# Welding Cast Iron



## One-match fire

Over the past several years, I have been fortunate to be able to break some cast iron parts for things I was moving from where they were to my shop where they are now.
I was told that the only good way to weld these parts back together was TiG.  Does anyone have anything GOOD to say about this?  I would really like to get these parts repaired.  

Two of the parts involve a large hand-spinner for collecting honey.  The spinner fell while in transit and broke not only the handle but the plate gear that actually drives the spinner. I have kept these parts in hopes that I would eventually become "less afraid" to try to weld them back together.  The handle isn't that critical but the gear wheel seem to need some accuracy.  

Does anyone have any suggestions?  Recently, I sent away for some EZ Weld TiG wire from a guy on Lopez Island in Washington State.  I saw these used on a video on YouTube by "Mr. TiG" and he gave them a very good review.  I'd like to use them and would be interested in knowing if anyone else has any experience with them or was Mr. TiG just blowing welding smoke?

Thanx
Trim sends


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## buddy3223

The major problem that you will run into welding cast iron is it will crack as it cools.  You will have to preheat and then use some method to let it cool slowly. I have used everything from asbestos blanket to burying the part in floor dry coupound. I have never tried to weld cast with TiG but have had some success with a special high nickel rod, made just for welding cast iron. You would use acel/org to gas weld using this process.  Just be aware that the parts that you weld will not be as strong as they were before. Good luck with the repair you just have to use a process that will work for you.


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## Deerslayer

I have stick welded it on a few occasions using stainless rod, preheating cast iron first, I never knew about cool down slowly til now but I didn't have issues, it wasn't super thick either.


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## Kernbigo

The proper way to stick weld cast iron is pre heat it, but i have welded cast iron for 20 years not pre heating it with 99% success.If it has a crack drill both end of the crack so it don't run any further. Use 99% nickle rod, start out with a smaller rod weld a short run let it cool and weld some more on the root pass. Move on to a larger rod (1/8") and weld a little more trying not to generate to much heat. When done bury it in lime if you have some to let it cool slowly.


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## f350ca

I've never used Tig but hear it works well. I've used nickel rod with the arc welder, usually good success. Preheat if possible, weld in short stitches and peen the weld with the point of your welding hammer. Peening it helps relieve internal stresses in the weld. Peen the crap out of it. When your veaing out the crack use a carbide burr in a die grinder, an abrasive disk contaminates the surface with particles from the disk. On large parts I post heat the part with a propane weed burner then let it cool slowly.
For small parts as I expect your handle and gear are I'd braze it with oxy / acetylene. Again use a carbide burr to vee the crack.

Greg


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## joshua43214

I am not a welder. I hear this comment a fair bit though. I have always taken it with a grain of salt.
Gas welding borders on being a lost art. People raised in the world of cheap TIG, think that gas is obsolete.
Brazing is STRONG! It is often stronger than the base metal. TIG may indeed be the best way to repair cast, but I have seen far more failed TIG than failed braze.


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## FOMOGO

As Greg said peen the hell out of it between passes. I never let it cool completely between passes, but I hate wasting gas (read cheapskate). The post heat is also a good idea. Either bring the temp down over night in an oven, or use lime/sand, and a welding blanket to let it cool slowly. Mike


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## brino

another idea for pre- and post- heat........use a charcoal barbeque/grill.
preheat as much as required, do the welding deed(with peening), and finally put it back on the grill and just let it burn down and out overnight....a nice slow cooling.
be sure you have a way to lift, carry and position the part before you get it hot!
-brino


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## Wreck™Wreck

If the cast iron has a very high carbon content welding it will prove difficult regardless of the method employed. As mentioned above preheating and slow cooling is desirable if possible, also using a nickle filler wire designed for the purpose (GTAW process) will help a good deal.

NI 99 filler works well. Likely to be entirely more expensive then you would like.
http://www.use-enco.com/1/1/44657-e...ice-bare-nickel-tig-welding-brazing-rods.html


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## coffmajt

For the kind of repair you are attempting nothing will beat brazing = Some preheat with the proper flux and you can repair large cracks and breaks that will be at least as strong as the original part,  The problem with the nickel rod is as has been described before, it puts a lot of heat into a small area which creates large thermal stress.  In addition, if the repair is not successful then the welded area has a much higher residual stress plus a much different base metallurgy which pretty much renders future repairs impossible.  == Jack


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## hackley69

FWIW I have never tried but I have seen a 7018 rod used on cast with good results.


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## john.oliver35

I am a novice, but have brazed some cast iron successfully.  I had a little Jet 1018 woodworking lathe that got pulled off the table last year and the base broke in half.  Brazed it with oxy/acetylene and whatever Hobart bronze rod and Hobart brazing flux from Tractor Supply.  I believe I pre-heated the parts very slowly and conservatively and burned a lot of extra acetylene in the process!  But the brazing worked great and the repair has held.


