Home |
Search |
Today's Posts |
#1
|
|||
|
|||
??? about fiberglass roofing a houseboat
I have a houseboat whose roof has a bunch of thin
spider cracks, as well as some a bit bigger. The biggest ones aren't wide enough to get any more than a razor knife blade in, if that. I want to put some more fiberglass sheet on it, and have never done that before. Having talked to several people about it, the following is pretty much the impression I've developed about doing the job, and I'd appreciate any more suggestions or advice people are willing to sha · First, use something like a thin wheel on a grinder and dig out the larger cracks, then fill them in with rosin to make them strong...if that's not done before sanding, the cracks will fill up with dust and never get strength from rosin entering them. · Sand the area with medium grit sandpaper. · Clean area with acetone. · Cut fiberglass cloth to fit the area, then staple in place. · Saturate the cloth with rosin using a roller. Best to set up a cover like a tarp, because in direct sun the rosin could set up too quick. · After all that has been done and dries, apply gel coat ...I've heard to apply 1, 2 and 3 coats, so as yet don't have a good idea of how many to apply. One of the things I'm still trying to figure out, is how to deal with the excess rosin which will want to drip down the side of the boat. Can anyone suggest any good way(s) of dealing with that issue? |
#2
|
|||
|
|||
??? about fiberglass roofing a houseboat
|
#3
|
|||
|
|||
??? about fiberglass roofing a houseboat
On Sun, 08 Aug 2004 19:57:36 +1000, "K. Smith" wrote:
wrote: I have a houseboat whose roof has a bunch of thin spider cracks, as well as some a bit bigger. The biggest ones aren't wide enough to get any more than a razor knife blade in, if that. I want to put some more fiberglass sheet on it, and have never done that before. Having talked to several people about it, the following is pretty much the impression I've developed about doing the job, and I'd appreciate any more suggestions or advice people are willing to sha · First, use something like a thin wheel on a grinder and dig out the larger cracks, then fill them in with rosin to make them strong...if that's not done before sanding, the cracks will fill up with dust and never get strength from rosin entering them. Resin itself has very little strength so if you choose to fill the cracks first add some filler to the resin, say Q cells & make a paste (before you catalyse), although a layer of glass over the top should mean you don't really need to "fill" suck small cracks first. Thanks for the input! By now I've changed my plan somewhat. At this point I intend to fill the cracks with a filler material recommended by a guy who does a lot of this stuff, and works at Boater's World. That's in case water gets between the original roof and what gets added to it, and also to help hold it over through winter in case I don't get around to completing the job until spring. · Sand the area with medium grit sandpaper. · Clean area with acetone. That plan has changed too, and now I intend to add 1/4" plywood for that much extra strength, before doing the fiberglass. That could change too though... The original plywood idea was to save a bunch of sanding and acetoning of the original roof, and also add some strength. Then a couple of people told me that I need to use marine grade plywood. The expence of fiberglass and resin was significant, but now the cost of the plywood would become the biggest expence ....more than doubling the cost of the job. So now I'm left to wonder how much stronger, better, longer lasting would the plywood be to the project? · Cut fiberglass cloth to fit the area, then staple in place. Usually you paint resin onto the surface, then put the glass on, then use a metal roller to pull the resin up through the glass this stops bubbles being trapped under the glass (still use staples if you need to but into the wet glass) & by working the roller with the wet resin you give the binders in the chopped strand glass mat time to dissolve. So it's always best to put the resin on first (not too much) then lay the glass into it. Thanks. That's pretty much what everyone else has said. · Saturate the cloth with rosin using a roller. Best to set up a cover like a tarp, because in direct sun the rosin could set up too quick. Always do a test bit to ensure the amount of catalyst you'll be adding will give you a gel time of 20 to 40 mins, save there's a dramatic weather change you can then maintain your gel time with confidence. I've been told to use between 1% and 2%, and also not to use less than 2%, so still don't know quite how to think about that one. I do intend to rig a tarp to cover the work area, so the sun doesn't make things set up too quick. When working do small areas at a time. · After all that has been done and dries, apply gel coat ...I've heard to apply 1, 2 and 3 coats, so as yet don't have a good idea of how many to apply. Just resin with glass sets very porous. The gel coat is what makes it water tight. I have had various advice about that one. Most of it has been that there's no real need to use gel coat, but that any type of marine paint would work okay. One guy said he used gel coat, but it was too slippery so he went over it with Elastomeric....here at this marina most people suggest using that. The two people I talked to that do a lot of fiberglassing said just painting it would do, and both acted like it really doesn't matter what type paint. One of those guys did suggest