I just finished sanding the bottom of my 1978 Hunter 30 and digging out blisters. The yard put a moisture meter to the hull and to my surprise the hull is now quite dry. Consequently it seems smart to barrier coat the hull -- which I hadn't planned on or researched. Any advice? I'm down all the way to gel coat and used filled epoxy to fill the blisters. Thanks!
Epoxy Barrier Coat
- Thread starter Casey F
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Interlux 2000
I used Interlux 2000 as a barrier coat preventive medicine and have no blisters in 18 years. Used 2 continuously applied coats in one day, then lightly sand and applied 2 more continuous coats & lightly sand the next day before applying the bottom paint.
I used Interlux 2000 as a barrier coat preventive medicine and have no blisters in 18 years. Used 2 continuously applied coats in one day, then lightly sand and applied 2 more continuous coats & lightly sand the next day before applying the bottom paint.
Layers
If I remember correctly, the idea behind the barrier coat is to apply multiple layers so that you have a final barrier of a particular thickness. Barrier coating such as Interprotect 2000 have microscopic flat particles that overlap as you apply multiple layers, thus creating a barrier to water and osmosis. I think they recommended about six coats/layers. The best advice is to read the directions or contact Interlux and talk to them directly.
If I remember correctly, the idea behind the barrier coat is to apply multiple layers so that you have a final barrier of a particular thickness. Barrier coating such as Interprotect 2000 have microscopic flat particles that overlap as you apply multiple layers, thus creating a barrier to water and osmosis. I think they recommended about six coats/layers. The best advice is to read the directions or contact Interlux and talk to them directly.
barrier coat
I also have a 78 Hunter 30. Very few blisters and no barrier coat. I have to question the need on our boats, they were laid up thicker and heavier than those of today. I guess it might make you feel good to have it done though. Thats worth something.. What I'm wondering about is the rudder.
I also have a 78 Hunter 30. Very few blisters and no barrier coat. I have to question the need on our boats, they were laid up thicker and heavier than those of today. I guess it might make you feel good to have it done though. Thats worth something.. What I'm wondering about is the rudder.
Tech Rep
I'd second John T's suggestion and, if you want the best advise about 2000E, talk to the Tech Rep first thing this morning. This time of year they have a busy schedule. With 2000E you can keep applying coats without sanding so long as the last coat hasn't dried complete. The instructions on the can will probably mention this. Also, try downloading the more complete instructions from their web site as they'll be far more complete than what's on the can.
I'd second John T's suggestion and, if you want the best advise about 2000E, talk to the Tech Rep first thing this morning. This time of year they have a busy schedule. With 2000E you can keep applying coats without sanding so long as the last coat hasn't dried complete. The instructions on the can will probably mention this. Also, try downloading the more complete instructions from their web site as they'll be far more complete than what's on the can.
What about the rudder?
Hi Steve, I noticed very few blisters, too -- about 50 or so, although some of them might have been dry, so do they count? I'm not sure. Overall the bottom seems to be in great shape, illustrated by the fact that the bottom scoped out so dry. Maybe I don't need the barrier coat after all. Your comment about the rudder intrigued me, though. Why do you ask? I have noticed that there was some bondo on the rudder and a couple of areas that appeared damaged. I assumed the boat had a checkered past, perhaps...
Hi Steve, I noticed very few blisters, too -- about 50 or so, although some of them might have been dry, so do they count? I'm not sure. Overall the bottom seems to be in great shape, illustrated by the fact that the bottom scoped out so dry. Maybe I don't need the barrier coat after all. Your comment about the rudder intrigued me, though. Why do you ask? I have noticed that there was some bondo on the rudder and a couple of areas that appeared damaged. I assumed the boat had a checkered past, perhaps...
Bottom sealing
It is well worthwhile sealing the bottom in epoxy. These older Hunters are known for good bottoms. The osmosis issue is not glass thickness but the presence of partially cured resins. Hunter's early resins appear to have generally been mixed quite well. IF there is no osmosis present now, thank your lucky stars. Since the bottom is stripped, seal it anyway. We all have to sell out boats at some time and you will get either more $$$$ or a quicker sell if the bottom has been done. Buyers love this kind of perceived insurance. The rudder - they are notorious for water intrusion, usually where the post enters at the top. Even if you drill a million holes into the foam and leave it to dry for a winter it will still be wet. Freeze thaw will cause delamination but worse, the stainless web welds may let go and then your rudder spins around the post. The whole rudder needs to be stripped to the bones and rebuilt.
It is well worthwhile sealing the bottom in epoxy. These older Hunters are known for good bottoms. The osmosis issue is not glass thickness but the presence of partially cured resins. Hunter's early resins appear to have generally been mixed quite well. IF there is no osmosis present now, thank your lucky stars. Since the bottom is stripped, seal it anyway. We all have to sell out boats at some time and you will get either more $$$$ or a quicker sell if the bottom has been done. Buyers love this kind of perceived insurance. The rudder - they are notorious for water intrusion, usually where the post enters at the top. Even if you drill a million holes into the foam and leave it to dry for a winter it will still be wet. Freeze thaw will cause delamination but worse, the stainless web welds may let go and then your rudder spins around the post. The whole rudder needs to be stripped to the bones and rebuilt.
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