Loosening frozen SS bolts in Aluminum?

[do335]

I'm trying to remove the 5/16" stainless steel bolts holding down my aluminum traveler track. So far the bolt is winning the battle. I expect the interaction between the SS bolts and aluminum while being sprayed with sea water is the cause. I have tried applying an impact wrench and hammer with no movement. Next I used a welding torch and impact wrench with hammer and the bolt has rotated maybe 45 degrees so far. I have also tried connecting the bolt and track to my 12v battery supply with jumper cables hoping it would heat and loosen the corrosion, but there appears to be too much resistance for enough current to flow. Anyone have any sure fire ideas on how to loosen this bolt?

[Freesail99]

Maybe use a bolt cutter or a nut buster to get it off ? Sometimes it is the only way. If your traveler is mounted to the cabin top, a nut buster should work.

[sailingdog]

Have you tried PB Blaster penetrating oil?? Soak it with PB Blaster, and let it sit, spraying it again each day for a few days...then try it again.

[TrueBlue]

We went through a similar process as you described, while helping a friend replace his Genoa lead block tracks. After struggling with the bolts from the surface, we realized there were locknuts and backing plates beneath the deck - accessible from storage lockers and galley cabinets.

[sailandoar]

If you end up drilling out the bolt be sure to use 'cobalt steel' drill bits. Easily available and not too expensive but light years ahead of HSS (high speed steel) common drill bits for stainless drilling.

To loosen CRS in Aluminum, heat is the only reliable method I know of except for rumors of an acidic soak that takes out the corrosion. Doing that, the alum could easily be affected too, so it would be a delicate operation.

To use heat:
(1) With a yellow sooty flame coat the item to be heated with black soot.
(2) Adjust to neutral flame and heat the item until the soot begins to disappear and that is maximum tempeture. (This is a ballpark way to avoid melting the alum which is VERY easy to do.) One tries as much as possible to not heat the frozen fastening but just the surrounding aluminum.
(3) Quickly work to loosen the frozen fastening. If possible torque can be applied all during the heating and at some point the fastening will be felt to loosen.
(4) Repeat as needed.

When you have to use stainless in aluminum try to get fastenings that have rolled threads (hard to find) instead of the common cut threads, they do not gall/freeze as quickly/badly. Also, using a loctite thread locking sealant will help keep moisture out of the threads and prevent corrosion.

[hellosailor]

1-PBlaster, applied 2x daily for 2 days. It is NOT just an "penetrating oil" it chemically changes corrosion products.

2-CO2 or other "freezing" instead of heat. No chance of detempering the metal. Ice it down with a CO2 bottle (which will cost about $25 to refill) or pack it with a rag full of dry ice slush, made by chipping dry ice into alcohol. Let it ice down well, them pull the ice off and use the impact wrench. Repeat 3x if needed--I've never needed more than that.

There are some "freeze sprays" you can buy in electronics stores and other places for similar purposes, they are just not going to give you as much cold for the buck. And unlike liquid nitrogen (which you can buy from industrial gas suppliers too, just bring your own thermos) the CO2 should not be as dangerous to work with, or shatter the metals.

Remember, dry ice can give you frostbite, "safe" is a relative term.

[sailingdog]

I'm not a big fan of using a torch to heat up metal on a boat... since fiberglass boats burn very nicely. The CO2 suggestion makes a lot more sense, and has much lower major damage potential.

[gc1111]

I agree with TrueBlue. Work on the nuts. Soak them with PBlaster then unscrew them. More of the force that you apply goes to freeing the nut if you work on the nut side.

[sailingdog]

GC1111-

You're assuming that the underside is accessible, which it may not be.

[gc1111]

Right, but if there are nuts and washers on the underside, he is going to have to find a way to get at them. Otherwise they will just spin. And if you can get a wrench on them to hold them, it is well worth the effort to try to work on them.