using marine acrylic paint, and adding a bit of a sandy substance they sell to give the surface more texture. With gel coat one good application should be OK, it's pretty thick stuff but don't skimp, however "normal" gelcoat will leave a sticky tacky surface, so tell your supplier that you need some "wax in styrene" to add to it (about 1%) the wax will float to the top & seal the curing gelcoat from air allowing it to cure right through not leaving a sticky surface. Thanks. I'll ask around about that at the supply places. If it's a tricky surface (doesn't sound like it) you can spray some PVA over normal freshly applied gel coat to achieve the same outcome. One of the things I'm still trying to figure out, is how to deal with the excess rosin which will want to drip down the side of the boat. Can anyone suggest any good way(s) of dealing with that issue? Masking tape & throw away placky drip sheets from a paint shop etc. If you have a situation which doesn't allow, you can spray PVA over the lower surfaces (it's cheap mould release agent which sets quickly into a placky film) then when finished the drips etc will come away easily, the PVA is water soluble so can just be harmlessly washed off. K |
#4
|
|||
|
|||
??? about fiberglass roofing a houseboat
You do not need Marine Ply. The difference in Marine ply and normal outdoor
ply, is the marine ply will have no interior voids. All the plys are patched before bonding. No voids is good in a transom, with a big motor trying to flex the ply. For normal walking surfaces, a standard ACX with waterproof glue is fine. Bill wrote in message ... On Sun, 08 Aug 2004 19:57:36 +1000, "K. Smith" wrote: wrote: I have a houseboat whose roof has a bunch of thin spider cracks, as well as some a bit bigger. The biggest ones aren't wide enough to get any more than a razor knife blade in, if that. I want to put some more fiberglass sheet on it, and have never done that before. Having talked to several people about it, the following is pretty much the impression I've developed about doing the job, and I'd appreciate any more suggestions or advice people are willing to sha · First, use something like a thin wheel on a grinder and dig out the larger cracks, then fill them in with rosin to make them strong...if that's not done before sanding, the cracks will fill up with dust and never get strength from rosin entering them. Resin itself has very little strength so if you choose to fill the cracks first add some filler to the resin, say Q cells & make a paste (before you catalyse), although a layer of glass over the top should mean you don't really need to "fill" suck small cracks first. Thanks for the input! By now I've changed my plan somewhat. At this point I intend to fill the cracks with a filler material recommended by a guy who does a lot of this stuff, and works at Boater's World. That's in case water gets between the original roof and what gets added to it, and also to help hold it over through winter in case I don't get around to completing the job until spring. · Sand the area with medium grit sandpaper. · Clean area with acetone. That plan has changed too, and now I intend to add 1/4" plywood for that much extra strength, before doing the fiberglass. That could change too though... The original plywood idea was to save a bunch of sanding and acetoning of the original roof, and also add some strength. Then a couple of people told me that I need to use marine grade plywood. The expence of fiberglass and resin was significant, but now the cost of the plywood would become the biggest expence ...more than doubling the cost of the job. So now I'm left to wonder how much stronger, better, longer lasting would the plywood be to the project? · Cut fiberglass cloth to fit the area, then staple in place. Usually you paint resin onto the surface, then put the glass on, then use a metal roller to pull the resin up through the glass this stops bubbles being trapped under the glass (still use staples if you need to but into the wet glass) & by working the roller with the wet resin you give the binders in the chopped strand glass mat time to dissolve. So it's always best to put the resin on first (not too much) then lay the glass into it. Thanks. That's pretty much what everyone else has said. · Saturate the cloth with rosin using a roller. Best to set up a cover like a tarp, because in direct sun the rosin could set up too quick. Always do a test bit to ensure the amount of catalyst you'll be adding will give you a gel time of 20 to 40 mins, save there's a dramatic weather change you can then maintain your gel time with confidence. I've been told to use between 1% and 2%, and also not to use less than 2%, so still don't know quite how to think about that one. I do intend to rig a tarp to cover the work area, so the sun doesn't make things set up too quick. When working do small areas at a time. · After all that has been done and dries, apply gel coat ...I've heard to apply 1, 2 and 3 coats, so as yet don't have a good idea of how many to apply. Just resin with glass sets very porous. The gel coat is what makes it water tight. I have had various advice about that one. Most of it has been that there's no real need to use gel coat, but that any type of marine paint would work okay. One guy said he used gel coat, but it was too slippery so he went over it with Elastomeric....here at this marina most people suggest using that. The two people I talked to that do a lot of fiberglassing said just painting it would do, and both acted like it really