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Shortcut for replacing plywood core?
I have a Rhodes 22 sailboat with some plywood core in the bow that turned to
mush. Water entered through a poorly sealed hole for a cowl. Last October I scraped out the rotted core using wire. I was able to do this from the existing cowl hole. The core I now need to replace extends about 1 foot back & 180 degrees from the edge of the cowl opening. Ideally I would push in epoxy with filler to fill the void but can't see an effective way of doing that & repair such a large area. Then I thought about how handy it would be to use an expanding foam to fill this area & then seal the edge with epoxy at the cowl. The deck is very strong & does not flex. I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. Any thoughts on fixing this without cutting some fiberglass skin would be appreciated though I do have excellant access to the damaged area from inside the boat. Thanks Marc |
Shortcut for replacing plywood core?
On Fri, 27 Feb 2004 07:27:26 -0500, "Marc Beroz"
vaguely proposed a theory .......and in reply I say!: I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. nuff sed. It's a boat. Your life may depend on it. It's a stress area. You have access. Do it properly. I would also be looking at what is wrong with the design/surrounds that the ply turned to mush. Why did the water get in? Design or build? Accident? rebuild the area and some around it. Boats are not cheap. I have a Rhodes 22 sailboat with some plywood core in the bow that turned to mush. Water entered through a poorly sealed hole for a cowl. Last October I scraped out the rotted core using wire. I was able to do this from the existing cowl hole. The core I now need to replace extends about 1 foot back & 180 degrees from the edge of the cowl opening. Ideally I would push in epoxy with filler to fill the void but can't see an effective way of doing that & repair such a large area. Then I thought about how handy it would be to use an expanding foam to fill this area & then seal the edge with epoxy at the cowl. The deck is very strong & does not flex. I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. Any thoughts on fixing this without cutting some fiberglass skin would be appreciated though I do have excellant access to the damaged area from inside the boat. Thanks Marc ************************************************** ** sorry ..........no I'm not! remove ns from my header address to reply via email Spike....Spike? Hello? |
Shortcut for replacing plywood core?
I'd make use of that access from below, cut GOOD plywood (marine or ext fir)
to fit and glue it in with West System epoxy making sure theply is well bonded with the old (solid) ply. My opinion fwiw. Merlin. "Old Nick" wrote in message ... On Fri, 27 Feb 2004 07:27:26 -0500, "Marc Beroz" vaguely proposed a theory ......and in reply I say!: I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. nuff sed. It's a boat. Your life may depend on it. It's a stress area. You have access. Do it properly. I would also be looking at what is wrong with the design/surrounds that the ply turned to mush. Why did the water get in? Design or build? Accident? rebuild the area and some around it. Boats are not cheap. I have a Rhodes 22 sailboat with some plywood core in the bow that turned to mush. Water entered through a poorly sealed hole for a cowl. Last October I scraped out the rotted core using wire. I was able to do this from the existing cowl hole. The core I now need to replace extends about 1 foot back & 180 degrees from the edge of the cowl opening. Ideally I would push in epoxy with filler to fill the void but can't see an effective way of doing that & repair such a large area. Then I thought about how handy it would be to use an expanding foam to fill this area & then seal the edge with epoxy at the cowl. The deck is very strong & does not flex. I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. Any thoughts on fixing this without cutting some fiberglass skin would be appreciated though I do have excellant access to the damaged area from inside the boat. Thanks Marc ************************************************** ** sorry .........no I'm not! remove ns from my header address to reply via email Spike....Spike? Hello? |
Shortcut for replacing plywood core?
On Fri, 27 Feb 2004 21:59:12 +0800, Old Nick
wrote: nuff sed. It's a boat. Your life may depend on it. It's a stress area. You have access. Do it properly. I would also be looking at what is wrong with the design/surrounds that the ply turned to mush. Why did the water get in? Design or build? Accident? rebuild the area and some around it. Plywood is not a suitable core. It has the same problem as any non-end-grain wood core. Moisture travels along the grain. Water will get in somewhere sometime. Rodney Myrvaagnes NYC J36 Gjo/a "Accordions don't play 'Lady of Spain.' People play 'Lady of Spain." |
Shortcut for replacing plywood core?
"Marc Beroz" wrote in message ...
