I need advise as to the best sealant for installing new ports and windows. The various marine supply stores are giving me conflicting advise. One store recommended 5200 polyurethane. After what I went through to get the old ports out, I never want to see that stuff again. Another prominent store surggested 101 polysulfide. Hunter Corp. mentioned Dow Corning 795 and the window supplier surggested G E silicone. Please give me the reason you would chose one appose to another.
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Suggest Dow 795
Denise: I would suggest that you use the Dow 795. This stuff lasted for the past 15 years. 5200 is a SOB to remove in the case that you do need to rebed the port at any time. Not sure about the other options. The question is where are you going to get the Dow 795? Do not know if it is readily available. Hunter may be able to supply it.
Denise: I would suggest that you use the Dow 795. This stuff lasted for the past 15 years. 5200 is a SOB to remove in the case that you do need to rebed the port at any time. Not sure about the other options. The question is where are you going to get the Dow 795? Do not know if it is readily available. Hunter may be able to supply it.
Do you ever want to take them out again?
I am planning on installing new stainless steel ports on my Hunter 34 this weekend and I plan to use 3M 4200 (I may be a few hundred off of the exact number but I know it is in the 4000 category). It is designed to be a ‘semi-permanent’ sealant. In reality you will probably die before this stuff lets go. The 5200 is a permanent sealant – the boys at 3M are VERY serious about the word permanent. The only thing worse is MarineTex!!! (sp?) One piece of advice – buy a lot of the 3M sealant remover and a lot of paper towels. This stuff works great with 3M products. Get the sealant off of the deck before it dries or you will have a BIG job ahead of you. My new ports are slightly slanted down to provide the all elusive drainage that the standard Hunter ports lack. This means I have to cut the fiberglass – ouch. I hope the trim ring hides the overlap.
I am planning on installing new stainless steel ports on my Hunter 34 this weekend and I plan to use 3M 4200 (I may be a few hundred off of the exact number but I know it is in the 4000 category). It is designed to be a ‘semi-permanent’ sealant. In reality you will probably die before this stuff lets go. The 5200 is a permanent sealant – the boys at 3M are VERY serious about the word permanent. The only thing worse is MarineTex!!! (sp?) One piece of advice – buy a lot of the 3M sealant remover and a lot of paper towels. This stuff works great with 3M products. Get the sealant off of the deck before it dries or you will have a BIG job ahead of you. My new ports are slightly slanted down to provide the all elusive drainage that the standard Hunter ports lack. This means I have to cut the fiberglass – ouch. I hope the trim ring hides the overlap.
New Ports
Steve is right about not using 5200 above the waterline. The 3M 4200 will work well. The 5200 release agent really does help. I used it this past weekend to help in removing my shaft strut. The strut was on so tight even after removing the two bolts that it would not budge. Spraying the release agent on a little at a time and removing the loosened 5200 made the job go quickly.
Steve is right about not using 5200 above the waterline. The 3M 4200 will work well. The 5200 release agent really does help. I used it this past weekend to help in removing my shaft strut. The strut was on so tight even after removing the two bolts that it would not budge. Spraying the release agent on a little at a time and removing the loosened 5200 made the job go quickly.
Dow Sealant Source
Dow sealant is available from Hunter Marine. Your trivia for today is that Bayliner also uses Dow sealant, at least as of a few years ago. Black is more UV resistant than white so if you have a choice I'd spring for black.
Dow sealant is available from Hunter Marine. Your trivia for today is that Bayliner also uses Dow sealant, at least as of a few years ago. Black is more UV resistant than white so if you have a choice I'd spring for black.
795 sources
Most commercial construction suppliers (NOT Home Depot) carry 795. It is used to seal fixed windows in commercial buildings, and is a silicone product but "stickier". You may be able to buy a tube from a commercial glass contractor. If you go to a supplier, they may not be set up for retail sales. Contact your local Hunter dealer (Sailors Wharf?) and they should stock it. Also, if you check inside a 90's era Hunter, I think they use it at the bulkhead/overhead junctions
Most commercial construction suppliers (NOT Home Depot) carry 795. It is used to seal fixed windows in commercial buildings, and is a silicone product but "stickier". You may be able to buy a tube from a commercial glass contractor. If you go to a supplier, they may not be set up for retail sales. Contact your local Hunter dealer (Sailors Wharf?) and they should stock it. Also, if you check inside a 90's era Hunter, I think they use it at the bulkhead/overhead junctions
Please don't use 4200 or 5200
The port sealants need to flex, and if you fix the ports to the hull, the joint will fail, or the port will fail, and leaks will re appear. I bought a good GE silicone sealant from Mark at Mark Plastics, he is at 1-909-7705 (Corona CA).
