All of the side windows on my Hunter 30 have developed cracks. What is the correct sealant to use, and is there a good way to go about installing the new windows?? John
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Talk to the Mfg
I'll warn you now, this is long... Bomar/Gray, which makes basically the exact replacement recommends 3M 5200 ONLY (I think that's still the case) for their windows. After installing 4 I have done almost everything wrong, and so can speak with some authority on how to do it right. DON'T USE SILICONE - trust me on this one. Selecting the windows - if you can find ones which match the *angle* of your cabin walls, water will drain better - mine are a little shallow, and I get a little water in after a rainstorm when I open the window because the gutters don't fully drain. I can't recall if this is an option though. 1) Bomar/Gray (sailnet.com carries, btw) assumes you are mounting into a solid, cored sidewall. If your 30 is like mine, it's just the outer skin and the inner skin, no core. Hunter used aluminum T-nuts and stainless screws (good combo there eh?) so you'll find most of them rotted/frozen. But on the new windows you will find mounting holes on the inside portlight/trimplate, none on the outer - fairly useless...so I would fill in the old screwholes with epoxy/glass (I didn't and regret it). I think it would also be prudent to glass the 2 skins together (outer deck and liner) - that way water can't creep between the gap and leaks will be easier to trace. Before doing this, dry-fit the windows and make sure the fit is good - I had to deepen the gutter/runoff notches. The only problem with ditching the screw-holes is you lose any ability to clamp the window in place using the screws, and 5200 takes FOREVER to cure. More on this later. I think a good theory is that the goop on the outside of the window is really your seal and you don't worry about glue on the inner side - that way you won't trap water or disguise the location of the leak. You basically are using glue to seal the entire gap, and the trim-ring is just cosmetic so bear that in mind. Now place the new window in, and dry-fit (use a buddy) Tape (3m blue stuff) around the outside trim-ring (wide tape). Leave perhaps 1/8" gap between the tape and trimplate. Then also run tape around the inner window overhang. This allows you to use a generous amount of 5200 and still get a clean line when you pull the tape. Let the 5200 skin over pretty well before pulling the tape. You might have to cut it, but better than drips. I would also tape the outer face of the trim-plate (I find 5200 in my belly-button, ears, etc weeks later, so pays to be cautious). Remove the trimplate, goop 5200 generously (but not too much - you just want a little squeeze-out on both sides of the trim-plate. Place the window, place the trimplate, clamp as below...the portlight and trim-ring should 'float' in the goo - so don't clamp too tight. Ideas for clamping the inner portlight: 1) Use the damn screwholes - then you have to fill them with something - stainless will cause rust-streaks, and bronze will cause green streaks - your choice. If you do this, maybe also cut some masonite/starboard to slide between the 2 hulls to provide a more-better grip for the screws. This is because there is a gap between the walls which the screws are going to try to close, potentially warping the sidewalls. 2) There is a sticky tar-like substance that auto-windshield installers use. Comes in a rope, and should provide a good bond to the inner hull liner. Might not be compatible with the plastic though. 3) Build a jig which goes on the outer hull and provides enough room for you to work around. Basically a sheet of plywood with 4 legs, then a threaded rod leading to a smaller piece of plywood inside the window. Tighten nuts on the threaded rod to clamp the window in place, then apply a liberal amount of 5200 to the gap, place the trim-ring and go home for the night. 4) A really good and patient friend. You will need to rig, and prepare to empty, a foley/texas catheter, as well as provide a beer-bong. 5) Turn the boat upside down and use sand-bags. 6) Those adjustable shower-rods maybe... But now you have counter-sunk screw-holes on the inner window and nothing in them...Oh crap use the screws...it's only 12 more opportunities for each portlight to leak. Some might argue this makes the window stonger anyway (stronger than 5200? Hahahahahahahaha I laugh in their face) Oh, and the new plastic yellows much worse than the old stuff - so maybe count on painting the damn things after a year - probably with paint which is incompatible with the plastic... I wonder if those ones from newfoundmetals are any better... Anyone else? In any case...have fun. -Keith