I have a Rhodes 22 sailboat with some plywood core in the bow that turned to mush. Water entered through a poorly sealed hole for a cowl. Last October I scraped out the rotted core using wire. I was able to do this from the existing cowl hole. The core I now need to replace extends about 1 foot back & 180 degrees from the edge of the cowl opening. Ideally I would push in epoxy with filler to fill the void but can't see an effective way of doing that & repair such a large area. Then I thought about how handy it would be to use an expanding foam to fill this area & then seal the edge with epoxy at the cowl. The deck is very strong & does not flex. I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. Any thoughts on fixing this without cutting some fiberglass skin would be appreciated though I do have excellant access to the damaged area from inside the boat. Thanks Marc Hey Marc, It sure was nice of "OLD NICK" to give out such good advice for free! Here's what I understand of your situation: 2 layers of fiberglass, 1/2 to 3/4 inch of mush in between them for diameter of approx. 2 sqft. and you have access to this mush through a small (6in.max)hole in the middle once you removed the cowl. The "right" way to fix this would be to rip off the top fiberglass skin and expose all of the rotten plywood, then replace the core material and apply a new fiberglass skin, then re gelcoat the whole thing recreating the antislip patern on the deck somewhere during the process. I suspect that this may not be the best solution for you for whatever reason. A 22 ft sailboat with a cabin trunk does not have a very large fordeck,and does not have a large unsupported area. So lets look at the the desired outcome before we go straight to fixes. You want to replace the core with as little effort as possible and still have a safe boat. The core simply seperates the two layers of f/g to make for a stiffer panel section. To do this, the core needs to be VERY WELL bonded to both top and bottom skins. If your deck feels stiff with the mush inside, it's probably fairly well build (or at lease the top layer is fairly thick). Using 2 part polyurathane foam is an accepted practice in boat building, especially by power boat builders. They tend to use 2 part P/U foam to do everything from filling holes and deadair space to bonding (non structual- eg: fish wells) items to the boat. This stuff sticks to anything and is just as dense as cheap end-grain balsa core - which is used in most boat decks built post 1975ish. I would suggest that you go ahead and try the 2 part P/U foam but with these precautions: get ALL of the rotten wood out, throughly clean the area between the skins with acetone (3+ times), mix very small batches of foam and let it expand and dry before applying the next batch(this stuff expands so much that it WILL push the 2 layers of f/g apart if it is trapped. once all of the foam is in, router out (or cut manually) about 3/4 of an inch back from the opening where you filled and replace with thickened epoxy. Give yourself enough room so that the screws that keep the cowl on bite into the epoxy rather than the foam. IMPORTANT things to remember: 1. Get all of the "soft" wood out 2. clean throughly with acetone 3. mix small batches 4. let each batch cure before applying next batch(make sure you get it into all of the corners 5. seal all edges with epoxy (just like wood, the foam will absorb water, so keep it dry at all cost 6. Spend more of your time on the water Cheers R. |
Shortcut for replacing plywood core?
Thanks for your comments. I've responded to some of your points below.
Here's what I understand of your situation: 2 layers of fiberglass, 1/2 to 3/4 inch of mush in between them for diameter of approx. 2 sqft. and you have access to this mush through a small (6in.max)hole in the middle once you removed the cowl. That's correct. The core is 1/2" plywood. The "right" way to fix this would be to rip off the top fiberglass skin and expose all of the rotten plywood, then replace the core material and apply a new fiberglass skin, then re gelcoat the whole thing recreating the antislip patern on the deck somewhere during the process. I figured if I removed a fiberglass skin, it would be the inner one since I have good access & I wouldn't have to deal with the non-skid. This leads me to another question if I go this route. In one area the mush core has been removed all the way to the edge of the deck. To replace this core, how close to the hull/deck joint should I cut the fiberglass skin? If I cut too close to where the deck meets the hull, I won't have enough space to grind out a bevel & then reglass the skin back into place. On the other hand, the further out from the hull I stay with my cut, the harder it will be to get a good bond between the new core I install & the inner fiberglass skin that I did not cut out along the edge of the hull. (I'm having a hard time describing this.) I've been mulling