How to break rust bond

ldj · Oct 9, 2019

My old screw type mechanical press is rusted together and can't get it to turn. I have used phosphoric acid, PB Blaster, WD40. I soaked good with one then cleaned it off good and tried the other, no luck so far. I have thought about taking it to a powder coat place and see if they would put in their oven. I think they go up to 400* and don't know it that would brake the rust bond, any one know? Any other ideas appreciated. I don't want to heat with torch because I afraid I can't heat even enough to keep from cracking. It is mostly cast iron

TimV · Oct 9, 2019

Lots of possibilities, and every has their favorite magic elixir, but don't be afraid of a bit of heat. You WANT to heat it unevenly--that's what breaks the rust bond. Spray it up with whatever you want (PB Blaster's my go-to for such things, but to each their own) and go around it with a propane torch. Keep heating, cooling, spraying, and working the handle and sooner or later she'll turn. Sometimes candle wax dripped on the threads and heated will work its way into the mechanism.

neverfear · Oct 9, 2019

X2 on heat and candle wax.

Jeff NWOH · Oct 9, 2019

I've heated many a cast iron piece red hot
in one area to get a bolt out. Manifolds,
heads, etc... I've never had one crack.
I wouldn't be afraid to put the heat to
it.

MarkB_MI · Oct 9, 2019

400°F isn't nearly hot enough to break rusted iron loose. Don't try to heat the casting with your torch because it will take way too much heat. Focus your acetylene torch on the screw close to where it enters and exits the casting.

NC Wayne · Oct 9, 2019

As others have said, heat and some
penetrant work, but they leave out another
important thing, vibration.

Once you have the first two going,take an
appropriately sized hammer, and tap, tap,
tap, around the threaded area. As long as
you are tapping, and not HAMMERING, you
shouldn't have to worry about breaking
anything, but the vibration will work on
the bond.

I've had stuck bolts, and hydraulic
fittings, that I've had wrenches and
cheaters on, that wouldn't break loose.
I'd hit them with a hammer a few times,
(in tight places I've used a small air
hammer and hold it back so it just taps)
and with the hydraulic fittings
especially, taken them off with my fingers
afterwards.

Good luck.

Bob Harvey · Oct 9, 2019

X 17 Heat and wax. Will not happen instantly. Got an air chisel ? Use it to vibrate.

da.bees · Oct 9, 2019

Short of red hot which is not a good idea for this,much of the benefit of heating is pulling oil in as parts cool. Put some penetrating oil on joint where parts meet and you would like oil to get between parts. Quickly heat part until you see oil boil or smoke,stop heating and keep joint wet with penetrating oil until part cools. If time allows,do this ever 2-8 hours for as many days as you can afford. Keep trying to wiggle it. Once you get the smallest movement,things will start going better. At some point oil will seep into joint as it's applied. Time and patience is the key. It took a long time getting in that shape,it will take time to get it back.

4play · Oct 10, 2019

Did the phosphoric acid look like it did much? That is a pretty weak acid and if you want to try another acid then I would get muriatic acid. Just keep away from the fumes and spillage.

CCer · Oct 10, 2019

My GO-TO tool is a steam cleaner, Heat and water pressure has loosened many seized threads for me. With tapping and turning.

Dick L · Oct 10, 2019

Not many here have heated their house with a coal burning cast iron pot bellied stove that was red hot all winter long. Or the cast iron cook stove that not only cooked the food and was the source of all hot water as well as heated the kitchen where you would get dressed in sub zero mornings.

Mike M · Oct 10, 2019

Don't be in a hurry. Soak it in a bucket of diesel fuel and set it back in the corner and check on it in a month or more.

Determined · Oct 10, 2019

Iodine

Mutt and Jeff · Oct 10, 2019

build a fire under it
big bowl or bucket with vent holes around the lower rim

fire hardwood, coal tend and roast it

maybe even squirt oil at it and watch the flames and smoke

work it back and forth till free

Calvin Innes · Oct 10, 2019

I was working on a dozer head with several broken studs years ago and a fella told me to heat the head and put bees wax on the broken studs. I didn't have bees wax so used a candle and I was amazed how easily they came out. The heat doesn't need to be terribly hot, not even "spit-sizzling hot" as dad used to say. It is amazing how well the wax flows into the voids around the rust and things begin to work on out. Been doing this for years.
Hope this helps.

dr sportster · Oct 10, 2019

An iron casting should not crack with some heat . Don't be afraid of a torch if you need it. Heat- wax

Dick L · Oct 10, 2019

Forgot all the cast iron skillets and cook ware. Bib cast iron kettles to scald hogs and then to turn the fat into lard.

How to break rust bond

ldj

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TimV

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neverfear

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Jeff NWOH

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MarkB_MI

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NC Wayne

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Bob Harvey

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da.bees

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4play

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CCer

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Dick L

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Mike M

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Determined

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Mutt and Jeff

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Calvin Innes

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dr sportster

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Dick L

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