aluminum and steel fusing?

[patrickbwells]

Today I began to remove and replace some of the stanchion posts on my Cascade 36'. Some of the bolts on the stanchion post mounts on the aluminum toe rail are completely seized up. There is corrosion where the steel bolts touch the aluminum threads in the clamps, it almost looks like a weld. They may not have been unscrewed for 30 years. I tried a little liquid wrench (big mistake, one drop in the water caused a 6' x 6' foot oil sheen) but it didn't help. Any suggestions for how I could go about freeing them?

[Faster]

It's probably the corrosion that is gripping the bolts.

You may get somewhere with an impact driver if you have the room to use one. Looks like this:

http://en.wikipedia.org/wiki/Impact_driver

With the correct bit or socket you strike the end with a mallet and at puts a twist on the screw at the same time it pushes hard into it. Very effective as long as the underlying structure is sound (ie no bounce)

[sailingdog]

I would try using PB Blaster or some other penetrating oil and let it sit for a while—at least a day or so. Then try using the impact wrench. The corrosion is probably galvanic corrosion caused by the saltwater, stainless steel and aluminum. BTW, when you replace those bolts, use tefgel or lanocote to help prevent the corrosion from happening again.

[JouvertSpirit]

I wonder how long it will take wikipedia to drift the entire knowledge base toward the money trail.

Kids are using this dynamic "encyclopedia" as an absolute gospel of truth.

[redcorvette1995]

You mean Wiki is the gospel? ;-)

[sailaway21]

Since heat of any significance is out of the question, I would recommend the penetrating oil. You may have to let it sit for a number of days and keep reapplying it. You don't need a lot of it, but keep applying it so that capillary action can draw it in to the threads. When this fails, as I suspect it might, I would recommend you drill them out with a left hand thread drill. This will be easier if the heads are not snapped off. Take a ***** punch and strike it in the center of each head so you can center your bit. Use a drill bit smaller in diameter than the threads, about the diameter of the bolt measured from the depth of the thread. Anotherwords, if the bolt diameter is 1/4" then you'll probably want a 3/16" bit. You may well find, that as you are drilling them out, they will spin out on the threads. Hollowing out the bolt, and the heat from the bit, are often enough to do that. I recommend using some light oil, like machine oil or thread cutting oil, as you drill. This will keep you from losing the edge and temper of your bit as you work. Good luck

[cockeyedbob]

patrickbwells,

Stainless fasterers in aluminum, correct?

I occasionally troubleshoot and repair high speed packaging equipment, primarily dairy, and corrosion of aluminum with stainless fasteners is always a problem. The last thing I want to do is twist off a capscrew!

Try very hot water and a lot of LIGHT taps with a SMALL hammer. After a few hundred LIGHT taps you'll see a white mush start to form around the threads as the corrosion begins to break down. PATIENCE is the key and the process actually takes less time than drilling out the stub and retapping. Please, LIGHT taps, don't beat it to death. You want to be able to fit a wrench on the head of the capscrew. Use a BOX wrench that fits, not a Crescent or open end!

No guarantees, but it works for me!

Best wishes ...

[resdog]

Cockeyedbob has the answer. I can guarantee an impact driver will twist the heads off of stainless bolts or screws.

[sailaway21]

That's a damn good idea me cockeye!