Removal of broken SS bolt from aluminum?

[Angela]

It's been so long since I've had a broken bolt that I've forgotten my removal lesson.

When disassembling and removing my aluminum railing on my flybridge, one of the four stainless bolts that holds the whole thing together (the rest of the joints are welded) broke when I was unscrewing it. I got the railing apart, but I'll need to get this broken bolt out in order to reassemble it. It didn't break off at the surface, meaning there is about 3/4" of the bolt sticking out. It was mostly the head that broke offStainless bolt stuck in aluminum - how do I get that out? I tried turning it with some channel locks - no joy.

 

[Artzco]

A small propane torch will give you enough heat to make is loosen and turn out slowly using a good vise grips. This how I got my bolts out of a aluminum boarding ladder.

 

[captddis]

Heat up the surrounding area with a torch is usually the only way. If it is not threaded into the aluminum, a few good whacks will often dislodge the corrosion.
I never put a fastener into aluminum without some kind of sealer or antiseize.

 

[Angela]

Thanks. A torch it is! The hole is a threaded one. When I put this back together, is that gray anti-seize paste the right stuff to use or is there something better for those putting those two kinds of metal together?

 

[Artzco]

Yes. Anti-sieze and the best I've seen for this application is Tef-Gel. You should be able to find it at Boat Owners Warehouse.

http://www.tefgel.com/contain.php?param=tefgel_infor

 

[rsmith]

Or dielectric grease at the automotive store

 

[MikeP]

There's a ton of stuff that generally works fine for anti seize. I have never seen any difference in the performance of the various products. Unlike penetrants that claim to be able to loosen seized fittings, anti-sieze products actually work!

If you are worried about salt water/galvanic corrosion re different metals, Perfect Seal (the gasket sealer) is an excellent anti-seize AND you can use it for gaskets as well.

 

[lumina]

Hi All,

Ang, all good advice above, my only thoughts are turn SLOWLY !!!

I set out to remove my transome door recently. The enormous stainless steel hinge was held on by four 1/2 inch by 3 inch stainless bolts, that haven't turned in 35 years, which are screwed into an aluminum plate.

I tried everything then the yard tried everything then I tried everything again. I got 3 out and the last one snapped off at the head.

I said very bad words.

So I punched out the hinge pin and brought the door home with the hinge attached to it. Used a hammer to break the hinge loose from the door. There was no way to grab the bolt so I drilled it and used a hardened steel extractor and penatrants. Extractor snapped. Try and find a drill to drill thru an extractor......no such luck.

Long story short, I had to drill around the bolt into the aluminum plate and used a Dremel to finish cutting out the aluminum encased bolt.

Here's what it looked like when we finally got the bolt out !

 

[luckydave215]

I did a write up on this subject a few years ago, here it is:

TIG welding...your friend

As a master fabriactor, I've removed broken/stuck/shattered/ blind hole pins/taps/drills/etc a zillion times.
If it's a tap, tig weld onto the back of the tap, making sure to weld all the pieces together (they usually shatter lengthwise) and buld up a "T" handle drop by drop. The heating/cooling cycle breaks up the molecular bond at the point where the tap is sticking and anneals the tap so it doesn't shatter more when you twist on it. After it cools, apply Moly Dee (accept no substitutes!) and the offending part can usually be turned out with fingers. If you don't get all of the part the first time the Moly Dee can easily be washed out with a squirt of acetone so you can try again. Most oils can't.
This only works on a gounded part of course.
For broken drills/pins and so on, make a mini slide hammer with a pointed tip. ground the slide hammer (grounded/conductive parent part not required) and weld it onto the end of the pin. Let cool and tap out the stuck part. I've used this method on 1-1/2" drills in huge die plates and 1/64" pins in the brass body of $300,000 microscopes, and everything in between. The guy who broke the thing (the guy who's ass you're saving) thinks you're a genuis.
If you don't happen to know a weldor who's NASA qualified to weld space flight hardware (like me) find the guy that builds towers in your local yard, he can probably help you out.

 

[lumina]

Hi All,

Thanks Dave, I'll save this away for future disasters.

 

[GJH]

Tef Gel is absolutely da stuff for dissimilar metals, especially aluminum/stainless which was the main objective for it.