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#1
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crack fix - fiberglass
Howdy all,
I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? |
#2
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Use your second approach. Definitely put a cloth patch over the job; four or
six oz cloth is sufficient. DO NOT us poly resin; use epoxy.Smooth with filled epoxy. Barrier coat if you are really fussy. Bob Swarts "Chris" wrote in message .. . Howdy all, I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? |
#3
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I'd go with door #2.
A 4" angle grinder ($12 from Harbor Freight or Bargain Supply) will make quick work of the grinding. Sneak up on it. It cuts quick. Get to the clean solid stuff. Fill the vee with epoxy thickened with fiberglass particles and thixotropicized (I don't know the structure you're patching, so this is the best strength stuff.) West #403 plus #406 (colloidal silica) or equivalents. One or two layers of glass over the fix -- slather them with epoxy thickened with #406 and then cover with vinyl to save a lot of fairing and sanding. Force the air bubbles out the side with your fingers. When cured, wash, sand to roughen, then spray with Rustoleum primer followed by Rustoleum white paint. Fix the beds on your trailer so it doesn't crack again. Roger http://home.earthlink.net/~derbyrm "Chris" wrote in message .. . Howdy all, I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? |
#4
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On Thu, 29 Sep 2005 16:17:27 -0700, "Robert or Karen Swarts"
wrote: Use your second approach. Definitely put a cloth patch over the job; four or six oz cloth is sufficient. DO NOT us poly resin; use epoxy.Smooth with filled epoxy. Barrier coat if you are really fussy. Bob Swarts If the crack area of the hull is convex outwards, preparing an epoxy resin glass patch on kitchen plastic works nicely - held on with duct tape pro temp, of course. This can give an excellent surface finish to the repair. Brian Whatcott Altus OK |
#5
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You didn't say visible from the inside, or the outside, or both. Or if you
intend to patch from the inside or the outside. And I guess at 16' it' an outboard? I've got some visible cracks at the bottom of my hull on my 16ft runabout. |
#6
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Chris wrote:
Howdy all, I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? Close, no cigar. Grind the Vee on the outside, feathering out 5 times the thickness of the glass, leave it rough. Wash it with acetone. Laminate several layers of glass, starting with a narrow strip, covering with wider strips until you fill up the Vee. Smooth and paint / gelcoat. Wet the glass, but try to use more glass and less resin. Squeeze the bubbles out (don't mix the goo too vigorously, just thorougly) using a serrated roller made from 2 sizes of washers loose on bent threaded rod with locked nuts. Clean tools with acetone. You should also do the same on the inside, or could just lay a couple of wider strips on the roughened inside, where you can, washing the cleaned inside with acetone before laminating. You will find polyester strong enough, if you get enough thickness and surface area covered and well bonded. Epoxy would be stronger, but is overkill, and will make the question of refinishing the exterior gelcoat into a can of worms, because poly gelcoat doesn't stick to epoxy, so you would need to redo the entire hull with epoxy paint to achieve a Bristol appearance. Polyester Gel coat is just catalyzed polyester resin with pigment and a little thickener, like silica gel, or, I am sure others have their favorites. You can brush it on with several / many thin freshly mixed coats applied while the hull is still tacky and buff it flat and smooth. It is self levelling, especially if you can turn the boat so you are painting on the level. If you get a good colour match (on the bottom? who cares?) you won't be ashamed of it. Don't use bondo, it just isn't as good as it could be, with automotive fillers, etc. Are you sure the cracks go right through? If so, gring the crack a little beyond the torn glass. You may only want to redo the gelcoat, if that is as deep as they go. Water collects in boats, even condensation can get inches deep, and rain could be getting in, too. Terry K |
#7
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Listen to Terry. Filled resin has no place in this repair.
