Restoration Tips 10-15-14: 3M 5200 is not a general adhesive/sealant.
Welcome to the first ever “Restoration Tip of the Week.” I decided it would be nice to share a little nugget of knowledge about Ensign restoration every week to help us all get through the long winter and think happy thoughts about our boats. Some of these tips may be things you already knew, or maybe don’t even agree with, but the intent here is to share how we tackle projects at Ensign Spars and hopefully give some help to the do it yourselfer.
I went out to the shop and asked the guys what our first tip should be and as my lead carpenter, Mark, crawled out of the back of an Electra we are working on, he said “5200 is not the answer to everything!” I laughed as he threw the motor mount backing plate on the floor, and then I thought about all of the times we struggle with parts that were sealed down with 3M 5200 that should not have been.
So here is the first ever “Restoration Tip of the Week (RTW)”; 3M 5200 is not a general adhesive or sealant. 5200 is a structural adhesive/sealant that has minimal applications on an Ensign. Around the shop, we only use it in two places; 1. The hull/deck joint when sealing a new deck on a new or old boat 2. When installing the stem head fitting.
Generally speaking, the question I ask myself before any sealing project is “will someone want to take this apart and check on it in the near future?” The next questions is “is the sealant also going to work as an adhesive, and if so, how much work is it doing?” When looking at the hull and deck joint for an Ensign, I don’t anticipate anyone taking it apart for the next 50 years or so and the 5200 is serving as part of the bond that holds the hull and deck together. For the stem head, again, I don’t anticipate anyone taking that fitting off until they would want to take the deck off, and I feel it doesn’t hurt to add some additional holding power to a critical stay attachment.
On the other hand, hardware, coaming boards, windows, chain plate covers, and even mooring cleats, are parts that can break, wear out, or become outdated. I strongly encourage you to use 3M 4200 or a similar product to seal these items. We did a restoration on a boat this winter and had to leave the coaming boards on because we were physically unable to remove them from the boat due to 3M 5200.
From the perspective of using 5200 as an adhesive, we are generally using West System epoxy as our critical adhesive. 5200 does have some flexibility, and thus has some advantages over epoxy, but in the case of critical parts like backing plates and specialty attachment points, we use epoxy with some kind of thickener.
I hope this first RTW was helpful to everyone!