The Official "What Did You Do To Your Mac Today" Thread!
- Thread starter Sock Puppet
- Start date
Well I finally got started on my big winter project. This crack was visible when I bought the boat, and I knew I was gonna have to tackle it someday.
So I made 2 cuts along the surface of the glass and it came right up. (I'm sure it let loose of the core wood long ago)
You can see that the crack formed along a joint in 2 panels of core plywood. The black, rotted wood was right along that crack, but the darker-stained wood was wet downhill from the opening.
So I kept removing soft, rotten wood till I got to healthy, hard core material and was left with this
And finished my day in the boat by grinding and sanding the edges of my future repair.
So... This will sit till next weekend (or whenever I can get back to it), when I can start laying up new glass. On that note: I was planning on just using glass for the whole repair (not bothering with new core). This will be fine, right? The only downside being a little added weight? This is my first real fiberglass job, any help is appreciated.
So I made 2 cuts along the surface of the glass and it came right up. (I'm sure it let loose of the core wood long ago)
You can see that the crack formed along a joint in 2 panels of core plywood. The black, rotted wood was right along that crack, but the darker-stained wood was wet downhill from the opening.
So I kept removing soft, rotten wood till I got to healthy, hard core material and was left with this
And finished my day in the boat by grinding and sanding the edges of my future repair.
So... This will sit till next weekend (or whenever I can get back to it), when I can start laying up new glass. On that note: I was planning on just using glass for the whole repair (not bothering with new core). This will be fine, right? The only downside being a little added weight? This is my first real fiberglass job, any help is appreciated.
My .02.. I think if I had to do that, I might put some thin plywood on top of the inside liner but under the deck just to form a flat base to work on for the deck repair. I would use only epoxy (Im only familiar with West Systems and think it would work well) and lay down a number of glass layers that get well bonded to the beveled edges of the deck. Once you had a good structure of glass and epoxy in place, I would think it would be just fine to also add in a layer of plywood filler for the simple reason that its a way cheaper way to build up to the height you needed . You probably also will need some of the silica epoxy thickener at some stage in the repair to build that up/ smooth.
Once you have the epoxy/glass/filler done and it has the cosmetic surface you want (I have no idea how to get this.. I would probably just go for smooth), you have to protect the epoxy from UV and gelcoat wont stick to epoxy. I would just use some marine top side paint that is compatible with the epoxy you use. If you are not careful with the paint selection and process, you could end up having to scrape it off it it stays gooey from some strange interaction with the relatively fresh epoxy.
One question that I just have an opinion on.. should you try and bond the top hull to that inner liner.. or should you try and keep them separate to that they can flex like in the original build? Those two parts must be bonded together right under the mast attachment since the inside bulkhead works to support the down force from the mast. I dont think it would matter much either way..
Note.. you possibly could get away with polyester resin for that repair and some resource may even recommend that. My experience is that polyester is a somewhat OK glue but new polyester on old polyester just has a lot higher chance of delamation compared to epoxy. On the other hand, if you were really set on gelcoat for the final layer, gelcoat will stick to polyester resin. If I were doing that, I would use epoxy.
Once you have the epoxy/glass/filler done and it has the cosmetic surface you want (I have no idea how to get this.. I would probably just go for smooth), you have to protect the epoxy from UV and gelcoat wont stick to epoxy. I would just use some marine top side paint that is compatible with the epoxy you use. If you are not careful with the paint selection and process, you could end up having to scrape it off it it stays gooey from some strange interaction with the relatively fresh epoxy.
One question that I just have an opinion on.. should you try and bond the top hull to that inner liner.. or should you try and keep them separate to that they can flex like in the original build? Those two parts must be bonded together right under the mast attachment since the inside bulkhead works to support the down force from the mast. I dont think it would matter much either way..
Note.. you possibly could get away with polyester resin for that repair and some resource may even recommend that. My experience is that polyester is a somewhat OK glue but new polyester on old polyester just has a lot higher chance of delamation compared to epoxy. On the other hand, if you were really set on gelcoat for the final layer, gelcoat will stick to polyester resin. If I were doing that, I would use epoxy.
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Walt, I was thinking of trying to inject some thinned epoxy in between the cabin liner and hull. Make some 2x4 stands and just wedge them vertically between the berth and liner to apply upward pressure while it cures and create a tight bond... Still haven't decided what to do for finish...
I have been working a lot with epoxy since my other hobby is making cedar strip canoes.
I don't recommend you fill the space between the outer deck and the liner, you will waste a lot of epoxy for no reason and, since it does flow liberally until it starts curing, you might find leaks in unexpected places, it is very hard to contain and you will risk pouring gallon after expensive gallon of the stuff until you figure out where it is all going. It's just like slow water.
