Aluminum TIG 1/2 plate to 1/4 plate

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OK here's the situation, i have some T joint and Lap joint to TIG, all joint are 1/2 to 1/4 inch!the weld are 2 inch long and chamfer preparation already made!The set up to weld this is the following:-Miller Syncrowave 350LX (rent machine)-5/8 opening ceramic difuser-1/8 tungsten zirconiated (the brown one)-argon gasmy question is this needed to pre heat with O/A torch before start my welds or the machine will be enough strong to melt the 1/2 part of the joint ? Is pre heating with TIG torch only all over the joint can do the same job or its better to pre heat with O/A torch flame before ?Some people told me that is better to pre heat with O/A torch before, but my guess is the O/A torch produce less heat than the TIG torch so its probably useless to pre heat with something that produce less heat than my TIG torch even if i should wait couple secondes at the beginning of the joint!    Its only my guess i don't have a lot of experience so i can be wrong!I also want to know is this true with aluminum the chamfer prep should be deper and bigger than normal steel ?all advice about welding aluminum with this set up are welcome to!Last edited by LayoutMan; 12-07-2012 at 03:50 PM.Calculator > Bevel Square
Reply:I would say you got plenty of juice behind you espescially if chamfered, beings your wiring can handle the machine. If you feel you fall shy you could always try a helium argon blend. BC would be the guy to help you with that, but in my basement I could SQUEEZE 1/4 out of a 180amp machine, so I think you should be fine. Here's a pic of some 1/4 with a 180amp machine with straight argon. Attached ImagesI hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Shovelon would be the guy to talk to about helium/argon blends.   the pre heat is designed to bring the entire workpiece up in temp to say 250F. aluminum is a giant heat sink and sucks heat away from the weld area very fast.   so u need more amps initially till the aluminum heats up from welding.  hence why you back off the pedal as you get a few inches into the joint.   Preheat reduces the heat sink effects of the peices you are welding. so you need less amps to weld them.   Wit that machine I don't see you will have a problem with what you want to weld.    There may be some benefit to preheating the 1/2 plate but not the 1/4 inch...  I actually watched shovelon weld a piece of 1/4" plate to a 1"block of aluminum with my Lincoln V205T  but then Terry is a master TIGger..Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:well, preheating never hurts, I have welded similar thickness without preheat though.make it super clean so you can turn the balance on max DCEN I had only bad experience with zirconiated tungsten ..--------------------------------------------------------------www.becmotors.nlyup, I quit welding.. joined welder anonymous
Reply:Originally Posted by Donoharmwell, preheating never hurts, I have welded similar thickness without preheat though.make it super clean so you can turn the balance on max DCEN I had only bad experience with zirconiated tungsten ..
Reply:Originally Posted by Donoharmwell, preheating never hurts, I have welded similar thickness without preheat though.
Reply:Originally Posted by soutthpawYep, red thoriated or Blue Lanthanated would both be better choices for a transformer TIG
Reply:Fascinating. Thats some thick aluminum. From what I have learned here on WW that is challenging due to the fast heat transfer and the potential change in molecular / strength properties.Would a copper, or even steel backing, if practical, be useful to slow the temperature delta?Lincoln AC/DC 225/125 and WP17. 75A AC is for pipe thawing!HH 140 - new addtion 9/2012.I didn't agree, but hoped for Hope and Change.I got change for myself and my family: for the worse.This is the reality of: Barackalypse Now. Again.
Reply:75%Argon/25%Helium. 5356 filler. You got the horsepower. Have at it.How big is the finished part?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:I wouldn't TIG it. Light it up the MIG and spray transfer it.   Spray will look damn close to TIG.
Reply:Originally Posted by aDreamSoRealI wouldn't TIG it. Light it up the MIG and spray transfer it.   Spray will look damn close to TIG.
Reply:Nahhh, its not a hobby garage job haha i can't change many things except use different tungsten, i work in a company and this set up is what i have to deal with! i don't see big probleme and i'll be able to figure out how to deal with the job when i'll start next week after couple welds, the main question was about welding 1/2 plate with this set up because i never weld aluminum thicker than 1/4 inch thick!  thanks all for all answer, all advice is still welcome i only start the job at the end of the next week!Calculator > Bevel Square
Reply:and we don't have spool gun set up so MIG is not something i can try! @SHOVELON, i don't really understand what you ask by the finished size, but the complete pieces is a little bit hard explain especially due to my english, its something like 10 frames made of 2" 1/2 X 2" X 1/4 angles and they are all covered with 1/2 plate, the 1/2 plate is welded to the angles frame and most of the requiered welds are 2" in 12" everywhere on the pieces in lap joint, and couple places are but joint!So if i understood, pre heating a little with O/A torch the 1/2 plate only could be a good idea right ?Last edited by LayoutMan; 12-08-2012 at 12:03 PM.Calculator > Bevel Square
Reply:Originally Posted by LayoutManand we don't have spool gun set up so MIG is not something i can try! @SHOVELON, i don't really understand what you ask by the finished size, but the complete pieces is a little bit hard explain especially due to my english, its something like 10 frames made of 2" 1/2 X 2" X 1/4 angles and they are all covered with 1/2 plate, the 1/2 plate is welded to the angles frame and most of the requiered welds are 2" in 12" everywhere on the pieces in lap joint, and couple places are but joint!So if i understood, pre heating a little with O/A torch the 1/2 plate only could be a good idea right ?
Reply:Just done the job tonight after 2 full time welding days, pre heating the 1/2 plate was the key, every drops of filler rod melted perfectly with the base aluminum, im surprise how aluminum don't move that much with all that heat compare to stainless steel!Calculator > Bevel Square
Reply:Originally Posted by LayoutManJust done the job tonight after 2 full time welding days, pre heating the 1/2 plate was the key, every drops of filler rod melted perfectly with the base aluminum, im surprise how aluminum don't move that much with all that heat compare to stainless steel!
Reply:Pics or ban!-AaronJet 17.5" Drill Press1942 South Bend 16x84 Lathe1980s Miller 320A / BP --- 2013 Power Mig 2562012 Jet 7x12 Horizontal BandsawVictor O/A Setup
Reply:The most important question is:How large are these sheets of 1/2 and 1/4 inch aluminum???AWS certified welding inspectorAWS certified welder
Reply:Originally Posted by LayoutManall advice about welding aluminum with this set up are welcome to!
Reply:Originally Posted by Donald BranscomThe most important question is:How large are these sheets of 1/2 and 1/4 inch aluminum???