 degrees C), so you need to keep the weld zone temperature below 800 degrees. Alternatively, you can weld with argon as the shielding gas.Austenitic stainless steel is easy to read when welded: A good weld is straw-colored. It is likewise easy to detect carbide precipitation: The metal turns black. Material that turns blue or purple indicates possible carbide precipitation.The three main culprits responsible for carbide precipitation are too much heat, too slow travel speed, and inadequate shielding." - The Fabricator (Apr'07)"Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi