gbroughman
Member
- Joined
- Feb 9, 2015
- Messages
- 10
- Location
- USA
- Vessel Name
- MY Big Woody
- Vessel Make
- Grand Banks Alaskan
I am at the final stages of a major restoration project on a 1973 49' Grand
Banks Alaskan and have to make a decision on caulking the bottom. The boat is in a yard in Saint Pete Florida and I cannot find anyone who does conventional cotton caulking and have been looking into alternatives.
A couple of notes. The boat has been out of the water for over a year and after the initial wood shrinkage all of the seams opened up and allowed me to reef all materials out of them. The prior owner used 5200 as seam material and as one expects it pulled the wood off the sides of the seams in some places. Having spent days using a razor blade, I was able to clean them up somewhat. I developed a hatred for the stuff. There were three plank replacements I inherited, that used only 5200 (no cotton) and they will have to be cut out with a blade to replace them.
My initial distaste for 5200 has come full circle though. The replaced planks look like they are good for life and I started looking at that as an alternative to cotton caulking.
So without starting a word war of traditional methods I would like to know if anyone has tried using a modern sealant/adhesive as the only caulking? I would like to propose something different. This is what I am thinking.
1. Use a dado blade and/or a router to cut a consistent width seam, taking out the bevel.
2. Inserting a really thin strip of softwood at the stringers to minimize caulk intrusion into the boat.
3. After priming, fill the entire seam with a 5200 like product.
4. Water the hull inside and out to get to the proper moisture content.
5. Trim off excess proud material to get a flat paintable surface for bottom pain.
The pros of this method are
1. It is a permanent waterproof hull with wood continuing to be in contact with the water.
2. Plank separation due to fastener failures would not be a critical issue as each plank is "glued" to the one above and below.
3. In worm infested waters the likeliest infestations take place in the seam where conventional caulking fails.
4. Does not rely on a "soon to be lost" skill set of cotton caulking. Can be a DYI project.
The cons would be
1. The seams are somewhat permanent. In the case of a plank failure you would have to cut it out with a circular saw and plunge cutter in order to replace it.
2. Timing of installation with wood swelling and curing time could cause a squeeze that might break fasteners.
3. The time that the boat is out of the water and the drying shrinking process would have to be watched to avoid letting the seams open up enough for the bond to break.
I have been looking on the forums and the internet but have not found anyone doing this. Am I missing a big issue? Positive feedback would be appreciated.
Gerry
Banks Alaskan and have to make a decision on caulking the bottom. The boat is in a yard in Saint Pete Florida and I cannot find anyone who does conventional cotton caulking and have been looking into alternatives.
A couple of notes. The boat has been out of the water for over a year and after the initial wood shrinkage all of the seams opened up and allowed me to reef all materials out of them. The prior owner used 5200 as seam material and as one expects it pulled the wood off the sides of the seams in some places. Having spent days using a razor blade, I was able to clean them up somewhat. I developed a hatred for the stuff. There were three plank replacements I inherited, that used only 5200 (no cotton) and they will have to be cut out with a blade to replace them.
My initial distaste for 5200 has come full circle though. The replaced planks look like they are good for life and I started looking at that as an alternative to cotton caulking.
So without starting a word war of traditional methods I would like to know if anyone has tried using a modern sealant/adhesive as the only caulking? I would like to propose something different. This is what I am thinking.
1. Use a dado blade and/or a router to cut a consistent width seam, taking out the bevel.
2. Inserting a really thin strip of softwood at the stringers to minimize caulk intrusion into the boat.
3. After priming, fill the entire seam with a 5200 like product.
4. Water the hull inside and out to get to the proper moisture content.
5. Trim off excess proud material to get a flat paintable surface for bottom pain.
The pros of this method are
1. It is a permanent waterproof hull with wood continuing to be in contact with the water.
2. Plank separation due to fastener failures would not be a critical issue as each plank is "glued" to the one above and below.
3. In worm infested waters the likeliest infestations take place in the seam where conventional caulking fails.
4. Does not rely on a "soon to be lost" skill set of cotton caulking. Can be a DYI project.
The cons would be
1. The seams are somewhat permanent. In the case of a plank failure you would have to cut it out with a circular saw and plunge cutter in order to replace it.
2. Timing of installation with wood swelling and curing time could cause a squeeze that might break fasteners.
3. The time that the boat is out of the water and the drying shrinking process would have to be watched to avoid letting the seams open up enough for the bond to break.
I have been looking on the forums and the internet but have not found anyone doing this. Am I missing a big issue? Positive feedback would be appreciated.
Gerry