What you should do is trace the opening and make a plug out of 1/4" plywood as tight fitting as possible. Soak the plug with resin (both sides), let it cure, wash off the blush with mild soapy water, the blush is the waxy deposit that sometimes develops on the surface especially if you use cheap resin.
Make a glue of silica and wood flour of the consistency of peanut butter and use it to glue the edges of the plug to the opening. Don't glue it to the liner because we don't know what effect the shearing forces will have. Obviously the liner was meant to move separately from the hull, there may be a reason so, don't second guess the designers.
Once your plug is set and cured into place build up with fiberglass soaking one layer at the time making sure that the old plywood is well soaked. The fiberglass should be cut to the shape of the opening except for the last layer that should overlap it slightly. If you want perfection with a small chisel, remove the gelcoat around the opening for about 1/2" around and extend the last glass plug to cover the overlap.
Let it cure for a couple of days, wash with warm water and soap and sand smooth.
You can probably finish it with Interlux paint, the white is close to the Mac classic white. If you need an anti slip finish get the kiwi grip kit, I never used it but my local Marina swears by it, they have the original grey. Do not use polyester resin, it's pure unadulterated crap and it stinks!!
Feel free to contact me anytime
Bill
I don't recommend you fill the space between the outer deck and the liner, you will waste a lot of epoxy for no reason and, since it does flow liberally until it starts curing, you might find leaks in unexpected places, it is very hard to contain and you will risk pouring gallon after expensive gallon of the stuff until you figure out where it is all going. It's just like slow water.
What you should do is trace the opening and make a plug out of 1/4" plywood as tight fitting as possible. Soak the plug with resin (both sides), let it cure, wash off the blush with mild soapy water, the blush is the waxy deposit that sometimes develops on the surface especially if you use cheap resin.
Make a glue of silica and wood flour of the consistency of peanut butter and use it to glue the edges of the plug to the opening. Don't glue it to the liner because we don't know what effect the shearing forces will have. Obviously the liner was meant to move separately from the hull, there may be a reason so, don't second guess the designers.
Once your plug is set and cured into place build up with fiberglass soaking one layer at the time making sure that the old plywood is well soaked. The fiberglass should be cut to the shape of the opening except for the last layer that should overlap it slightly. If you want perfection with a small chisel, remove the gelcoat around the opening for about 1/2" around and extend the last glass plug to cover the overlap.
Let it cure for a couple of days, wash with warm water and soap and sand smooth.
You can probably finish it with Interlux paint, the white is close to the Mac classic white. If you need an anti slip finish get the kiwi grip kit, I never used it but my local Marina swears by it, they have the original grey. Do not use polyester resin, it's pure unadulterated crap and it stinks!!
Feel free to contact me anytime
Bill
Great advice Bfranchini on the epoxy method. Cant beat advice from a wood boat builder! The one thing I still am not sure of is should you attempt to bond the inner and outer hull sections. I remember that Willsnow also had an unusual crack sort of close to the mast on the inner liner and what caused that.. who knows but maybe something stressful (either a one time event or just how the boat was put together) is related to both of those cracks? And if you bonded the two hull peices together, would you make things worse? I tend to think those two pieces were not bonded together just because Mac didnt think it was necessary and worth the extra material and labor cost. My 02.. (which could be wrong) - for this particular boat that has the two cracks, I think I probably would attempt to bond them together.
If you did decide to bond the two hull parts together (????), I think I would do that with glass and epoxy. Prepare those inner surfaces as best you can, then wet glass small sheets and push them between the two hull pieces forming somewhat of a U on its side shape. Build this up with a fair amount of glass. Then finish the repair like Bfranchini outlined.
But.. still some doubt.. should those two hull parts be bonded together..
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Willsnow, does the crack on your Mac continue down the trunk?
Some miscellaneous thoughts and notes:
No water coming into the boat from here as best I can tell
It goes about 1/2 way down the trunk or about 2'
Thanks Bill. I was planning on injecting West System six10 thickened epoxy in between the liner and hull, then applying pressure up from inside so the 2 panels contact each other. One reason for this (and partly why I don't necessarily trust the boat builders...) is that my deck lay-up ends at that wood. So, from top-down: gelcoat, glass, wood core... and then air. The core wood isn't even sealed on the bottom side. I will take your advice and try to get a wood plug cut to take up some of that space. Thanks
And Walt is correct. I can't find a picture of it, but I do have a crack on the cabintop liner. It runs fore-aft across the molded arch that goes across the roof, between the trunk and the outer hull. I don't know what caused it and don't know if epoxying these two together will make any difference.
I do have one question that I guess hasn't been answered by the videos I've been watching: can I apply as many layers as needed, all at once? I think each layer has to cure till it starts to kick, but can I then put on the next layer of glass/resin and do the whole layup in one day? I'm using 105 resin/205 fast cure hardener.