The port sealants need to flex, and if you fix the ports to the hull, the joint will fail, or the port will fail, and leaks will re appear. I bought a good GE silicone sealant from Mark at Mark Plastics, he is at 1-909-7705 (Corona CA).
What did he sell you!
John: What did Mark sell you? It really amazes me how many sailors are enamored with 4200/5200 and why? Suppose they have not used the other products on the market.
John: What did Mark sell you? It really amazes me how many sailors are enamored with 4200/5200 and why? Suppose they have not used the other products on the market.
McMaster Carr Supply Co.
McMaster Carr Supply Company (732) 329 3200 These guys have everything. I called them and they can get the Dow Corning 795. I am doing the window thing this year too.......
McMaster Carr Supply Company (732) 329 3200 These guys have everything. I called them and they can get the Dow Corning 795. I am doing the window thing this year too.......
Dow #739
I spoke with Hunter 1 week ago looking for seal kits for my 83 Hunter windows. They don't have the seal kits but instead suggested I use Dow #739--not #795. Not sure what the difference is, if any. When I get ready to buy I will call Dow Customer service to find out the best product. They should also be able to tell me where to buy it as a retail customer. If you find out what the best product is please send me an email at wlkirch1@msn.com.
I spoke with Hunter 1 week ago looking for seal kits for my 83 Hunter windows. They don't have the seal kits but instead suggested I use Dow #739--not #795. Not sure what the difference is, if any. When I get ready to buy I will call Dow Customer service to find out the best product. They should also be able to tell me where to buy it as a retail customer. If you find out what the best product is please send me an email at wlkirch1@msn.com.
Check out the Dow Corning Site too.
Dow Corning has a good site about their products. www.dowcorning.com You can look up the products and find dealers too. You can search on the different products and get detailed product information.
Dow Corning has a good site about their products. www.dowcorning.com You can look up the products and find dealers too. You can search on the different products and get detailed product information.
LifeCaulk?
What about using Lifecaulk Polysulfide, is this essentially the same as the Dow product?
What about using Lifecaulk Polysulfide, is this essentially the same as the Dow product?
Word of caution, Ted
(I posted this last week on a similar thread) The sealant generally referred to as "Life Caulk" or "Boat Life" is a polysulfide. Polysulfide sealants will attack some plastics which include the portlights made by Gray. They attack the plastic very slowly and soften it which adversely affects its engineering properties. The 3M products (5200 and 4200) are polyurethanes. They (as well as the silicones)generally do not attack plastics but subsequent disassembly can be very difficult. Silicones make ok sealants in a lot of circumstances but they are generally not very good adhesives. That's where the 3M's really shine. btw: Polysulfides were first developed by Morton Thiokol. They are the folks that built the space shuttle booster rocket o-ring seals that failed on the disastrous Challenger flight.
(I posted this last week on a similar thread) The sealant generally referred to as "Life Caulk" or "Boat Life" is a polysulfide. Polysulfide sealants will attack some plastics which include the portlights made by Gray. They attack the plastic very slowly and soften it which adversely affects its engineering properties. The 3M products (5200 and 4200) are polyurethanes. They (as well as the silicones)generally do not attack plastics but subsequent disassembly can be very difficult. Silicones make ok sealants in a lot of circumstances but they are generally not very good adhesives. That's where the 3M's really shine. btw: Polysulfides were first developed by Morton Thiokol. They are the folks that built the space shuttle booster rocket o-ring seals that failed on the disastrous Challenger flight.
O-Rings
Remember, it was very cold that day. There was ice in my front yard as I watched the shuttle blow up from my front window on that January morning. I don't think the material of the o-rings was designed for cold temperatures. Don't forget, they also made o-rings that worked just fine on scores of other flights. Oh, by the way, McMaster-Carr has a GREAT web site for on-line ordering! http://www.mcmaster.com/
Remember, it was very cold that day. There was ice in my front yard as I watched the shuttle blow up from my front window on that January morning. I don't think the material of the o-rings was designed for cold temperatures. Don't forget, they also made o-rings that worked just fine on scores of other flights. Oh, by the way, McMaster-Carr has a GREAT web site for on-line ordering! http://www.mcmaster.com/
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