Welding a cast boat manifold...

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To start, I knew this wouldn't be easy...   A friend of mine dropped off a cast manifold from a boat. We had an unexpected cold snap early last winter, the manifold still had water in it and cracked. I'm pretty sure that it is cast steel, but I'm not 100% sure that it's not cast iron. It threw sparks, and shined like steel when ground.  I grooved out the crack and decided to try the Tig with 70s-2. I did not preheat thinking I could get away without if I worked slowly in short beads.  The 70s-2 seemed to flow smoothly for the most part. Unfortunately, upon cooling the weld cracked right down the middle. Now I have a few questions:1. Because the 70s-2 rod seemed to adhere to the manifold is it safe to assume that it is cast steel? I assumed the 70s-2 would ball up and not adhere well.2. This is a large manifold, preheating will not be easy. Could post-heating the weld with a torch to slow cooling help?Thank you in advance.
Reply:Grind out the filler you used and try some 309.Trust me....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterGrind out the filler you used and try some 309.Trust me....zap!
Reply:Piece of cake..NO pre heat NO post heat just do it and keep it small..Just get it to melt and you will be OK......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterPiece of cake..NO pre heat NO post heat just do it and keep it small..Just get it to melt and you will be OK......zap!
Reply:Originally Posted by makoman1860Just as an FYI. The manifold is iron, not steel. We usually spray weld them if we need to, or we use regular iron filler, flux and the O/A method.
Reply:Replacements are not too expensive.  Anything else cracked?
Reply:Originally Posted by blackbartReplacements are not too expensive.  Anything else cracked?
Reply:If it were me I would do exactly what Zap said.  I don't think he would steer you wrong.GravelThe difference between theory and practice is that in theory there is no difference.
Reply:Originally Posted by GravelIf it were me I would do exactly what Zap said.  I don't think he would steer you wrong.
Reply:Do Not use the Ni-rod / arc welding method, the repair will not be long lived. If it is a freshwater application, brazing is a sound repair method. It is not so much the nickel content that is the issue, as it is built up strain and rapid cooling caused by trying to use Tig for this repair. We have been down that path many times trying to save time and labor, but always end up going back to the spray welding, O/A welding and brazing methods. A V8 non-cat manifold should be easy to come by, we still turn them out every day.
Reply:makoman1860,Could you elaborate on the "spray welding" process you use?   Is it the same thing as what this guy is doing in the video in post #43 over in this thread?http://weldingweb.com/vbb/showthread.php...41#post4196441
Reply:Originally Posted by zapsterI try not to steer anybody wrong but sometimes things get in the way and a head on collision is unavoidable....If you see one coming.... DUCK!...zap!
Reply:Yes that is the process. We use Eutectic CPE11498 powder, but there are others that will be fine. Many of the cruiser manifolds are actually welded from the factory on a production basis, mainly to weld shut core printouts from the casting process. We use both pre and post heating as well. For prototypes we will use spray, O/A or brazing depending on the application. Like I said before, we have been down the tig path many times, it never works out as well.
Reply:I picked up some 309 per zap's recommendation. Not to say anyone else is wrong, but I tend to follow zap's advise first. I'll post my results.
Reply:Originally Posted by ncologerojrI picked up some 309 per zap's recommendation. Not to say anyone else is wrong, but I tend to follow zap's advise first. I'll post my results.
Reply:Originally Posted by ncologerojrI picked up some 309 per zap's recommendation. Not to say anyone else is wrong, but I tend to follow zap's advise first. I'll post my results.
Reply:Originally Posted by makoman1860Do Not use the Ni-rod / arc welding method, the repair will not be long lived. If it is a freshwater application, brazing is a sound repair method. It is not so much the nickel content that is the issue, as it is built up strain and rapid cooling caused by trying to use Tig for this repair. We have been down that path many times trying to save time and labor, but always end up going back to the spray welding, O/A welding and brazing methods. A V8 non-cat manifold should be easy to come by, we still turn them out every day.
Reply:Mercury Marine yes.
Reply:Based on my past experience with attempting to use tig to repair cracks in a cast iron manifold I believe I have to agree with makoman1860.   You might luck out and get it but the odds are against it happening.   If I was the one who had to do it I would braze weld it with what is commonly referred to as "low fuming bronze" rod.
Reply:Originally Posted by 4956Based on my past experience with attempting to use tig to repair cracks in a cast iron manifold I believe I have to agree with makoman1860.   You might luck out and get it but the odds are against it happening.   If I was the one who had to do it I would braze weld it with what is commonly referred to as "low fuming bronze" rod.
Reply:One last commentOn Re-Sale value.A repaired manifold will make the average boat buyer gun shy.They understand enough to know that repaired freeze cracks mean underlying damage which is why you are selling it.My neighbor buys and sells boats, all Inboards. If he goes to look at one and sees a cracked Manifold, he'll start low balling due to underlying damage which can show up later or not. He brings them home, pulls the heads, inspects, then re-installs with a replacement manifold. Most Boats he runs them at least a month to make sure nothing else comes up, then sells.
Reply:How did this repair turn out? Interested because we spend more time than we should at Bull Shoals and these type repairs pop up from time to time at a local marine shop.