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Author Topic: smile repair  (Read 1771 times)

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KWKloeber

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Re: smile repair
« Reply #15 on: June 12, 2021, 05:11:29 PM »

Md
Hard to tell from the pic but are you actually grinding on the joint or on the lead. When I draw a line // to the joint it appears that you ground 2-3Ē below the joint.  Optical illusion maybe?
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

mdidomenico

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Re: smile repair
« Reply #16 on: June 13, 2021, 12:19:36 PM »

i slipped with the angle grinder.  40grit flap disc takes off a lot in a hurry, there's a slight ridge.  the camera and sun make it look much worse then it really is.  a quick knock down and it should be good
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1989 Cat34 #856, original m-25xp

mdidomenico

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Re: smile repair
« Reply #17 on: June 13, 2021, 12:23:32 PM »

mdid : Beside the crack, I'm wondering where the RUST stain came from???  In the 1989 C34 production there should have been a solid fiberglass keel stub under the bilge!

dunno, it's possible it isn't rust at all but rather just dirt.  (though i agree it does look like rust)  the boat sat up on the hard for 5yrs before i got her, so it's also possible there was a leak through the keel bolts that's been plugged by grime.  and now that i've tightened the bolts the grime might be acting like a gasket.  clearly not ideal, but i'm not dropping the entire keel to figure it out.
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1989 Cat34 #856, original m-25xp

mdidomenico

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Re: smile repair
« Reply #18 on: September 29, 2021, 05:17:44 AM »

now that august has passed and the burning ball of fire in the sky has moved a few inches further away, i'm back to this.  i tried in august to get some done, but even the slow epoxy kicked in smoking glory too fast to work with.

i sanded back more of the paint/gelcoat to open the area up a little more.

then i followed with thixo in the seem.  i pushed as much of it as i could into the joint using a putty knife.  in hindsight, i'd probably skip this if i had to do it again.  thixo is a pain the neck.  i broke one caulk gun and the hardware stores don't usually carry the 8:1 guns.  so between it hardening in the mixing tube and the fact that you need the hands of giant to get it out it didn't go great.  it's also seriously sticky.  much more so then regular epoxy.

after the thixo geled, i put two layers of 1708 glass over top.  i ran out of time and could no longer crouch under the boat anymore, so i'll have to sand it a little and put an additional layer over top.  after that i'll fair it out and it should be done

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1989 Cat34 #856, original m-25xp

KWKloeber

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Re: smile repair
« Reply #19 on: September 29, 2021, 07:57:11 AM »

Iíve never tried that stuff. I just fill a west systems cartridge with my own mix, and then can control the additive/viscosity/cure time.
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Ron Hill

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Re: smile repair
« Reply #20 on: September 29, 2021, 02:28:20 PM »

Guys : Now after all that work fixing the smile - during the next haul if you let the yard allow the hull to rock back  - you'll open up your smile fix and be staring all over again!!  I only allow the block to be under the nose with NO block further back under the wing.  A set of jackstands will keep the hull from rocking back!

Make the yard lower the boat so the weight is on the nose of the wing.  The factory told me to have 75% on the weight on the nose keel and 25% on the jackstands/cradle.   

A few thoughts
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mdidomenico

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Re: smile repair
« Reply #21 on: September 30, 2021, 05:16:37 AM »

Iíve never tried that stuff. I just fill a west systems cartridge with my own mix, and then can control the additive/viscosity/cure time.

i hadn't either.  the theory was that the thickner/additives they used are more elastic then normal 406 or something akin.  so if there's flex the bond might hold better.  i'll concede that might totally be in my head.

i'll also note, that there's apparently something mixed into it as i have a rash on my arm where it touched me, which doesn't happen with regular west/totalboat epoxy.  so there's that.

so given the hassle, the expense of the stuff, and now my arm, unless i see some clear advantage down the road i'll probably skip thixo for anything in the future :)
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1989 Cat34 #856, original m-25xp

KWKloeber

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Re: smile repair
« Reply #22 on: October 01, 2021, 06:44:12 PM »


Iíve never tried that stuff. I just fill a west systems cartridge with my own mix, and then can control the additive/viscosity/cure time.


i hadn't either.  the theory was that the thickner/additives they used are more elastic then normal 406 or something akin.  so if there's flex the bond might hold better.  i'll concede that might totally be in my head.

i'll also note, that there's apparently something mixed into it as i have a rash on my arm where it touched me, which doesn't happen with regular west/totalboat epoxy.  so there's that.

so given the hassle, the expense of the stuff, and now my arm, unless i see some clear advantage down the road i'll probably skip thixo for anything in the future :)



I don't know how that stuff compares to the G-Flex (which can be used in the West cartridges.)  I'm torn between the concept of using something that allows a flex and normal epoxy because the joint is going to be covered with glass/epoxy that will not want to give at all anyway.  My entire keel surface is bed in 5200 with a band of 2-3 layers of epoxy/triaxial cloth around the joint.  Nary a problem.
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

mdidomenico

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Re: smile repair
« Reply #23 on: October 02, 2021, 02:38:48 PM »

put the third layer of glass on.  used a west systems roller this time.  made the process MUCH easier then trying to push the stuff in with a brush.  i'm debating on whether to put another layer.  i don't think it needs it.  now i have to figure out what to cover it with.  if i cared about a smooth hull i might fair it out, but that seems a waste, i might just use a barrier coat and then bottom paint.  any products recommended?
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Noah

