Re-gelcoating my deck: Project thread

[UNCIVILIZED]

That AC coveralls idea is pretty slick. Might have to borrow it from time to time

[Suijin]

Originally Posted by minaret

Don't take your initial sanding past 80, then apply at least three heavy coats of gelcoat as a primer (4 is better) and sand out to at least 220 (320 is better) before applying paint. After you apply primer gel guide coat and skip straight to 150 or even 180, depending on whether you roll applied or sprayed. Use either PVA or surface seal, not both, with no accelerators. I reduce with MEK and/or styrene monomer to promote flow. Keep at it!

What? I thought I could get away with putting the paint down on the old gelcoat once I got the non-skid off. There are a few areas where I went down to the glass, but they are pretty few and patchy. Why do I need to put new gel down, particularly on areas where there's already a good amount of thickness left even with the molded-in non-skid ground off?

My revised plan has been to simply restore the gelcoat where I'm not putting non-skid down. That may change after I attack the repairs on the cracks. If I can't get a decent enough match to have them blend to my satisfaction, Plan B will be to put down new gel. If I go that route, putting down 3/4 coats for primer for the non-skid will be easy.

[Suijin]

So I've been going back and investigating cracks more carefully. As suspected, many of them do go into the glass. In many cases the top level of resin appears intact, but a bit more grinding and as soon as you're into the CSM you can see it. None of the cracks appear to go deeper into the first layer of cloth.

So I'm wondering how to approach this. The cracks is around the forward salon hatch and on both sides of the cockpit combing, primarily. There are some around the galley hatch, and a couple that extend forward along the cabin side a short ways at the turn from the deck to the cabin side.

With respect to the hatch, I'm wondering if it's not ultimately easier to just grind out a picture frame square around the whole thing and lay down new glass, instead of trying to do a patchwork, then fair and gel the whole thing back up. Seems a bit daunting but perhaps less work and easier to manage. The same question applies to the cockpit, although some of the cracks are more distributed.





I guess one question is whether with the cracks only going into the CSM whether reglassing is necessary. In a few spots I know it is, but wondering if I can get away with just new gel on the shallower grinds.

[UNCIVILIZED]

For the two areas above, it seems like the problem ultimately stems from flexing, due to insufficient stiffness. And with a hatch, it's easy to build up a stiff, raised flange/base to mount it on. Along with a breakwater around 3+ sides of it to further add to the stiffness of the deck in the area.

As to the cockpit coamings, I'm in need of a bit of caffeine prior to tackling that one
Looks like the stresses from the jib track are pulling on the joint where the deck meets the cockpit coaming more than at the toerail, but as to how to sort that out ??? Well, other than major deck surgery

[Suijin]

Originally Posted by UNCIVILIZED

For the two areas above, it seems like the problem ultimately stems from flexing, due to insufficient stiffness. And with a hatch, it's easy to build up a stiff, raised flange/base to mount it on. Along with a breakwater around 3+ sides of it to further add to the stiffness of the deck in the area.

As to the cockpit coamings, I'm in need of a bit of caffeine prior to tackling that one
Looks like the stresses from the jib track are pulling on the joint where the deck meets the cockpit coaming more than at the toerail, but as to how to sort that out ??? Well, other than major deck surgery

Well the boat is 31 years old and the cracks only appeared in the last few years. I am likely going to reinforce the combings under the winches. If there is stress it's from the winches, not the jib tracks I think.

The hatch is already mounted on a stiff, raised flange. But a another layer of cloth around it is not going to hurt

[jhulmer]

Suijin
Are you sure the core didn't get wet, freeze and buckle those areas? That is what I'm finding on a couple places on my deck project. Where I'm having to replace coring, the gel is cracked like yours but different.

Around fill fittings and a dorade I have stress cracks in the gel and glass in a pattern that radiates out from a center. I plan to grind the area and add a layer of glass.

just a thought.
Jim


edit: What I did was drill a 1/4" dia hole in a suspected area into the core and if the tailings were wet or damp I drilled multiple 3/8 holes in the area until I got dry coring then put a fan blowing over the holes continuously until dry. Worked well. I am now injecting the holes with thickened epoxy to fill and tie the deck to the liner. I just don't trust the moisture meters.
just realized I'm redundant here from a earlier post.


Thanks for the continued posts!

[Suijin]

Jim, no the core did not get wet. If you look back a few posts you'll see that I went over it with a moisture meter and it's all good, even a spot that I thought was not.

