Cleaning up stainless fasteners in aluminum masthead
I have to remove remove most of the stainless fittings and fasteners currently in my aluminum mastheads.
How do I do this with the least damage to the masthead?
Is it important to remove old bolts that are already sheared off? Should I just cut them off flush on the other end?
What can I do to make it easier on the next poor sucker (probably myself!) who has to work on it years later?
Should I try to re-paint them after I finish other stuff?
I have two composite masts, but the masthead is a thick aluminum plate. (I believe it has a pipe welded to it and then glassed inside the mast) The masts are approaching 30 years old, and there are a BUNCH of stainless fasteners in it. Some are tapped. Some are through-bolted. Some were sheared off by a prior owner. Some were sheared off, but left dangling on the bottom. There are a few extra holes. It was once painted, but much of that has come off as well. Here are a few pictures.
A view of both masts from the top; Mizzen on left, Main on right
The bottom view of the Main mast top
The bottom view of the Mizzen mast top
Well you sure cant use HEAT and things like PB BLASTER are marginal once the SS and Alu have tried to become one piece
This leaves drilling for the stuff that breaks BUT i cant see why the locknuts would not come off ?
I expect the nuts will come off without any grief, but I'm not sure the bolts will come out next--I've created more of those "leftover" parts myself on other mastheads.
This time, I have the luxury of time to do my research to figure out the right way--Other jobs are keeping us busy until we get started on this.
This is a good reason why you should be using TefGel or Lanocote when fitting fasteners. It helps prevent this from happening. :)
Heat isn't the greatest idea, since the aluminum may be tempered and will lose much of its strength if heated by a torch. PBlaster is a good option, but generally takes a lot of time and is not always successful one badly corroded aluminum.
Put a piece of pipe over the ends of the wrenches, and bust those suckers off. Then you might be able to punch them out, or at least get some PB directly on the problem......i2f
Looking at the top pictures i see 1/4-20 flat head screws and looking at the bottom i see 1/4-20 lock nuts or 5/16 what size is the wrench (7/16 or 1/2)that fits the nuts
The fact that ARE nuts leads me to believe that your stuff is through bolted and the screws should be pretty easy to get out
It is a carbon mast SO i would go REAL easy on the hammer :)
And now the hard part....
OK, I did the easy bit--I sprayed everything with PB Blaster (a couple times) and I got all the nuts off except for two that had resin all around them.
I believe I succeeded in removing bolts that only had two or three years to corrode in there. The "hard cases" are left--mostly factory installed bolts from 1981. They include a few sheared off bolts (#10 and #8), a bunch of #10 flathead bolts, a couple of 1/4-20 bolts, and the bolts for the ground lugs.
I can think of a few options to get them out:
Which ones on my list would you try?
Here are views of the current state, top and bottom. Ignore the odd strings--I also removed cables and left stuff for pulling new ones in.
If you're going to use a screwdriver, at least use a screwdriver in an impact wrench or impact driver... it is far more likely to work and far less likely to strip the head.
Which ones on my list would you try?
On #1: You are right about heat. Freezing the aluminum will shrink it, and might free it up. I don't see any downside.
On #2: Since you are not going to reuse the screws, knock yourself out.
On #3: You are right, go ahead.
On #4: I don't hold much hope, but again, nothing to lose.
On #5: NO NO NO. You can fracture the carbon mast. You can't take back that last tap with the hammer.
On #6: As you note, probably a waste of time, but nothing to lose.
On #7: I would start here. If you need a hole in this location, get GOOD drill bits, the size of the hole, use a center punch backed up by an anvil or something equally as dense so that it doesn't transmit shock to the mast, and drill away. It will be the least like to do damage, both to the mast and to yourself.
HOWEVER, note that I am only looking at pictures, it's not my boat, and the guy on scene can get a better idea of how hard the bolts and screws are siezed in the holes. You don't seem to be cursed with impatience, and that's a good thing. Good luck.
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