Brazing cast iron

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I can't recall ever brazing cast iron. Both pieces are cast. The Lovejoy coupling has about .003" clearance on the IH mower flywheel/pulley.

Will there be warpage?

Do I need to preheat the flywheel? Should I put the assembly in my wood stove till I get some color?

Should I only braze the joint at the base of the coupling? If I braze the top also, can I expect the brass to flow into the joint?

Is a propane/oxy cutting torch good enough?

I have plenty of coated brazing wire. Is that OK?

Please hit me with more advice if you feel I need it. Thanks

I would be pretty tempted to use silver solder, get the pieces fairly hot and then put the heat to it locally 'til the solder flows, and try to cool slowly. It shouldn't warp too bad if it is not clamped. Not an expert, just what works for me.

I dont think the lovejoy coupling is cast iron.Ive replaced many that were bad worn and still holding.This is a job for a good welder not a first timer.Welding steel to cast will take preheat and slow cool down.

I turned both pieces in my lathe. The coupling is definitely not steel.

Lovejoy also makes powered metal couplings. Can't say that I have ever worked with it. Perhaps it machines like cast iron. Dunno

If you have the ability machine a key way into each piece I would key the coupling on and secure it with set screws and some red loctite. Those lovejoy couplings sometimes break when whatever they are driving breaks or seizes. I always try to plan what the situation is going to be when the next component in the system lets go. HTH, Jf

Been in the welding business over 30 years and I surely still don't know it all by any means, but I have done numerous brazing jobs that resembles this one,and here's how I would do it. I would run a long bolt through the shaft hole and put a flat washer on each side and a nut and tighten it snugly to keep the coupling from cocking. I would then set it on some fire brick and preheat the whole thing to about 500 Deg. with a big rosebud torch.Then I would change to a large brazing tip. Start heating the pulley about one inch back from the coupling concentrating most of the heat on the pulley, being care to keep both pieces about the same temperature. Don't let the coupling get too hot. When both pieces become a dull red start adding the filler rod. Don't try to get too much build-up the first pass. Just get a good thin coating on both pieces all the way around, then you can go around it as many time as you want until you get as much build-up as you want. At this point, put the rosebud back on and preheat everything back up to a good even temperature and cover it with a welding blanket or put it in a barrell of dry sand or oil dry and let it cool slowly. It will not crack or warp if done correctly. Good Luck

Hello Wardner,
I would drill in each piece 3 1/4" holes, in the pulley and the coupling. The holes on both pieces at least 3/8' deep. You can then use dowel pins or hard bolts.
You can braze it then to keep it from moving.
The torsional strenght is in the dowel pins.
Bolt it together to braze it to keep all the parst lined up!.
Guido.

I do have a Bridgeport but neither piece can be cut with a key cutter or endmill. They both have to be broached with the quill going up and down (forever).

I thought about drilling and reaming for several roll pins at the annular joint but the clearance (my mistake) of 003" makes that unlikely now. There is also the possibility of fracturing the coupling.

I think the brass has plenty of torsional capacity for this application. Thanks.

Yep, I have a rosebud, Not sure about the large brazing tip. Thanks for the detailed how-to description.

No silver solder in stock at this point but that could be remedied. Wondering what the annular clearance would need to be.

Personally... I'd bevel it out and weld it with a Sodel 35 NiRod...
Preheat it first to ~400 +/- a bit, weld it, heat ti evenly again then let it cool again.

I guess brazing it would work too but I'v ejust never been a big fan of brazing cast.

Cracking will be your biggest worry, but if you preheat it and then reheat after so that it heats evenly, then cools evenly it should be OK.
I just let them cool in open air.
May not eb right but it seems to work...

Rod

Loctite and probably others make a shaft and bearing mount that is similar to the threadlocker but for shafts. I think there are even compounds for restoring worn shafts to size. The lovejoy coupling could be hardened and heat will soften/weaken it. Why not put some more set screws in the coupling? You could even drill into the pulley a bit so the set screws go in further. Dave

Wardner,

Welding man is probably your best answer.
The only suggestion I have is more preheat is
better and the other material to use would be
cast iron in stick form . Do yourself a favor
and don't even consider any form of arc weld.

george

Yep, welding is not an option. If I make a mistake, both pieces will probably wind up in the junk pile.

I'm a welder at heart, but on this one I'd drill for 3 set screws set in Loc-Tite with a key-way.

I'd flat spot the set screws mating face.