However, the gelcoat was pretty seriously chalked when I got the boat and I did not get to rescuing it before another winter had passed, during which there was a fair amount of ice on the deck. I'm assuming that the porous, chalked gelcoat absorbed water and then the cycling of freezing/warming cracked it. Most of the cracking is in areas where ice collects and is the slowest to melt. The hatch is a bit of a mystery, as it's a hight point and right adjacent to a bulkhead that is solid.

In any event, I want to ensure that the repair is adequate and that it forestalls this happened again for as long as possible. I'm leaning towards taking it down all the way around the edge and laying in more glass along the radius.

[jhulmer]

Originally Posted by Suijin

Jim, no the core did not get wet. If you look back a few posts you'll see that I went over it with a moisture meter and it's all good, even a spot that I thought was not.

However, the gelcoat was pretty seriously chalked when I got the boat and I did not get to rescuing it before another winter had passed, during which there was a fair amount of ice on the deck. I'm assuming that the porous, chalked gelcoat absorbed water and then the cycling of freezing/warming cracked it. Most of the cracking is in areas where ice collects and is the slowest to melt. The hatch is a bit of a mystery, as it's a hight point and right adjacent to a bulkhead that is solid.

In any event, I want to ensure that the repair is adequate and that it forestalls this happened again for as long as possible. I'm leaning towards taking it down all the way around the edge and laying in more glass along the radius.

This sounds plausible as the cracks do look similar to what I'm seeing on my project. So maybe it is from the pressure of ice. I sure can't answer that but either way it has to be fixed.
I'm In agreement on fixing it right this time because this is turning into a lot of work and I don't want to do it again! Oh! and I haven't even started the hard part yet!

[Zach]

Good thread.

They make 5/8-11 roloc adapters, I've bought a few on Ebay as that seems to be the only place they exist... Lets you mount a roloc on a mini-grinder.

3M 4" Roloc scotch brite rubber pad holder backer 5/8"-11 arbor grinder TS TSM | eBay

Something I'd throw out there, is that it is worth your time to fair in the 6 inches or so to each side of the cabin and toe rail.

Reason being, you can sand from that area up into the fillets. If the non-skid area is still high and low, you have to use a wee-baby block and keep a careful touch not to ride up on the high and dig in to the round. That isn't so bad with paint, as you don't run through the grits or buff.

I like to mud hog the non-skid off, and use a steel straight edge about a foot long to bring it down to the same level as the area that needs to be shiny. I've got an old National Detroit that is a sweet heart, she'll freeze your hands off but makes beautiful surfaces. The good thing about a mud hog, is that you can guide coat a surface and jump grits. 80 to 320? No sweat if there is material that sands the same, it's going to be damn flat.

Pick on and fill the low spots around the deck drains and hawse pipes, as low spots where water gathers are your dirt spots when you are done. Awlgrip doesn't like to remain under-water for very long, which sadly can be a month of rainy days and standing water. If you are going to get blisters, they happen there. Or small puddles around stanchions.

Remember that you can trowel gelcoat.

Roll on a coat thick, wait for a it to tack up enough to start being sag-free, take a yard stick or sheet rock trowel and pull off the excess, remove the excess from the boat. Flatten out any drag lines, or over-fill with new. Then either spray or roll on enough that you get a full cure on the thin areas. It also helps a bit if you add just a touch of tint to the troweled coat so when you get to the low spot, you know its time to stop rather than sand in a new low spot. Don't tint the top coat.

I'm a fan of getting that sort of stuff fair, before spraying thinned. Mainly so that you get a feather edge around any repairs. It takes a fair bit of material to fill a holiday or a slight under-filled area that has left a hard edge. If you are thinned enough to spray nicely you can get solvent popping and porosity if you try to put a triple pass on around the same spot to fill/cover. Solvent popping really sucks to find when you start buffing, you see it when the buffing compound fills up the pits.

That is something else, to find, as by that point you've got taped and bleeding finger tips that are too sore to even pick up anything to throw across the boat yard...

So, going backward to fairing... Once you have a 6 inch wide pass around the cabin, you can push a 16 inch board around the boat with 80 grit. Once its flat, its flat and you can run through the grits in no-time. The shorter the board you have to use, the longer it takes to get an OCD quality job. Shiny isn't always fair, and fair isn't always shiny... but trying to buff low spots in inside corners hurts my soul just a little bit.