Got all my glass and resin supplies ordered last night... We'll see how this goes....
Regarding laminating glass with epoxy, I think based on my past experience that the only issue with lots of layers of lamination at once is simply heat build up. You have to mix small batches of epoxy and use it fairly quickly as a large batch all in a small area (like in the mixing container) can go off real fast, get very hot - even flame/fire burn the boat up hot. I dont think you have the "wax" issue with epoxy if lamination layers are done one after the other before the epoxy has cured...
I've been a busy boy this week. it began by burying an electrical plug in the transom and hard wiring it to the battery for charging. no more dragging an extension cord into the cabin and digging into the battery compartment to hook up a charger. now I'll be able to just plug in my Ctec smart charger from the outside and have a cold one.
Because I already had the glove box out, to wire the charger plug, I built a new full width retainer bar and cleaned that area up a bit.
Inside the cabin there was no cover plate over the winch, and the hole in the plywood must have been carved out with a pocket knife, so I build a nice polished aluminum cover plate and screwed it on.
also note the new round digital volt meter above the fuse panel. much more accurate for keeping track of remaining battery charge.
We decided the v-berth was just to confining for old people like us, so I made a few modifications to allow the cabin to become a queen size bed. that began by building a new table, that locates more solidly in the fiberglass lips, and doesn't have the 3/4" high rim to lay on.
wood rails were fabricated and mounted on the sides of the walk through to support a new cover, which completes the sleeping area.
I hadn't even noticed, until the first trial fit of the walkway cover, that the port side fiberglass bench is about 3/4" lower than the starboard side. I don't know that we'll feel that when sleeping anyway, but it did require that the wood cover be cut near the table end, and a piano hinge installed, to allow everything to set flat.
Cheers,
Russ
Because I already had the glove box out, to wire the charger plug, I built a new full width retainer bar and cleaned that area up a bit.
Inside the cabin there was no cover plate over the winch, and the hole in the plywood must have been carved out with a pocket knife, so I build a nice polished aluminum cover plate and screwed it on.
also note the new round digital volt meter above the fuse panel. much more accurate for keeping track of remaining battery charge.
We decided the v-berth was just to confining for old people like us, so I made a few modifications to allow the cabin to become a queen size bed. that began by building a new table, that locates more solidly in the fiberglass lips, and doesn't have the 3/4" high rim to lay on.
wood rails were fabricated and mounted on the sides of the walk through to support a new cover, which completes the sleeping area.
I hadn't even noticed, until the first trial fit of the walkway cover, that the port side fiberglass bench is about 3/4" lower than the starboard side. I don't know that we'll feel that when sleeping anyway, but it did require that the wood cover be cut near the table end, and a piano hinge installed, to allow everything to set flat.
Cheers,
Russ
I fully concour with Walt, epoxy can get awful hot and, aside from curing prematurely, it can actually start a fire if the batch is large enough, not to mention pouring it inside bulkheads. To prevent this from happening in the pot, use a shallow container like a small disposable paint tray. As far as the theory of many laminations goes, there are two sorts of interactions: the chemical when you layer over a not fully cured area (less than 24 hrs) and the mechanical. The first is the strongest because the layers cure as one and bond, the latter is better if you want a smooth clear finish as in my canoes, still awfully strong but requires washing and a light sanding to rough up the surface. This is especially true if you are using cheap epoxy that releases a lot of blush. Best use West System, it cures clear and with virtually no blush.
Yeah, mine does have a crack down the trunk too. Haven't decided what to do with it yet. This is the winter of fiberglassing, sanding, painting, and re-bedding every piece of deck hardware. It's not as sexy as previous winters projects, but more necessary.
Cant you see or get to that side of the dagger board trunk from inside the cabin? Seems it be about where the bulkhead is on the 26S just under the mast.. I suppose you could also just leave that crack in there and never fix it as its way above the water line. The worst thing might simply be a place for rain water to leak in??
Russ, I like your bed. Looks like it will be very comfy plus have lots of height above you. I have to crawl in and out of my bed/cave (but like it also).
Russ, I like your bed. Looks like it will be very comfy plus have lots of height above you. I have to crawl in and out of my bed/cave (but like it also).
Went sailing today, put boat in "Hove To" and "we" watched the last nine minutes of the Bronco/Patriot game.
Pictures show the boat in Hove to for the last part of the game. Boat drifts at about 1.5 knots like this.
Pictures show the boat in Hove to for the last part of the game. Boat drifts at about 1.5 knots like this.