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## David VanNorman

Like some have said Preheat Braze and slow cool .I have used Kitty litter to bury parts in and cooled them that way.


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## Ulma Doctor

braze em' up, you'll be glad you did.
tig is great, but you'll need lots of patience, gas and time if the repairs are going to be extensive.
you can set up and braze it in a very short time. 
if you are anything like me, the tig repair process will take exponentially longer to complete.
good luck either road you decide to travel.


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## Eddyde

+1 on brino's BBQ grill approach. I used that method when I repaired a cracked coal stove chimney manifold a few years ago. I was pre and post heating with a torch and stick welding it, just like others have said I used short welds and peened it well but it kept cracking. I had welded cast successfully before without too much trouble but that part was real nightmare. As a last attempt, I tossed a bag of charcoal in the Webber grill, fired it up, got the part pre heated and welded all the cracks, put the lid on, closed the air vents and let die out. Part cooled without cracking and is still in use. I don't remember the rod I used but it was bought from McMaster Carr, recommend for cast iron.


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## brino

Hi All,

While we are discussing weld peening, I have a related question.......

Would using a needle de-scaler on an air-powered hammer give similar results to manual hammer peening?
Something like these:
http://www.harborfreight.com/19-pc-needle-scaler-replacement-set-62483.html
http://www.harborfreight.com/catalogsearch/result?q=needle+descaler

It could sure save the shoulder, elbow and wrist.......
Whadya think?

-brino


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## FOMOGO

The air hammer might be a little to much, but the needle de-scaler might work well. Have  always just used a frantic chipping hammer, but if you did a lot of it a shot-peening cabinet would be great for most stuff. Mike


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## maker of things

I guess you will be the first one here to try it.  Apparently that stuff is an internally fluxed blend and has been around for many many years( if we believe what we read on some very unfriendly forums).  It looked like it worked for Mr. Tig in the video.  Based on searches I have done I think this is the rod http://eureka-china-jining-kaitai.com/upload/products/66/66_20107261444.pdf

I say try the EZ weld filler and let us know.  With farm equipment in the family I have the "opportunity" to weld cast fairly regularly and would welcome skipping the pre/post heat hassle.


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## Kernbigo

like i stated before i have welded cast iron for 20 years and they say pre heat it but i can count on 1 hand how many times i have done it. Gouge it out real well with a bur, use a small er rod for the root pass, only short wolds let it cool weld some more, follow up on the next pass with a larger rod, (99% nickle) not ni rod. Put it in lime or sand to cool. If it is a crack you are welding drill the end of the crack so it won't run further and last of all fill the drilled holes. There is nothing wrong with brazing i have done both just prefer  ark.


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## Sitting on Blocks Racing

I've have done Tig with Silicon Bronze wire.   Some preheat, weld 1/2" let cool a little, weld 1/2" in a different spot and repeat.


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## dirty tools

depending on the thickness of the cast iron.
small parts per say 1/4" in thickness and less than 2" I would TIG weld with SST rod no pre or post heating required.
Larger parts would require pre heat and post heating you can use either brazing of SST welding can be used.


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## One-match fire

OK so not much experience with the EZ weld TiG wire.  It appears that most agree with pre-heating and then using stick with 99% Ni (if I read that right).

I also have an Irwin vise that a friend of mine broke shortly before he died.  Since it was broken completely (along the column that sits over the acme threaded rod, I decided to try that first with the EZ weld TiG wire.  Considering the explanation given by "Mr. TiG" on the video, I just decided to try it exactly like he described.  I cleaned the two pieces scrupulously and wiped it with acetone.  I did not preheat.  After going to the Miller Welder Calculator (I use that for guidelines to set things up) I turned up the amperage on the TiG to about 160. (It is a Lincoln 175 Square Wave).

Now it is important to understand that when I was working, I got to spend a good deal of money on good tools, knowing that eventually I would stop working and want to have those tools to "play with" on my farm.  I'm not a "nice car, or nice clothes kind of guy, but I have a really bad "Tool Jones".  I'm especially bad about getting really good layout and measuring tools. (Read: WoodPecker T squares, etc).

Given that, I bought what I thought are good tools, including a Lincoln PowerMiG 216, an ESAB 700 plasma cutter and the Square Wave 175...all brand new.  NO second hand equipment for those.  I buy a lot of second hand equipment for a lot of things, mostly hand tools (especially if I recognize the make and age and condition).  

Additionally, I was NOT trained in the metal arts after 9th grade (some 51+ years ago) I have learned practically everything I NOW know by either just messing with it and seeing what happened or watching MrPete222 on YouTube and a few other well presented videos on using the lathe, milling machine and some other kinds of equipment.