Hutchins makes a white 16 inch board, a speed file that is ever so slightly flexible, that works well for cutting down high spots with sticky 80. 3M makes a stiff vinyl padded 16 inch board that works very well in the 220-320 grits to make things flat. Once you get there, you can go back to a rubber block and go up the grits as high as you want. It helps a lot to be flat enough, that there are no low spots that a rubber block spans. Full-stop... If the rubber block spans them, then in order to get our your orange peel you have to sand for days and make a low spot the size of your rubber block.

If... everything is damn flat, you spray your thinned gel and sand with the 16 inch board until you have an even coat, then there are no low spots. Keep sanding till you have a haze of scratches in the bottom of the peel, and switch grits.

Once your corners are fair and flat, you can put an inch thick foam soft interface pad on your DA and power sand your fillets with 320-400 grit to remove orange peel and stipple before you hand sand.

Remember that the key to sanding fillets, is don't sand your fillets. If they look good now just sand for tooth and adhesion.

Dry guide coat, and slow speed take it off the orange peel. That makes life a bit easier once you can do that, as buffing them takes no time at all once everything is flat, as you can use a foam interface pad to help out with the buffing... Aqua buff 2000 is nice to work with as you can wet sand back at 800, and once you have contact everywhere buff till done.

If you have a lot of cracked areas tight together like around your hatch, remember that Mat is cheap and easy to work with, and adds a bit of stiffness. You can grind out a 5 inch wide stripe that takes almost all the cracking and lay in a torn layer of mat. Make the repair wide enough that it reaches into the non-skid area. If you over-fill the low spot so that it overlays over a blue masking tape line to border the area that is good... you can grind down to the tape, until you can peel it off and you have a feather edge that is a tape line over-filled.

If you want some extra strength, you can pull the roves out of woven roving and wrap it around your hatch frame. Dunk a strand into your resin and let it wet out fully, and then smash into your first layer of mat. Instant unidirectional-reinforcement. They also make good bulk for rebuilding the inside radius of a corner fillet. Fillets made of uni-fiber don't generally stress crack. Over-fill the low with mat, two layers above 75f gives enough thickness to damn near surface cure without any wax or PVA, then just grind off the sticky.

If you use a 6 inch wide air roller, and are careful to follow the contours you should be able to grind in 40 minutes or so. Once your polyester reaches its peak exo-therm temp and starts coming back down, its done shrinking for the most part. Unless you paint it black and sit it outside...

I have a grinder that normally has a disc on it pad just for this so I don't throw them away when boogered... Tip the grinder up just a touch, and grab material from under the sticky. Sort of like grinding tar off a deck... don't grind the sticky stuff, grind the stuff under the sticky stuff.

Grind down till fair.

Depending on how close the rest of the area is, a layer of finish cloth over the mat and gone over with a body spreader makes things fair enough that when you grind back there are no lows to fill. The finish cloth gets ground off because it is already high, it just proofs out that you've got an even surface. Grind back till you see what it is supposed to look like, and stop... DA with 80 grit until you have a feather edge.

I use a paint stir stick for fairness guide on those type repairs, once it makes contact the whole way across from the good into the bad you can kiss it with a 16 inch board and 80 grit and see if you have contact everywhere. Make the inside edge just a touch low, basically just tip the grinder in ever so slightly to take off enough to leave a slight low, say a 64th or a split in two sharp pencil line of a low to your stir stick. That way when you DA it there is no way to burn off your gelcoat on the inside corners.

Change the pad on your DA. They curl up with use. Once you start thinking 220 grit, you want a flat pad. You want a flat pad from the start, but they wear out. One day you'll be working up to a fillet or raised portion of the deck with a worn out pad and it digs a trough in before you get rid of your guide coat. That is just enough to put a halo around things 3/4 of an inch away from the edge. Hmm, must be low... looks low, looks low, burn through... 220 doesn't cut that much slower than 80, so if it is fair to your block or board and the DA disagrees, change the pad!

Cheers,

Zach

[minaret]

Originally Posted by Zach

Good thread.

They make 5/8-11 roloc adapters, I've bought a few on Ebay as that seems to be the only place they exist... Lets you mount a roloc on a mini-grinder.

3M 4" Roloc scotch brite rubber pad holder backer 5/8"-11 arbor grinder TS TSM | eBay

Something I'd throw out there, is that it is worth your time to fair in the 6 inches or so to each side of the cabin and toe rail.

