View Full Version : Loosening corrded aluminum parts

Buddy Sharpton
08-08-2001, 09:27 AM
While I continue to build the MarshCat, I've run into a maintenance problem on my wife's Boston Whaler. It has a supposed to be removable rear fishing seat which consists of a cast aluminum socket with a flange about 9" in diameter with a recessed 4" deep socket to hold the 3" diameter mill finish hollow aluminum tube pedestal. It was last removed about December, but the boat is stored outside under a cover with the seat in the mounted position. It now is stuck fast, first time it has done so in 13 years. I've tried tapping with a hammer and twisting with a pipe wrench but it won't free up. I soaked it with penetrating oil overnight and this morning it's still frozen. Can anyone suggest something like Muriatic acid or such hardware store stuff which can dissolve what I assume is aluminum oxide without damaging the gelcoat cockpit sole? I always wash the boat before storing with fresh water so this was definetly put away wet. and likely saw rainwater as well. There is no way to drain the socket so it is always found holding water, but till now thwre has never been a problem. I suppose lithium grease from here on in. Thanks for your help. Buddy

08-08-2001, 12:54 PM
If the flange can be removed you could take the whole thing to a machine shop, engine builder, someone with a press and have it pressed out. Aluminum galls rubbing on itself and needs lubrication like fat thunder-thighs need cornstarch http://media5.hypernet.com/~dick/ubb/biggrin.gif

08-08-2001, 02:42 PM
The problem is that corroded aluminum takes up more space than un-corroded aluminum (i.e. it has galled ...). About the only thing I could suggest is that you try sweating the socket with a propane torch while you use a strap wrench on the seat tube. This is kind of touchy since it won't take long for the seat tube to heat up also, but there is far more seat tube than socket. Failing that, remove the damn thing and clamp the seat tube to a saw horse and drive the socket off with blocks of wood (to protect the socket face.

One more thing . . . if you do insist upon lubricating the aluminum in the future, be careful of what lubricant you use or you could wind up accelerating any corrosion rather than preventing it (remember that carbon also shows up on the galvanic series charts - right up at the noble end).

[This message has been edited by PugetSound (edited 08-08-2001).]

Norm Harris
08-08-2001, 03:41 PM
I recently restored a whisker pole with Vinegar. The jaw of the pole end had frozen and beating it with a hammer didn't help. Also, the leaf spring that holds the jaw closed was frozen.

Since the diameter of the pole is fairly small and I could freely move the pole, I was able to stand the end in a bucket of cooking vinegar poured straight from the bottle. Within 12 hours it was free.

I recommend that you soak a rag in vinegar and wrap the pedestal. Keep the rag wet and eventually you should be able to free the parts.


08-08-2001, 05:38 PM
Folks,think I'll try that vinegar idea on my flashlite.I was away from gatsby for a considerable period.When I checked her out the other day,I found my favoritest flashlite with the batts.all gooed up.I got all but one batt.out.That last one is stuuubern.
It's one of those high tech alum.jobs with ring seals and all.
I have tried everything (almost) untill I heard the vinegar idea.Any other thoughts on what I might try? http://media5.hypernet.com/~dick/ubb/confused.gif

[This message has been edited by dasboat (edited 08-08-2001).]

08-10-2001, 07:22 PM
The vinegar trick works because it is etching the aluminum. Not a problem so long as you remember to neutralize it with soap and water.

08-10-2001, 08:29 PM