So, now you have some idea of how I am going about all this. So, in the pursuit of this style of learning, I went ahead and tried the TiG with the EZ weld TiG wire.  My results were quite good (at least they seem pretty good at the moment.  I have not worked on the parts I mentioned earlier since there was NO going back if I boogered them up...(which HAS been known to happen in the past. Since that vise was already broken, I figured there was nothing to lose by trying.  I did wire brush it before cleaning the edges.  I did clean with acetone and let it dry.  Then I just tried it.  Since I have NEVER had a welding class or instruction other than how to strike an arc with a stick when I was 14, I figured I would have to break down and just try it.  So far, it worked pretty good.  I have not put the vise back together since I had the two parts in completely different buildings which are pretty far apart.  I am trying to decide whether I want to "improve" what I did or wait to see what happens when I put that vise back together and crank down on that handle.

So, that is what has happened so far.  I do have the Oxy-Acet rig so I can always resort to that but other than knowing how to light the torch and do a bit of cutting with it,  I am not yet schooled in how to weld with it...or braze (which means I really don't know the difference.)

I'll let you all know what happens.  It is a work in progress .

For now, I am still working on getting all those Foley-Belsaw carbide grinders back to working properly.  I had to tear the 367 down to "parade rest" today and clean every single part.  One of the way rods wouldn't come out so I managed to coax it out with a brass hammer and then I put it on my Smithy lathe with a steady rest and turned about .005 off of the end that was binding.  I also used a bore grinding tool on the drill to clean up the holes through which the rod passes, figuring that both techniques would afford me an easier re-assembly...and it did.  I put that machine back together and am now in the process of getting it set up according to the book.

I got the FB 357 carbide grinder working yesterday but am missing the critical chart at the end of the book called the "Hook and Top Clearance Angle Chart" which is no where to be found.  It is driving me crazy.  I spent about an hour trying to develop an equation for grinding the faces and that worked out well. I still don't have an equation for solving the distance on the tangent for the top clearance angles.  If anyone knows of or has a copy of that chart, I would be eternally grateful for a copy.
Cheers,
Trim sends


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## benmychree

coffmajt said:


> For the kind of repair you are attempting nothing will beat brazing = Some preheat with the proper flux and you can repair large cracks and breaks that will be at least as strong as the original part,  The problem with the nickel rod is as has been described before, it puts a lot of heat into a small area which creates large thermal stress.  In addition, if the repair is not successful then the welded area has a much higher residual stress plus a much different base metallurgy which pretty much renders future repairs impossible.  == Jack


I quite agree with you, I have brazed cast iron for perhaps 50 years, and always have good results; one trick I use is after preparing the part by veeing out, and setting it up, I coat the area to be welded with silver solder flux, this helps protect the metal from oxidation while heating it up; in my opinion most fluxes for brazing cast iron are near worthless, I use a flux from the Anti Borax Company EZ #3, it is black in color and is leagues in advance of any of the other fluxes.  For such as exhaust manifolds, I use the torch and flux coated rod from Eutectic, it handles much easier than the old square cast iron filler rods and separate flux, as it melts at a slightly lower temperature and wets out on the base metal.


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## machinist18

I have had good luck welding cast iron using Allstate products. First clamp your part back together. Then Using Allstate champfer rod at about 200/220 amps hold your rod almost parallel to the work and strike your arc. then move the rod rapidly following the crack and form a gouged out channel. When you have a good channel, switch to Allstate #8. That's a cast iron rod. For 1/8" rod use about 80/90 amps and weld up the crack. You may have to peen the weld some but usually it will work out fine without that.  I've been using this method successfully for over 30 years. Good Luck.


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## machinist18

I have also use the cast iron method that I just posted to weld mild steel to cast iron successfully.


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## scsmith42

I have used all of the methods described herein (except for the EZ weld TIG rod) at various times over the past 35 years, and they all work.  A couple of months ago I ordered some EZ TIG rod though and plan on trying it on my next CI weld project.

For peening, my preference is to use a needle scaler.  It's fast and effective; the only drawback is the noise.

A bucket of sand is a good option in lieu of using lime for slow cooling post-welding.  When immersed in the sand heavy parts are still warm 24 hour later.

Stainless arc rod works well on heavy castings, and when I used to weld up chambers on racing heads it was my preferred filler rod to use.  Nickle rod is the standby for arc welding, and you can also wire brush the flux off and use the same rod as a filler for TIG welding.

The benefit of TIG is that your heat is in a concentrated area, and if you're welding a thinner casting (such as a boat manifold) you will have less distortion with TIG than brazing.

Drilling the ends of the crack help a lot in terms of preventing it from "growing" while you're welding.

BTW - those are some neat tips from Ben re the silver solder flux and filler suppliers.


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## fixit

In my other life, when I worked for a living maintaining compressors (up to 2000 hp & 7200 volt) we often used   http://www.locknstitch.com/index.html  for CAST IRON repair. The first I saw it I was not sure but soon became a believer.

Fixit


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## SE18

I've used brazing rod for cast. The method of heat I have used recently is a carbon arc torch, attached to a Marquette stick welder. I would have used oxyacy but the acy tank is empty and the filling place is far away. I do have nickle rod but haven't yet tried it out.


