Hello Everyone,
I have a crack in my mercruiser engine under the intake manifold. It is about six inches long. I am going to give welding it a shot, can't hurt. Anyway I came across a site that claims to have a rod that will not crack cast when welding it. They say it has 300% more elongation than the Nickel rods. Anyone heard of muggyweld.com, or better yet, used any of their 77 rod for welding cast? It is pricey rod, but if it works, it will be worth it to me. Thanks in advance.
Dean
Never heard of it myself..... The old school guys taught me to drill expansion control pilots at the ends of the cracks, heat the hell out of the area with a few torches & guys if any are around and fill it in with Ni. rod. Slowly let it cool and hope for the best. I'd be interested to hear if it works with the new rod or what has been experienced while using it.
All the best, Rob
I use to and still do at times, drill small hole at each end of the crack. Using the NI rod, weld about an inch at most. Then ping the weld. Ping is to take a sharp end of the chipping hammer and make little dents in it. This is sort of a stress relief. Let it sit until you can lay your bare hand on the weld. If you can lay your hand on it, then repeat above steps. This way, there is no preheat or post heating. You can have the part just laying around and walk by and weld a little and then go on with other jobs. This process has worked for me for a long time and this is from one of the old school guys.
Preheating, slow cooling and peening are necessary to prevent shrinkage stresses. These stresses do not occur on many repair jobs, so the precautions are not necessary. If you are welding two pieces together that do not form a loop, cooling shrinkage will result in movement, but no stress. Compare the welding of a straight bar with a break to a spoked flywheel with a break. As the weld cools, the bar merely gets a little shorter, with no thermal stress. The flywheel, on the other hand, will try to shrink against the cold unwelded structure around it, which is sure top make it crack.
The reason I am bringing this up is that may welds can be done very easily, but people have been warned so many times they are afraid of them.
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shrinkage
together
Thanks everyone for your input. I will be giving it a try in the near future and I will let you know how it works out. Thanks again.
"RDF" wrote : ?? ^^^^^^^^^^^^^^^^^^^ RDF, if you will ask me a question, I will be happy to try to answer it.
No, Leo- We all have ways of doing things, I just tossed in what I knew. I don't think the being afraid had any influence on how to do something. Granted, several accepted and time proven methods exist. I place quality over anything and I felt a "sting" since doing things right is paramount and side stepped way too often- not to even contemplate accusing you of such but the comment
"The reason I am bringing this up is that may welds can be done very easily, but people have been warned so many times they are afraid of them."
I was a bit lost by why this was even mentioned. I guess we can't all be perfect. At least I admit it.
Rob
BTW, peening introduces compressive stresses in the surface. This eliminates a lot of the tensile stresses introduced by the welding process.
Stick welding, especially with thick fluxes, became a whole lot more fun after I discovered an air chisle. Little did I know, while I was pinging the heck out of the surface, I was also making a stronger weld.
-Jeff Deeney-
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