welding cast iron

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i have a exhaust manifold that need some welding. what is the proper way to do this?  can i tig weld it? i have reading on the internet, that i should use stainless rod?  i have some 316 rod,  will this works?
Reply:A picture of where the manifold is broken would help. In most cases exhaust manifolds are extremely dirty. It may be more feasible to prep it and braze it with a o/a torch. whatever method you use it should be preheated and then cooled very slowly.
Reply:There is a kid named Lance on here that does You tube videos. He has successfully welded Exhaust manifolds with all kinds of rod including 7018Look him up on here and YouTube.
Reply:Check this out. www.muggyweld.com or 309L or silicon bronze or lock and stich.
Reply:muggyweld.com as previously mentioned is good.  Another company featured on youtube's "ChuckE2009" (aka: "Lanse" here on welding web) channel, is a company called "Rockmount."   They specialize in alloy metal wire, stick electrodes and tig wire consumables.  They have a great selection of cast iron consumables you should check out.  Click on the link below:  http://www.weldit.com Click on "Products" --> "cast iron."Also, go to YouTube and type in "ChuckE2009" and view his videos on welding cast iron.  He has a ton of good $h!t Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
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Reply:The best way I've found is to take the thing to an engine shop for hot tanking( do they still have those up'ar ?) then blast it, prep it and use a good braze like Hilco F. Put it on a gas( or coal) BBQ get it wide open hot(? 600F +), braze, put it back on to cook a minute, close it down lid and vents shut. It takes hours to cool and holds. On charcoal it's all day or night to cool. The 7018"cold" looks ok for some things but the manifold is exposed to tons of vibration and thermal movement. An engine-tranny-etc. isnt.....just a couple hundred degrees.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:You really need to post a pick of what you are working with. A heat cracked manifold is much different than working with a nice solid manifold with a "simulated" crack and needs to be handled different depending on what you are doing. For sure when you have finished with the repair you will need to surface the manifold or it will almost certainly crack again regardless of how you weld it.
Reply:Steffen,       I offer my 2 cents worth.First let me say, I am an amateur welder, have been studying and practicing for 60 years. I have taught basic oxy/ac, smaw, and tig and supervised craftsmen in the same while earning a living as maintenance supervisor in a chemical plant (Dupont) . My addiction to old machinery and engine work has given many lessons for me and my friends. In high school (1955-1959) I supported my habit with Pap's old smiths torch crafting split manifolds and hot rod exhausts but was 23 years old before being introduced to the use of true cast iron WELDING rod for the "impossible" welding of cast iron. Like any weld that melts the base metal in a puddle while adding compatable filler rod, the key word is compatable, so the best filler is usually a piece of the same alloy as the parent metal. Too much to consider in managing the expansion/contraction of cast iron being welded to do it here, so let me refer you to a publication addressing cast iron weldng in more than 50 pages-at a time when acetylene welding was king and arc welding was a interesting second but not at all well developed. Please look at : openlibrary.org and a book titled "Oxy-Acetylene Welding" by Samuel Wylie Miller---dated 1916. You will see more than 1 copy listed but one is available to read online.     For me welding cast iron with cast iron rod and Oxy-Acetylene process is superior and more reliable, but I have a friend who does some TIG successfully after preheat -mostly to modify tractor cylinder heads-sometimes using CI rod usually using bare nickel.     Rebuilding broken fins on Motorcycle cylinders and heads is easy and the bolt hole broken off manifolds is so easy I don't even try to reattach the small broken off piece-just build it up with rod file it flat and drill and tap.Very controllable weld puddle and if done with care , no hard spots. Work vertical or horizontal overhead no problem--the weld deposit is so viscous it just sags a little. If the weld is near a edge or end--minimum preheat and slow cool and the finished weld is just like the parent metal. The rod is getting harder to find but is inexpensive compared to nickel or special and I have used clean metal broken from a similar part. Some people say old piston rings are a high quality filler and cheap as dirt. The flux is important and is for cast iron WELDING---brazing flux will not do. If you ride your counter man at the local welding supplier he may be able to interpret the books his boss has entrusted to him but most will declare you crazy and insist on getting the brazing flux. DO Not give in-after a few inquires and insults to his proficiency before his superior he can be brought around. While we are close to the brazing subject for manifolds let me point out the problem with braze in being "hot short" or weakened at a lower temperature than the parent metal. Braze is fluid in application at a low red heat for steel and cast iron, and a manifold on a hard working engine runs fairly red in places so the braze may yield. Sorry to be so long winded-just couldn't quit.
Reply:Thanks for the link to openlibary.org.  Thats a keeper for sure.