I'll warn you now, this is long... Bomar/Gray, which makes basically the exact replacement recommends 3M 5200 ONLY (I think that's still the case) for their windows. After installing 4 I have done almost everything wrong, and so can speak with some authority on how to do it right. DON'T USE SILICONE - trust me on this one. Selecting the windows - if you can find ones which match the *angle* of your cabin walls, water will drain better - mine are a little shallow, and I get a little water in after a rainstorm when I open the window because the gutters don't fully drain. I can't recall if this is an option though. 1) Bomar/Gray (sailnet.com carries, btw) assumes you are mounting into a solid, cored sidewall. If your 30 is like mine, it's just the outer skin and the inner skin, no core. Hunter used aluminum T-nuts and stainless screws (good combo there eh?) so you'll find most of them rotted/frozen. But on the new windows you will find mounting holes on the inside portlight/trimplate, none on the outer - fairly useless...so I would fill in the old screwholes with epoxy/glass (I didn't and regret it). I think it would also be prudent to glass the 2 skins together (outer deck and liner) - that way water can't creep between the gap and leaks will be easier to trace. Before doing this, dry-fit the windows and make sure the fit is good - I had to deepen the gutter/runoff notches. The only problem with ditching the screw-holes is you lose any ability to clamp the window in place using the screws, and 5200 takes FOREVER to cure. More on this later. I think a good theory is that the goop on the outside of the window is really your seal and you don't worry about glue on the inner side - that way you won't trap water or disguise the location of the leak. You basically are using glue to seal the entire gap, and the trim-ring is just cosmetic so bear that in mind. Now place the new window in, and dry-fit (use a buddy) Tape (3m blue stuff) around the outside trim-ring (wide tape). Leave perhaps 1/8" gap between the tape and trimplate. Then also run tape around the inner window overhang. This allows you to use a generous amount of 5200 and still get a clean line when you pull the tape. Let the 5200 skin over pretty well before pulling the tape. You might have to cut it, but better than drips. I would also tape the outer face of the trim-plate (I find 5200 in my belly-button, ears, etc weeks later, so pays to be cautious). Remove the trimplate, goop 5200 generously (but not too much - you just want a little squeeze-out on both sides of the trim-plate. Place the window, place the trimplate, clamp as below...the portlight and trim-ring should 'float' in the goo - so don't clamp too tight. Ideas for clamping the inner portlight: 1) Use the damn screwholes - then you have to fill them with something - stainless will cause rust-streaks, and bronze will cause green streaks - your choice. If you do this, maybe also cut some masonite/starboard to slide between the 2 hulls to provide a more-better grip for the screws. This is because there is a gap between the walls which the screws are going to try to close, potentially warping the sidewalls. 2) There is a sticky tar-like substance that auto-windshield installers use. Comes in a rope, and should provide a good bond to the inner hull liner. Might not be compatible with the plastic though. 3) Build a jig which goes on the outer hull and provides enough room for you to work around. Basically a sheet of plywood with 4 legs, then a threaded rod leading to a smaller piece of plywood inside the window. Tighten nuts on the threaded rod to clamp the window in place, then apply a liberal amount of 5200 to the gap, place the trim-ring and go home for the night. 4) A really good and patient friend. You will need to rig, and prepare to empty, a foley/texas catheter, as well as provide a beer-bong. 5) Turn the boat upside down and use sand-bags. 6) Those adjustable shower-rods maybe... But now you have counter-sunk screw-holes on the inner window and nothing in them...Oh crap use the screws...it's only 12 more opportunities for each portlight to leak. Some might argue this makes the window stonger anyway (stronger than 5200? Hahahahahahahaha I laugh in their face) Oh, and the new plastic yellows much worse than the old stuff - so maybe count on painting the damn things after a year - probably with paint which is incompatible with the plastic... I wonder if those ones from newfoundmetals are any better... Anyone else? In any case...have fun. -Keith
Contact Hunter
I believe you are talking about the non-opening plexigas sidewindows. I replaced mine and the windshield last year because of extensive crazing that led to cracks. Call Hunter and they will supply you with precut replacements and the recommended sealant. I believe it is Dow Chemical 265, which is the same stuff used to hold highrise windows from getting sucked out by wind pressure. It has adhesive qualities and will remain flexible for many years. 3M 5200 is not recommended in this case because it is a structural adhesive and it will be extremely difficult if not impossible to replace the windows again. Mike Thomas at Hunter is very helpful. Good luck. It's an easy project.
