Penetrating oil for old bolts/studs on exhaust manifold

[skipmac]

Originally Posted by Canibul

There's just something ironic about working to break a frozen bolt out and then reinstalling it with Loctite to make sure it doesn't come out.

Yes, that thought did occur to me as well. But Loctite, depending on red, blue or green, is removable and I believe also electrically isolates the different materials.

[HappyMdRSailor]

Originally Posted by Canibul

I know, I know. It all looks like one big Corona commercial......from afar.
We laze in our hammocks under gently swaying palm trees sipping funny colored drinks with funny names and paper umbrellas brought by dark eyed native girls, and hire droves of motivated locals with tools, experience and craftsmanship to rebuild things quickly at sixty cents a day.....

Guess we better take the boat up through the Bahamas and back to pick up a can of oil...

60 cents a day??

You're getting the tourist price BROTHER!

Originally Posted by HappyMdRSailor

Just a wonder... popped into my head, and I' DEFINITELY NOT a chemist... We're talking about an oxide seizing the SS/AL interface... All this talk about sulphuric make sense too... But what say you to the known dissolvers of calcium oxides??? Yes, I know the calcium isn't there, but white oxide byproduct may be similar??? Muriatic or one of the toilet cleaners that works so well on barnykeels???

Originally Posted by Canibul

Just found a thread on a Practical Machinist forum about removing a stuck aluminum bike seat post from a steel frame. Several of those guys say that lye ( sodium hydroxide) attacks the aluminum without hurting steel. That's easy enough. Active ingredient in oven cleaners and toilet cleaners. I'll try that on the stainless screw embedded in the block of aluminum like what's-his-name's sword stuck in the stone.

Maybe we're on to something???

[RogerLloyd]

I would like to know how to remove aluminium stanchions from aluminium bases. Any ideas?

[Canibul]

Originally Posted by RogerLloyd

I would like to know how to remove aluminium stanchions from aluminium bases. Any ideas?

I think you're seeing a variation of the same issue, aluminum oxide binding. When that stuff turns to powder it expands in volume and packs everything around it. I've noticed that there is a level of this going on even between two different aluminum alloys in contact with each other, although probably not as pronounced as aluminum in contact with vastly dissimilar metals. If we can figure out what will dissolve aluminum oxide, perhaps a lot of these issues will fall back under some control.

Surely there are chemists who sail. Perhaps they're just too intelligent to get involved with online forums.

[Wulf]

Just ran across this on an old post in samsmarine.com...

As one who has removed hundreds (maybe thousands by now) of galvanically frozen SS bolts from aluminum, bronze, stainless, and titanium parts over the 32 years I've worked at the Scripps Institution of Oceanography machine shop, I have some expertise in this area.
As mentioned by others, oil, low heat, and shock sometimes works. But not usually. And it usually destroys the part you're trying to save.
There's another way.......
If applying heat with a flame torch, heat the FASTENER (if it's sticking out of the parent part) instead of the parent aluminum. Heat it fast, and heat it yellow hot. The idea is to soften the fastener at a time when It's too big (from thermal expansion) for the (still cold) hole it's in. This is easier than you think as the oxide layer between the parts is a thermal insulator. When the fastener turns butter soft from the heat it plastically deforms to a smaller size, and the heat/cool cycle also breaks up the molecular bond between the fastener and the threaded hole. While the part is still hot (but not glowing) apply Moly-Dee tapping fluid to the threads. Use real Moly-Dee, accept no substitutes! If the first attempt is not successful, Moly-Dee may be completely washed out of the work area with acetone, most cutting fluids can not be removed easily, if at all.
The heat will cause the Moly-Dee to rapidly "wick" down the threads, and it's presence will prevent galling the softened threads during removal. After cooling, the fastener can usually be simply spun out with your fingers.
The BEST way to remove galvanically frozen fasteners is to find someone who is an artist with a tig welder. Have him weld up a "handle" out of droplets on top of the fastener making sure to heat the fastener yellow hot in the process. This works on fasteners broken flush, or even below the surface. I've removed plenty of microscope sized fasteners this way.
It is also the only civilized way to pull blind pins out of holes. For pins weld a small slide hammer to the end of the pin.
Taps broken in holes usually split along the long axis, make sure to weld all the pieces together before adding handle droplets so they don't "wedge" against each other during removal.
Follow with Moly-Dee as above

[Wulf]

And this one from researchgate.com...

