How to free SS bolt from corroded aluminum fitting

[a64pilot]

Originally Posted by 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.

Heating the bolt will expand the bolt and may break the bond, also aluminum is an exceptional heat sink, it will draw the heat out of that bolt quicker than you would think, so far as heating the aluminum I wouldn’t. Surely you won’t get it hot enough to melt, but you could certainly ruin its heat treat and you don’t want to do that, cause I feel fairly certain that a mast is heat treated. Then there is the anodizing, I’m not sure hot hot it takes to ruin it.

You may get lucky and get it out, but I’d prepare myself to drill it out, and go back with a threaded insert.

[garyfdl]

Originally Posted by 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.

Aluminum melts at around 1200F you can melt it with a propane torch. Heating the bolt should prevent melting the aluminum accidentally, but still break the bond between the two metals.

[Boatyarddog]

Originally Posted by garyfdl

Aluminum melts at around 1200F you can melt it with a propane torch. Heating the bolt should prevent melting the aluminum accidentally, but still break the bond between the two metals.

This maybe true for a sheet of aluminum, say .010" thick, if your talking about a step base its a lot thicker than this.
Our business of outboard sales, causes us to repair salt water corroded parts regularly, we use oxy/acetylene which heats much hotter than propane but will not melt castings, but will burn right thru sheet aluminum that is thin.
Aluminum is a great conductor of heat as mentioned, propane may help but rarely with thicker projects. It is usually Heat and Beat, as best as possible.
Do not heat the bolt , heat the surrounding area, to expand the hole, it's going to cool quickly, so you'll have to repeatedly heat and quickly shock the bolt or turn it then repeat the process.
SV Cloud Duster

[oOoOoOo]

Having a lot of experience with rusty bolts on cars and such, I can say that heat is 1000% more effective than any penetrating oil. A trick that really helps that no one mentioned yet is to put the piece in water directly after heating. This will definitely shock it loose.

[roverhi]

For an aluminum casting might just hook the positive lead directly to the casting to heat the aluminum. In any case, multiple iterations of heating and quenching with penetrating oil will be needed unless you get lucky. An impact wrench also helps.

Jumper cable trick.
Hook jumper cables up to the battery as you normally would. On the other end put a bolt (1/4" x 2" bolt works fine) in the postive lead clamp of the jumper cable. Clamp the negative lead as close to the offending bolt as possible. Touch the bolt in the positive lead clamp to the head of the fastener. You set up what is essentially an arc welder. Will heat the fastener to a cherry red if left in contact long enough. It also gets the fastener way hotter than you can with a MAPP torch. It works really well as it only heat up the area of the fastener and not burning up the surrounding country side like you do with a torch. It is really the only way to get serious heat to a fastener if there is painted surfaces or plastics close by. Quench the heated fastener with penetrating oil. Try to remove the fastener with an impact driver, either manual or power. Repeat the process till you break the fastener loose. Other than using the trick to remove all the fasteners on a 44 year old mast, used it to get corrosion welded bolts out that passed through substantial aluminum castings on my self steering vane.

Having said the above, the hardest fastener to remove is not one that is threaded into aluminum but one that simply passes through an aluminum casting like cleats, etc. Getting the bolts out of the self steering casting took something north of 25 iterations, heating with the jumper cable and quenching with penetrating oil over many days. A good idea to coat the shaft of any fastener in aluminum cleats or castings with Lanocote.

[jmschmidt]

Impact wrench.

[CarlF]

Before resorting to heat - which can damage the mast or fitting - use a better penetrant. WD40 is pretty much useless. My favorite has been Kroil but I've learned something today from Bill about Mouse Milk. I just ordered some.

If three days of daily treatment with one of these doesn't work, then you'll have to go to something riskier.

Also. As a few have mentioned get a tube of tef-gel. Always put it on any stainless screw going into aluminum. Just a wee bit works. And if you have free time some afternoon, consider reinstalling or replacing any stainless screws in your mast that aren't already frozen after putting on some tef-gel. In 20 years I've never had a tef-gel treated screw freeze.