T_Bone

I am starting to like the pins and chemicals solution. It's quick and easy. If it fails, I can always use "Plan B" which would be brazing.

Although I have welding equipment, I am by no means a proficient welder. Seems like a high risk for failure and ruined parts.

Yep, I am going to do the set screws solution first.
Thanks.

If you weld or braze it, bury the casting in a box of floor dry, heat the casting and when done cover it completely and leave it alone for about 12 hours. This allows and very slow cool down.

However, Beings you have a lathe, you should get a browning taper sleeve and machine the lovejoy to match the taper OR get a lovejoy with a taper center in it. A ready made one will be backward for access to the screws that clamp it down on the casting.

Another way to secure the lovejoy is to put it on with loctite and let it set up then, drill and tap vertically (as shown) splitting the hole down the mating surfaces, 1/4 inch set screw should take the torque ok, put three 1/2 long set screws in with a bit more loctite and it will serve a long time.

Adding set screws to just tighten down on the shaft will work loose in short order. Cast is soft and the lovejoy set screws would soon eat out a hole in the casting. .003 is to much fitting clearance.

I guess you need to ask yourself how many times you want to 'fix' this thing?

I'm looking at those pieces and can't for the life of me figure out what the purpsoe of those parts is... I mean, you have a flywheel/pulley with what appears to be a 'C' series belt. That's a good deal more power than any number of setscrews will ever carry. I'd think that it either wants to be through bolted to the shaft or pinned in some kind of manner with dowels so that it can transmit some torque.

The Loctite shaft and bearing fitter (green slime) that someone mentioned is good for tightening up a fit to take the slop out but it's not going to carry any torque. It also needs to harden for 24+ hours at a fairly good room temperature.

Brazing is certainly an option... but I always worry about it's strength. Seems pretty soft to me. Weaker than the cast itself, so you'll never get better, or even near as good as you had.

If I couldn't weld it myself, I'd take it to someone who could...
I've got a lot of pieces of cast around here that are welded with Sodel 35 rods... that by the standards given by other posts should ahve failed. Must be magic or somethin'

Good luck.

Rod

and if you like, fire it in a couriour bag and send it 'here'. I'll weld it in under an hour and send it back to you....
If you get the pre/postheat right, there's no risk whatsoever in welding that thing.
Controlling expansion and contraction is the hardest part and that shouldn't be hard on a simple pulley.
A spoked pulley is MUCH more interesting.


Rod

Alright that International piece is good cast steel,dont know about the other piece but it probably is too.The main thing is to get it straight somehow and held that way,straight.Then I would just weld it with 7018,6011,or Mig.Braze would work too but I would have it together and be using it before you got it brazed.What I might do is machine a groove around the top so I could get more weld on it,that way it would hold better,but a good weld on it will probably work.I would preheat it some.I think it would be a mistake to braze it because you would have to get it real hot.Its not a good idea to shock cast is why I say preheat it,but glowing red is a lot hotter than I would be comfortable with while brazing it.Its good cast steel and will weld with a rod.That Lovejoy coupler is the only thing that is bothering me and it looks to be steel or something.I might try to weld on it first just to see what happened.The three set screws is a good idea too.

Don't you think a 10,000 degree arc and molten rod would get it real hot? First you say it's cast steel and then you say it's not good to shock cast. If it were cast steel, arc welding wouldn't be a problem as long as the lovejoy coupling is also steel. He mentioned in his post that he doesn't want to weld it for fear that it could be ruined. I realize that there can be more than one way to repair things but you seem to be very unsure with your ideas. I suggested shaft and bearing mount because if it didn't work, nothing is ruined. Also, there are big differences between 7018, 6011 and MIG when considering what process to use. Now I know why some of the electrical guys on here roll their eyes at some responses. If you're not sure if your suggestion will work and might ruin the part, why even post? I think in the past you mentioned that you're not a licensed welder but have done some welding. That seems to me like someone who drives a passenger car telling a formula 1 driver how to drive. That's just my observation though. Dave

Vertical set screws could work. The newest high tech motorcycle sprockets are made that way. They use a lightweight aluminum inner piece that bolts to the hub and a hardened steel ring for the sprocket teeth for longer wear. If the loctite bearing mount isn't strong enough, I think there are epoxy's that would work since it's a belt drive and not a gear or chain drive. Dave