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## Firestopper

TIG  use silicon bronze
Arc  use nickel rod
Gas welding use brazing rod
I haven't done much cast repair lately, but when I did, I always controlled  cooling down  using temp sticks and light peening as mentioned.


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## Highsider

As a 40 year manual machinist in heavy industry I'm not primarily a welder, but I've done my share.  The very best way to weld cast iron that I've found is to use some of the hi-dollar Cast iron stick rods from Certanium or other premium manufacturers.   In most cases, no preheating is necessary. (but it never hurts)     Vee the crack out generously from both top and bottom.   Tack the ends of the crack insuring the proper alignment and leave a bit of gap for penetration, even if you have to grind it in.   Skip weld the first pass (top and bottom) to minimize heat warping.   Peen well after each pass to relieve stress.   When the vee begins to get wide enough to require multiple passes each side, start alternating top to bottom every couple of beads still with plenty of peening.  If the Cast iron is old and oily, don't despair, these rods will burn the oil out ahead of the puddle.  Just wire brush well after each pass with a SS brush.   The heat will build up enough each pass to preheat for subsequent passes.  I've repaired 3" cross sections in cast iron this way and never had a piece of Cast Iron break again.   After welding, pack in some sort of insulating medium and cool slowly  for at least a day.  If it's a cosmetic repair, build up slightly above the original surface and dress back down to fair it into the original contours.  After a paint job, you'll never know it had been broken.


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## Broomstraw

Okay...please note...I am not a professional welder, but this has worked for me in the past.  I have an old Ford square baler that uses Cast Iron "needles" for the twine.  My baler got out of time and broke both of these.   First off, I bought a new set.  Within a 100 bales these broke again.  I carried these to a local welding shop and was told that it was going to cost as much to have them welded as a new set.   Talked to a retired welder and this is what he told me.

First off....get some agriculture lime.  Use a disposable Turkey Roasting pan that you get at a big box store.  Put as much lime in this pan as it will hold.  Put it in the oven at 350-400 degrees and let it sit there for a couple of hours.  I stir it about half way through the heating process.  Remove this just before you are ready to weld.

I am using a Lincoln Cracker Box welder AC only. (DC would be better, but this is what I have.)  Did the normal prep work by cutting some recess bevels on the pieces.  I used a small propane torch to heat the pieces.  Use NICKEL rods to do the welding.  These are normally coated with black flux.  They are not cheap.  Adjust welding amps to where you get a good bead.  Weld the pieces together.  As soon as you are finished, cover these with the HOT  lime.  This lime will help the pieces cool slowly.  The next day remove the pieces and do the clean up with your grinder/flap wheel.  Check the welds for voids/pitting.  If you need to re-weld / fill in the gaps....repeat the above process.  The lime will help dissipate the heat evenly and prevent it from cracking at the welds.

I used this process to weld the needles on the baler.  This was 10 years and about 15,000 bales ago.  Worked!


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## larryr

One-match fire said:


> Over the past several years, I have been fortunate to be able to break some cast iron parts for things I was moving from where they were to my shop where they are now.
> I was told that the only good way to weld these parts back together was TiG.  Does anyone have anything GOOD to say about this?  I would really like to get these parts repaired.
> 
> Two of the parts involve a large hand-spinner for collecting honey.  The spinner fell while in transit and broke not only the handle but the plate gear that actually drives the spinner. I have kept these parts in hopes that I would eventually become "less afraid" to try to weld them back together.  The handle isn't that critical but the gear wheel seem to need some accuracy.
> 
> Does anyone have any suggestions?  Recently, I sent away for some EZ Weld TiG wire from a guy on Lopez Island in Washington State.  I saw these used on a video on YouTube by "Mr. TiG" and he gave them a very good review.  I'd like to use them and would be interested in knowing if anyone else has any experience with them or was Mr. TiG just blowing welding smoke?
> 
> Thanx
> Trim sends


i have used stick,tig and braze to repair cast iron. cast is a very unforgiving material  the size shape and metalurgy can effect what type of repair will work best. there are a few basic procedures that are followed by most welders they are pre heat  peen and slow cool and cross your fingers you don't heat the dreaded "ping" while its cooling. for the average joe, your best chance of success is brazing followed by a tig using silcon bronze rod. there are all sorts of "miracle rods" sold for cast iron repair. before you spend your hard earned money talk to some professional welders.


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## Snag_one

I've had good luck with Invar 42 nickel/iron tig rod . The new cast iron fire pot welded very nicely , but the old grates from a wood burning stove were a disaster ... I couldn't even get brazing rod to puddle and wet that stuff . I've heard similar stories about welding/brazing CI exhaust manifolds . Preheat is important in some cases , especially if there is a possibility of a cooling weld being put into tension because of the shape of the item . Peening helps a lot , mostly because as you peen the hot weld bead you're actually causing the metal to expand sideways and eliminating the tension stresses . 
  I've also used some strips cut from an old CI stove door (about 1/8" square)  to successfully weld a part . Be sure to grind/sand as much of the rust as you can from the strips .


