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I Forge Iron

Anvil Repair "on the cheap"


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I picked up this 90 lb anvil for $20 a while back and want to get some opinions on how I plan on repairing it.

I was thinking about building up the missing section of the face with 7018 and then putting a hardface on it using this: http://www.amazon.co...e/dp/B000RGN1TY. I think I can keep the cost down quite a bit with this approach, but don't want to waste my time if it's not going to work.

A few things to keep in mind:

1) I plan on using this for light work
2) I'm not concerned about messing it up and consider it a learning experience. Worst case, I'm out some money in electrodes and still have a hardy hole and a horn to work with.
3) I don't want to spend a lot of money on expensive HF rods. I've read Robb Gunther's Anvil Restoration procedure where he recommends Stoody rod, but the stuff isn't cheap and I've read elsewhere that I'd be better off putting the money towards a different anvil.

What do you think? Is 7018 a good (or at least acceptable) base material to put a hardface on? The mfgr description of the HF rod linked above states, "Used to effectively wearface a part to extend its life. Provides medium hardness and impact resistance. Gives abrasive wear resistance. Deposits are not machineable or forgeable. Up to Rc53."

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In our blacksmiths association we used 7018 to build up and repair our anvils at our blacksmith shed and they have held up fine. They do need to be dressed with a soft wheel from time to time but have held up well. I have friends who have have used 10018 and they are very pleased with the results and it seems to wear well. I have a no name 385lb anvil that someone at sometime repaired the edges I believe with some type of welding rod that was not hard surfacing. I use E70S-2 TIG filler rod to fill in the hammer marks and deformed edges usually once a year and I use it everyday.

It is hard to tell from the pictures of your anvil but it seems that hard face of the anvil came off or they carbon arced it off. You will have to find out if the the base is a cast iron in which case you will have to use a nickel 99 rod for your first pass,and or 7018, 8018, 9018, 10018 filler rod for your first pass and build up. Some might disagree with me on the low hydrogen rod for cast iron repair but it is a exceptable procedure for cast iron repair according to the book " Metals and How To Weld Them " by, Lincoln Electric. you should preheat the anvil to 400 degrees before you start.

I am sorry but, I have no experience with the hard surface rod in your link. So I can not give you advice on that.

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If I was to do this "on the cheap" I would do it this way.

Get a piece of good steel the correct thickness to be even on top after I had milled the bad area flat. Then I would drill and tap a series of 1/2-20 holes and attach the new face with flathead screws. Torque the xxxx out of them, and then weld the heads over. All edges would be prepped before installation in order to weld them to the remaining face, and sides.

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Why is it important to pre-heat an anvil before welding? I've heard you don't have to do it if you're using a MIG welder, but for Arc welding you need to pre-heat to 400. Why would you need to do it for one and not the other, and what benefit does it provide? What happens if you don't pre-heat?

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You know how you can "quench" high carbon steel by putting it hot in contact with a cold anvil or post vise? You know how brittle quenched but not tempered high carbon steel is?

When you weld on high carbon steel you preheat (and sometimes post heat) the work so it doesn't "auto-quench" itself leaving a very brittle untempered area in the heat affected zone. If it does quench the temperature does an automatic temper on it.

Helps prevent cracking in the HAZ and in general less thermal shock is a good thing especially in high carbon steels!

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Why is it important to pre-heat an anvil before welding? I've heard you don't have to do it if you're using a MIG welder, but for Arc welding you need to pre-heat to 400. Why would you need to do it for one and not the other, and what benefit does it provide? What happens if you don't pre-heat?


Believe it or not there is a lot of moisture trap in your anvil. Depending on how much humidity in the air there is at the time when you preheat your anvil will start to sweet and you will be able watch the water come out of your anvil. You can do it with out preheat but you run the risk of porosity in your welds and innner pass cracking of the welds. It also takes away a condition called thermal shock which can cause other cracks unknown to the eye to grow bigger. Remember when you preheat it is better to bring up your part slowly with a propane torch like a weed burner rather than a oxy-acetylene torch. You want the part to be the same temperature all the way through. Not just on the surface.
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Helps prevent cracking in the HAZ and in general less thermal shock is a good thing especially in high carbon steels!


So, if I understand you correctly, pre-heating is more for the high-carbon faceplate and not the anvil base since that would be low carbon, correct?

Also, what is it about the MIG welding process that causes you to not need to do a pre-heat (or maybe I just heard incorrectly that you don't have to pre-heat with MIG)?
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So, if I understand you correctly, pre-heating is more for the high-carbon faceplate and not the anvil base since that would be low carbon, correct?