Look,you dont want to weld with a rod on it right from cold,but you could,and it might not crack.Yes its hot but its not like getting a piece of cast red hot.Seems to me you just dont think you can weld cast with a rod.I bet if you look,you can see lots of things welded with a rod made out of cast steel.I just said something like this a month or so ago.Go look at an old Road Grader then post back about the 7018 welds all over it.Cast steel is not cast iron.Cast steel will crack,but you also have to be careful of how hot you get it,or get the whole piece hot.Something like that I would run a pass around it and not even worry about it because its good cast steel,you arent welding more than a couple of inches.Why do I say that?Because I have done it.White hot melting right at one spot being welded is way different than red hot big area heated with a torch.Now I know how to weld.I know about this stuff because Ive done it.Im about tired of you coming along and saying things,well just like you did now.What are you 135 fan the welding coordinator?I suggest you know what you are talking about before you start mouthing at me.You are so smart,what is the difference between 6011,7018 and MIG?7018 AND MIG have 70,000lbs tensile strength,6011 is 60,000 lbs tensile strength,which is way more than brazing which might be 20,000 lbs tensile strength,if you can do it right and very few people can now days.7018 is not a deep penetrating rod,but it is a strong weld,which means you need a v or groove to weld something good with it.Also mentioned in my answer.I think what you are is somebody that thinks they know a lot,but dont really know anything.Welding with 6011 is maybe the least strength of the other ways but it penetrates the deepest.I would weld with that in short welds.The reason I say that is I just figured out that cast steel could be welded with it.I heard it could and tried it.I only have welded 2 things with 6011,but niether of them cracked,but I didnt weld over 3/4 of an inch at a time.One of those things I welded was a pulley on a International combine that looked a lot like the one in the picture,the other was a steering box on a International 300 tractor.Both times I heated with a torch first to not shock it so bad.Now if you are just set on trying to ridicule me I cant stop you I guess.However I dont know everything and admit that.Like If that Lovejoy coupler is powdered metal,it might not work to weld it because it will pull the weld right out of it maybe.It looks like it might be cast steel in the picture,which is why I said I would weld on it a little first to see if it can be welded.Now what is wrong with my answer?Can you tell if a piece in a picture is made from powdered metal or cast steel?I know I cant.I think I have answered your response.I dont care if you like me or not.You arent going to tell me I dont know anything.You also arent going to tell me what ones to answer or not.Ive taken welding certification tests before,but no I didnt go to a school or get a license.I know there are smart welders out there.Electrical people might or might not be a welder.Also lots of people are always saying to use nickel rod on cast steel.Its not necessary.Nickel is also brittle.It will work on something that doesnt have a lot of stress on it,but if it has stress on it,it will crack.I doubt one out of 10 people with a welder could even manage to make a good weld with a nickel rod compared to a good weld with 6011.Say something about that if you know so much.What is nickel rod made for?Why would you pay 5 times more to weld with it,when you can fix it better with 7018?If I had that piece I would have already welded it and been using it.Now you want try try to make it like I am somebody that tells people stuff that is wrong,and he didnt even feel confident he could fix it at all to start with.He also didnt say how much pressure was going to be on it or anything else either.I did as good as I could with what I had to work with.I usually say I could be wrong,but I didnt this time because I was confident I was right.

Also I did say the 3 set screws was a good idea,and it is.Especially if that coupler is not steel.I just dont see why you are jumping on me for my answer?Get up on the wrong side of bed or something?