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## goboughner

I have had much success with flux coated brazing rod and oxy/acetylene torch. I brazed the handle back on for my mothers cast-iron frying pan and it never failed. I also brazed a crack in the base of my 5" cast iron bench vise ,years ago and it's still working. The last  braze job I did was on the apron on my HF 12x36 lathe that broke when I tipped it over on it's face while trying to move it alone(dah).


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## One-match fire

Nice work.  
OK, so the term "Brazing" has come up numerous times.  I do have an O-A rig and two torches. One for welding and one for "silver soldering" carbide tips on saw blades.  Is THAT the torch you would call "Brazing"?  
I guess I just don't understand the difference other than the size of the hole in the end of the torch and the gas settings.  Do any of you have an "easily understood by an amateur" explanation of "brazing" when working on Cast Iron?"
It turns out I am finding more broken cast iron things that need to be repaired.
Cheers,
Trim sends


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## Ulma Doctor

Brazing is the joining of metals with bronze bearing alloys.
the parent metal is not melted, just the brazing rod, you can use a welding tip, but mind your heat
unless you are braze welding. then both the parent metal and rod are melted to form another alloy.


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## One-match fire

OK, I get that part. Now, the question is about the brazing rod.  Is there a nomenclature to use when I go to the welding shop to buy it or will they just KNOW what I need?  I am THAT new when it comes to this.

I have some rod that I got some years ago and have been saving till I learned how to use it.  I'm not the kind of guy that just starts melting metal til I know why I am doing it. At the moment I don't know the "nomenclature" of this rod. I have on with some white "flux" on it and some without that flux.

What I got from this is I can use the welding torch but "mind your heat"...to me is a bit vague. Can you please explain what that means?  (I really DON'T understand the technical terminology here.  I have training in another field and am trying to learn this as I go. I can cut, clamp, cauterize and sew it back together with relative skill. Working with metal has a few similarities but I always had to fix what I was working on "with the engine running" so to speak ) .
Would it be OK to ask for specifics in terms of "rod number", gas settings (PSI for Oxygen and PSI for acetylene). I do follow directions well.  
Thanks
Trim sends


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## Ulma Doctor

mind your heat, means that if you use a large welding torch and get too close to the work,
you can easily turn brazing into braze welding which is not always a good thing.
to braze you want the parent metal to be hot but well below it's melting point.

you'll want to practice with your flux covered rod until you feel that you have mastered it. flux covered makes it very easy to braze.
the fluxless rods should be scrutinized as to reveal their make up, sometimes steel welding rods are stored in close proximity to bronze bearing filler rods
you don't want to make the mistake of using a steel rod when you should be using bronze alloys to braze
bare bronze rod is ok to use, you'll need to use borax as a flux and reapply often to achieve good result.

personally, i prefer Harris LFB (low fuming bronze)1/8" flux covered rod when brazing
your torch settings will be determined by tip size
but a pretty good place to start is 2-5 psig regulated acetylene,  10-20 psig Oxygen
you'll want a neutral flame.
you'll know you have neutral when there is a blue cone and the torch goes near silent
if you need more information, i'm happy to add more


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## planeflyer21

Keith Rucker just did a video on repairing a broken cast iron gear, by brazing in new metal and then cutting new teeth:


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## One-match fire

Ulma Doctor said:


> mind your heat, means that if you use a large welding torch and get too close to the work,
> you can easily turn brazing into braze welding which is not always a good thing.
> to braze you want the parent metal to be hot but well below it's melting point.
> 
> you'll want to practice with your flux covered rod until you feel that you have mastered it. flux covered makes it very easy to braze.
> the fluxless rods should be scrutinized as to reveal their make up, sometimes steel welding rods are stored in close proximity to bronze bearing filler rods
> you don't want to make the mistake of using a steel rod when you should be using bronze alloys to braze
> bare bronze rod is ok to use, you'll need to use borax as a flux and reapply often to achieve good result.
> 
> personally, i prefer Harris LFB (low fuming bronze)1/8" flux covered rod when brazing
> your torch settings will be determined by tip size
> but a pretty good place to start is 2-5 psig regulated acetylene,  10-20 psig Oxygen
> you'll want a neutral flame.
> you'll know you have neutral when there is a blue cone and the torch goes near silent
> if you need more information, i'm happy to add more



Now I am getting somewhere. So, what I am hearing is that melting the brazing rod is like using a "hot glue"!  You don't melt the CI, just the brazing rod. I went out today and bought some brazing rod. I got about 5 # of 1/16" and about 0.4# of 1/8" rod.  The tube said,"Brazing rod" so I don't think it is steel.  I didn't read the components but will tomorrow.

