Stick Welder for Extracting Broken Bolts

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My first time and it did not work out. As you can see, the broken bolt, which had originally broken flush with the end of the nut is on the left and the new nut/bolt combo I installed are on the right. What you see on the end of the broken bolt is the sheared weld where I had welded on a 3/4-10 nut on to the end of the broken bolt. The bolt is 3/4-10 and had been in place undisturbed for 11 years and I am in the rust belt with a lot of salt used in the winter.

I first tried 7018 and wasn't getting good penetration, so I switched to 6010 and the broken weld you see in the pictures was done with 6010. As you can see I was able to achieve a good weld on to the end of the broken bolt but it still wasn't enough to spin the bolt. The seized bolt was subjected to being welded on four times, so it was heated up pretty well four times and it still did not break loose.

Any thing I could have done better? I started off soaking the rusted bolt with acetone/atf over a few days and it did not help. I tried heating the nut/bolt with a propane rosebud tip running off a bar-b-q tank and that did not help. I did not have my oxy-acetylene set up with me, the bolt might have come off had I heated the nut/bolt white hot.
 
I have not tried this yet, but candle wax is said to be a superior penetrating libricant when heated in situations like this. I've been told there is a specially made wax for the job but have never seen it.
 
I would have tried laying on a bead on the nut itself to get it screaming red hot after welding the nut onto your stuck bolt and then giving the works oil to hopefully shock the bolt into submission. Maybe even drilling in from the top to get oil into the center. A few good beats with a heavy hammer while hot. Nothing like working on farm equipment for many years to get a few tricks.
 
If you have access to a mill you can remove your weld with an End Mill and then you will be able to drill into the bolt either for easy out or drill and tap for next size up. I have actually taken a drill bit that is one or two tenths of a millimeter smaller than the diameter of the bolt and drilled it. All that is left is thin shell of threads and I clean them out with a tap. But you have to be perfectly centered(center bit) and have a good solid drill press or mill.

You could always try welding it again it looks like your existing weld did not weld to the sides any. I see clearance all the way around. We always use MIG welder at about 22V in our die repair shop. Place a nut over it, that's a little smaller than the bolt hole, that way you are protected from welding your sides up. Try to get 100% coverage inside the bottom of the nut and Fill it up with as hot of a weld as you can get away with without melting your nut away. We always let the weld cool for at least 30 seconds but it may help if you can heat the body(unit bolt is broke off in) up with a torch. You just don't wanna crank on that nut while the weld is still super hot. Then I just put a 12 or 15 inch adjustable wrench directly on the nut.
 
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I have removed hundreds of broken bolts by welding, and IMO I would have just cut the long hex nut off from the beginning, and as you did weld a new nut on.
 
There's a stick rod called TS-12 that loves to burn hot and penetrates well and is strong and an excellent choice for welding broken things back together. But it would also work well in this situation. TS-12 Tig filler Rods are even better.

A number 5 easy out can withstand more torque than most welded nuts. Welding nuts can work and does sometimes but I will always elect to drill for easy out first.
 
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IF it is seized bad enough drilling will be the only option. Welding removes the temper from the bolt and it will just ring off.
 
as mentioned before, much easier to just remove and weld on new.

ive seen just a wax ring from a toilet bowl be used around the shop for penetration...surprising but seemed to work well
 
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I know that crayons do not work, I don't know what kind of so called wax they use.
 
The nut just acts as a fence to prevent you from welding the broken bolt to the surrounding metal and becomes sort of a handle. During the actual welding, the bolt needs to become red hot. In doing so it tries to expand, and being confined by the surrounding metal, it deforms instead. When it cools down, it becomes smaller than the hole it's in and that's what makes it easy to remove. I think the reason it didn't work for you is that you didn't have much metal surrounding the broken bolt, and it expanded along with the bolt preventing the needed deformation. If it was in a larger piece of metal you probably would have been ok.
 
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Why not just grind that old one off and replace it like you already did? If you can weld a new one on, why not just do that instead of welding nuts on?
 
Originally Posted By: pcoxe
The nut just acts as a fence to prevent you from welding the broken bolt to the surrounding metal and becomes sort of a handle. During the actual welding, the bolt needs to become red hot. In doing so it tries to expand, and being confined by the surrounding metal, it deforms instead. When it cools down, it becomes smaller than the hole it's in and that's what makes it easy to remove. I think the reason it didn't work for you is that you didn't have much metal surrounding the broken bolt, and it expanded along with the bolt preventing the needed deformation. If it was in a larger piece of metal you probably would have been ok.


That makes sense. As I mentioned in my post, the bolt got pretty hot four times, so I was expecting it to come off.

As to why I did not just replace the nut, two reasons
1) I wanted to gain some experience extracting broken bolts.
2) New nut entailed a trip to my fastener supplier. I had on hand a bolt I could have used had I been able to remove the broken bolt.
 
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