It is quite obvious that you don't know very much about welding. Cast steel is easily welded but since cast steel is usually thicker sections preheat is a good idea. Preheat is good on any thick sections. Cast iron will crack, not usually cast steel. I don't think you fully read the posts that he had put up. Other welders also didn't suggest arc welding it. If tensile strength is the only thing to consider when choosing a rod or welding process, what's the need for so many different rods and processes? Why not just make one 70,000 psi wire? If MIG is so good, how come stick isn't obsolete already and what about TIG, it's such a slow process? MIG is much easier to learn. In a lot of cases brazing is the preferred method for joining cast iron and has very similar properties to cast iron. Brazing is also good for dissimilar metals. I have brazed cast test pieces and also gas welded cast test pieces. When either one is broken, the original cast will break and not the repaired part if done right. The cast pieces are bevelled and then the bevel is filled entirely with filler metal, just like pipe welding for example. Nickel rod is made for welding some types of cast iron. 7018 is only a last resort for a part that isn't very critical. 6011? Most welders use DC machines and 6011 is rarely seen in most welding shops. 6010 however is preferred because it has better penetration and meets code requirements. Lincoln makes the preferred 6010. 6011 was made so a welder could have a similar type of rod to 6010 to use on an AC welding machine. Although some people have successfully welded cast iron with 6011, it is not the recommended rod. The 6011 puddle cools quicker which is why it is good for out of position welding but for cast iron is more likely to cause cracking. I have never claimed to know everything about welding but when several others experienced with cast iron recommend not using arc welding and then you suggest to use it along with other ill informed ideas, will just confuse the original problem. There are many good books on welding available and I think you could do yourself a favour and look through them. This would give a much better understanding of the different processes and applications. It would also make you a little more qualified since you have something to reference. Welding is as much education as it is practical experience. It doesn't appear that you have much of either. You say that you were confident that you were right this time but other times you aren't. It you aren't confident, why respond? If you are so confident, why all the I thinks in your post. You just figured out that cast steel could be welded with 6011? Why have all the welding engineers and metalurgists(sp)when we can just figure it out on our own. Imagine how much money companies could save by not having to do testing and quality control or even having to have educated and qualified welders when someone could just figure it out. Why have engineers design vehicles and crash test them if we could just figure it out on our own. Myself, I'm glad there are educated people to figure these things out. Otherwise there would be a lot of catastrophic disasters in the world. Maybe not so much on a pulley with a lovejoy coupler but you never know? Dave

Well a lot of dis information is being put out.Lets just get to what is going on when you answer a question here.Some of these guys are good with a welder,this one isnt.I can braze,but I bet lots of people that have a torch cant.He said he had a welder but wasnt good with it.Until you came along and tried to make me into a liar because I didnt go to some school somewhere,I was telling him he could use what he had.Also my way of doing it is better than using nickel.7018 is no"last resort"way to weld anything.It seems you do know that cast steel can be welded with a rod.Also its not the big deal that cast iron is.I would not attempt to tell somebody how to weld cast iron because I dont know how and you need a blacksmith.If you can weld it with a rod,and it goes on a tractor or truck,I probably did it before.There are lots of people that are better at welding than me,even went to school.Yet why are they saying weld cast steel with nickel rod?As if its some big mystery and forbidden to weld cast steel with 7018?I dont know.I weld about everything with a MIG,and even have welded cast steel with a MIG.This guy had a welder,I answered his question.Now it didnt sound as if I was a professor,or like I was building a nuclear power plant or something.I didnt have a bunch of formulas and boring talk about other stuff that probably didnt apply any way.I just told him how he could weld it with his welder.I suggest you not read my answers about welding from now on if you are going to be a jerk about it.I want to leave room for others to put up an answer is why I write the way I do.I know I dont know everything,and I havent welded everything either.I also know how to weld and have welded lots of things,but I am not the best or even the most knowledgeable welder by any means.There are things about welding cast steel that are a little tricky,and it will crack if you get it too hot or try and work with it too cold.But it is no great mystery to weld cast steel.Also there are ways of welding it that are just as good as a new piece of cast steel and you cant even tell very easy it was welded,by using a torch.However a guy with a welder,thats not sure about welding,trying not to mess up what he has,not wanting to spend 2 or 300 dollars,can actually weld it with stuff he has,for a few dollars,if both pieces can be welded,or he can put some set screws in it since he seems more confident with machining.Sorry I fail to see what you are trying to accomplish by jumping on me.I have read books about welding,and probably will read some more,but nothing beats doing it.What book did you read that told you 7018 was a temporary fix?I know I dont want to read that one.Also a lot of the reason there seems to be a big mystery about all this is welders who do this every day probably are not going to tell you how to weld it.Some of the best stuff if you can figure out how to get into it about welding is by the Army,or the Government at least,on the internet.Its been a few years but I stumbled on to that one day and learned some from it.That was a couple of computers ago and I dont remember how to get in it now.

