How to free SS bolt from corroded aluminum fitting

[coopec43]

I am trying to free a stainless steel bolt from the aluminum mast step. I've spent about a week giving the bolt a squirt of WD40 each day but it hasn't made any difference.

Is there a time honored way to do it?

I came across a forum where it was suggested a 50:50 mixture of acetone and ATF (Auto Transmission Fluid?) would free up the bolt. It just so happens I have acetone and ATF fluid so I'm giving it a try. Ill keep squirting it daily for about a week and see what happens.

How to free a steel to Aluminum corrosion bond

Any other suggestions apart from heat?

[Jim Cate]

Coopec, there have been endless discussions of this vexing problem, with dozens of proposed solutions, some of which MAY work in some cases. But it is hard yakka at best.
.
Do a bit of searching and you will find lots of suggestions.

And BTW, WD-40 is not very good at penetrating oil applications. The acetone/ATF mixture is as good as any in my experience, and well worth trying.

Good luck with the research and the job.

Jim

[coopec43]

Originally Posted by Jim Cate

And BTW, WD-40 is not very good at penetrating oil applications. The acetone/ATF mixture is as good as any in my experience, and well worth trying.

Good luck with the research and the job.

Jim

Yes, I've often wondered about WD40 penetrating qualities.

If acetone doesn't penetrate the corrosion I can't think of anything else that would.

Thanks.

[Jubilee39]

I have had occasional success with a pencil propane torch heat directly on the bolt. Problem is if you are too aggressive with the flame you could damage the surrounding paint. The stainless will expand, aluminum expands faster but the movement between may allow your penetrate to wick itself in. Shock treatment then might work using an impact tool.

[coopec43]

I've got a propane torch but I was not too sure whether to heat the aluminum or bolt. Because they expand at different rates then heating either would surely break the bond (in theory)?


I've got a rattle gun so maybe that's the go. My Son is back from the country now and he is a diesel engine fitter so I'll see what he says.(I bet he has to sort out this sort of problem all the time)


Thanks

[a64pilot]

You can try penetrating solutions, can’t hurt to try, but I suspect you will end up heating and beating, and eventually wringing it off, and then drilling.

On edit when you try the rattle gun go both ways trying to get it shook loose, sometimes it works, also try it with the part hot.
I don’t know exactly what happens when SS screws or bolts sit in aluminum long enough, but they usually pretty much become rivets.

When installing SS into aluminum try to keep them separate, Teflon tape or tef-gel or if a larger part cut a piece of plastic like from a milk jug to sit under it, it’s an electrical current that your trying to keep from happening so you need insulation

[tkeithlu]

It is telling that WD-40 also puts out a penetrant version of itself. I have not found penetrant alone to be much help in any case of stuck/corrosion.

Heat: Unfortunately, the melting point of aluminum oxide is way over the melting point of aluminum. You may need an oxy/acetylene torch to supply enough heat to really loosen the joint, and then you need to be careful that you don't melt the aluminum fitting. You can't use it starting to glow as a warning, as you can with steel.

[Northbound44]

Impact wrench is the best efficient way I found to break the bound to corroded aluminum.
You’ll have thereafter to tap a new larger thread or better use stainless steel Heli coil insert to repair the corrosion damaged thread and insure you’ll not have this problem again

[pierrrre]

Here are a few videos that might help you in your search for the "perfect" penetrating fluid. I bought myself a can of seafoam after watching these videos and I find that it works better than anything else I had in my garage.

https://www.youtube.com/watch?v=xUEob2oAKVs

https://www.youtube.com/watch?v=st8dkGzJWtg

[tkeithlu]

Good point, Northbound.

Somehow stainless steel has a reputation for being a super metal - corrosion free, hard as a rock, etc. It's not. It is gummy. Brass and 1020 ordinary steel machine better, and it is surprisingly easy to shear - far easier than say a Grade 5 bolt.

To my dismay I've sheared a 1/4" ss bolt with my DeWalt 1/4" portable impact wrench.

Be careful! All of a sudden loosening a corroded bolt becomes an extraction job.

When you are up to your ass in alligators, it is hard to remember that the task was draining the swamp. That's not a political comment.

[anacapaisland42]

MOUSE MILK.....It's a very high quality aircraft penetrating lubricant, few drops each day on bolt for about 5 days then put a wrench to it.
Probably available from your local higher quality indusrial supply shop or local airplane service place or

https://www.amazon.com/Mouse-Milk-Oi.../dp/B0049C7170

Bill[


QUOTE=coopec43;3119744]I am trying to free a stainless steel bolt from the aluminum mast step.

[garyfdl]

You didn't say how big the bolt is, but given that it is in mast step, I guessing it's rather small.

I suggest using heat, judiciously, focusing on the bolt. Don't heat the aluminum, it melts too easily, let it get it's heat from the bolt. Then I'd bang on the flat of the bolt head with a hammer. If you can't hit the head because of clearance issues, try using a drift pin/punch/another bolt against the stuck bolt and pound on that. Then try and remove it by hand, not with an impact. SS is actually pretty soft and the impact might twist off the bolt-head.

You could also try thermal shocking the pieces. Heat them up the same way, then pour water on them till they cool than try and turn the bolt.

Either way, you are probably going to have to make repeated attempts, before it comes loose.

Good luck!

[hlev00]

Heat expands so why heat the bolt? The aluminum will heat much faster too. Also doubtful you will heat aluminum to its melting point.

[boatman1]

Heat (more than you’d wish to apply) and more heat. As the piece into which your fastener is threaded cools, you can feel the bolt freezing up again. Not so bad if the pieces involved are in a location where you can lay the torch to them: not feasible if you risk setting fire to a surrounding area. In that case it’s pretty major surgery.

[Boatyarddog]

Originally Posted by coopec43

I am trying to free a stainless steel bolt from the aluminum mast step. I've spent about a week giving the bolt a squirt of WD40 each day but it hasn't made any difference.

Is there a time honored way to do it?

I came across a forum where it was suggested a 50:50 mixture of acetone and ATF (Auto Transmission Fluid?) would free up the bolt. It just so happens I have acetone and ATF fluid so I'm giving it a try. Ill keep squirting it daily for about a week and see what happens.

How to free a steel to Aluminum corrosion bond

Any other suggestions apart from heat?

is the step still attached to the deck?
Is it off, but has a stuck bolt stud in it?
The process will vary with other possiabilities.
If the step is off, cut the shank(threaded end) off flush with a die grinder, or grind flush with the base.
Use a punch to dimple the cut end in the middle, the penetrant works even better if you shock the bolt repeatedly, hammer and punch, every day for a week or so, even less.
The vibration will allow the penetrant to creep down the threads, and dissolve the corrosion.
Then try to turn it, a little at a time back and forth if it's moving at all you'll eventually loosen it.
If that doesn't work, you'll have to drill it out, this can be tricky.
Using a small sharp drill bits , titanium bits, progressively drill a bigger hole down the shaft center.
Once you get to the size of the bolt, the side will come away from the hole, and you should be able to pound out the carcass.
It's always a difficult job and one that can be frustrating.
Have any pictures of what your working on so we can see better?
SHOCKING THE BOLT WORKS WELL.
Cheers,
SV Cloud Duster