Here's my follow up.
Didn't find Kroil or CorrosionX in the few stores near my boat, so I bought
SiliKroil and CB4 CorrosionProof.
Spent the day applying them to the several nuts and bolts I wanted to
remove, tapping them with a nailset and hammer, tried to remove them.
Finally drilled out the end of the 5/8" bolt, didn't have any luck using an
extractor, but used vise grips to twist the bolt inside the gunwale until I
had enough thread protruding to twist and pull it out. The bolt was held by
a nut inside the gunwale; the bolt ran through the backing and mounting
plates, but wasn't threaded through them. Comparing the old bolt to it's
replacement reveals that the bolt did not shear and was not corroded. The
threads of the bolt and the mount it screws into were in good condition,
except for the beginning threads of the mount which were
stripped/crossed/unusable.
During the original installation the bolt was threaded into the mount,
passed through the mounting and backing plates, flat and lock washers, and
then the nut. I suspect that after the nut was drawn up tight, continued
turning resulted in turning the bolt and unthreading it from the mount to
the point where it was held only by a few threads. Some severe bumping
probably caused the last few threads to lose their grip, allowing the bolt
to separate from the mount.

"Gene Kearns" wrote in message
...
On 5 Jun 2004 10:55:24 GMT, Marshall Banana wrote:

Also Sprach Joe :

"Jack Goff" wrote in message
m...

"bomar" wrote in message
...
In this situation heat is probably out of question...
so-
KROIL.
A little had to find, but works wonders.
If not that, PB Blaster (most parts stores)
WD 40 is WORTHLESS for this.


www.kanolabs.com manufactures and sells Kroil and their other products
direct from their website.

Jack

Good stuff, but there is better-
http://corrosionx.com/

Corrosion-X is a fine, but messy preventative, but a **** poor
penetrant. Kroil is a fine penenetrant, but there is one even
better. http//www.mousemilk.com/ Ask any experienced A&P mechanic.

Dan


Kroil is better than Mouse's Milk for most applications. Mouse's Milk
was designed to remove carbon from and free up waste gates... it's
forte isn't garden variety corrosion, though it will work.

It may be possible to drill and tap the broken bolt with a 1/4 or 5/16
inch thread and remove using a slide hammer.

Make absolutely sure to drill in the center... since you eventually
may be forced to drill the bolt out with a 17/32 drill and clean up
with a 5/8 tap... (assumes 5/8-11 thds.)
--
23' Grady White, out of Southport, NC.

http://myworkshop.idleplay.net/cavern/
Homepage
http://www.southharbourvillageinn.com/directions.asp Where Southport,NC
is located.
http://southharbourvillageinn.linksysnet.com Real Time
Pictures at My Marina
http://www.thebayguide.com/rec.boats Rec.boats
at Lee Yeaton's Bayguide