Home Forums Hunting & Shooting Gunsmithing Best penetrating oil?

For tough jobs, I use a mixture of Kroil oil, Type-F ATF (old school ford), Aggressor parts washer solvent, D.O.T. 3 Brake Fluid and acetone. I mix in a 125ml amber glass bottle with approximate amounts as follows: 50% Kroil, and the next remaining 3 in equal parts leaving enough room for 2-3 tablespoons of the Acetone to shake well. Then I heat my screw by using a variable wattage soldering iron and with the iron touching the screw slot and set about 15 watts to draw in the solvent then soaking overnight. If you have the opportunity, reapply solvent a few times during the soaking period and increasing wattage setting if additional heat is needed. This works very well for me on tight screws or bolts.