mast to mast base corrsosion

[Hymodyne]

corrosion between mast base and bottom of mast tube will not allow me to separate the two, even after screws were removed or drilled out if they sheared. I've saturated the base with pb baster, but other than a few air bubbles at the joint, no movement.

my mast base is cast aluminum, and has a insert for the deck about the size of a snickers bar. I put a wrench on this part and tried to shake and move the base with no luck. Top mast cap came out fine, lower one has seen more salt water.

Suggestions?

James

[ndutton]

Is the mast off the boat on horses? Mast length?

[Mo]

Any Pictures?

[Hymodyne]

mast is on horses on the ground and 37 feet in length. Pictures tomorrow.

[ndutton]

Buy 10' sticks of the cheapest ½" metal pipe you can find, 4 of them. Insert them into the mast from the top, threading each length to the last until the assembled length reaches the mast step. A few love taps with a hammer should do the trick. Roll the mast between taps to work evenly around the mast step. PVC is too flexible to transfer the striking force over 40 feet effectively.

[Hymodyne]

A friend with a boat at the yard brought an electrician's fishing wire that we used to thread the new coax the length of the mast. First attempt the shepherd's crook at the end of the wire caught the wiring for the mast light and broke it, so now I have to replace that too
one step forward...
James

[Clucas]

Buy 10' sticks of the cheapest ½" metal pipe you can find, 4 of them. Insert them into the mast from the top, threading each length to the last until the assembled length reaches the mast step. A few love taps with a hammer should do the trick. Roll the mast between taps to work evenly around the mast step. PVC is too flexible to transfer the striking force over 40 feet effectively.

Good idea. Since the mast and the base are both aluminum, I don't know whether heat would help (if they were dis-similar metals, then yes). That said, could try a propane torch and applying a candle stub where the base and mast meet -- capillary action might draw in some of the wax and help loosen things up. I wouldn't go crazy with it though. You might try it where the screws were -- I'm guessing corrosion where the stainless screws and aluminum are what's causing the problem.

[JOHN COOKSON]

I vote for heat + impact with a metal pipe down the mast. If you are near the water be careful the base does not land in the water should it pop loose.
I've been around this mulberry bush stripping the end fittings off a boom. Heat from a propane torch and impact did the trick.

TRUE GRIT

[Hymodyne]

we got the wire unstuck and eventually threaded the new coax. pulling the base off wasn't necessary.

James

[ndutton]

How do you re-step the mast with the base stuck on it?

[JOHN COOKSON]

How do you re-step the mast with the base stuck on it?

How did you unstep the mast with the base stuck on it?
Neil: Isn't the base attached to the boat in some way or am I not remembering correctly? Would a keel mounted mast make any difference?

TRUE GRIT

[ndutton]

Neil: Isn't the base attached to the boat in some way or am I not remembering correctly? Would a keel mounted mast make any difference?

Every sailboat I ever built (100's) or was otherwise involved (many 100's more) regardless of size had the mast step affixed to either the deck via stainless lag bolts into a reinforcement/compression post structure in the case of deck stepped masts or via stainless machine screws into a structural steel armature in the bilge in the case of keel stepped masts. The step fit into the mast's heel to check fore and aft and lateral movement.

Following James' thread I could not help but think a stuck mast step is not a normal condition so with the mast on horses this is the ideal time to deal with it. It's reasonable to assume the mast end has been corroded, probably on the inside where it cannot be seen, the reason the step is stuck. There is no greater force on a sailboat than mast compression so if it were me I'd want that area to be as pristine as humanly possible and to that end step removal, careful inspection and possible remediation would be high on my project list. Remediation might be as simple as drilling water drain holes to keep the step area as dry as possible.

Like I said, now is the time. Sorry for preaching James, just expressing my concern.

[JOHN COOKSON]

Isn't there a product that acts as a barrier to electrolysis between metals?
When I had my mast dropped years ago my rigger used something like that. I think it was aluminalstic?
My rigger suggested it so there would not be electrolysis between the mast and the step.

TRUE GRIT

[ndutton]

I prefer NOALOX, an anti-oxidant compound used in the electrical industry for aluminum wire terminations. Even Home Depot carries it.

[Hymodyne]

the mast base fits into a space on the deck. I will continue to try to remove the base and address the corrosion.

Thank you for the replies and concern,

James