Broken L24 rear cylinder head stud - Tips wanted for drilling & tapping in situ

[black gold man]

https://www.youtube.com/watch?v=fqZYgReuywM Ever see this

[Zed Head]

Wow, a Canadian stoner.  Had to listen hard to translate what he was saying.

This guy is apparently saying that the whole stud dissolves or is corroded away.  But he doesn't show it.  Why would you make a 4 minute video but not show the most important part?  Looks fake.  Where's the myth buster guys?

 I've wondered if something like Naval Jelly, or phosphoric acid solution wouldn't dissolve/reduce the rust.  The hard part though is getting it in to the threads.

[Mark Maras]

 This was to good to be true until I Googled the subject. It appears to be true. Apparently this method will remove a ferrous screw, bolt, etc. from any non-ferrous metal. It will still require removing the manifold(s) on a Z but being able to let the bolt dissolve instead of fighting it with implements of destruction is fantastic. Oh yeah, one more thing. This method will also dissolve the stud and anything else that broke off in the stud such as a drill bit, tap or a bolt extractor.

 Who's going to the first to try it? Alum is avail. in the spice section of WM. I checked my spares hoping? that I had a head with a broken stud. No luck?

  

[Patcon]

4 hours ago, black gold man said:

https://www.youtube.com/watch?v=fqZYgReuywM Ever see this

That was really cool! Corroded the stud right out of the aluminum. If I heard him correctly, he used Alum...

[Zed Head]

The question would seem to be about time.  Did he wait three minutes or three weeks.

And there's no need to corrode the whole stud, just reduce the diameter slightly.  Something's wrong here folks.  Lots of show, with the drug inferences and the weird Canadian curse words.  Then magic happens and the stud is gone.

[Mark Maras]

 

Had to listen to him a couple of times but he said 30 hrs. I think that may be optimistic but after reading a few forums It appears that this method is used by many people in the repair bus. A fellow in the musical instrument repair bus. says steel screws broken off in brass instruments used to be a problem. Now they submerge the brass part in boiling alum and water and the screw disappears.

 I agree with Zed Head. IF the method works that well and depends on electrolysis, the threads on the stud should be the first to go. Maybe pluck it out in 10 hours. No need to make it disappear. The 30 hr. wait may have more to do with drugs.

 

[Zed Head]

I browsed around the internet a bit.  Seems like drills and taps are the most common items removed using alum solution.  I wonder if the stainless steels are affected the same way?  The aluminum is unaffected because it has a protective layer of oxidized aluminum.  I think that stainless steel works in a similar fashion, forming a protective layer.  Might have problems with the stud materials used.

Still, worth a shot on studs in aluminum heads.  Studs in exhaust manifolds or engine blocks, out of luck.

I wonder also what the bubbles are.  Could be oxygen or hydrogen, depending on the chemistry.  I'm not even thinking about doing a chemistry equation but someone out there might.

[Zed Head]

Here is a sign that the internet is taking over the internet.  I don't know if this is circular logic, circular illogic, or circular something else.  I do feel like I went around in a big circle thought.

https://en.wikipedia.org/wiki/Alum

From the wiki:

Industrial uses

" Alum solution has the property of dissolving steels while not affecting aluminium or base metals, and can be used to recover workpieces made in these metals with broken toolbits^[5] lodged inside them.^[6] As considerable expense and/or effort may have gone into machining a specialist part, this can be a worthwhile exercise. "

Reference [5] -   https://www.youtube.com/watch?v=fqZYgReuywM AvE demonstrates usage of Alum to remove a broken stud from an aluminium engine head

Reference 5 is the Spice video.^^^^^ that BGM posted.  The link is messed up.  

[Mark Maras]

 I'm ready to thank that DIY Hoser up North. He taught me a clever method that seemingly most of the industrialized world already knew.

 ZH, I'm curious why the method couldn't be used on blocks or manifolds? I must be missing something.

[Patcon]

Because the Alum isn't selective, it will attack the block as aggressively as it attacks the stud. It would work on an aluminum intake but ZH was referring to the cast exhaust manifold, I believe, which would also be attacked by the Alum.

[Namerow]

Outstanding video.  Hoser gods Bob and Doug MacKenzie and Red Green would be proud!

Since I brought this whole topic up in the first place, I may as well volunteer to take on the role of 'Test & Analysis Department' on behalf of everyone else.  Here's what I plan to do over the next couple of days:

1. I still have a snapped-off (steel) bolt that's firmly stuck in the (aluminum) housing of the Honda Civic wiper motor that I plan to install in my Z.  That bolt has defied heat, shock, ATF/acetone and torque.  And the thread length is only 1/2" or so!  It simply will not budge.  So: this will become my test piece for the alum/water/hydrogen peroxide treatment.  I'll report back on Monday morning.  Stay tuned.
    
2. Later next week, I'm having lunch with a friend who has a PhD in chemical engineering.  I'll ask for an explanation of the science (or lack thereof) behind exposing iron/steel/aluminum to alum/water/hydrogen peroxide.

I hope this works out better than the experiment I tried with boiling lemon juice as a parts cleaner.  What a mess that made!  (Didn't work either)

[Bonzi Lon]

I used this method as a watchmaker once.  Boiling alum water in a copper pot.  Dissolved the broken screw in about an hour.  Smaller screw of course. 

 

Bonzi Lon