Now the heat issue appears to be variable.  As I said, I have two torches. One that has quite a large hole and that I remember was purchased specifically to do welding. It gets pretty hot.  The other has a smaller hole and that seems to give  a "cooler" flame.  It is the one I use to "silver solder" the carbide tips on a blade.  It gets pretty hot but nothing like the other one.  

I get the gas settings.  That part is easy.  Just needed to know what they should be.

One of the other guys mentioned using the Black Flux and I have a 5# bucket of it that was just shipped from  Balboa Supply in San Diego.  I'll try using the flux coated rod first (1/8") and see how I do.  I have lots of old broken CI things around this farm that I can practice "brazing" on that stuff before I try to fix the parts I need to repair.  Since they are old, I don't think I'll get a "second chance" if I booger it up.

The video is helpful. Thanks PlaneFlyer21.  In my working days I was known by pilots in the US Navy as the guy they "love to hate and hate to love" .

Additionally, I should thank Ulma Doctor for your kind guidance as well.  I will put it to practice as the "weather permits" because if I am reading this right, cold weather is NOT a good time to work with CI because it would cool TOO FAST after the application of the heat. My shop is at the best of times around +50*F if I have the fire going all day.  Otherwise, it is often about 3-5*F above ambient temperature which is often in the +20*F to +30*F... It gets down to -30*F at times here so even with the best of fires AND the "jet engine" heater it can be pretty cold.

Once I have worked with this a bit and get the hang of it, I'll come back and report my experience. 
Thanks again for the help.
Cheers,
Trim sends


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## Ulma Doctor

hot glue would be a good analogy. it looks like you got the rod covered!
dependent on how thick of a section of CI you are repairing, would be the deciding factor in which tip to choose
start with the smaller tip and adjust the gas pressures to low settings like if you were silver soldering, unless you were going after large game.
not knowing your torches, i'd guess about 5 psi acetylene ,  10-15 psi O2 and see how that treats you
brazing is surprisingly forgiving, if you mess up, heat the part back up and knock the brazing out, or knock the pieces apart again.
i have repaired CI in very cold weather, no worries
keep a bucket of sand or wood/or charcoal ashes handy, when your repairs are done, stick em in sand or ashes- you'll be ok
the ashes or sand allow the CI to cool slowly
i'm happy to share what i know.
i'm glad that you can put the knowledge to use


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## Firebrick43

Ulma Doctor said:


> Brazing is the joining of metals with bronze bearing alloys.
> the parent metal is not melted, just the brazing rod,



This is partially incorrect.  Brazing has nothing to do with the filler metal(but is commonly a bronze) but the temperature.  American welding society says that any filler metal in a joint above 840* F but not melting base metal is brazing.  Below 840 is soldering.  

Technically what most individuals refer to "silver soldering" is actually silver brazing.  These are a silver phosphorous copper alloy.  Common is 5-15 percent silver but some less common is 55 percent or greater.  This needs no flux on copper but does on dissimilar metals, steels, and such. 

There are silver solders but you will see them melt in the 400-500 temp range and are called "silver bearing solders" to avoid confusion the afore mentioned misnamed silver soldered.  100 years of bastardization is hard to kill

There are also aluminum based brazing rods and other uncommonly seen alloys  such as nickle.  

Silicon bronze is a common tig rod without flux.  Do to the shielding gas flux is not necessary on clean metals.  Cast iron because of its make up is never clean and needs flux 

Gas brazing rod is of lower quality in that the components don't have to be as pure as tig rod as there is no electrode to contaminate.  Most of the time it has flux pre applied but buy it without as time and handling can knock it off.  You need extra flux any how so buy bare rod and heat them dip the rod in the flux.  Flux sealed in it tin never goes bad nor do bare rod.  

As far as welding cast goes.  Cast rod with cast flux is the best,  the results are a weld that is indistinguishable from the parent weld.  It's also hard and involves a flame table(or someone with a rosebud) to keep the part dull red in heat as you weld.  

A bronze braze would be my choice for small and thin casting.  Doesn't work as well on manifold.  

Stitching is a good choice for cracked heads, blocks, and large castings. This that preheat and welding will distort(and likely crack).  

Nickle arc welding is my last choice.  It's one many make do to lack of skill,knowledge  or tools of the other processes.  I have magnafluxed many nickle welds and most have micro cracks parallel to the weld bead even when done by excellent welders and correct technique.  

Many time this is still "good enough" and of no issue.  Heck many blocks and heads are prone to cracking I. Certain spots (some models I have seen 95% cracked) and still don't leak or give issues.


