Introduction: Rusted Stuck Seized Parts, Free at Last

Picture of Rusted Stuck Seized Parts, Free at Last

It's rusted on and won't come off. Some reach for a certain stinky penetrating solvent (WD40) but it doesn't really work well for this kind of thing. Here's what does:

Shock and awe (there are no lubricants or solvents in this particular 'ible).

Shock is provided with a hammer. Awe comes from the awesome power of hellfire... or a little propane torch, pick one.

This technique has resurrected many rusty bikes in salty places like Montreal.

Remember to vote for me if you find this knowledge useful. 


So many people have spoken of their success with various penetrating oils, I can't even keep track of them anymore. Please view the comments at the end.

Some people have kindly spoken in favour of penetrating lubricants as well. Whyteboar, Cross and toad all advise using PB Blaster and letting it soak in repeatedly. mastershake916 is partial "Yield" by Chemsearch and dlaninga1 suggests JB80 metal conditioner. rimar2000 says "You MUST try using liquid phosphating. You can dip the pieces many hours or days into normal liquid phosphating. It does not attack hands or skin."

Also, mastershake916 asked what I wanted the cog for. It was going to go on a Stokemonkey electric bike motor using an adapter but I changed my mind. You see, I'm building a electric/solar/pedal car in an attempt to merge the superb efficiency and light weight of an electric bicycle with some of the features of a car.

Kevanf1 had a neat idea: "...putting the lot into a freezer for 24 hours. Then try heating. But this time you will not have to bring the metal up to red hot and thus not risk changing the crystalline composition of the metal". Someone buy this dude a beer.

Step 1: Needful Thingies

Picture of Needful Thingies

-Punch (if you're freeing something like a stuck, busted off bolt)
-Blowtorch (mixed gas if you're in a hurry, otherwise sometimes even a candle can work fine)
-Water (optional)
-Real gasmask (very nice to have. I use mine daily. Heck, I have two for when a guest visits.) 
-Love (you're gonna be hammering, torching, shocking, twisting... it's helpful to love the process)

And regular tools for your part eg. vice, wrench, screwdriver etc.

Step 2: Knock Knock Shock

Picture of Knock Knock Shock

Knock knock.
Who's there?
Hammer who?
Uh oh. 

Since you've already tried your regular methods, here's where we apply some shock. 

My theory here is that two pieces of metal have rusted into each other under compression so a sudden shockwave passing through the material will cause a sort of whiplash effect allowing the parts to jump apart for an instant. They may even loosen themselves a little. 

So give the parts a sharp tap with the hammer. Recessed things may be easier to reach with a punch. BUT, be careful here. The point is to shock the part but not to bend it all out of shape. Place and power your hits such that you don't permanently distort your item; otherwise you may end up having more trouble getting it off. Be especially careful if you're using a punch, you don't want to flare out and expand a bolt that's stuck in a hole.

Hit hard but not too hard. 

This step is dedicated to The Lightning Stalker who says "there is just no replacement for the "heat it and beat it" method". Sexy times.

Step 3: Torch Time

Picture of Torch Time

Try to undo the thingie. Is it loose? Great!

If not: Apply fire. Put on your gasmask first though; often grease, paint, and little bits of plastic end up getting burt up in the crossfire. Don't breath this. 

Heat until red hot. Unless you're working on aluminum. As Esmagamus kindly reminded me, aluminum melts before it glows. You might not want that.

The theory for this step is that the parts will heat up and expand at different rates due to their being different sizes, slightly different materials, unevenly heated, etc. This difference in expansion probably causes little micro-shifts at the rusted/stuck surface. Once you have broken this seal, static friction goes waaay down. 

Note: heating up metal can change its properties considerably. I've included a random time-temperature transformation chart (TTT) just to make it look complicated. 

Optional: pour on water. I think rapid, uneven cooling might shock the parts apart more. Also I don't have to wait for things to cool. This can make steel more brittle, meh. 

Pro bike shops might use an oxy propane or oxy acetylene torch. I just use propane which takes longer. In a pinch I once used a candle for an hour and that worked too. 

Step 4: Hammer Time, Take Two

Picture of Hammer Time, Take Two

Try unscrewing it now. Usually your part will come off at this point but mine was still solidly stuck. Sometimes a few more taps with the hammer will make all the difference at this stage. This was the case in my example here. 

Step 5: Free at Last

Picture of Free at Last

Free at last, free at last. Thank God almighty. We are free at last. 
-King Jr. Martin Luther 

After trial by hammer,
trial by fire,
trial by water,
and trial by hammer again for good measure,
the part comes off like it was never stuck in the first place, if you're lucky. 

Epilogue: There were a couple of cracked teeth. This might have happened when I hammered after I poured on water. The rapid cooling may have made the metal brittle. Whatever, this type of sprocket is prone to broken teeth...


chuck1260 (author)2016-09-07

Kroil has always worked for me, even on old maniford bolts. Kano Labs makes it and you can buy it from them...

jbrobertson59 (author)2013-08-10

What I use as a pipe fitter on rusted flanges is kroil oil best I have found next to a torch and a beater

MR_Huns (author)jbrobertson592014-09-06

+1 for kroil. Its the best!!!

