How do I get a stainless pin out of an aluminum masthead?

[Icarus]

Originally Posted by Jim Cate

Not sure just whom you are disparaging here, Icarus, but if it is me, well, how come? Just what is ridiculous?

Jim

What's ridiculous is to have dozens of blogs of how to extract a stuck SS pin from an Alu masthead unit.
How many comments does it take to remove the pin?
Seems to be trending.
The overkill is ridiculous.
I am sure you could have figured that out as well?

Anyway, it was not aimed a you ...........

[GreenWave]

So it is okay for you to respond with nothing pertinent and we can not write how we would approach this? More heat… that is what is needed.

[Don C L]

Originally Posted by Icarus

Anyway, it was not aimed a you ...........

must have been me then.

The just-soak-it-and-whack-it method does not always apply and does not always work. Thus the reason for the "ridiculous" number of approaches to the problem.

I am not suggesting that using dry ice is always practical, or even necessary, for everyone. I am just saying it worked for me.

You are free to ignore this thread if it bothers you.

[C420sailor]

Many ways to skin a cat.

I for one appreciate reading the many methods. It’s good having different tools in your figurative and literal toolbox.

[BBill]

Originally Posted by garyfdl

Lot's of good ideas!

I especially like the C-clamp socket /arbor press. Try after heating or soaking the parts.

A word on heat be careful! Aluminum melts at about 1200 F. That's less than half that of stainless.

I would not bang on the pin directly with a hammer. Use a drift, or even a center punch. There's less risk of breaking the mast head or mushrooming the pin.

Good luck!

THIS ^^^^ Aluminum will go from solid to liquid puddle in the blink of the eye and the signs of it give about the same notice.,,which is shiney bluish color for a nano second. A torch is the very best way to experience a flash puddle. A heat gun is more forgiving. Either way do several heat/cool cycles and do penetrating oil while hot. It will pull the oil in.

[Reefmagnet]

Actually, the guaranteed way to remove a stuck stainless pin/ bolt/ screw from aluminium is to heat the pin with at least a mapp gas torch until it glows dull red. I've done this a number of times. This turns the oxide binding the parts to a brittle sand like substance, allowing the part to be easily removed. The reason why the aluminium has little danger of melting is because the oxide acts as a thermal insulator and the aluminium is one of the best conductors of heat you can get. It's just like pistons in an engine where the combustion temps are much higher than the melting point of the piston.

[BBill]

Originally Posted by Reefmagnet

Actually, the guaranteed way to remove a stuck stainless pin/ bolt/ screw from aluminium is to heat the pin with at least a mapp gas torch until it glows dull red. I've done this a number of times. This turns the oxide binding the parts to a brittle sand like substance, allowing the part to be easily removed. The reason why the aluminium has little danger of melting is because the oxide acts as a thermal insulator and the aluminium is one of the best conductors of heat you can get. It's just like pistons in an engine where the combustion temps are much higher than the melting point of the piston.

Am I confused or are are you confusing combustion chamber temp with exhaust temp? Al piston crowns certainly melt at their melting temp if mixture is set that high and stays there. If memory is right a diesel combustion chamber temp is about 1/2 of Al melting temps and crown temps about 1/2 of that. Exh temps are hotter.

[Cheechako]

Originally Posted by Reefmagnet

Actually, the guaranteed way to remove a stuck stainless pin/ bolt/ screw from aluminium is to heat the pin with at least a mapp gas torch until it glows dull red. I've done this a number of times. This turns the oxide binding the parts to a brittle sand like substance, allowing the part to be easily removed. The reason why the aluminium has little danger of melting is because the oxide acts as a thermal insulator and the aluminium is one of the best conductors of heat you can get. It's just like pistons in an engine where the combustion temps are much higher than the melting point of the piston.

That will ensure you destroyed the surrounding aluminum... But you'll get the pin out!
It doesn't have to melt to be junk, it'll be dead soft now.

[Reefmagnet]

Originally Posted by Cheechako

That will ensure you destroyed the surrounding aluminum... But you'll get the pin out!
It doesn't have to melt to be junk, it'll be dead soft now.

No it doesn't. Obviously you've never done it yourself and if you have, you've done it wrong.

[Reefmagnet]

Originally Posted by BBill

Am I confused or are are you confusing combustion chamber temp with exhaust temp? Al piston crowns certainly melt at their melting temp if mixture is set that high and stays there. If memory is right a diesel combustion chamber temp is about 1/2 of Al melting temps and crown temps about 1/2 of that. Exh temps are hotter.

Are you sure you're not getting confused with the ignition temperature of diesel fuel? It can burn at over 2000 deg C inside a combustion chamber.

[BBill]

Originally Posted by Reefmagnet

Are you sure you're not getting confused with the ignition temperature of diesel fuel? It can burn at over 2000 deg C inside a combustion chamber.

You're talking totally different metrics. How hot diesel ignites or temps it can burn in a combustion chamber isn't how how engine parts get. All I can say is there are plenty of engineering temp charts for fuels and internal combustion engines...none show anything near 2000c. I just reviewed a bunch of them to revive my memory. Pick any chart and any part...630c is close to the max combustion chamber temp.

Whether the oxide coating between pin and masthead is a good enough insulator is a wag and I hope people will be cautious in following that info.

[Reefmagnet]

fyi, 630 Dec C would destroy silicon alloyed casting aluminium. As used in cast pistons and heads. It's also pretty amazing that EGT's can be higher on hard working engines than your claimed values, despite how rapidly exhaust gas cools as it leaves the combustion chamber. But if you think you know better. that's ok.

[BBill]

Originally Posted by Reefmagnet

fyi, 630 Dec C would destroy silicon alloyed casting aluminium. As used in cast pistons and heads. It's also pretty amazing that EGT's can be higher on hard working engines than your claimed values, despite how rapidly exhaust gas cools as it leaves the combustion chamber. But if you think you know better. that's ok.

Being amazed says it all. You mean claimed values by the entire engineering world. Universally published temps for pistons are around 300c with 630c combustion temps depending on fuel grade. Exh temps taken just outside the cyl are hotter. Every serious drag racer or pilot on the planet also knows this.

[Reefmagnet]

Originally Posted by BBill

Being amazed says it all. You mean claimed values by the entire engineering world. Universally published temps for pistons are around 300c with 630c combustion temps depending on fuel grade. Exh temps taken just outside the cyl are hotter. Every serious drag racer or pilot on the planet also knows this.

Obviously all these other people on the planet are also unaware that a dull red heat represents a temperature somewhere between 500 and 550 degrees C. Which is kind of ironic, don't you think?

Aluminium alloy hot shorts at around 680 degrees C, if that helps.

[BBill]

Originally Posted by Reefmagnet

Obviously all these other people on the planet are also unaware that a dull red heat represents a temperature somewhere between 500 and 550 degrees C. Which is kind of ironic, don't you think?

Aluminium alloy hot shorts at around 680 degrees C, if that helps.

Ironic is you questioned exh gas temps being hotter.

Its already been posted...you are likely ruining the temper. Al yield strength reduction in fires...as high as 50% reduction at 150c. What is the yield strength on 6061 after being exposed to your heating method at 500c-550c? How hot did the masthead get? I'll answer that for you...you have no clue.