this over for awhile & been been thinking I'd cut the deck's lower fiberglass skin about 2.5 inches away from the hull. Any thoughts? I suspect that this may not be the best solution for you for whatever reason. A 22 ft sailboat with a cabin trunk does not have a very large fordeck,and does not have a large unsupported area. The only reason I was looking for an alternative is that I want to minimize down time. I was looking to make the quickest repair without sacrificing safety. I thought that if I made a foam repair & that failed, I could always do the traditional repair at some point in the future. So lets look at the the desired outcome before we go straight to fixes. You want to replace the core with as little effort as possible and still have a safe boat. The core simply seperates the two layers of f/g to make for a stiffer panel section. To do this, the core needs to be VERY WELL bonded to both top and bottom skins. If your deck feels stiff with the mush inside, it's probably fairly well build (or at lease the top layer is fairly thick). Using 2 part polyurathane foam is an accepted practice in boat building, especially by power boat builders. They tend to use 2 part P/U foam to do everything from filling holes and deadair space to bonding (non structual- eg: fish wells) items to the boat. This stuff sticks to anything and is just as dense as cheap end-grain balsa core - which is used in most boat decks built post 1975ish. I would suggest that you go ahead and try the 2 part P/U foam but with these precautions: get ALL of the rotten wood out, throughly clean the area between the skins with acetone (3+ times) I assume you get the acetone in there by shooting it in with a syringe & then allowing it to evaporate out? , mix very small batches of foam and let it expand and dry before applying the next batch(this stuff expands so much that it WILL push the 2 layers of f/g apart if it is trapped. I've looked at the foam products & have wondered how I could get 2 part foam back far enough between the skins. Is there any way to spray it rather than pour it? Or are you thinking that I close off the cowl hole in the inner skin and then pour 2 part foam in from above the deck. I don't have experience with 2 part foam. Is it real viscous prior to setting up or will it flow? What if I used 1 part spray foam? once all of the foam is in, router out (or cut manually) about 3/4 of an inch back from the opening where you filled and replace with thickened epoxy. Give yourself enough room so that the screws that keep the cowl on bite into the epoxy rather than the foam. Agree IMPORTANT things to remember: 1. Get all of the "soft" wood out I can get all the soft stuff out that I can move with a 1/16 inch diameter piece of wire but that won't be as good as having good access to the problem area with a skin removed. 2. clean throughly with acetone 3. mix small batches 4. let each batch cure before applying next batch(make sure you get it into all of the corners 5. seal all edges with epoxy (just like wood, the foam will absorb water, so keep it dry at all cost 6. Spend more of your time on the water The more I consider the obstacles, the more I think I may just have to bite the bullet & get to work cutting glass. I'd be interested in what you think. Thanks, Marc |
Shortcut for replacing plywood core?
Rodney,
What do you suggest I use for core? Marc " Plywood is not a suitable core. It has the same problem as any non-end-grain wood core. Moisture travels along the grain. Water will get in somewhere sometime. Rodney Myrvaagnes NYC J36 Gjo/a "Accordions don't play 'Lady of Spain.' People play 'Lady of Spain." |
Shortcut for replacing plywood core?
Merlin,
Since I want to re-gelcoat the patch on the inner skin, I was thinking I should use a polyester laminating resin. Am I wrong here? Marc "MMC" wrote in message . com... I'd make use of that access from below, cut GOOD plywood (marine or ext fir) to fit and glue it in with West System epoxy making sure theply is well bonded with the old (solid) ply. My opinion fwiw. Merlin. |
Shortcut for replacing plywood core?
Nick,
Your point is well taken. Water intrusion was due to the plywood never having been properly sealed at the cowl. The caulking at the cowl failed & that's the tragic end. Marc "Old Nick" wrote in message ... On Fri, 27 Feb 2004 07:27:26 -0500, "Marc Beroz" vaguely proposed a theory ......and in reply I say!: I don't think my foam idea is a smart thing to do but I thought I would ask your opinion before I abandoned the idea entirely. nuff sed. It's a boat. Your life may depend on it. It's a stress area. You have access. Do it properly. I would also be looking at what is wrong with the design/surrounds that the ply turned to mush. Why did the water get in? Design or build? Accident? rebuild the area and some around it. |
Shortcut for replacing plywood core?
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Shortcut for replacing plywood core?
