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Advice on replacing mast deck plate

Posted: Sat Oct 28, 2017 7:58 pm
by Tedd
I have to replace the mast deck plate on my 1995 Mac 26S. Any advice from anyone who's done it before? At first glance it looks pretty straightforward, but I do have a couple of questions. If I use heat to soften the sealant before removing the old plate, how hot is too hot for the fibreglass? Does anyone know what kind of resin Macgregor used when building these boats? Also, would 3M 5200 be a good choice of sealant when I install the new plate, or is it too strong? I want something that can be removed later, if necessary. (Not that I expect to need it, but one never knows.)

Thanks for any advice,

Tedd

Re: Advice on replacing mast deck plate

Posted: Sun Oct 29, 2017 5:02 am
by NiceAft
I would think that 3M 4200 would be a better choice. The sealant seals, bolts do the holding.

Not ever being on your class of Mac, I don’t have a clue about any of your other concerns. :(

Ray

Re: Advice on replacing mast deck plate

Posted: Sun Oct 29, 2017 6:44 pm
by Maraquita
Just finished replacing one on my 26D. No heat was required, the sealant had dried out so severely that I used a 1 inch thin bladed putty knife and it popped off. I cleaned up the old sealant with Scotch Bride and the same putty knife. That being said, if you do opt to heat it up, any hair dryer style heat gun will not harm the fiberglass (in my experience), but don't try to use a torch of any kind. With that you are almost guaranteed to burn it.

I agree that GM 4200 is a better solution than 5200. 4200 is what I used, 5200 is on there forever!

Re: Advice on replacing mast deck plate

Posted: Mon Oct 30, 2017 6:22 am
by AndyVS
I also used a heat gun and putty knife and it popped right off. I used Compass Marine's Bed-It butyl tape to seal. It seals great and is removable. http://www.pbase.com/mainecruising/buy_bedit_butyl_tape

I replaced my mast step with the 2 part hinged version from Blue Water Yachts. It's gentler on the mast base when raising and lowering. It's a bit larger than the old one and the bolt holes don't line up so the old holes have to be filled. There was a bit of measuring to ensure the mast ended up in the same position before I drilled the new holes. http://shop.bwyachts.com/SearchResults. ... ep&Submit=

I also added a base plate under the step so that when I move halyards to cockpit, there is a place to attach the blocks. I believe I ordered the DH 2890.
https://www.dwyermast.com/items.asp?cat ... zer+Plates

Andy

Re: Advice on replacing mast deck plate

Posted: Mon Oct 30, 2017 6:41 am
by Sumner
AndyVS wrote:....I used Compass Marine's Bed-It butyl tape to seal. It seals great and is removable. http://www.pbase.com/mainecruising/buy_bedit_butyl_tape....Andy
I bed almost everything now on both boats with the Bed-it butyl tape. Good stuff and I'd use it in this situation also,

Sumner

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1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Wyoming, Idaho, Canada, Florida

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Re: Advice on replacing mast deck plate

Posted: Tue Nov 14, 2017 7:11 am
by Tedd
Thanks to everyone for the great replies. I haven't yet made up my mind whether I'll use the 4200 or that butyl tape -- might depend on availability.