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## One-match fire

Firebrick43 said:


> This is partially incorrect.  Brazing has nothing to do with the filler metal(but is commonly a bronze) but the temperature.  American welding society says that any filler metal in a joint above 840* F but not melting base metal is brazing.  Below 840 is soldering.
> 
> Technically what most individuals refer to "silver soldering" is actually silver brazing.  These are a silver phosphorous copper alloy.  Common is 5-15 percent silver but some less common is 55 percent or greater.  This needs no flux on copper but does on dissimilar metals, steels, and such.
> 
> There are silver solders but you will see them melt in the 400-500 temp range and are called "silver bearing solders" to avoid confusion the afore mentioned misnamed silver soldered.  100 years of bastardization is hard to kill
> 
> There are also aluminum based brazing rods and other uncommonly seen alloys  such as nickle.
> 
> Silicon bronze is a common tig rod without flux.  Do to the shielding gas flux is not necessary on clean metals.  Cast iron because of its make up is never clean and needs flux
> 
> Gas brazing rod is of lower quality in that the components don't have to be as pure as tig rod as there is no electrode to contaminate.  Most of the time it has flux pre applied but buy it without as time and handling can knock it off.  You need extra flux any how so buy bare rod and heat them dip the rod in the flux.  Flux sealed in it tin never goes bad nor do bare rod.
> 
> As far as welding cast goes.  Cast rod with cast flux is the best,  the results are a weld that is indistinguishable from the parent weld.  It's also hard and involves a flame table(or someone with a rosebud) to keep the part dull red in heat as you weld.
> 
> A bronze braze would be my choice for small and thin casting.  Doesn't work as well on manifold.
> 
> Stitching is a good choice for cracked heads, blocks, and large castings. This that preheat and welding will distort(and likely crack).
> 
> Nickle arc welding is my last choice.  It's one many make do to lack of skill,knowledge  or tools of the other processes.  I have magnafluxed many nickle welds and most have micro cracks parallel to the weld bead even when done by excellent welders and correct technique.
> 
> Many time this is still "good enough" and of no issue.  Heck many blocks and heads are prone to cracking I. Certain spots (some models I have seen 95% cracked) and still don't leak or give issues.


This is a very helpful explanation.  I have copied it to study, along with most of the others because at my age, short-term memory is something that gets tested and sometimes fails.
Cheers,
Trim sends


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## Ironken

I run CI like Firestopper said, with a twist.......Not saying this is any better but, I use Aluminum Bronze and AC to TIG braze CI with good results. AL or SI Bronze isn't all that expensive either.


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## Joncooey

This is an old link, but, if anyone is still interested; Ni-rod is the best, (in my opinion) for stick.  However, 99%, 91%, etc, are super expensive.  They are classified as machinable.
  A less expensive alternative that I use ($8 per pound compared to $50 per pound) is Lincoln Ferroweld.  Every company has their own version.  Only draw-back is that they're not classed as machinable.  (You need to use a grinder). 
  Still need to pre-heat, but I have had good results. 

  Jon.


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## fixit

In my other life befofe retirement I installed & repaired Large Air Compressors we used this method of repairing some cracked & broken casting. It works & many of the old machines are still running today.

http://www.metalcrackstitching.com/


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## SE18

I used expensive ni rod for welding a steel plate atop a cast iron harbor freight anvil.


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## David VanNorman

I have also used a cast iron rod with a torch that is machinable and works quite well with preheat and a slow cool down in sand or kitty litter.


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## Ed ke6bnl

One-match fire said:


> This is a very helpful explanation.  I have copied it to study, along with most of the others because at my age, short-term memory is something that gets tested and sometimes fails.
> Cheers,
> Trim sends



I have used sil-floss for copper to copper and it works well, BUT I know it will not be good for lets say copper to steel, what flux can be use to use sil-floss for dissimilar metals.


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## David VanNorman

I've learned to not use a grinder to v the crack but use a carbide cutter to do it. the pre heat ard slow cool down are to me the most important. The thinner the piece is the more it needs the pre heat. just my two cents.


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## Tony Wells

One thing I have to respectfully disagree with Mike on, and that's using a neutral flame. I was taught to use a slightly oxidizing flame when brazing steel and CI and a stronger oxidizing flame when gas welding brasses and bronze alloys. Not that you can't do an adequate braze job with a neutral flame, but the temp is higher with an oxidizing flame and you want to leave as little carbon contamination when welding the brass family. 

Note though, the strong oxidizing flame temp is too high for welding steel. Your puddle will boil, the carbon in the base material will combine with the oxygen and become brittle and subject to cracks.

There are many write-ups online about it. I'm going from what school taught a couple of years ago , and listening to a lot of old grumps, one of them being my grandad.


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## FLguy

Tony Wells said:


> One thing I have to respectfully disagree with Mike on, and that's using a neutral flame. I was taught to use a slightly oxidizing flame when brazing steel and CI and a stronger oxidizing flame when gas welding brasses and bronze alloys. Not that you can't do an adequate braze job with a neutral flame, but the temp is higher with an oxidizing flame and you want to leave as little carbon contamination when welding the brass family.
> 
> Note though, the strong oxidizing flame temp is too high for welding steel. Your puddle will boil, the carbon in the base material will combine with the oxygen and become brittle and subject to cracks.
> 
> There are many write-ups online about it. I'm going from what school taught a couple of years ago , and listening to a lot of old grumps, one of them being my grandad.