On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz"
wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. You could also glass it solid, although you would be adding weight just where you don't want it. I think you are right about cutting out the inner skin, leaving enough edge to feather and glass it back. If you started with a piece of good marine plywood with no voids and covered it in epoxy before starting, you might be able to keep it dry as long as the rest of the boat will last. You could also get away with solid _white_ oak for a good while. Not red oak. Do you know how old the boat is, and how long it took to get the current problem? Also, do you know there is not more of the same elsewhere? Rodney Myrvaagnes NYC J36 Gjo/a "Biologists think they are chemists, chemists think they are phycisists, physicists think they are gods, and God thinks He is a mathematician." Anon |
Shortcut for replacing plywood core?
Rodney Myrvaagnes wrote: On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz" wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. I agree with the foam, but you are dead wrong about the balsa... I've replaced the balsa core in many decks where the endgrain balsa has acted like a sponge and totally rotted out. Don't believe me ? For an example, take a look at: ftp://ftp.sailnet.com/pearson/pearso...ted%20core.jpg (sorry about the long address). Brian Cleverly (to reply direct, replace the first "z" with an "n" in the header address) |
Shortcut for replacing plywood core?
On Sat, 28 Feb 2004 18:24:10 -0800, Brian Cleverly
wrote: Rodney Myrvaagnes wrote: On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz" wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. I agree with the foam, but you are dead wrong about the balsa... I've replaced the balsa core in many decks where the endgrain balsa has acted like a sponge and totally rotted out. Don't believe me ? For an example, take a look at: ftp://ftp.sailnet.com/pearson/pearso...ted%20core.jpg Pearson used balsa in non-end-grain orientation in early boats. I have a 24-year-old boat that has suffered numerous insults and repairs and is still strong and just passed a survey. It is cored with Baltek end-grain. If the end-grain core is not bonded to the outer layers, water can travel between, as it can with any core. It does not travel fast across the grain inside the wood. Rodney Myrvaagnes J36 Gjo/a MOM CASTS TOT IN CEMENT Most experts voice cautious optimism |
Shortcut for replacing plywood core?
Rodney, Brian and Marc,
Boy, I wish I had time to tell you all everything I've seen and done in the last fifty plus years. But - let my start by saying that the picture - though good - is a bad example. Just like so many things, when it was first done, builders didn't understand how much trouble they were starting. Many builders used endgrain block filler like that. The only ones that made it work use a filled area around each block the sequester them. The companies the used block without that left a gap between the blocks that served as a conduit for any water that got into the construction. They builders that used bound sheet of end grain balsa did a little better, but since those where largely laided up construction, the inner layup usually left at small gap the the core edge that again was a good conduit for water. There were places in my current boat that had marine plywood for a high stress area in a layup of balsa core. In some of those where the bedding on deck had gone bad, the plywood was shot, though the adjacent balsa core was saturated and delaminated it was still there. I could have dried it out and reused it. Closed cell foam is no answer either. I have a Whaler sailing dink out here that was mistreated and now weighs in at 300+. I have also ben contracted to repair laid-up foam core structures that were delaminating because of water intrusion damage. The only answer I have come up with that makes any sense is: Do not trap water. If there might be a place it can get in, make sure it has a way out. Do your best to keep it out, but the thing that caused the problem was the the water stayed in. Drain holes in the inner deck skin will stop the migration of moisture in the core right there. If you are going to rebuild a cored structure, learn all about vacuum techniques for laminating. That is the only way that I have found to create the solid lamination required. Matt Colie Rodney Myrvaagnes wrote: On Sat, 28 Feb 2004 18:24:10 -0800, Brian Cleverly wrote: Rodney Myrvaagnes wrote: On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz" wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. I agree with the foam, but you are dead wrong about the balsa... I've replaced the balsa core in many decks where the endgrain balsa has acted like a sponge and totally rotted out. Don't believe me ? For an example, take a look at: ftp://ftp.sailnet.com/pearson/pearso...ted%20core.jpg Pearson used balsa in non-end-grain orientation in early boats. I have a 24-year-old boat that has suffered numerous insults and repairs and is still strong and just passed a survey. It is cored with Baltek end-grain. If the end-grain core is not bonded to the outer layers, water can travel between, as it can with any core. It does not travel fast across the grain inside the wood. Rodney Myrvaagnes J36 Gjo/a MOM CASTS TOT IN CEMENT Most experts voice cautious optimism |
Shortcut for replacing plywood core?
