Seriously rusted threads

[David Meiland]

I have a badly rusted screw jack that I'd like to resuscitate if possible. It has 2" Acme threads that are engaged a couple of inches. Is there something that will help loosen these?

[steves]

Heat , Oil , Shock (with a hammer,not electricity )

Repeat

[David Meiland]

I was hoping for a magic chemical.

[gburnet]

I was hoping for a magic chemical.

Here ya go...http://www.evaporust.com/

[newman]

PB Blaster works well

[dtnt48]

I have always had good results with this.
http://www.kanolabs.com/

[StephenS]

Dave,
Head to an autoparts store as their is an entire new line of (new to me) products which are night and day to yesteryears liquid wrench, marvel mystery oil etc.. PB Blaster is excellent for use and others have PTFE (not sure what it is) though now that I'm looking at the can, I see it is a Liquid Wrench product.. however the formula kicks in quick.

Use with plenty of adequate air.. These will knock you back if you inhale the mist which does linger.

[No faux zone]

For a moment I thought this might be about the Global Warming Thread and others similar to it.

Carry on...

[always-learning]

Dave,

I've used PB Blaster, with some success. IT generally comes down to heating the outer nut with a torch, and spinning it loose with a large bar or wrench.

I agree that heat is the best offense.

[Matthew_C]

I will have to recommend Kroil from kano labs as well. I use that quite often and it works well.

[Catspaw]

Oxy-acetylene torch. I've never met rusted nut or bolt that wouldn't come apart after heating it red hot with my magic "blue wrench".

- Rich

[Bill Robinson]

Soak it in Coke.

The Real Bill R

[Mark G]

Don't get it so hot that you un-harden the steel. Use a chemical.

[philthegreek]

If you want to try something old fashioned, try soaking the offending screwjack in diesel oil. Set it in a bucket of the stuff and let it sit for a few days. Then whack it a few time with a "persuader" and use opposing wrenches. If you have to work too hard at it, it might just be worth scrap weight. If you get it freed up, I would suggest you remove the screw, drill an appropriate hole 1/2 way down the base threads, and install a zerk fitting for easy future lubrication.

[charles]

Evidently there was a study done by Machinist's Workshop magazine in their April 2007 issue. The story looked at the different penetrating oils to see which one did the best job of removing a rusted bolt by measuring the pounds of torque required to loosen the bolt once treated. If the study was scientifically accurate, it turns out a home brew works best!

Here's the summary of the test results:

Penetrating oil ..... Average load

None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster .............. 214 pounds
Liquid Wrench ...... 127 pounds
Kano Kroil ............. 106 pounds
ATF-Acetone mix....53 pounds

The ATF is an acronym for automatic transmission fluid. You can readily get acetone and ATF, so mix some yourself and see if you can get the same results.