Ive spent 3 hours now looking on the internet for how to weld cast steel.I find lots of people talking about cast iron,no cast steel.It seems that for some kinds of things a torch is best with cast iron rod.Then a MIG with some brazing wire I never saw before.Then maybe 7018.I dont recall 6011 or 6010 being mentioned but MIG was mentioned.Now some of these people obviously had more experience than me.The main thing they said was its hard to tell what you have and there are lots of ways to weld it,blah,blah,blah.That it can make cast hard to machine and crack easy.Alright how do they come up with that?Read it in some book or were told that in some school.I can say I have seen it welded with 7018 and 6011 because I did it.The first time I welded a piece of cast was in about 1976.I was running a Cat No 12 Grader.There is a piece that adjusts the blade that broke.I took it to a welding shop.The welder said he was real busy and I could weld it myself if I was in such a big hurry.I said I could weld because I welded for 4 years but never welded cast.He then explained to me how to V it out,handed me some 7018 rods and said to just weld one pass but fill it up.I did and it held for the rest of the time I used the grader for about 3 months.I wasnt interested in machining it but I ground it down with a grinder no problem.Nickel rod is hard to weld with for a beginner.I have ground a lot of welds off of stuff made with a nickel rod so I could weld it with 7018.You dont have to agree,or even care as far as that goes,but I will put my experience up against theirs of the ones I read,and I doubt they know any more about it than I do.The old timers that did it every day dont post on the internet.I dont see anything that makes what the people that do post on the internet,that I have seen,say anything worth giving any more credibility to them than what I said.They experimented like I did and came up with what worked for them.Like right off at first on one of the websites it said ask an experienced welder if you have questions.I have done that.I even watched a guy braze up the back of an engine block and his customer came to me later complaining that he brazed it and didnt get a new block.I doubt anything I say is going to please you.I have welded a long time,but not everything.Ive welded skyscraper parts,and welded on trucks and farm equipment and structural steel.And Ive welded a little cast steel.Enough to know about nickel rod and to know about brazing and to know I can do about as good with a 7018 rod as any fixing of cast that I have seen.However I know ways that are better exist.I also know that all cast is not the same.USA made is good cast steel usually.I can also weld Aluminum with a MIG.I will say that there are people that seem to know things that dont really.Thats not me.If Im telling you something I know about it.There are people that think its impressive because they went to a school.In some cases going to a school might be impressive,but not all of them.You are getting less impressive to me every time you post.I dont care if you went to all the schools you didnt learn any manners.

OMG! Learning how to weld from the government? The army does use advanced welding procedures but they didn't come up with them alone. Manufactures and engineers and metalurgists all worked together along with the military, and others, with a solution to their welding problems. Cast steel is easy to weld and 7018 is the rod of choice. No one on this forum has recommended 7018 more than I have for almost every application. On cast IRON 7018 can be used on some less critical applications but is not the preferred method if other rods such as nickel rods are available. Nickel rods are not for cast STEEL. Gas welding and/or brazing are usually the preferred methods to repair cast iron. Some cast iron cannot be repaired. Several things would be very clear to anyone who is knowledgeable about welding. It is not hard to figure out that you are not very knowledgeable about welding. I'm not saying this to disrespect you. You have done some welding but certainly don't do it for a living. There is so much theory and know how about welding that no one could know all of it. Just ask any of the professional welders on this site, there are several. As far as I know, no one had ever mentioned static and dynamic loading before I came to this site. Trying to explain welding theory and applications with you is like the people debating how to hook up a back up generator with buickanddeere and John T. Just because some people have back fed a generator through a welder or dryer plug and it worked, doesn't mean their house couldn't have gone up in flames. It is the same trying to enlighten you regarging welding. By the way, the best steel generally comes from Japan but most steel is high quality. The pipe for the Alaska pipeline was made in Japan. That's a job they certainly didn't want to experiment with. I'm sorry if you feel slighted. It was not my intent. If you had fully read what the original poster had said, could have avoided this debate with you. Before experimenting, it's usually a really good idea to have some knowledge about what you want to do. For welding, this is most important. Have a good day. Dave

There is little sense arguing with some one who can not tell the difference bettween cast iron and cast steel, because he has them completely backwards. He says there is a lot of misinformation on here but the problem is the guy dosen't even realize most of it is coming from him.

(quoted from post at 16:09:42 10/09/09) I turned both pieces in my lathe. The coupling is definitely not steel.

Lovejoy also makes powered metal couplings. Can't say that I have ever worked with it. Perhaps it machines like cast iron. Dunno

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If that piece is made from sintered iron, yes it will machine like cast but it will also mean that welding it will be a waste of time due to the fact that when you heat sintered metals above a certain temperature it will shrink. this means that any weld areas will shrink and pull away from the weld, (meaning it will crack) silver soldering may be your best option, but you could try coating both surfaces with JB weld and clamping them together untill it cures. Another thing to note is that if you heat the coupler you should see that .003 clearance shrink down and it may even cause the coupler to grip the hub of your pulley.