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Menessis
01-22-2015, 06:48 PM
I have a seized up part that I need to get apart. I have tried penetrating oils and sprays and got no where. I wonder if an ultrasonic cleaner may help? I also have a jug of "Metal Rescue". Seems like good stuff. But it says "Metal Rescue™ is not recommended for use on magnesium or magnesium alloys". Now the part I am working on is a small tube with a rusty thread, threaded into some sort of "white" metal. How do I figure out if that "white" metal has any magnesium in it?

The rusty part is shown down inside and the nut turns on the thread. It should turn with just a light force with your thumb so I'm thinking it isn't a tight thread.

http://i835.photobucket.com/albums/zz279/NewMenessis/Siezed_zpsba6fad41.jpg

Any ideas?

Here is a link to the product if any one is interested: http://www.metalrescue.com/home.aspx


Thanks
Menessis

Joe Rogers
01-22-2015, 07:00 PM
Sounds like Evaporust...
Joe

brian Rupnow
01-22-2015, 07:12 PM
You may well have one of those cases where two dissimilar metals have, through electrolytic action, "grown" into each other at the contact area.Not much will overcome that except brute force, and you will destroy one or both parts.

EddyCurr
01-22-2015, 07:16 PM
Now the part I am working on is a small tube with a rusty thread, threaded into some sort of "white" metal. How do I figure out if that "white" metal has any magnesium in it?

The rusty part is shown down inside and the nut turns on the thread.Is there some reason that the object's purpose justifies use of Magnesium,
a more-readily available/affordable metal now than in the past,
but still expensive to acquire/fabricate relative to other choices.

If not, what does Metal Rescue say about compatibility with
zinc. I propose that your part could be die-cast.

.

flylo
01-22-2015, 07:28 PM
Put a drop on a non critical place on the white metal & see if it has adverse effects. I bet you'll be OK.

lakeside53
01-22-2015, 07:47 PM
Before you use anything "rust removal" boil it in detergent water to get rid of the oils/grease.

Fasttrack
01-22-2015, 07:53 PM
You may well have one of those cases where two dissimilar metals have, through electrolytic action, "grown" into each other at the contact area.Not much will overcome that except brute force, and you will destroy one or both parts.

My thought as well...

May be time to start thinking about how you will make or buy a replacement!

Menessis
01-22-2015, 08:19 PM
Well the only thing the Metal Rescue will harm is Magnesium. I just found an answer of sorts. A little citric acid on magnesium will react with it right away.

That part is a throttle grip off of a helicopter. It wasn't seized when it was removed. But who knows how long it has been sitting like that. Now it's stuck real good!

Any more ideas how to get it unstuck?

Menessis

tmc_31
01-22-2015, 08:37 PM
Electrolysis?

Tim

lakeside53
01-22-2015, 08:45 PM
Electroysis is not a good solution for "hidden" rust.

Use Evaporust. Doesn't affect "magnesium". Degrease first... with hot water/detergent. Won't be quick on a fine thread, but it will get there. Keep the solution 90-120F (light bulb works well).

BTW.. the part will not be "magnesium". If it has any, it's a mag alloy - Aluminum with Magnesium.

Gary Paine
01-22-2015, 08:53 PM
If you took the nut off completely will the center sleeve just pull out? It almost looks like a nut holding a flange of sorts captive under it. Is the end we can't see open or closed? If open, would a custom made drift coax it out?

LKeithR
01-22-2015, 09:22 PM
You may well have one of those cases where two dissimilar metals have, through electrolytic action, "grown" into each other at the contact area.Not much will overcome that except brute force, and you will destroy one or both parts.

I agree, too. If that is a helicopter part it could well have a higher magnesium content than "normal" magnesium/aluminum alloys. It tends to corrode badly under the right conditions, doesn't weld well and generally can be a b*tch to work with. Might be time to walk away...

Juiceclone
01-22-2015, 09:40 PM
I posted once on something like this a while back...I literally stumbled on the solution for me anyhow. The reaction between the alloy and ,usually, steel or SS causes the less "noble" metal to corrode and the products of this corrosion take up more volume than the original metals did....locking everything together. I've seen it crack open the alloy casting holding a stern drive unit in place. As stated above, clean off all oils or rust release agents first. Then heat the part a bit till too hot to touch and stick it in WATER. Cool > repeat > > as necessary. What I found was the corrosion products of, in my case alum alloy, are water soluble. Heating to about boiling temp and then putting in water should cause the water to be drawn in to the interface of the two metals. Repeating drives some in and some out but then quenching again draws more in. I was able to free up a steering shaft for a tractor that I had been heating and beating for two days before I found this.
In any event, let us know what worked. Good luck :>))

Prokop
01-23-2015, 10:29 AM
ATF and aceton is proven treatment for parts rusted together.

