Welding engine block

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Old 06-05-03, 02:26 PM
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Welding engine block

I have an engine that the rod took out part of the block near the bottom. I have a wire welder that I think can do the job but I dont have enough experience with cast iron to not ask some questions first. Should I heat the area first to minimize cracking? Are there any special tricks to cast welding that might help make the job go faster and easier? Thanks in advance for your comments!
 
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Old 06-05-03, 06:42 PM
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The you should preheat the area AND post heat the area. Allow the weld to cool slowly. Either way be sure to grind it to clean it up, and if any cracking occurs drill a stop hole. If you can find a lower nickel content rod, the block is less likely to re crack
 
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Old 06-12-03, 05:38 PM
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When welding cast Iron, I like to get the block warm, the larger the area, the better, If its an exhaust manifold and I can get the whole pc. up to temputure, I always braze it, thats always my first choice, however preperation is key, v-ee groove it and take a die grinder and grind a cross patern across the crack to create little nubs for the braze to stick to, then pre heat but do not let it turn red. you need to work quick, then braze it up, then post heat it as quick as you can, grind a point on your chipping hammer and start pecking away at the weld, what this does is as the part is trying to seperate you are stress relieving it and pushing the weld into the crack, the slower it cools the better.

When you have a big engine block it is not this easy, most people dont have a block oven, so I get out my nickle arc rod vee- grove the crack, the criss cross grinding is not neccesary, Preheat the area the closer to the crack the warmer, again do not over heat it, red is to hot, then make a pass, chip it, make another pass, I dont like to weld more than an inch at a time, chip it and dont forget to peck at it, then some times I will heat the area up againbetween passes, note, the key is to keep the heat as even as possible to prevent cracks, when your done, post heat it and then bak to pecking on it, this is the same as peening it, and let it cool down slowly and evenly. These methods are not out of a book but they work for me. and Iv'e done alot of tests. Iv'e had people tell me to heliarc it but a heliarc ( tig ) has to much of a concentrated heat, and cast iron does not like that. Good luck.
 
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Old 06-12-03, 10:23 PM
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I thought this thread was dead, so I did not add something I learned the other day on this very topic. In college they told use not to use nickel rods on cast because of their high tensile strength compared to cast. He suggested using a low nickel rod for such work. I think my teacher was ahead of his time because not low-nickel is all the rage for cast block repair. Fast forward till last week when this subject came up at work, I have changed jobs and at my new job we use 77 rods from http://www.muggyweld.com/cast.html because of there low nickel content, I am sure there are other products out there that are similar. 10 years ago everyone thought nickel was the way to go because of its high tensile strength, but more recently, research has proven that a high PSI metal in a soft metal such as cast is much more likely to re-crack because the cast is more ductile then the filler metal. If you visit the link above they explain it better than I can.
 
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Old 06-13-03, 05:39 AM
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Cast Iron Welding

I like the brazing Idea for this project. Can I use regular brazing rod, or should I ask for some special rod vis a vis low nickel, to do this? It sounds to me like you guys are using a regular stick welder in your examples. Does a wire welder need a special wire to do cast, and maybe a special mixture of shielding gas?
 

Last edited by WML13; 06-13-03 at 07:27 PM.
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Old 06-14-03, 08:29 PM
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Can you let us know how it goes? I'd be very curious to know how it turns out.
 
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Old 06-15-03, 02:30 AM
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I allways use Arc for this, when P.W. stops back in he can help you.
 
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Old 06-15-03, 03:58 AM
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Cast Arc Welding

With a handle like Weldgod, you probably do it quite a lot, while my arc, gas, and wire welding gets done usually gets applied in some type of fast emergency basis (and extremely part time) Im usually teaching myself as I go along. Everyones comments have been extremely helpful, (when wire units came along, it made my welding life MUCH easier. I can braze pretty well, and have mastered steel and aluminum with the wire unit. CycleZen is putting me up to a new challenge...I will wait to hear from Portable Welder on the brazing rod. Thanks guys!
 
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Old 06-23-03, 03:34 PM
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When using nickle rod I use an arc welder, however this does not mean you cant do it with mig, I just have'nt done it this way, I think the 75/25 is an ok gas to use. however, you may find you have to buy mig wire in a 10lb. spool verses a 1 Lb. tube of rod
Dont forget to weld a little at a time if you over heat one area more than another your inviting cracks.
As far as brazing rod I use a flux coated rod and the diameter varies depending on the size of the crack. get yourself a crown book and see what new rods they have out.
One of the other welding shops in town used to weld up heads for Roush racing when they would go through a port trying to port the heads, the method of repair for that is to spray weld,
this method uses metal powder and a special torch, they would never show me or wanted to talk about this process.
Remember, this is my method but I'm sure there are other methods that will work and they're always coming up with new and better filler metals so I will look into Weld gods site.

If you have an old block laying around do some testing before you scrap out a good block.
 
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Old 06-23-03, 05:03 PM
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Welding Cast Iron

Well, I have the perfect test block to play with, and I dont have a problem buying the 10# spool, because if I can train myself to do this, more opportunities will present themselves. After I retire maybe I will have more time to experiment with the stick welding unit. As with the other guys, I really appreciate your comments! Now I should probably take some courses in the local vocational school!
 
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