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Re: smile repair
« Reply #24 on: October 02, 2021, 05:01:45 PM »

Wow, that is a big patch. Youíve gone so far, I would take the final stepsÖÖfair it out with several layers of epoxy fairing compound, sanding in-between with a longboard, then 3-4 coats of Interlux InterProtect 2000e, then two coats of bottom. You askedÖ 8)
« Last Edit: October 02, 2021, 05:21:17 PM by Noah »
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Stu Jackson

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Re: smile repair
« Reply #25 on: October 02, 2021, 05:57:59 PM »

I agree with the idea of fairing.  Those small dimples from the weave of what you used will create crevasses for bad gunk to grow in if you don't, even when painted.
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KWKloeber

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Re: smile repair
« Reply #26 on: October 03, 2021, 01:34:31 AM »

I wished you had asked for guidance on glassing it up. What I see is having made yourself a LOT of unnecessary work to finish it smooth/correctly. 

The glass is used for structural strength not for bulk filling. So I would have banded the joint w/ 4Ē wide triaxial glass or even carbon fiber.  Thereís no reason to use glass on the nose above and below the crack - it doesnít add anything.

The remainder I would have filled to the band level w/ epoxy/successively less-hard filler.  Starting w/pure colloidal silica or microfibers.  You hit the first coat with a 60 grit angle grinder just to take off high spots/trowel lines.  Then proportion down the hard filler and proportion up medium or low density filler.   Just grade down to a pure medium density filler as the final layer, 120 grit sand, then last coat fair over the band and areas above/below to make a nice transition across it all, finishing off w/ 200 grit D/A or R/O sander.  You can use those type for the first couple hits, but an angle grinder just significantly reduces sanding/grinding time on very hard filler.

With the glass all over itís a HELL of a job to successively sand it level, no less smooth. Itís possible to make a nice finish w/o adding a lot of fairing but itís a BEAR to sand structural epoxy because itís got such a high shore hardness.

Just IMO, I would never leave a nice smile job looking like a mess that was painted over. But YBowYC.
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Wurlitzer1614

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Re: smile repair
« Reply #27 on: October 04, 2021, 11:46:15 AM »

mdidomenico- Thank you for the excellent documentation. Iím excited to see your finished product. Iíll be doing the same repair to our Ď88 before next summer.
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mdidomenico

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Re: smile repair
« Reply #28 on: October 05, 2021, 10:16:32 AM »

I agree with the idea of fairing.  Those small dimples from the weave of what you used will create crevasses for bad gunk to grow in if you don't, even when painted.

the other two layers of glass i sanded before i applied that last third, it smoothed out fairly well even without fairing compound.  the ridges aren't as deep as they might appear on camera.  even with a couple layers of bottom paint, i'm not entirely convinced it'll be any more crater'ish then the rest of the ballast.

but i'll concede it could always be smoother, its just whether all that sanding and fairing is worth the pain in my shoulders. i'm mean lets get real, i'm not racing and it's not a visible section of the boat, how smooth does it really need to be.
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1989 Cat34 #856, original m-25xp

mdidomenico

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Re: smile repair
« Reply #29 on: October 05, 2021, 10:24:26 AM »

I wished you had asked for guidance on glassing it up. What I see is having made yourself a LOT of unnecessary work to finish it smooth/correctly. 

The glass is used for structural strength not for bulk filling. So I would have banded the joint w/ 4Ē wide triaxial glass or even carbon fiber.  Thereís no reason to use glass on the nose above and below the crack - it doesnít add anything.

The remainder I would have filled to the band level w/ epoxy/successively less-hard filler.  Starting w/pure colloidal silica or microfibers.  You hit the first coat with a 60 grit angle grinder just to take off high spots/trowel lines.  Then proportion down the hard filler and proportion up medium or low density filler.   Just grade down to a pure medium density filler as the final layer, 120 grit sand, then last coat fair over the band and areas above/below to make a nice transition across it all, finishing off w/ 200 grit D/A or R/O sander.  You can use those type for the first couple hits, but an angle grinder just significantly reduces sanding/grinding time on very hard filler.

With the glass all over itís a HELL of a job to successively sand it level, no less smooth. Itís possible to make a nice finish w/o adding a lot of fairing but itís a BEAR to sand structural epoxy because itís got such a high shore hardness.

Just IMO, I would never leave a nice smile job looking like a mess that was painted over. But YBowYC.


what i've done really isn't that far from what you're describing.  the thixo filled in the gap and levelled out the deep grind i did to get back to the lead.  the 3 layers of 1708 bulked up the joint and filled in the depression from where i sanded the bevel out. 

also keep in mind what i didn't mention is the glass isn't totally wetted out at the top, i cut the piece oversize taped it to the hull and then painted on the epoxy.  the top edge is going to come down 2-3" inches and it should be fairly straight along a straight edge from top to bottom of the keel.  i'll check it when i go down this weekend.

as far as the front edge.  it was easier just to wrap it around the nose and move on. 

i'll hit it with a sander on saturday, we'll see how it looks.  i think the camera + angle might be making it look a lot worse then it is.
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