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Looks like your first mate was very intent on watching the game there Walt 
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I did a little continuation project on the cabin bed boards that I set up last week. I like having things stowed with some degree of organization rather than just throwing everything in a pile up front, so a place to stow the board was needed. this turned out to be a pretty simple modification, and it's worked out really well. a cedar post was fabricated and bolted in under the Port side cockpit cave. note the stud in the middle of the post, which is where the one and only wing-nut gets installed to retain the board. A small notch had to be cut in the fiberglass wall towards the stern, and a short piece of pvc pipe was slit down one side and inserted over the raw fiberglass edge to make sliding the board into place easier. with the notch in the rear and the wing-nut up front, the board is held in place really well so it won't be banging around down there wile sailing.
this is how it looks with the board installed:
The galley will reside in our attic at home, so a couple of these (stackable) plastic bins will fill that area and provide a dry place for cloths and food stuff etc.
Our weather has really started to feel like sailing time may be near, and the lakes have been filling nicely. we're getting VERY anxious to test this puppy out.
Russ&Jennifer
.I did a little continuation project on the cabin bed boards that I set up last week. I like having things stowed with some degree of organization rather than just throwing everything in a pile up front, so a place to stow the board was needed. this turned out to be a pretty simple modification, and it's worked out really well. a cedar post was fabricated and bolted in under the Port side cockpit cave. note the stud in the middle of the post, which is where the one and only wing-nut gets installed to retain the board. A small notch had to be cut in the fiberglass wall towards the stern, and a short piece of pvc pipe was slit down one side and inserted over the raw fiberglass edge to make sliding the board into place easier. with the notch in the rear and the wing-nut up front, the board is held in place really well so it won't be banging around down there wile sailing.
this is how it looks with the board installed:
The galley will reside in our attic at home, so a couple of these (stackable) plastic bins will fill that area and provide a dry place for cloths and food stuff etc.
Our weather has really started to feel like sailing time may be near, and the lakes have been filling nicely. we're getting VERY anxious to test this puppy out.
Russ&Jennifer
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Actually, this is from yesterday:
The backer board that was on the transom looked like it was in bad shape. It was a piece of plywood that wasn't finished. It was rotten and crushed, and I found a couple strange little beetles living in it when I took it off.
Underneath, the mess was mostly cosmetic and cleaned up easily. That bare area on the rub rail is just worn through the gel coat, but below are a few shallow gouges.
The bolts looked like they had been bedded with a household caulking, and it peeled away too easily. Definitely not 3M 5200 silicone.
My fix was to replace the the board with a piece of plastic delrin cutting board, cut to fit. This has many better properties than the plywood. It won't crush and has better wearing properties. Yeah, it's not "marine", but that piece of plywood wasn't either.
The entire area was cleaned and inspected. Fortunately (knock on wood) I didn't find any evidence of rotting core material when I poked around in the holes with a dental tool. I merely drilled holes in the new backer board so it would fit in the same place. The backing plate on the inside of the transom (which I forgot to photograph) is a nice piece of stainless steel with two stainless washers welded to it. It's quite hefty, so it was re-utilized. The holes were filled with and everything was bedded in marine silicone sealant to make a waterproof seal. New bolts and self locking nuts were installed
This is what I finished with:
The area where the gelcoat was rubbed off will get a touch-up in the future, as will the small gouges.
James
The backer board that was on the transom looked like it was in bad shape. It was a piece of plywood that wasn't finished. It was rotten and crushed, and I found a couple strange little beetles living in it when I took it off.
Underneath, the mess was mostly cosmetic and cleaned up easily. That bare area on the rub rail is just worn through the gel coat, but below are a few shallow gouges.
The bolts looked like they had been bedded with a household caulking, and it peeled away too easily. Definitely not 3M 5200 silicone.
My fix was to replace the the board with a piece of plastic delrin cutting board, cut to fit. This has many better properties than the plywood. It won't crush and has better wearing properties. Yeah, it's not "marine", but that piece of plywood wasn't either.
The entire area was cleaned and inspected. Fortunately (knock on wood) I didn't find any evidence of rotting core material when I poked around in the holes with a dental tool. I merely drilled holes in the new backer board so it would fit in the same place. The backing plate on the inside of the transom (which I forgot to photograph) is a nice piece of stainless steel with two stainless washers welded to it. It's quite hefty, so it was re-utilized. The holes were filled with and everything was bedded in marine silicone sealant to make a waterproof seal. New bolts and self locking nuts were installed
This is what I finished with:
The area where the gelcoat was rubbed off will get a touch-up in the future, as will the small gouges.
James
A friend of mine took these pictures of me a few days ago near the end of a sailing session. This is the entrance to the channel that goes under the London Bridge (the real one but moved to a small town out in the desert in the middle of nowhere in Arizona). At the other end of the channel is the entrance to the marina. Photo credit Carolyn Wilcox
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