spreaders question(s)

[alanhsails]

OK, the spreader tips on my boat have corroded such that I can't loosen the two allen screws that hold the tip pieces together. Has anybody else run into this and fixed it?

I thought my spreaders were carbon fiber, which seemed odd to me but ...?? However, now that I've taken a close look at them, I'm pretty convinced they're aluminum with this nifty overlay that makes them "look like" carbon. I was initially leery about using heat to try to loosen the spreader tip allen screws, but if the spreader is aluminum, maybe it's not really an issue? Thoughts?

I suspect these things have never been loosened since the day the mast was assembled, the rigging is REALLY old (I'm replacing it). I'm considering just letting the spreader tips stay locked together and just over-drilling the hole to fit pushing the swaged, threaded fitting through it. The spreaders are securely bolted to the supporting assembly and the "swept-back angle" and "up-angle" are solid as a rock so I have no concern about the spreaders "drooping". However, I thought I'd consult the wisdom of you lads and lasses before doing that.

[Pete]

The spreaders and tips are aluminum. If you're planning on replacing the shrouds I would cut and remove the shroud wire, remove the spreaders and soak the ends in diesel fuel for a few days and then try some heat. An impact driver might help break the Allen screws loose. If you can get it apart be sure to apply some 'Nevr Seize' to the thread on reassembly. Dissimilar metals in contact will always corrode, especially so in salt water. Good luck.

[alanhsails]

I gave up and the yard gave up trying to get those things loose, and they I just overdrilled the holes. They'll wrap it in seizing wire.

The yard guys confirmed that a prior owner wrapped the aluminum spreaders in carbon fiber. DO NOT DO THIS. Carbon fiber and aluminum do NOT get along and you'll get corrosion problems....which in fact one spreader already has. The yard manager thinks it's salvageable but I need to budget for new spreaders next season.

DO NOT WRAP ALUMINUM IN CARBON FIBER.

[Southern Gales]

Commenting for future reference...
The binding is caused by aluminum threaded hole and a stainless cap screw, dis-similar metal oxidation .
I was able to free two (2/ spreader) of the four screws with PB blaster, a burnzamatic and some cautionary force. I put the spreader vertical in a soft jaw vise to let gravity help out. I lucked out because the two screws that broke off did so right at the neck. I think this is a common breaking point. This allowed the end cap of the spreader to come off exposing the rest of the screw just enough to get a good hold with needle nose vise grips. I sprayed PB and let it sit for for 10 minutes then wiggled the screw CCW, CW, then apply heat, cool, more PB. I kept repeating until the screw loosened. This took about four tries over a day. Once the broken screw was out, I cleaned the threads with a tap, blew the hole out with air then threaded a screw coated with AD Diaper Ointment down the hole. This stuff is the poor man's Lanacaid because it contains lanolin which is used to help with the dis-similar metal issue.
Come to think of it, I just bought some Tuff-Gel to use during the re-assembly of the rudder cheek plates. That stuff will also work.