CRC also makes a very similar product to Aero Kroil called "Knock'er Loose." I have had success with this when Kroil was not available. I used to buy PB but these work much better. WD-40 has its place, but not for penetrating oil. I only use it as a light GP lubricant. Personally, I prefer CRC "PowerLube" to WD-40 anyway.

Old timers will remember "PowerLube" as "CRC 5-56," although I think they may still make the "5-56." It kind of split into 2 separate products, "Ultra-screwloose," and "PowerLube."

Tspherix (author)2013-07-20

Nee- Not a boy's name reference?

snotty (author)Tspherix2013-08-12

Is Nee a name? That's neat; what language is it from?

I was thinking of the Knights Who Say Nee:

Tspherix (author)snotty2013-08-12

On step 4 - the caption reads 'nee'. Reminded me of "Hanna is not a boy's name" (Online comic) - Hanna uses a Hammer as his weapon of choice, and commonly (emits) a "Gnee" word/sound/phrase when excited. Totally random, just reminded me. Surprisingly Appropriate.

Nice article. Love the Pix and commentary. :)

snotty (author)Tspherix2013-08-13

Well how 'bout that. "Hanna is not a boy's name" looks fun.

I'm glad you like the 'ible.

throbscottle (author)2013-07-18

You didn't mention impact drivers - gives shock and twist combined together. Wish I had one...

snotty (author)throbscottle2013-07-18

I wish I had one too :)

Quick-tune (author)snotty2013-07-31

I have one... but it don't help much with corroded parts - heat is the most successful path, Acetone and gear oil is really good if soaked for a couple of hours.

Quick-tune (author)Quick-tune2013-07-31

Also, for the record... WD40 was mainly developed for W(ater) D(ispersal) hence its usefulness in starting damp engines.

titchtheclown (author)2013-07-21

For loosening bolts and screws an impact driver is the ticket. I have an old fashioned hammering type one and an electric driver/ drill combo The dedicated impact drivers are better at loosening because the chuck on combo ones like mine loosens off in reverse. Air powered ones are for heavy duty jobs. My theory is that rust is brittle and hitting it with a hammer shatters it. High pressure water, air or spray lube also help to wash the gunk out of the way, as will washing in warm soapy water. I would mention the dishwashing machine but I don't want to get into trouble again.

Kevanf1 (author)2013-07-18

If the parts that are stuck are small enough you could try popping them into a polythene bag and then putting the lot into a freezer for 24 hours. Then try heating. But this time you will not have to bring the metal up to red hot and thus not risk changing the crystalline composition of the metal. Add to that, no indiscriminate banging with a hammer might equal no broken teeth on any cogs ;) Good 'ible' :)

snotty (author)Kevanf12013-07-18

Heeeey, that's a neato idea. Freeze it to un-seize it. Maybe freezing it in a deep freeze and then dunking in boiling water or hot cooking oil would work. Hmmm...

djimdy (author)snotty2013-07-20

I just realized that the local Kroger actually sells huge blocks of dry ice for dirt cheap. That's another possibility for running a major temperature differential.

Kevanf1 (author)snotty2013-07-19

Got to be worth a try if you have the time before resorting to heavier methods :) After all, it's not going to hurt anything. I'm thinking of the number of times I've slipped because of getting frustrated with a hammer and bashed myself up :(

Take care.


uncle frogy (author)2013-07-20

I'm leery of too much heat changing the temper of the steel so seldom use it. I have used many different kinds of penetrating oils and by luck found a product called Kroil. to be the best I have ever used a little vibration and some time and the parts become free.
I love retrieving things from the scrap heap

badams2 (author)2013-07-20

The only aerosol can worth having around the shop is Pennzoil Z-4.

I've busted so many rusted parts loose with it, plus it cleans dirty tools like nobody's business!

oilitright (author)2013-07-20

I've seen many items damaged with the heat and beat method. There are materials that won't hold up, like Aluminum. That said it does work sometimes. Personally what I reach for is AeroKroil from

I use several of their products. You may have to wait 24 hours but it has never failed me.

branman23 (author)2013-07-19

break free clp made by Safariland works really well also

wryce (author)2013-07-19

An old technique is the heat it up and melt some candle wax into it. then let it cool.

rimar2000 (author)2013-07-18

You MUST try using liquid phosphating. It converts iron rust into phosphate, making a lot easier to loosen pieces. You can dip the pieces many hours or days into normal liquid phosphating. It does not attack hands or skin.

Eventually, if the parts are TOO rusted, you must use Chlorhydric acid. it is FAR MORE aggresive, you must have a lot of safety measures: gloves, mask, work vest, safety shoes.

snotty (author)rimar20002013-07-18

Thank you! I've never heard of this method before. Could you write an instructable about it for us?

rimar2000 (author)snotty2013-07-19
The Lightning Stalker (author)2013-07-18

I hate to burst everyone's bubble, but WD40 is junk for this kind of thing. It was never intended for this purpose and barely works. Even antifreeze works better (because of the corrosion inhibitors). But there is so much better stuff out there now. Kroil, PB PartsBuster, Evapo Rust, CLR, the list is almost endless.