[Riddle]

Drilling it out with good high quality drill suitable for stainless is probably the least damaging solution. Slow drilling, lots of cutting fluid, sharp drill.
I have an aluminum boat and try to avoid SS bolts wherever I can. If it is unavoidable, use water resistant grease such as Lanotec when installing the bolts. Never any problem in unscrewing them again.

[Boatyarddog]

Originally Posted by Riddle

Drilling it out with good high quality drill suitable for stainless is probably the least damaging solution. Slow drilling, lots of cutting fluid, sharp drill.
I have an aluminum boat and try to avoid SS bolts wherever I can. If it is unavoidable, use water resistant grease such as Lanotec when installing the bolts. Never any problem in unscrewing them again.

Yes, titanium bits, oil or cutting fluid. And, Slowly drill it out
Heat is the enemy of drill bits, slow and steady, small pilot hole, work your way to the bolt size.
If you break it off in the hole, good luck.
So, slow, and keep it straight, you don't need a lot of pressure on it, let the bit do the work, and change it to a sharp one if it begins to smoke.
SV Cloud Duster

[mike d.]

If you have a propane torch, point the tip of the flame, which will have figure it's length from the torch head it is usually about 3 inches +- hit the bolt head for about ten seconds, then brush on the penatrant solution ! Walk away, do it again the end of the day, then again following morning ! Then rap the head with a hammer, don't slam just a wack ! Then try turning the bolt ! Repeat until it loosens ! You will not damage the mast ! The heat in the bolt will pull into the aluminum, which will pull in the penatrant ! I did this with our 52ft 40 yr old mast ! I had 1 screw on the spin pole track that would not budge, the track was junk, so I broke the track off around the screw! Pliers turned the screw ! After you are done run a tap through the hole to clean the threads, then use TefGel on the threads of the bolt, and in the hole ! Note i Used this method for screw down to No. 8 U. S. thread !

[sandy stone]

OK, I just found something today that I had never heard of before, but it really, really works. I had been trying to remove an injector from my engine for a week, tried Kroil, PB Blaster, heat, mechanical shock (ha!) but nothing worked. In desperation I searched the internet for something to chill the injector, thinking maybe shrinking it would break it loose. Turns out Autozone sells something called CRC Freeze Off, which is a combination freeze spray (like what you might use to frost drinking glasses) and penetrating oil. Got some, followed the directions on the can, and the injector came out! Still a bit of a struggle, but I had gotten nowhere for a week. Granted, this was not a stainless fastener in aluminum, but I highly suggest you try it.

[coopec43]

Originally Posted by 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.

Good point! A picture is worth a thousand words.

[Niall leslie]

Suggestion that usually works.
A- Use your favourite penetrating oil for a few days ( not WD 40 etc. they are not penetrating oils.)
B-Then use an electrical induction heater designed for the job on the bolt a couple of times allowing full cooling in between.
C- If A/B don't work then drill / punch it out using the appropriate tools and skills.
OR
D- Pay someone who knows what they are doing to remove it.
Cheers,
Niall.

[JC Reefer]

Do not drill it! Drilling is the most work and poses the highest risk.

Other members, please stop telling folks to drill out screws as a first resort, I beg you.

For 3 years I was the guy that disassembled furlers to replace the bearings on a daily basis. Profurl has some special problems as they mix SS and titanium screws into the aluminum hubs.

If your in the US southeast or Caribbean and sent your furler somewhere for repair or bearing replacement then there is a good chance it came to me.

I think we can all agree that furlers are exposed to seawater and are rarely taken apart.

DO NOT DRILL IT OUT. Drilling is a last resort after YOU have screwed up. You risk doing more damage to the relatively soft aluminum. In 3 years the only screws I every drilled out were because the owner (or someone) had attempted the work themselves and broke the screw head off or did some other bone headed error.

An impact wrench will work or it will break the head off. IMO an impact wrench is the second to last choice because it’s all or nothing.

Everyone is talking about penetrants, I like Vinegar. Cheap white vinegar. Take a piece of salt crust and put it in a cup of vinegar. You’ll see a chemical reaction taking place turning the elements in the salt into a gas.

Vinegar won’t easily work it’s way into the thread if your unable to fully submerge the part into a bath of it. You’ll need to use some heat.

Heat, a small amount of heat can be applied without damaging things. I think people get carried away with heat and end up burning things or weakling the metal. Do not bring the screw to a red hot glow, you’ll damage something.