Menessis
01-23-2015, 01:27 PM
Hi Gary. It's hard to explain. But I will give it a try. The nut threads on to a very short piece of rusty tubing. Maybe about 1/2" long tops. That rusty tube has a slot cut in it on the inside which slides on a tiny pin that is set in the aluminium tube that is inside of everything. I'm guessing that that slot isn't full length otherwise the nut would slide off the top. As is the nut and the rusty bit of tube slide freely up and down about 3/16". The problem with it is that the threaded part is how the tension is set on the throttle grip. And as if that's not enough the nut is in the way of the hole where the pin goes to locks the throttle handle on the shaft.

I like the repeated heating and cooling idea. I wonder if I put it on the stove in boiling water and go back and forth to cold tap water would work. ATF and acetone, mixed together?

BTW....I can't walk away! It's mine. :(

Thanks
Menessis

Juiceclone
01-23-2015, 06:23 PM
If it's rust between two ferrous metals the atf and acetone will work at least as well as any other stuff they sell. If it's the alloy that corrodes (white powdery or crystalline) then the oil based stuff doesn't touch it. If you can get water to go between the parts you will see a result almost immediately.

lakeside53
01-23-2015, 07:33 PM
Actually... Evaporust done right can work much better than just penetrating oils. Rust molecules are much larger than iron, so when the iron rusts it jams the connections. All acetone/atf does is act a lube. If it needs more than that, remove the rust and recover the missing gap.

fixerdave
01-24-2015, 03:22 AM
... ATF and acetone, mixed together? ...

They say a 50-50 mixture is one of the best penetrating oils you can get. It just doesn't keep well, so mix it up as needed. Oh, and avoid getting it on paint etc.. If you really need a penetrating oil, it can be worth a shot. Me... I'm lazy, most times wd40 is enough for me - little impact here and there to speed things up, maybe some heat. I've also heard of people taking seized-up stuff and just dumping it in a bucket of diesel and forgetting about it for a few months, or even longer. I'm generally not that patient and don't have cans of diesel laying about, but they swear by it.

But, next time I run into aluminium type corrosion, I'll probably try that boiling/cold water trick.

David...

Menessis
01-26-2015, 12:09 AM
Well I had it soaking for 12 hours now. It's nice and clean. Hasn't broke loose yet though. I will try to boil and cool routine next. What a PITA!

Menessis

Doozer
01-26-2015, 08:40 AM
... heat the part a bit till too hot to touch and stick it in WATER. Cool > repeat > > as necessary. What I found was the corrosion products of, in my case alum alloy, are water soluble....

What is the science behind that? Aluminum oxide is not water soluble.

--Doozer

Menessis
01-26-2015, 04:47 PM
I was thinking of heating and cooling to get the two parts expanding and contracting. Wish I could dream up a way to cool the inside ring and heat the outside??

Menessis

lakeside53
01-26-2015, 05:13 PM
Just heat it all - the Al-Mag will expand faster than the steel.

Black Forest
01-26-2015, 06:07 PM
If you were an octopus you wouldn't need the throttle to be mounted on the collector!

Black_Moons
01-26-2015, 06:21 PM
What is the science behind that? Aluminum oxide is not water soluble.

--Doozer

Add enough sodium hydroxide and it will be.. of course, the rest of the aluminum will quickly corrode away too trying to replace that lost oxide layer.

Menessis
02-01-2015, 11:01 PM
Truth be told BlackForest the throttle see very little use. But I can't install it back on the collective unless I move that nut!

Menessis

Don Young
02-02-2015, 10:32 PM
You might try heating the whole thing and then rapidly cooling the inner part with water. That is how the valve seats are removed from aircraft engine cylinders.


I was thinking of heating and cooling to get the two parts expanding and contracting. Wish I could dream up a way to cool the inside ring and heat the outside??

Menessis

Menessis
02-03-2015, 10:57 PM
I wonder what would be a good way to heat it. I have been using boiling water up to this point. Maybe a cooking oil? Don't think I want to use a torch.

Menessis

lakeside53
02-03-2015, 11:32 PM
Use a convection oven. Even heating, easy to control. I use a convection microwave (no microwave portion on!) for tempering, bearing heating etc.

Menessis
02-12-2015, 08:42 PM
Just an update. No time to tinker with this at the moment. I have it soaking in some penetrating oil.

Menessis

LKeithR
02-12-2015, 10:27 PM
...BTW....I can't walk away! It's mine...

If you actually plan to use that on a working helicopter you should be throwing that part away and getting a new one. You don't want to screw around with things like that...

SGW
02-13-2015, 05:56 AM
One thought -- for extreme thermal shock, dunk it in some liquid nitrogen, then heat the outside with a torch.

J Tiers
03-15-2015, 09:47 AM
Did you ever get the parts apart?

If so, what did you do?

I have to get an iron part off an alloy part, and so far nothing has worked. Not possible to get a gear puller, or similar part under it, as there is an extension off one side.

Daminer
03-15-2015, 02:23 PM
Local auto junk yard "go-to" guy saves used brake fluid they have to remove before cars go to crusher/dismantler. Keeps in spray bottles around the place for stuck and rusted up items. Brake fluid seems to get into anything, and if left overnight helps to free anything. Lug nuts on an old Chevy C-60 box truck (california wheels no less) would not budge. Soaked in brake fluid 24 hours and off they came. YMMV

Jim