Also, what is it about the MIG welding process that causes you to not need to do a pre-heat (or maybe I just heard incorrectly that you don't have to pre-heat with MIG)?


In general you should always preheat heavy weldments, heavy plate or cast pieces,no matter if they are high carbon or low carbon steel. It helps to relieve stress in your part. ;) Even in MIG welding you need to preheat large parts. Most welding procedures require it.
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Put in a more simple way,and simple is always good as far as I`m concerned,most weld failure from cracking takes place next to the weld(the heat affected zone,or HAZ) rather than in the bead area.Pre and post heat help to eliminate this problem .

After forging tools you would want to normalize to relieve stresses caused by forging right?If you didn`t and put the tools directly to work then,sooner or later, you could expect a failure of some sort unless you`re lucky.Think of your anvil as the tool that it really is and the weld creating stresses like forging would(the stresses are created differently but they`re still there)by using pre and post heat you reduce those stresses and they are no longer concentrated in the HAZ and act as a point that may crack while cooling or soon after you put the anvil to use by forging on it.
Think of it as cheap insurance,far less trouble and cheaper than gouging or grinding all the old weld and the crack out and starting again from zero.

BTW-welding with MIG is.pretty much, the same as welding with stick.Think of the wire as one very long,very skinny rod.The process is virtually the same,only the method of shielding changes.
This is a GREATLY simplified comparison meant to illustrate the need for pre and post heat,so you tech experts don`t need to pile on me and start in how the flux from SMAW helps with post heat and how MIG is not appropiate for certain work and positions and yadda,yadda ,ad nauseum.

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At the community college I went to they welded the in house fabbed anvils with .0625" innershield wire. Beads were the size of your finger. Post heat wasn't a problem, but overheating was if you were not careful. MIG can be appropriate, if done correctly.

A word on welding stresses. A weld bead shrinks as it cools. Being attached to the parent material it starts pulling at it as it cools. Keep adding more beads, and the pulling stress increases. I welded an 8" pipe to a 2" thick 24" diameter piece of plate for a vise base. Started laying the beads down, and didn't give it a second thought. When I was done that 2" thick plate had warped up enough into a bowl shape that it rocked instead of sitting flat. One way to help alleviate these stresses from shrinkage is to peen the weld as it cools. Peening spreads the weld as it is cooling, and helps to counteract the shrinkage of a non-peened weld. Another method that is sometimes used is alternating the welds form side to side, front to back, stitching, etc. These will help with warping, but the part would benefit from a normalizing post heating.

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As usual The Big Gun MD brings up an excellent point that I forgot,peening the welds.
I knew I was forgetting something that would help but as usual I started typing before the meds kicked in. :huh:
The point here is to do everything you can to not let the stresses build and especially to not let them get to the point where they cause something bad to happen.As the Doctor pointed out those forces can cause warping in relatively heavy sections and if the piece can`t move then it will most likely crack.
If I were doing the job I`d plan on both pre and post heat and have a needle gun or air hammer close by to peen the welds right after laying them down.I`d also decide on a plan for welding that would keep the beads short and staggered so as to minimize stresses.Better the cards be all stacked on the side of caution than to stack them against yourself.

Thanks again Bigguns for waking me up to peening the welds again.I ought to write that on a sticky note and put it somewhere I`ll see it in the morning.The forehead does not seem to be a good place,besides I`m running out of space up there.Even with the smaller post-its. :blink:

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I have heard the story of there being moisture in metal and when it is heated the moisture is driven out. Unfortunately that is not true. That moisture does not come from the metal but condenses from the atmosphere on the surface of the metal. It has to do with the dew point, and the metal being atthe right temperature to condense the water in the air.

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I have heard the story of there being moisture in metal and when it is heated the moisture is driven out. Unfortunately that is not true. That moisture does not come from the metal but condenses from the atmosphere on the surface of the metal. It has to do with the dew point, and the metal being atthe right temperature to condense the water in the air.

Having welded for over 40 yrs and seen one piece stay dry and the other get wet I have to wonder.
Ken
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Thanks for all the suggestions. I think I'm going to go the 7018 buildup route with 2 passes of HF rod on top. The HF rods are advertised as 'Medium' impact resistant, so I'll just have to wait and see whether that will be good enough. If not, I may try welding the plate on like HWooldridge describes here.