That said, there is just no replacement for the "heat it and beat it" method. In the right hands, a cheap welder can work wonders in all kinds of "sticky" situations. Just beware that once a fastener, chain, sprocket, or other heat treated part glows that its properties change and it has to be replaced. I would hate for someone to get injured or killed as the result one of these "repairs". God forbid someone should work on something for someone else and something like that happen.

Yup - you're right - WD-40 actually means "Water Displacing formula 40".... all it was meant to do is to get water out of ignition systems - when they consisted of points and condensers.....

Another spray out there is called ACF-50 - Anti-Corrosion Formula 50.... it about on par with Kroil, so it takes some time when there's lots of rust, and it's tough to find, as it's usually only industrial or aviation use.

I'd actually never thought of using CLR... being an acid, it should work well on rust...

Eromanga (author)nmcrae12013-07-18

40th attempt. It took 40 formulas until Norm Larsen got it right. ;-)

(Displacement, BTW).


throbscottle (author)Eromanga2013-07-19

Yeah, the WD stands for "We Did it"

Thanks for the explanation. My comment was getting too long to include such info.

Heat it and beat it? Heh heh heh. I've dedicated step two to you 8D

The pupils of my eyes are now a heart shape.


NitroRustlerDriver (author)2013-07-19

FYI, a 50/50 mix of automatic transmission fluid and acetone is a great penetrating oil. Check it out:

bpark1000 (author)2013-07-18

Another method when things are bad is to soak the parts in dilute hydrochloric acid (remove grease/oil first to allow acid penetration). This renders the rust soluble. You know it's working if the solution turns immediately brown (a clear brown like tea). Even better (if the parts are small and you have one) is to put them into a sonic cleaner (in a separate steel or glass beaker with the acid). Rinse the parts before resuming the hammer/heat regimen, so you don't have to deal with acid splatter/fumes. When you heat, you should stay below 400 degrees F. Avoid quenching.

Paul03 (author)2013-07-17

As a mechanic for 50 years I can say the ONLY method described that might work is heat. BUT no way in 10^6 years will a candle work. The whole mass will heat up equally and no affect on expansion differential. Fortunately you don't work for me. But you did show some neat meaningless pictures!

rimar2000 (author)Paul032013-07-18

Paul, fortunately I don't work for you, because you are prejudging.

Yes, heat expands proportionally ALL PARTS. That means "also holes". It is to say: if you have a 0.001 mm gap between two pieces, such gap will increase too.

GENERALLY heating uniformly all parts, they loose a bit more easily.

I could testify this in front a judge, based on my own experience.

ElectroFrank (author)rimar20002013-07-18

Heating an outer component rapidly may expand it away from an inner part before that heats and expands.

Also, different metals have different rates of expansion for the same temperature rise. This may have some effect in breaking rust between parts of different metals or alloys.

snotty (author)Paul032013-07-17

Well, all I can say is that the candle worked for me for a bicycle crank arm bolt. This is a small part so it seems that the candle flame was enough in this case; something on a car would probably have all its heat pulled away too quickly to be useful. I suppose the parts must have cooled down at a different rate when I removed the candle :)

dlaninga1 (author)2013-07-18

Not to be "that guy" but JB80 is a great "metal conditioner" made by Justice Brothers. If the heat and the banging don't cut it, give it a shot. Pick up two cans, you'll go through the first one the first day. No, I don't work for them.

snotty (author)dlaninga12013-07-18

Thanks for the tip!

brittniepearl (author)2013-07-18

best instructable ever.

snotty (author)brittniepearl2013-07-18

I'm glad you like it. It was fun and that's what it's all about eh.

mwork (author)2013-07-18

An old time solution that works really well is to simply drop the rusted parts in a bucket of kerosene and leave them for few days.

Esmagamus (author)2013-07-18

You missed the most important warning of all: aluminium melts before it glows.

snotty (author)Esmagamus2013-07-18

Yes! Thank you for reminding me. I added your warning in the torch step.

mastershake916 (author)2013-07-18

I'm wondering, why did you want that little cog off of the freewheel? Does it have a thread size that is useful for any applications outside of a free-wheel cluster?

snotty (author)mastershake9162013-07-18

Sometimes I do this to remove the other gears from a free-wheel cluster like in step 25 of

Here's a funfact though: Freewheel threads are the same as standard bottom bracket threads so you can use a bottom bracket lock ring if you're making a fixie with a freewheel-style hub.

Whyteboar (author)2013-07-18

PB Blaster works considerably better than WD40. Just a FYI for next time.

Cross_ (author)Whyteboar2013-07-18

Another vote for PB Blaster. Takes a couple of minutes to soak in but does a good job with rusted parts.

toad (author)2013-07-18

Try penetrating lubricant thinner than wd 40 like pb blaster, many soaks and time. leverage. applying heat to bikes does bad things. From a land were everything rusts

About This Instructable




Bio: Careers: documentary filmmaker, DOP, engineering student, practical environmentalist, idealist. Loves: bicycles and when weeds grow in the city. I'm from western Canada, Yukon, Japan ... More »
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