Rodney Myrvaagnes wrote: On Sat, 28 Feb 2004 18:24:10 -0800, Brian Cleverly wrote: Rodney Myrvaagnes wrote: On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz" wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. I agree with the foam, but you are dead wrong about the balsa... I've replaced the balsa core in many decks where the endgrain balsa has acted like a sponge and totally rotted out. Don't believe me ? For an example, take a look at: ftp://ftp.sailnet.com/pearson/pearso...ted%20core.jpg Pearson used balsa in non-end-grain orientation in early boats. If you look closely, you will see that this was in fact endgrain. I've had exactly the same situation with Cal (not early ones), and Ericson boats. I have a 24-year-old boat that has suffered numerous insults and repairs and is still strong and just passed a survey. It is cored with Baltek end-grain. If the end-grain core is not bonded to the outer layers, water can travel between, as it can with any core. It does not travel fast across the grain inside the wood. Agreed, certainly it can travel like that. It is not obvious in the photo (I wish I had a better one) but there was clear evidence of the blocks being bonded top and bottom, plus I had to break off numerous polyester ridges that existed between the blocks. However, the original poster asked your recommendations for core and you didn't even hint that he would have to be extremely particular with the way he installed balsa. FWIW, when I install new balsa I saturate it with Sys 3 "Clear Coat" epoxy. As an aside, that particular Pearson has been cut-up and buried in landfill due to the discovery of gross amounts of delamination in the hull layup. Brian Cleverly (to reply direct, replace the first "z" with an "n"). Rodney Myrvaagnes J36 Gjo/a MOM CASTS TOT IN CEMENT Most experts voice cautious optimism |
Shortcut for replacing plywood core?
Matt,
Thanks for your comments. I hope the original poster takes note of the steps required to correctly install balsa core should he decide to go that way. Brian Cleverly (to reply direct, replace the first "z" with an "n"). Matt Colie wrote: Rodney, Brian and Marc, Boy, I wish I had time to tell you all everything I've seen and done in the last fifty plus years. But - let my start by saying that the picture - though good - is a bad example. Just like so many things, when it was first done, builders didn't understand how much trouble they were starting. Many builders used endgrain block filler like that. The only ones that made it work use a filled area around each block the sequester them. The companies the used block without that left a gap between the blocks that served as a conduit for any water that got into the construction. They builders that used bound sheet of end grain balsa did a little better, but since those where largely laided up construction, the inner layup usually left at small gap the the core edge that again was a good conduit for water. There were places in my current boat that had marine plywood for a high stress area in a layup of balsa core. In some of those where the bedding on deck had gone bad, the plywood was shot, though the adjacent balsa core was saturated and delaminated it was still there. I could have dried it out and reused it. Closed cell foam is no answer either. I have a Whaler sailing dink out here that was mistreated and now weighs in at 300+. I have also ben contracted to repair laid-up foam core structures that were delaminating because of water intrusion damage. The only answer I have come up with that makes any sense is: Do not trap water. If there might be a place it can get in, make sure it has a way out. Do your best to keep it out, but the thing that caused the problem was the the water stayed in. Drain holes in the inner deck skin will stop the migration of moisture in the core right there. If you are going to rebuild a cored structure, learn all about vacuum techniques for laminating. That is the only way that I have found to create the solid lamination required. Matt Colie Rodney Myrvaagnes wrote: On Sat, 28 Feb 2004 18:24:10 -0800, Brian Cleverly wrote: Rodney Myrvaagnes wrote: On Fri, 27 Feb 2004 23:10:29 -0500, "Marc Beroz" wrote: Rodney, What do you suggest I use for core? Marc Closed cell foam or end grain balsa, if bonded properly, will isolate places where water penetrates. I agree with the foam, but you are dead wrong about the balsa... I've replaced the balsa core in many decks where the endgrain balsa has acted like a sponge and totally rotted out. Don't believe me ? For an example, take a look at: ftp://ftp.sailnet.com/pearson/pearso...ted%20core.jpg Pearson used balsa in non-end-grain orientation in early boats. I have a 24-year-old boat that has suffered numerous insults and repairs and is still strong and just passed a survey. It is cored with Baltek end-grain. If the end-grain core is not bonded to the outer layers, water can travel between, as it can with any core. It does not travel fast across the grain inside the wood. Rodney Myrvaagnes J36 Gjo/a MOM CASTS TOT IN CEMENT Most experts voice cautious optimism |