doesn't matter what type paint. One of those guys did suggest using marine acrylic paint, and adding a bit of a sandy substance they sell to give the surface more texture. With gel coat one good application should be OK, it's pretty thick stuff but don't skimp, however "normal" gelcoat will leave a sticky tacky surface, so tell your supplier that you need some "wax in styrene" to add to it (about 1%) the wax will float to the top & seal the curing gelcoat from air allowing it to cure right through not leaving a sticky surface. Thanks. I'll ask around about that at the supply places. If it's a tricky surface (doesn't sound like it) you can spray some PVA over normal freshly applied gel coat to achieve the same outcome. One of the things I'm still trying to figure out, is how to deal with the excess rosin which will want to drip down the side of the boat. Can anyone suggest any good way(s) of dealing with that issue? Masking tape & throw away placky drip sheets from a paint shop etc. If you have a situation which doesn't allow, you can spray PVA over the lower surfaces (it's cheap mould release agent which sets quickly into a placky film) then when finished the drips etc will come away easily, the PVA is water soluble so can just be harmlessly washed off. K |
#5
|
|||
|
|||
??? about fiberglass roofing a houseboat
If it just small cracks then laying down more cloth is probably
overkill. I'm going through the same kind of exersize after removing my teak decks. If the old surface is gelcoat, then laying cloth over it is a bad idea. The gelcoat will have to be removed to get to the existing glass. The secondary bond characterists of resins over gelcoat is not good. The solution that I am using is applying 2 coats of epoxy barrier, then a 2-part polyurethane finish. Doug s/v Callista wrote in message ... I have a houseboat whose roof has a bunch of thin spider cracks, as well as some a bit bigger. The biggest ones aren't wide enough to get any more than a razor knife blade in, if that. I want to put some more fiberglass sheet on it, and have never done that before. Having talked to several people about it, the following is pretty much the impression I've developed about doing the job, and I'd appreciate any more suggestions or advice people are willing to sha · First, use something like a thin wheel on a grinder and dig out the larger cracks, then fill them in with rosin to make them strong...if that's not done before sanding, the cracks will fill up with dust and never get strength from rosin entering them. · Sand the area with medium grit sandpaper. · Clean area with acetone. · Cut fiberglass cloth to fit the area, then staple in place. · Saturate the cloth with rosin using a roller. Best to set up a cover like a tarp, because in direct sun the rosin could set up too quick. · After all that has been done and dries, apply gel coat ...I've heard to apply 1, 2 and 3 coats, so as yet don't have a good idea of how many to apply. One of the things I'm still trying to figure out, is how to deal with the excess rosin which will want to drip down the side of the boat. Can anyone suggest any good way(s) of dealing with that issue? |
#6
|
|||
|
|||
On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson" wrote:
If it just small cracks then laying down more cloth is probably overkill. I want to add some strength to it. It still feels strong, and there aren't any spots I feel a danger of falling through, but it's 30 years old too. I'm thinking if I add another layer of cloth, or maybe even 2, it should last another 30 years. I'm 45, and would like it to outlast me. I'm going through the same kind of exersize after removing my teak decks. If the old surface is gelcoat, then laying cloth over it is a bad idea. The gelcoat will have to be removed to get to the existing glass. The secondary bond characterists of resins over gelcoat is not good. Thanks for that. Other people have said the same thing. I have two possible approaches in mind in an attempt to overcome that problem. 1. sand it off, down to the old glass 2. apply a layer of 1/4" plywood (the following is posted twice in this thread): I've been told that if I use plywood, unless I use marine grade it will eventually buckle and swell because only marine grade is treated in a way which removes all moisture from the wood. So even if I get a good seal on it, unless I use marine grade the moister which is contained in the wood will make it swell. That doesn't really make sense to me since if it's not swolen when I put it on, I don't see why it would swell later if it doesn't absorb any more moisture, but two different people have told me the same thing. The solution that I am using is applying 2 coats of epoxy barrier, then a 2-part polyurethane finish. Doug s/v Callista Thanks again....I'll look into doing that. |
#7
|
|||
|
|||
On Fri, 13 Aug 2004 18:49:33 GMT, "Calif Bill" wrote:
You do not need Marine Ply. The difference in Marine ply and normal outdoor ply, is the marine ply will have no interior voids. All the plys are patched before bonding. No voids is good in a transom, with a big motor trying to flex the ply. For normal walking surfaces, a standard ACX with waterproof glue is fine. Bill (the following is posted twice in this thread): I've been told that if I use plywood, unless I use marine grade it will eventually buckle and swell because only marine grade is treated in a way which removes all moisture from the wood. So even if I get a good seal on it, unless I use marine grade the moister which is contained in the wood will make it swell. That doesn't really make sense to me since if it's not swolen when I put it on, I don't see why it would swell later if it doesn't absorb any more moisture, but two different people have told me the same thing. |
