went back 3 pages saw no links to this-no pre heat? anyone know more about these welding electrodes?

Cummins Diesel Cast Iron Exhaust Manifold Repair

 

I dunno man, looks kinda iffy to me. I haven't welded much cast so this sure beats me. It might just work, I'd like to get someone that has used this to chime in and see what they say.

 

yes cast iron can be welded. talk to an older welder. there is a certain rod they'll usually tell you to use and there is a method. what i've been told is to pre heat then weld some then pre heat then weld again. its not just gonna be perfect your first time. it may look horrible but deffinitely ask an older welder about this. most people dont do this anymore

 

I have welded lots of cast over the years what i prefer to do is get your stuff in order make yourself a box out of styrofoam to insulate it to let it cool slowly on your welding table bolt your exhaust down to prevent warping drill a 1/8 hole at the end of the cracks get a heat pencil 400 degrees heat up the area let-it cool for a couple of minutes and do again get some heat all the way in the manifold weld about an inch at a time then preheat do till done and stay away from the bolt holes if you do have to weld one of them you will have to take it to a machine shop and have it edm'ed it will be so hard you cannot drill it been there done it as far as welding a wire feed works great set it hot slower wire and weld as fast as you can it will weld weird but once you get the hang of it you will understand how it welds and then but your box over it and let it cool slowly do not touch or peek for at least 12 hrs

I took a broken manifold for a case tractor must have been in 30 pieces took a piece of 1/2 flat iron mounted it to it and welded it up took me all day but that has been 10 yrs ago and still works to this day you would have to have the new mating surface machined and the holes opened up with a edm make sure your heat is at 400 till done

 

I always heat them in an oven to 400 then weld then pack it in sand to slow the cooling.

 

The success rate on welding cast depends a lot on the quality of cast. I weld on old tractor parts all the time that hold up well with it, but a lot of this newer stuff is cheep Chinese cast that has massive amounts of air and impurities in it. This is why it cracks in the first place and why it doesn't hold a weld very well.

You may be able to do this if the crack is short and the weld goes quick. Longer welds get the piece to hot. You also need to drill a small hole at each end of the crack to keep it from spreading.

The article linked may say all of this, sorry, didn't read through it though. The problem with doing this though is that even if your weld is successful it will only be short term. The problem with these manifolds was a design flaw that will only crack again in the same or different place. There is just to much expansion and contraction in this design and makes it crack in the weakest spot, so it will just find the next weakest spot and do it again.

 

Grind a valley into the crack, just like in the video stop drill the crack. Either us a rose bud to keep the piece hot. Or like the guy above^ and through it in the oven. Then get some nickel rod. when the guy was saying 72, and 77 that means the amount of nickel in the rod in percentage. Nickel rod cost allot more than your standard rod.

 

drill both ends of the crack to prevent propagation then use a carbide bit to grind a u groove into the area (grinder wheels tend to smear the carbon around and make welding difficult) then preheat the piece in an oven or very carefully with a torch to about 400 degrees when it reaches temp use a high nickel rod sold at most farm supply stores it should say cast rod somewhere on the packaging then after you get it welded put it in the oven before it can cool much and let it cool slowly by turning it down about 100 degrees every hour when it finally cools enough to replace you can blend grind the weld back or leave it as is if you feel comfortable. any stops and starts you make need to be ground or the trapped slag will cause a new crack! make sure to keep the piece around 400 too hot will cause the entire thing to develop cracks and too cold will cause the weld to crack.