 I was taught many years ago the same. Use to silver braze tool blanks for Acme Gridleys before tool form grinding.


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## Ed ke6bnl

Ironken said:


> I run CI like Firestopper said, with a twist.......Not saying this is any better but, I use Aluminum Bronze and AC to TIG braze CI with good results. AL or SI Bronze isn't all that expensive either.


I have si bronze and have used it with tig and DC but you are saying to use the SI Bronze with AC correct?


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## Ironken

I hav not used SI bronze with good results on AC but, I have used AL bronze on AC with decent results. Cast Iron and me have a tumultous relationship. Sometimes we get along great, other times we hate each other.


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## Subwayrocket

Pre heat the part and have a "nest" of fiberglass insulation ready to put it in when it's hot and ready to weld. Weld it right in the nest of insulation. You can use 625 rod for cast . It is mostly a nickel rod , nickel doesn't shrink much like most iron/steel based rods. But the whole part will still contract when it cools, and that is the problem. If you have a torch on and ready, you can use it to prevent fast cooling of the part...Slowly less and less heat, then cover it with more insulation or figerglass matte plus insulation to continue cooling. If it is a "static" kind of part that doesn't see alot of stress, torque, vibration or cyclic physical or heat stresses, it is more likely to hold . Brazing it may be a better choice. I'm trying to envision the part you have...seems like it's some kind of hand cranking thing ...if that is the case, it may not see high torques and heat cycles. A buddy brought me a walk behind dirt backfill tamper. There is a cam inside it that bolts to the inside base, the engine turns this cast iron cam block which wobbles inside, pounding the base and tamps the backfill down . One of it's corner bolt tabs broke half off ...something like this was NOT a good candidate for welding. It would see thousands of high torque vibrating stresses . Yes you can weld cast iron and some are very good at it, but it's not like steel where the weld area is usually stronger than the parent material. Cast aluminum is much easier to weld than cast iron . I would suggest searching Jody Colliers youtube channel , weldingtipsandtricks 
...He will give you the low down on welding cast iron ...and just about anything else too !  
I think you've got a good chance with a low stress kind of part you've got there . Good luck !   Post some pics ! 
~Steve


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## brino

Ironken said:


> I have used AL bronze on AC with decent results.



Jody recently did a video on TIG brazing and he does some silicon-bronze and Al-bronze(DC and AC), although mostly on mild steel:
http://www.weldingtipsandtricks.com/tig-brazing-vs-welding.html

-brino


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## FLguy

brino said:


> Jody recently did a video on TIG brazing and he does some silicon-bronze and Al-bronze(DC and AC), although mostly on mild steel:
> http://www.weldingtipsandtricks.com/tig-brazing-vs-welding.html
> 
> -brino


Thanks Brino, Sure wish I could get as good as he is or somewhere close. Practice, practice I know, but.....


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## deyve

One-match fire said:


> Over the past several years, I have been fortunate to be able to break some cast iron parts for things I was moving from where they were to my shop where they are now.
> I was told that the only good way to weld these parts back together was TiG.  Does anyone have anything GOOD to say about this?  I would really like to get these parts repaired.
> 
> Two of the parts involve a large hand-spinner for collecting honey.  The spinner fell while in transit and broke not only the handle but the plate gear that actually drives the spinner. I have kept these parts in hopes that I would eventually become "less afraid" to try to weld them back together.  The handle isn't that critical but the gear wheel seem to need some accuracy.
> 
> Does anyone have any suggestions?  Recently, I sent away for some EZ Weld TiG wire from a guy on Lopez Island in Washington State.  I saw these used on a video on YouTube by "Mr. TiG" and he gave them a very good review.  I'd like to use them and would be interested in knowing if anyone else has any experience with them or was Mr. TiG just blowing welding smoke?
> 
> Thanx
> Trim sends


Hi - retired boilermaker here - this is critical, after grinding area to be welded, finish of with a file or burring tool, you must remove the last few thousands of an inch before welding. Also preheat, then weld with high nickel content rod just one inch at a time, then very quickly peen the weld with a light hammer. continue till finished. The problem with cast iron is that there are so many types its difficult to give advise, experimentation and experience is the key. last, if the casting is cracked and not broken, drill a 6mm hole at eack end of the crack to prevent further cracking as ou weld, also use the BACK STEP METHOD OF WELDING - hope tis is of some use.


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## brino

Hi @deyve



deyve said:


> this is critical, after grinding area to be welded, finish of with a file or burring tool, you must remove the last few thousands of an inch before welding.



Can you expand on/explain this? 
Is it about removing any contamination from the grinding disk itself?

Also, you don't mention post-heat or slow cooling. In your experience is it required?

Thanks!
-brino


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