#8
|
|||
|
|||
wrote in message ... I have a houseboat whose roof has a bunch of thin spider cracks, as well as some a bit bigger. Is the roof structurally sound? What you describe seems to be a bit of overkill if the basic roof is sound and just needs to be made watertight. My houseboat came with a rubber coating that has been working really well. Check out www.deckrite.com Rod |
#9
|
|||
|
|||
wrote in message ... On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson" wrote: If it just small cracks then laying down more cloth is probably overkill. I want to add some strength to it. It still feels strong, and there aren't any spots I feel a danger of falling through, but it's 30 years old too. I'm thinking if I add another layer of cloth, or maybe even 2, it should last another 30 years. I'm 45, and would like it to outlast me. I'm going through the same kind of exersize after removing my teak decks. If the old surface is gelcoat, then laying cloth over it is a bad idea. The gelcoat will have to be removed to get to the existing glass. The secondary bond characterists of resins over gelcoat is not good. Thanks for that. Other people have said the same thing. I have two possible approaches in mind in an attempt to overcome that problem. 1. sand it off, down to the old glass The only way to lay down new glass reliably. 2. apply a layer of 1/4" plywood So how would you bond the plywood to the gelcoat? (the following is posted twice in this thread): I've been told that if I use plywood, unless I use marine grade it will eventually buckle and swell because only marine grade is treated in a way which removes all moisture from the wood. I doubt it. From what I understand, marine ply just has waterproof glue and fewer voids. So even if I get a good seal on it, unless I use marine grade the moister which is contained in the wood will make it swell. I suppose that it depends upon how the ply was stored prior to you laying it down. That doesn't really make sense to me since if it's not swolen when I put it on, I don't see why it would swell later if it doesn't absorb any more moisture, but two different people have told me the same thing. Swollen indicates sever moisture content. It can look totally fine but still have high moisture content. Once you seal it in then the moisture can cause problems. The best solution of you feel that you need additional strength is to grind off the gelcoat and lay down glass. The solution that I am using is applying 2 coats of epoxy barrier, then a 2-part polyurethane finish. Doug s/v Callista Thanks again....I'll look into doing that. If you don;t need additional structural strength, then this seems to be sufficient. |
#10
|
|||
|
|||
wrote in message ... On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson" wrote: If it just small cracks then laying down more cloth is probably overkill. I want to add some strength to it. It still feels strong, and there aren't any spots I feel a danger of falling through, but it's 30 years old too. I'm thinking if I add another layer of cloth, or maybe even 2, it should last another 30 years. I'm 45, and would like it to outlast me. I'm going through the same kind of exersize after removing my teak decks. If the old surface is gelcoat, then laying cloth over it is a bad idea. The gelcoat will have to be removed to get to the existing glass. The secondary bond characterists of resins over gelcoat is not good. Thanks for that. Other people have said the same thing. I have two possible approaches in mind in an attempt to overcome that problem. 1. sand it off, down to the old glass The only way to lay down new glass reliably. 2. apply a layer of 1/4" plywood So how would you bond the plywood to the gelcoat? (the following is posted twice in this thread): I've been told that if I use plywood, unless I use marine grade it will eventually buckle and swell because only marine grade is treated in a way which removes all moisture from the wood. I doubt it. From what I understand, marine ply just has waterproof glue and fewer voids. So even if I get a good seal on it, unless I use marine grade the moister which is contained in the wood will make it swell. I suppose that it depends upon how the ply was stored prior to you laying it down. That doesn't really make sense to me since if it's not swolen when I put it on, I don't see why it would swell later if it doesn't absorb any more moisture, but two different people have told me the same thing. Swollen indicates sever moisture content. It can look totally fine but still have high moisture content. Once you seal it in then the moisture can cause problems. The best solution of you feel that you need additional strength is to grind off the gelcoat and lay down glass. The solution that I am using is applying 2 coats of epoxy barrier, then a 2-part polyurethane finish. Doug s/v Callista Thanks again....I'll look into doing that. If you don;t need additional structural strength, then this seems to be sufficient. |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
??? about fiberglass roofing a houseboat | General | |||
rec.boats.paddle sea kayaking FAQ | General | |||
fiberglass pontoon leak on boat slip, HELP! | General | |||
rec.boats.paddle sea kayaking FAQ | General | |||
Plywood & Fiberglass deck | Boat Building |