Saturday, February 13, 2010


One day I was down below checking the mast area and noticed some water dripping off one of the bolts that held the deck mast collar to the partner area. This is not good. So I figured it was time to re bed the mast collar. Since water was leaking from the deck. The photo below shows the  mast collar as it is installed on the deck.
I was not looking forward to this because the scuttle butt was that this collar was bedded at the factory with 3M 5200 adhesive. This is known as an especially tenacious adhesive. People often say once you use 5200 on something consider it permanently attached to your boat. I had owned BIANKA for over ten years at this point and as far as I knew the mast collar had never been removed. So I was expecting a real battle in getting the metal collar removed from the deck.
I removed all the bolts and took out a mallet, heat gun and chisel expecting to spend a lot of time trying to remove the collar. Much to my surprise the collar just lifted off with a simple hand pull. So it goes! No wonder it had been leaking as the bond between the 5200 and the cast aluminum collar was virtually non existent. I also found the the remaining 5200 was still very pliant after all these years as shown below:
This pulled off rather easily too. There was some of the adhesive that need to be cleaned up however. For this I used a product called Anti-Bond 2015 . It really helps in removing and cleaning up adhesives like 5200. I just sprayed it on the area I where I wanted to remove the adhesive and let it sit for a bit. Then I used a Proprep detail scraper to peel the remaining 5200 from the area.
In a few minutes I had the whole collar area cleaned and ready for a new coat of 5200 for re bedding the mast collar. A quick wipe down with a little solvent on a rag to remove any of the residue remaining. I also did the same for the underside of the metal mast collar.



Now that it is time to re bed I wanted to make sure I would avoid getting any of the 5200 on the bolts as I insert them. I want to be able to remove them easily in the future. NOTE: I do put a dab under the bolt head to seal it where it rests on the mast collar.  I made circles around the bolt holes with 5200. This would allow me to insert the bolts cleanly back into the holes without getting the 5200 on the threads. But would also make sure the bolts were sealed when the collar was put back on the deck. As shown below:
NOTE: You can also see the blue 3M masking tape that I installed around the outside of the collar before I removed it. It helps make it easier to clean up any of the 5200 that squeezes out from under the collar. I also put 5200 on the underside of the mast collar in a continuous heavy bead again avoiding getting it into the bolt holes. I then placed shims on the deck and rested the collar on them so that it was slightly raised off the deck. This allows me to place the bolts in the holes without getting 5200 on the threads as I insert them:
After the bolts were installed and the shims removed the collar was laying on the deck. I applied a little pressure to set the collar. But, because 5200 takes a number of days to fully cure. I waited a week before I tightened the bolts down to secure the collar. The collar was re bedded three years ago and has not leaked since. Hopefully, it will be another twenty years before I have to do it again.

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