Welding Cast Iron

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