I believe you are talking about the non-opening plexigas sidewindows. I replaced mine and the windshield last year because of extensive crazing that led to cracks. Call Hunter and they will supply you with precut replacements and the recommended sealant. I believe it is Dow Chemical 265, which is the same stuff used to hold highrise windows from getting sucked out by wind pressure. It has adhesive qualities and will remain flexible for many years. 3M 5200 is not recommended in this case because it is a structural adhesive and it will be extremely difficult if not impossible to replace the windows again. Mike Thomas at Hunter is very helpful. Good luck. It's an easy project.
Dow Corning 795
DC-795 is what I used for my non-opening ports. It was a little hard to find so you might have to do some research. In seattle it was Something- Sash and Steel. It was undoubtedly worth the effort. Hunter product might be different now. See archives for more.
DC-795 is what I used for my non-opening ports. It was a little hard to find so you might have to do some research. In seattle it was Something- Sash and Steel. It was undoubtedly worth the effort. Hunter product might be different now. See archives for more.
THE correct sealant is
I disagree with both Patrick and Monty. The correct sealant to use on plactic and Lexan is Dow Corning 739 - not DC795 as mentioned. When I was at the Hunter plant in Sept of last year the sealant in use on the production floor was DC739. While in the past Hunter may have used DC795 but it has long since been phased out. If asked, the Hunter support sales staff may have been trying to sell you some DC795 as it may have been left over - but the latest and correct sealant is the DC739. Whats the difference - ?? DC795 is a construction sealant used in sealing windows etc in buildings. DC739 is an aircraft sealant used to seal windshields etc in aircraft - more akin to our needs. All this said - I would like to add - in no uncertain terms - that one should not even think or attempt a seal job with out the use of the DC OS2 cleaning agent. It comes in a pressureized can and should be used to clean up the old stuff and acts as bonding set to the sealant as it flows on to the gel coat, plastic or AwGrip paint and adheres to the Lexan or plastic window blank. This use of DC OS2 cleaner is a must. I have tried to use DC795 on my HL35 skylites and it did not seal propperly. I tried DC739 and it did the same thing - after one year the sealant started to develop gaps and the water leaked in. My last sealing party was with OS2 and it (the sealant in the gap) has adhered in an excellent manner to the deck and Lexan walls with out any gaps or separation being developed. In short don't even think about a seal job with DC739 unless you clean and prepare both surfaces with OS2 - a special bonding agent from Dow Corning. I find that, locally I have to order the DC products as they do not seem to be on the shelves. Guess it depends on the size of the city And in closing - do not use 3M 5200 as this is an adhesive and not a sealant. Ever try and remove 5200 -
< DC739 is soft, flexable and removable in case you have to re seal in four years or so Seal on < RD
I disagree with both Patrick and Monty. The correct sealant to use on plactic and Lexan is Dow Corning 739 - not DC795 as mentioned. When I was at the Hunter plant in Sept of last year the sealant in use on the production floor was DC739. While in the past Hunter may have used DC795 but it has long since been phased out. If asked, the Hunter support sales staff may have been trying to sell you some DC795 as it may have been left over - but the latest and correct sealant is the DC739. Whats the difference - ?? DC795 is a construction sealant used in sealing windows etc in buildings. DC739 is an aircraft sealant used to seal windshields etc in aircraft - more akin to our needs. All this said - I would like to add - in no uncertain terms - that one should not even think or attempt a seal job with out the use of the DC OS2 cleaning agent. It comes in a pressureized can and should be used to clean up the old stuff and acts as bonding set to the sealant as it flows on to the gel coat, plastic or AwGrip paint and adheres to the Lexan or plastic window blank. This use of DC OS2 cleaner is a must. I have tried to use DC795 on my HL35 skylites and it did not seal propperly. I tried DC739 and it did the same thing - after one year the sealant started to develop gaps and the water leaked in. My last sealing party was with OS2 and it (the sealant in the gap) has adhered in an excellent manner to the deck and Lexan walls with out any gaps or separation being developed. In short don't even think about a seal job with DC739 unless you clean and prepare both surfaces with OS2 - a special bonding agent from Dow Corning. I find that, locally I have to order the DC products as they do not seem to be on the shelves. Guess it depends on the size of the city And in closing - do not use 3M 5200 as this is an adhesive and not a sealant. Ever try and remove 5200 -
< DC739 is soft, flexable and removable in case you have to re seal in four years or so Seal on < RDWhat do you disagree with Capt Bob?
