tig welding 7075 al, what happens

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I need to fill in some indentations in 7075 aluminum, I've been told 7075 is not weldable. What does that mean? will the filler not stick? These are dents about .005 deep and .125 long on a 1.000 thick piece. The area would then be sanded flush.Any advice before I just try it.ThanksVan
Reply:http://www.esabna.com/us/en/educatio...4-and-7075.cfm
Reply:Just so happens I have done the same kind of repair on 7075 molds and dies. The lucky thing is there is not structural integrity involved in the finished weld. The weld is not under tension so should not crack out. Here is what we do. Clean the surface thoroughly and heat to 200 degrees for an hour to remove any moisture from the surfaces. Then at 200 degrees quickly spot fill the dents with 4043 about 2 mm or 3/32" high.  After welding take a plannishing hammer and squash/peen the dent welds near flat to compress the porosity that is surely going to form. If you squash them down enough, they become insignificant. Then dress.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:thanks for all the replies, I'll try it and see what happens in a test piece.Van
Reply:This link from the Lincoln Company states that 7075 should never be welded for structural purposes but that it is used in injection molding dies and they may be welded. http://www.lincolnelectric.com/en-us...qs-detail.aspxMiller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set