Crystalline Al2O3 at room temperature is hardly soluble in any solvent, even concentrated acid or alkali, for kinetic reasons. Only amorphous Al(OH)3 may be soluble. Al2O3 only reacts with as strong solvent as melted NaOH.

Doesn't look promising.

[Canibul]

Originally Posted by Wulf

And this one from researchgate.com...

Crystalline Al2O3 at room temperature is hardly soluble in any solvent, even concentrated acid or alkali, for kinetic reasons. Only amorphous Al(OH)3 may be soluble. Al2O3 only reacts with as strong solvent as melted NaOH.

Doesn't look promising.

yes, I found that site, too. But notice how many people mention sodium hydroxide as well as hydrofluric acid ( nasty stuff).

This from wikipedia on that:
"highly corrosive, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the 17th century,"

And what we're working with here is an oxide. Personally I don't think I want to try to play with hydrofluric even if I could find it down here. Lye, we can get.

[skipmac]

Originally Posted by Canibul

yes, I found that site, too. But notice how many people mention sodium hydroxide as well as hydrofluric acid ( nasty stuff).

This from wikipedia on that:
"highly corrosive, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the 17th century,"

And what we're working with here is an oxide. Personally I don't think I want to try to play with hydrofluric even if I could find it down here. Lye, we can get.

Found the same site. Seems like similar google searches return similar results.

Regarding HF (hydrofluoric acid), don't even think about it. It can kill you. I know of two people that died handling HF.

I just spoke with a friend that's a chemical engineer and have a call in to another friend that is a graduate chemist. So far no guaranteed solutions. The most promising is a mix of chromic and sulfuric acids or just sulfuric. I'm looking into that a little deeper. Initial comment from the CE is H2SO4 doesn't aggressively attack Al or SS alloys but does react with AL oxide. He also found reference to Aluminum Jelly for cleaning and brightening but would it wick into threads to break a bolt free?

[Canibul]

So, a quick check could be made with some loose aluminim oxide and battery acid /electrolyte.


I had already decided not to mess with HF. I can't even be trusted with a paintbrush.

Little Willie was a chemist.
Little Willie is no more.
What he thought was H20
was H2SO4....

[Tingum]

Roger, I am sorry but most likely you are screwed. Aluminum to aluminum is very tough to undo. ALWAYS use Never Sieze when you put it together. I put never seize on anything I think I might want to remove!

[skipmac]

Originally Posted by Canibul

So, a quick check could be made with some loose aluminim oxide and battery acid /electrolyte.

Had thought of that. Have an old battery by the garage waiting to trade in. Can pull a little acid out of that. I think battery acid is fairly dilute, someone said +/-35% but that should be good enough to do the job. Learned that diluted acid is more corrosive than pure anyway. Now if I can find something less expensive than the SS fasteners stuck in my mast for a test..... just in case. Guess I could sand off a bit of oxide from somewhere and put that in a jar with a little piece of AL and a SS screw and see which ones get eat up the fastest. (that's technical chemical terminology for you amateurs. )

Originally Posted by Canibul

Little Willie was a chemist.
Little Willie is no more.
What he thought was H20
was H2SO4....

Now that makes me feel old. First heard that one over 40 years ago.

[captain58sailin]

When using Never seize on aluminum parts, you want to make sure it is the nickel based and not the copper based type.

[skipmac]

Originally Posted by captain58sailin

When using Never seize on aluminum parts, you want to make sure it is the nickel based and not the copper based type.

Didn't know there are two versions of Neverseize. Definitely no copper on AL. Had an AL skiff once the PO painted with copper bottom paint. Every time I put it in salt water a hand full of rivets would pop out.

[Canibul]

Why not use tefgel?

[AZ-Oldguy]

So, once steel studs are removed from a hot running part like a manifold, would you want to use anti-seize of any sort during assembly to make the part easier to remove in the future? Or would the heat of operation cause problems?