Spatter Question

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Some tools used in welding have copper in them because copper resists the blobs of spatter from steel as it's being welded.  I assume it's because molten steel won't be as likely to fuse with a metal that isn't steel.  Would aluminum or stainless steel resist spatter in a similar way?Last edited by Jack Olsen; 04-16-2009 at 01:05 AM.
Reply:They would in a similar way.  ALU would get a fair burn in from a molten steel blob and stainless it would probably stick to but would be easier to remove.  They are generally copper coated as solid would be too soft for some apps and too expensive.
Reply:The spatter sticks to the stainless just as it does to mild steel. I don't know about the aluminum though.I suppose it doesn't stick to the copper because it dissipates the heat to fast (just a guess).Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:Copper has a very high heat conductivity, so small particles hitting the surface will cool before they give off enough heat to melt the surface. Better put, the copper conducts the heat from small particles away fast enough that the copper never gets to the molten, or at least, bonding temperature.Since aluminum melts at a much lower temperature, it isn't as good as resisting spatter unless it has a thick oxide coating which does have a very high M.P.Stainless can have a higher M.P. but also has lower heat conductivity so probably isn't much different than carbon steel, depending on the particular alloy; I'm sorta guessing on this one.
Reply:We use copper blocks as chills when welding pads for alloy chemistry analysis.  Even in prolonged contact with molten steel, their is virtually no bonding between the copper blocks and the steel puddle.The two are somewhat analogous to oil and water.  Their is limited "soluability" for iron(steel) in copper and vice versa.  That said, you can get some transfer of copper into a molten puddle of iron(steel), and the little bit that can dissolve is usually bad for the steel's mechanical properties.I know some structural steel construction applications(storage tanks) are sensitive to arcing across ground clamps.  This is because most ground clamps are brass(copper), and the little bit of copper that dissolves into the melted spot created by a bad ground connection can make a weak spot in the metal.Getting back to the OP's question, the spatter from welding steel doesn't stick as well to aluminum in part due to the thermal conductivity of aluminum; which others have mentioned.  You also should remember that there is a very thick oxide layer on an aluminum surface.  That oxide layer has a much, much higher melting point than either steel or aluminum metal.  So long as the heat input from the spatter doesn't melt the aluminum under the oxide layer, the spatter should stick poorly or not at all.Stainless steel still has a lot of iron in it, and poor thermal conductivity.  If anything, I'd expect weld spatter to stick worse to stainless steel; unless the chromium oxide layer on the surface performs the same function for stainless steel as it does for aluminum.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I'm thinking of using aluminum for a backsplash on a steel welding table.  It sounds like it would work reasonably well, although not as well as a copper backsplash.That said, would the thickness of the aluminum itself matter?  Its mass would affect its ability to absorb and dissipate heat, but I can't imagine it would effect that oxide surface layer.And since this would be a vertical surface, spatter could hit it, but wouldn't really be allowed to sit on top of it.  I'm guessing that this would reduce the ability of the molten steel to heat up -- and melt -- the aluminum.  But that's just a guess.Last edited by Jack Olsen; 04-16-2009 at 05:17 PM.
Reply:It wont look to good for long!
Reply:Aluminum holds up pretty well.  I have patched holes in alot of sheet metal by taking a piece of scrap aluminum and holding it as a backer to the hole and welding it up with a mig.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Is the AL free?If not why spend the extra $$$Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Yes, it's free.  And I don't have the right size steel for the same application.
Reply:Originally Posted by A_DAB_will_doI know some structural steel construction applications(storage tanks)
Reply:Originally Posted by Jack OlsenYes, it's free.  And I don't have the right size steel for the same application.
Reply:Maybe a bad choice of words...Oil storage tanks are structures, and support the weight of their contents without any outside buttresses or supports.  I suppose by my definition an aluminum soda can is a structure as well.Didn't mean to muddy the waters... Originally Posted by qaqcI guess I've never considered steel storage tanks to be a structural item??