Terry Spragg wrote: Chris wrote: Howdy all, I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? Close, no cigar. Grind the Vee on the outside, feathering out 5 times the thickness of the glass, leave it rough. Wash it with acetone. Laminate several layers of glass, starting with a narrow strip, covering with wider strips until you fill up the Vee. Smooth and paint / gelcoat. Wet the glass, but try to use more glass and less resin. Squeeze the bubbles out (don't mix the goo too vigorously, just thorougly) using a serrated roller made from 2 sizes of washers loose on bent threaded rod with locked nuts. Clean tools with acetone. You should also do the same on the inside, or could just lay a couple of wider strips on the roughened inside, where you can, washing the cleaned inside with acetone before laminating. You will find polyester strong enough, if you get enough thickness and surface area covered and well bonded. Epoxy would be stronger, but is overkill, and will make the question of refinishing the exterior gelcoat into a can of worms, because poly gelcoat doesn't stick to epoxy, so you would need to redo the entire hull with epoxy paint to achieve a Bristol appearance. Polyester Gel coat is just catalyzed polyester resin with pigment and a little thickener, like silica gel, or, I am sure others have their favorites. You can brush it on with several / many thin freshly mixed coats applied while the hull is still tacky and buff it flat and smooth. It is self levelling, especially if you can turn the boat so you are painting on the level. If you get a good colour match (on the bottom? who cares?) you won't be ashamed of it. Don't use bondo, it just isn't as good as it could be, with automotive fillers, etc. Are you sure the cracks go right through? If so, gring the crack a little beyond the torn glass. You may only want to redo the gelcoat, if that is as deep as they go. Water collects in boats, even condensation can get inches deep, and rain could be getting in, too. Terry K |
#8
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How I would fix it:
I would grind the inside, only, and put 3 to 4 good layers of glass inside, starting with mat, then roving, then mat, then roving, in progressively larger pieces. Do it all at one time. The resin that seeps outside then is sanded smooth to the hull. A little gel coat with some scotch tape over the patch, then sand with 600. Jim wrote: Listen to Terry. Filled resin has no place in this repair. Terry Spragg wrote: Chris wrote: Howdy all, I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. My ideas have been the following: 1. The ugly job - rough up the area around the crack and put a few fiberglass patches on it (poly resin & cloth) - paint over it 2. Cleaner job - grind out the crack and a bit of the area around it (make a V) - fill with fiberglass resin, or epoxy resin using a filler - not sure if a cloth patch on top of this would be necessary. - paint over it What do you guys think given the considerations? Close, no cigar. Grind the Vee on the outside, feathering out 5 times the thickness of the glass, leave it rough. Wash it with acetone. Laminate several layers of glass, starting with a narrow strip, covering with wider strips until you fill up the Vee. Smooth and paint / gelcoat. Wet the glass, but try to use more glass and less resin. Squeeze the bubbles out (don't mix the goo too vigorously, just thorougly) using a serrated roller made from 2 sizes of washers loose on bent threaded rod with locked nuts. Clean tools with acetone. You should also do the same on the inside, or could just lay a couple of wider strips on the roughened inside, where you can, washing the cleaned inside with acetone before laminating. You will find polyester strong enough, if you get enough thickness and surface area covered and well bonded. Epoxy would be stronger, but is overkill, and will make the question of refinishing the exterior gelcoat into a can of worms, because poly gelcoat doesn't stick to epoxy, so you would need to redo the entire hull with epoxy paint to achieve a Bristol appearance. Polyester Gel coat is just catalyzed polyester resin with pigment and a little thickener, like silica gel, or, I am sure others have their favorites. You can brush it on with several / many thin freshly mixed coats applied while the hull is still tacky and buff it flat and smooth. It is self levelling, especially if you can turn the boat so you are painting on the level. If you get a good colour match (on the bottom? who cares?) you won't be ashamed of it. Don't use bondo, it just isn't as good as it could be, with automotive fillers, etc. Are you sure the cracks go right through? If so, gring the crack a little beyond the torn glass. You may only want to redo the gelcoat, if that is as deep as they go. Water collects in boats, even condensation can get inches deep, and rain could be getting in, too. Terry K |
#9
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Chris wrote: I've got some visible cracks at the bottom of my hull on my 16ft runabout. This past summer when using the boat I was getting a bit of water in it after having it sit for a while in the water (the bilge pump easily took care of it). I'm now thinking that these cracks may be the cause and water slowly seeps into the boat. Now, my question about how I should attempt to fix this giving the following considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year. 3. I don't want to spend a lot of money as its not worth it. snip Based on the above, you need a functional repair, but this is no gold plater, so the finish of the repair can basically be slim or none; however, the repair should do a proper job. My solution will be prejudiced since I run an epoxy shop. IMHO, polyester is for shower stalls, not boat repairs. 1) Buy a 1 qt kit of laminating epoxy, a yard of 17 oz biaxial, knitted glass, some 2" chip brushes and some latex gloves. 2) Flip boat upside down and grind back from the crack about 4" using a 24 grit, right angle sander. Leave the sanded surface ROUGH, the rougher the better. 3) Lay 2 layers of 17 oz glass using the 2nd layer to over lap the first layer about (1")-(1-1/2") all around. 4) Let cure 48 hours, then scuff up with 24 grit sander and lay 2 more layers of 17 oz glass as above. 5) Wait 48 hours then fair edges of patch fair with boat using 24 grit sander. 6) Flip boat over, scuff up inside and lay 2 layers of glass, same as outside. 7) Get a beer, maybe 2. 8) Allow inside patch to cure about 72 hours, then relaunch boat and enjoy. Notice the lack of labor intensive finish work? OK, if you are fussy, fair out edges of inside patch, otherwise, forget it. Lew |
#10
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Before you get too carried away on what type of patch job, you might ought
to find out why it cracked. Plenty times hull cracks on fiberglass boats are due to some type of structural failure of the hull's support system. This type of problem could be something like a failure in the tabbing of the stringers and or bulkheads. Also a broken or rotten stringer or bulkhead. For instance if the is crack running transverse to the hull's length it could be caused by bulkhead damage. If the crack runs lengthwise, then maybe its a failed stringer causing the crack. If your boat has a hull liner which covers all the these structural things, you will have to remove the liner to make the repair. This is usually a big job so do some poking around thru the hatches or other access to it's hidden parts and get an idea of where the stringers are (these are the ones running lenghtwise). Then take a rubber hammer and tap up and down thelenght of the hull bottom about where you think these stringers are. If you find areas where the hull flexes along the stringers then you probably have some structural problems causing the problem. You might want to get some good fiberglass boat repair books. -- Ron White Boat building web address is www.concentric.net/~knotreel |
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