I said that the Hunter product might be different now. I have the impression that 795 is more of an adhesive than the 739 product. I do not know for sure. My 37.5 ports do not have any screws and are held in place by the 795 only. If the newer models have some attachment screws that may be the difference. Again, I don't know for certain. Ask Hunter if you want to know for sure. The company in seattle was Colorado Sash and Steel as I recall now. They had lots of it in stock and it was quite reasonable in price - comparable to caulk.
I said that the Hunter product might be different now. I have the impression that 795 is more of an adhesive than the 739 product. I do not know for sure. My 37.5 ports do not have any screws and are held in place by the 795 only. If the newer models have some attachment screws that may be the difference. Again, I don't know for certain. Ask Hunter if you want to know for sure. The company in seattle was Colorado Sash and Steel as I recall now. They had lots of it in stock and it was quite reasonable in price - comparable to caulk.
Thanks Capt Bob,
You've answered my question about my skylights on my L35.5. I removed and resealed them last year with 739 and they started leaking almost immediatly. I thought I was being very careful and doing a good job, but alas they leaked anyway. What is DC OS2? Is it a liquid that you apply before the sealant? Where do you get this stuff? I ordered the video from Hunter on replacing the skylights and there was no mention of any cleaner/activator.
You've answered my question about my skylights on my L35.5. I removed and resealed them last year with 739 and they started leaking almost immediatly. I thought I was being very careful and doing a good job, but alas they leaked anyway. What is DC OS2? Is it a liquid that you apply before the sealant? Where do you get this stuff? I ordered the video from Hunter on replacing the skylights and there was no mention of any cleaner/activator.
Guess I was lucky
Mine don't leak and it really rains here. There's a video? Hunter didn't mention it. I can't disagree with Captn Bob because aircraft specs are tough to beat. I installed the windows exactly a year ago and Hunter said to use 795. Proper surface preparation is key to the success of this project. ALL of the old sealant must be removed and the surface must be residue free of any oil, detergent etc. New caulking/sealant will not bond properly to old. Read the instructions carefully. Any recommended bonding agents should be considered. I did not use a bonding agent. You have to work fast and get the plexiglas in place before the sealant forms a skin. Don't do it on a hot, sunny or windy day. The plexiglas side windows on our boat have an 1 to 1 1/2 inch chamfer on the top. Without the chamfer the plexiglas would only have a 1/4" contact with the fiberglas frame. Something to consider if you decide to have a local plastic supplier cut your replacements because I doubt that few could duplicate the ones that Hunter sent without special tools. I noticed that the new Hunters have a new window system with a metal frame. I hope this is an improvement especially for future replacement.
Mine don't leak and it really rains here. There's a video? Hunter didn't mention it. I can't disagree with Captn Bob because aircraft specs are tough to beat. I installed the windows exactly a year ago and Hunter said to use 795. Proper surface preparation is key to the success of this project. ALL of the old sealant must be removed and the surface must be residue free of any oil, detergent etc. New caulking/sealant will not bond properly to old. Read the instructions carefully. Any recommended bonding agents should be considered. I did not use a bonding agent. You have to work fast and get the plexiglas in place before the sealant forms a skin. Don't do it on a hot, sunny or windy day. The plexiglas side windows on our boat have an 1 to 1 1/2 inch chamfer on the top. Without the chamfer the plexiglas would only have a 1/4" contact with the fiberglas frame. Something to consider if you decide to have a local plastic supplier cut your replacements because I doubt that few could duplicate the ones that Hunter sent without special tools. I noticed that the new Hunters have a new window system with a metal frame. I hope this is an improvement especially for future replacement.
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