Removing Broken Studs by Welding a Washer and Nut

[Tom Wesenberg]

I was asked about removing broken head studs, so here it is again.
You buy some flat washers with a 7/16" hole in the middle. Center each one over the broken stud then turn up the heat on the MIG welder to 125 amps, as that's the most my MIG welder has. Slow the wire feed to about half, then start the wire welding right in the center of the stud and work it around until it welds to the washer. Let it cool for a few minutes, then weld a large nut with about a 9/16 or 5/8" center hole to the top of the washer by welding right in the center and let the weld flow go out to the nut until the nut is full and level to the top. Let it cool enough to touch it, then use a box wrench or socket on the nut to unscrew the broken stud. The idea is to get as much heat as possible down into the stud, so when it cools it will shrink enough to break the rust bond. If the nut and washer break off just repeat the same way again. This has never failed and most times it works on the first welding try.

[edmondclinton]

I do the same thing except I use an ordinary stick welder. If the stud is broken off deep below the deck it has to be built up to have metal to weld the washer to. Sometimes I don't even use a washer and just weld the stud up as like a little knob and just weld the nut to the knob.

The arc does not fuse the electrode steel to the iron as it melts but it is strong enough to knock a little of the edge off the block threads if one is not careful. I make sure that the rod is as vertical as can be and have no problems.

I just use an ordinary 6013 rod. However, there is a rod made by the electrode manufacturers that is made specifically for this purpose and nothing else. I don't have the number but it would not be hard to find.

[holdover]

I do as above with one addition after the welding I touch a wax candle around the washer and let it melt, it seems that the wax is drawn into the threads and helps break the rust bond, been doing it for over 50 years and never had to drill out the stud yet.

[edmondclinton]

Originally Posted by holdover

I do as above with one addition after the welding I touch a wax candle around the washer and let it melt, it seems that the wax is drawn into the threads and helps break the rust bond, been doing it for over 50 years and never had to drill out the stud yet.

Sounds good but what if the nut breaks off and you have to re-weld with the wax melted down in there?

[pat in Santa Cruz]

I like to use an impact tool on it with lots of Kroil.

[Chris Haynes]

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I just weld a blob on the broken stud, bolt, ETC then grab it with a pair of vice grips and unscrew it.

[edmondclinton]

Originally Posted by Chris Haynes

I just weld a blob on the broken stud, bolt, ETC then grab it with a pair of vice grips and unscrew it.

I've done that too but you have to build up quite a long extension sometime to get enough to grab if the stud is broken off deep in the hole. Easier for me to weld on a nut. But to each his own.

[C26Pinelake]

Originally Posted by Tom Wesenberg

I was asked about removing broken head studs, so here it is again.
You buy some flat washers with a 7/16" hole in the middle. Center each one over the broken stud then turn up the heat on the MIG welder to 125 amps, as that's the most my MIG welder has. Slow the wire feed to about half, then start the wire welding right in the center of the stud and work it around until it welds to the washer. Let it cool for a few minutes, then weld a large nut with about a 9/16 or 5/8" center hole to the top of the washer by welding right in the center and let the weld flow go out to the nut until the nut is full and level to the top. Let it cool enough to touch it, then use a box wrench or socket on the nut to unscrew the broken stud. The idea is to get as much heat as possible down into the stud, so when it cools it will shrink enough to break the rust bond. If the nut and washer break off just repeat the same way again. This has never failed and most times it works on the first welding try.

After Tom had previously posted this suggestion my mechanic called to say I had a broken stud. I told him about Tom's suggestion. He called back in a couple hours and told me he had been successful. Now both the mechanic and I think Tom is a brilliant man. Thank you once again my friend from me and my mechanic. Wayne

[Tom Cavallaro]

Before the head bolt breaks, wouldn't it be wise to put a torch to heat it up first? If it creates a contraction on the bolt and a expansion on the head, it sounds like it would save a lot of headaches to me.

[BILL WILLIAMSON]

Friend Ron, was an artist at torching broken studs out of cast iron blocks, with a small cutting tip!! The oxidized metal would just blow out, like a sparkler, leaving only a few dingle berries in the threads. They came out easy, with a pick & a thread chaser.
DON'T TRY THIS, WITHOUT PRACTICING ON SOME WORTHLESS CASTINGS, FIRST!! Ron led sort of a CHARMED life!!
Bill W.

[Kurt in NJ]

Originally Posted by Tom Cavallaro

Before the head bolt breaks, wouldn't it be wise to put a torch to heat it up first? If it creates a contraction on the bolt and a expansion on the head, it sounds like it would save a lot of headaches to me.

\I used to think that way, now for head studs if they don't come out with the first heating I just twist them off and go to the washer/nut method. it is quicker

Sometimes the location or size of the broken bolt ---or screw prevents using the washer, I use a piece of copper and weld through a hole to prevent damage ---this has worked well for small screws into aluminum for holding dist caps on ,the coipper can be a sheld to keep sparks and splatter from getting into the wrong places and guides the weld to only the broke screw area

If the problem is deep in a hole I have made a sheet metal tube to prevent damage to the recess and weld from sticking to the wall --recently I removed locking lug bolts that were stuck in a 2 inch deep hole, with the mig welder I built a shaft long emough to grab with a pipe wrench, as I got toward the surface I changed the round "shaft" into a wide flat to make it easy to grip,

[holdover]

Edmondclinton
"Sounds good but what if the nut breaks off and you have to re-weld with the wax melted down in there?"

never yet had one break in all these years, but if one did I am sure the extreme heat from the stick or mig or tig welder (which ever one you are using) would vaporize the wax without issue.

[James Rogers]

One thing I find using this method is, what causes the first try to fail is if the welding is done to a cool block. I noticed the block will act as a heat sink and draw the heat from the weld away from the contact area. When I weld one, I first, heat the block and stud with a torch keeping the washer close and the mig at the ready. When the block is hot and the stud is slightly red, I place the washer over the stud and immediately weld it. I place the nut on the washer and weld it, let it cool slightly and use some penetrant and let it cool to touch. Use an impact to remove the stud. I never fail doing it this way.