I have one last question. I'll be using a Lincoln 225 AC buzz box to do the 7018, but I'm confused about the rod that I'll need. I just learned that there's 7018 and a 7018AC, but from what I can tell, the plain old 7018 will work on AC only machines, but the box says that they are "Not recommended for low-voltage AC welders." Unfortunately, the don't really tell you what that means.

So, what in the world is a "low-voltage" AC welder? Do I need to buy the more expensive 7018AC rods, or will the "normal" 7018 rods be okay for a Lincoln 225? I believe the L225's are rated at 80 OCV - is that too low? Will cranking up the current compensate?

Just when I thought I had all the answers.... :blink:

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Thanks for all the suggestions. I think I'm going to go the 7018 buildup route with 2 passes of HF rod on top. The HF rods are advertised as 'Medium' impact resistant, so I'll just have to wait and see whether that will be good enough. If not, I may try welding the plate on like HWooldridge describes here.

I have one last question. I'll be using a Lincoln 225 AC buzz box to do the 7018, but I'm confused about the rod that I'll need. I just learned that there's 7018 and a 7018AC, but from what I can tell, the plain old 7018 will work on AC only machines, but the box says that they are "Not recommended for low-voltage AC welders." Unfortunately, the don't really tell you what that means.

So, what in the world is a "low-voltage" AC welder? Do I need to buy the more expensive 7018AC rods, or will the "normal" 7018 rods be okay for a Lincoln 225? I believe the L225's are rated at 80 OCV - is that too low? Will cranking up the current compensate?

Just when I thought I had all the answers.... :blink:


I believe your tombstone AC welder would be considered low voltage. By low voltage there are two types in your machine open circut and welding voltage. Open circut is when there is no arc present and welding is when there is. I will try not to get to technical on this so some will not bash me on this. But your machine is considered to be a AC rectifier which means it puts out AC current only. Then there are machines that put out AC/DC current which are called transformer rectifiers. These machines usually have higher voltage output. The only difference in the 7018 and 7018AC is the coating on the rod. The 7018AC will help with a easier starting arc and maintaining your arc. You can use either on your machine.
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Welders like the Miller Thunderbolt AC are known as low voltage welders. The reason is that they have a lower OCV on their high current range, which is the trade off for getting higher current on a 50 Amp circuit. If you run on their low current winding, the OCV is more like an industrial welder like a Miller Dialarc. See if you can bum a few rods off the LWS or a pal. Try the AC and non-AC versions. You will figure out what we are talking about right away. It is much easier to lose the arc with the standard lo-hy electrodes. The AC variety is very forgiving. In fact, at the big box stores, the only ones they sell are the 7018AC, probably to minimize complaints from DIY'ers with low OCV homeowner type welders. I would go as far to say that there is little difference between a Tombstone and an Idealarc when running these AC electrodes. I miss the industrial welders when I am welding big steel (1" or more), but all I got at home is a 50A circuit.

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It is much easier to lose the arc with the standard lo-hy electrodes. The AC variety is very forgiving. In fact, at the big box stores, the only ones they sell are the 7018AC, probably to minimize complaints from DIY'ers with low OCV homeowner type welders.

Thank you - that makes a lot of sense.

So, bottom line, it sounds like if I can learn to hold an arc with 7018, then the weld should be just as good as the AC variety. It also sounds like it should help improve my welding skills.
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  • 1 month later...

Well, I finally finished it and am pretty happy with the results. The real question, the most important, is will it hold up. I ended up using about 5lbs of 7018 and just over 4lbs of HF rod. Total cost was around $50 ($24 for the HF rod, around $10 for the 7018 and the rest in grinding wheels and a flap disk). Anvil cost was $20, so I've got about $70 and 30-ish hours invested.

I built up most of the missing plate with 7018 (picked up a new welder that does DC). I laid down all but the last three layers, ground the 7018 flat, and did ball-bearing drop test to see how it rebounded (not very good, I found out - about 50% and pretty decent dents in the surface from the drop). All passes were peened with an air chisel and then wire-brushed.

I then did the last three passes with this stuff http://www.amazon.co.../B000RGN1TY,and, after several hours of grinding / touch up, re-did the drop test. It looks to me to be about 85% rebound with a 1" ball bearing (approx. 8.5" return from a 10" drop), although it does leave a tiny "scuff" mark in the surface. I'm not sure it's the best rod to hardface with, and I may still end up having to put a plate on it like HWooldridge did in this thread. I also put a thin layer on the table (left the horn alone). The color match is perfect - can't see any difference between what was left of the original plate and the repair.

I threw in a couple of "before" pictures for reference.

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Edited by wrkn4alivn
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