http://www.transomrepair.com/
I used this stuff to fix the tansom on my boat. And its waterproof. On Fri, 27 Feb 2004 23:07:39 -0500, "Marc Beroz" wrote: Thanks for your comments. I've responded to some of your points below. Here's what I understand of your situation: 2 layers of fiberglass, 1/2 to 3/4 inch of mush in between them for diameter of approx. 2 sqft. and you have access to this mush through a small (6in.max)hole in the middle once you removed the cowl. That's correct. The core is 1/2" plywood. The "right" way to fix this would be to rip off the top fiberglass skin and expose all of the rotten plywood, then replace the core material and apply a new fiberglass skin, then re gelcoat the whole thing recreating the antislip patern on the deck somewhere during the process. I figured if I removed a fiberglass skin, it would be the inner one since I have good access & I wouldn't have to deal with the non-skid. This leads me to another question if I go this route. In one area the mush core has been removed all the way to the edge of the deck. To replace this core, how close to the hull/deck joint should I cut the fiberglass skin? If I cut too close to where the deck meets the hull, I won't have enough space to grind out a bevel & then reglass the skin back into place. On the other hand, the further out from the hull I stay with my cut, the harder it will be to get a good bond between the new core I install & the inner fiberglass skin that I did not cut out along the edge of the hull. (I'm having a hard time describing this.) I've been mulling this over for awhile & been been thinking I'd cut the deck's lower fiberglass skin about 2.5 inches away from the hull. Any thoughts? I suspect that this may not be the best solution for you for whatever reason. A 22 ft sailboat with a cabin trunk does not have a very large fordeck,and does not have a large unsupported area. The only reason I was looking for an alternative is that I want to minimize down time. I was looking to make the quickest repair without sacrificing safety. I thought that if I made a foam repair & that failed, I could always do the traditional repair at some point in the future. So lets look at the the desired outcome before we go straight to fixes. You want to replace the core with as little effort as possible and still have a safe boat. The core simply seperates the two layers of f/g to make for a stiffer panel section. To do this, the core needs to be VERY WELL bonded to both top and bottom skins. If your deck feels stiff with the mush inside, it's probably fairly well build (or at lease the top layer is fairly thick). Using 2 part polyurathane foam is an accepted practice in boat building, especially by power boat builders. They tend to use 2 part P/U foam to do everything from filling holes and deadair space to bonding (non structual- eg: fish wells) items to the boat. This stuff sticks to anything and is just as dense as cheap end-grain balsa core - which is used in most boat decks built post 1975ish. I would suggest that you go ahead and try the 2 part P/U foam but with these precautions: get ALL of the rotten wood out, throughly clean the area between the skins with acetone (3+ times) I assume you get the acetone in there by shooting it in with a syringe & then allowing it to evaporate out? , mix very small batches of foam and let it expand and dry before applying the next batch(this stuff expands so much that it WILL push the 2 layers of f/g apart if it is trapped. I've looked at the foam products & have wondered how I could get 2 part foam back far enough between the skins. Is there any way to spray it rather than pour it? Or are you thinking that I close off the cowl hole in the inner skin and then pour 2 part foam in from above the deck. I don't have experience with 2 part foam. Is it real viscous prior to setting up or will it flow? What if I used 1 part spray foam? once all of the foam is in, router out (or cut manually) about 3/4 of an inch back from the opening where you filled and replace with thickened epoxy. Give yourself enough room so that the screws that keep the cowl on bite into the epoxy rather than the foam. Agree IMPORTANT things to remember: 1. Get all of the "soft" wood out I can get all the soft stuff out that I can move with a 1/16 inch diameter piece of wire but that won't be as good as having good access to the problem area with a skin removed. 2. clean throughly with acetone 3. mix small batches 4. let each batch cure before applying next batch(make sure you get it into all of the corners 5. seal all edges with epoxy (just like wood, the foam will absorb water, so keep it dry at all cost 6. Spend more of your time on the water The more I consider the obstacles, the more I think I may just have to bite the bullet & get to work cutting glass. I'd be interested in what you think. Thanks, Marc |
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