You can heat the metal up enough to boil water (or vinegar) that is sprayed on it and then allow it to cool down. I use a water bottle filled with vinegar. Poke a hole in the cap and you have a squirt bottle.

Do this at least 5 times spraying the screw with vinegar on the cooling cycle using up a 16 ounce bottle of vinegar.
When cooling some of the vinegar will be sucked into the threads as air inside the screw retracts from its expanded state.

If you have done the salt crust in vinegar test like I said then that’s what will be happening in the threads. The now trapped vinegar will turn the salt crust into a gas further loosing the grip.

You can use any penetrant but be carful as some are flammable.

Try tighten the screw slightly then try loosening. After your 5 heat/cool cycles.

This method will eventually work. Threads will be intact, nothing will need repair.

When assembling, thread coating products that others have mentioned are definitely worth it. Lambacoat is one product.

If you end up drilling then congrats for screwing up. But if you must The advice I have seen is correct (slow speed, sharp bit, cutting oil). But you should not need to drill it.

Though its a tough bolt, try and be gentle. It will save you effort and money later.

Let us know how it goes.

[Boatyarddog]

Originally Posted by JC Reefer

Do not drill it! Drilling is the most work and poses the highest risk.

Other members, please stop telling folks to drill out screws as a first resort, I beg you.

For 3 years I was the guy that disassembled furlers to replace the bearings on a daily basis. Profurl has some special problems as they mix SS and titanium screws into the aluminum hubs.

If your in the US southeast or Caribbean and sent your furler somewhere for repair or bearing replacement then there is a good chance it came to me.

I think we can all agree that furlers are exposed to seawater and are rarely taken apart.

DO NOT DRILL IT OUT. Drilling is a last resort after YOU have screwed up. You risk doing more damage to the relatively soft aluminum. In 3 years the only screws I every drilled out were because the owner (or someone) had attempted the work themselves and broke the screw head off or did some other bone headed error.

An impact wrench will work or it will break the head off. IMO an impact wrench is the second to last choice because it’s all or nothing.

Everyone is talking about penetrants, I like Vinegar. Cheap white vinegar. Take a piece of salt crust and put it in a cup of vinegar. You’ll see a chemical reaction taking place turning the elements in the salt into a gas.

Vinegar won’t easily work it’s way into the thread if your unable to fully submerge the part into a bath of it. You’ll need to use some heat.

Heat, a small amount of heat can be applied without damaging things. I think people get carried away with heat and end up burning things or weakling the metal. Do not bring the screw to a red hot glow, you’ll damage something.

You can heat the metal up enough to boil water (or vinegar) that is sprayed on it and then allow it to cool down. I use a water bottle filled with vinegar. Poke a hole in the cap and you have a squirt bottle.

Do this at least 5 times spraying the screw with vinegar on the cooling cycle using up a 16 ounce bottle of vinegar.
When cooling some of the vinegar will be sucked into the threads as air inside the screw retracts from its expanded state.

If you have done the salt crust in vinegar test like I said then that’s what will be happening in the threads. The now trapped vinegar will turn the salt crust into a gas further loosing the grip.

You can use any penetrant but be carful as some are flammable.

Try tighten the screw slightly then try loosening. After your 5 heat/cool cycles.

This method will eventually work. Threads will be intact, nothing will need repair.

When assembling, thread coating products that others have mentioned are definitely worth it. Lambacoat is one product.

If you end up drilling then congrats for screwing up. But if you must The advice I have seen is correct (slow speed, sharp bit, cutting oil). But you should not need to drill it.

Though its a tough bolt, try and be gentle. It will save you effort and money later.

Let us know how it goes.

After 5 years of continuous, dealing with corrosion and Aluminum, SS castings, drilling out fasteners, is now common place.
In a business you rarely have time to slowly let any process take place.
It's just a common procedure, there are some tricks but not that many.
Sharp bits, a bit of heat, thread soak, all of it.
The real damage starts when it gets beaten on, mushrooms the head of the bolt, destroying the casting.
At that point if it's removeable, then take it somewhere they do this for a living.
You'll be better off than in your under equipped garage.
Trust me on that, I do this everyday!
SV Cloud Duster