Reason being, you can sand from that area up into the fillets. If the non-skid area is still high and low, you have to use a wee-baby block and keep a careful touch not to ride up on the high and dig in to the round. That isn't so bad with paint, as you don't run through the grits or buff.

I like to mud hog the non-skid off, and use a steel straight edge about a foot long to bring it down to the same level as the area that needs to be shiny. I've got an old National Detroit that is a sweet heart, she'll freeze your hands off but makes beautiful surfaces. The good thing about a mud hog, is that you can guide coat a surface and jump grits. 80 to 320? No sweat if there is material that sands the same, it's going to be damn flat.

Pick on and fill the low spots around the deck drains and hawse pipes, as low spots where water gathers are your dirt spots when you are done. Awlgrip doesn't like to remain under-water for very long, which sadly can be a month of rainy days and standing water. If you are going to get blisters, they happen there. Or small puddles around stanchions.

Remember that you can trowel gelcoat.

Roll on a coat thick, wait for a it to tack up enough to start being sag-free, take a yard stick or sheet rock trowel and pull off the excess, remove the excess from the boat. Flatten out any drag lines, or over-fill with new. Then either spray or roll on enough that you get a full cure on the thin areas. It also helps a bit if you add just a touch of tint to the troweled coat so when you get to the low spot, you know its time to stop rather than sand in a new low spot. Don't tint the top coat.

I'm a fan of getting that sort of stuff fair, before spraying thinned. Mainly so that you get a feather edge around any repairs. It takes a fair bit of material to fill a holiday or a slight under-filled area that has left a hard edge. If you are thinned enough to spray nicely you can get solvent popping and porosity if you try to put a triple pass on around the same spot to fill/cover. Solvent popping really sucks to find when you start buffing, you see it when the buffing compound fills up the pits.

That is something else, to find, as by that point you've got taped and bleeding finger tips that are too sore to even pick up anything to throw across the boat yard...

So, going backward to fairing... Once you have a 6 inch wide pass around the cabin, you can push a 16 inch board around the boat with 80 grit. Once its flat, its flat and you can run through the grits in no-time. The shorter the board you have to use, the longer it takes to get an OCD quality job. Shiny isn't always fair, and fair isn't always shiny... but trying to buff low spots in inside corners hurts my soul just a little bit.

Hutchins makes a white 16 inch board, a speed file that is ever so slightly flexible, that works well for cutting down high spots with sticky 80. 3M makes a stiff vinyl padded 16 inch board that works very well in the 220-320 grits to make things flat. Once you get there, you can go back to a rubber block and go up the grits as high as you want. It helps a lot to be flat enough, that there are no low spots that a rubber block spans. Full-stop... If the rubber block spans them, then in order to get our your orange peel you have to sand for days and make a low spot the size of your rubber block.

If... everything is damn flat, you spray your thinned gel and sand with the 16 inch board until you have an even coat, then there are no low spots. Keep sanding till you have a haze of scratches in the bottom of the peel, and switch grits.

Once your corners are fair and flat, you can put an inch thick foam soft interface pad on your DA and power sand your fillets with 320-400 grit to remove orange peel and stipple before you hand sand.

Remember that the key to sanding fillets, is don't sand your fillets. If they look good now just sand for tooth and adhesion.

Dry guide coat, and slow speed take it off the orange peel. That makes life a bit easier once you can do that, as buffing them takes no time at all once everything is flat, as you can use a foam interface pad to help out with the buffing... Aqua buff 2000 is nice to work with as you can wet sand back at 800, and once you have contact everywhere buff till done.

If you have a lot of cracked areas tight together like around your hatch, remember that Mat is cheap and easy to work with, and adds a bit of stiffness. You can grind out a 5 inch wide stripe that takes almost all the cracking and lay in a torn layer of mat. Make the repair wide enough that it reaches into the non-skid area. If you over-fill the low spot so that it overlays over a blue masking tape line to border the area that is good... you can grind down to the tape, until you can peel it off and you have a feather edge that is a tape line over-filled.

If you want some extra strength, you can pull the roves out of woven roving and wrap it around your hatch frame. Dunk a strand into your resin and let it wet out fully, and then smash into your first layer of mat. Instant unidirectional-reinforcement. They also make good bulk for rebuilding the inside radius of a corner fillet. Fillets made of uni-fiber don't generally stress crack. Over-fill the low with mat, two layers above 75f gives enough thickness to damn near surface cure without any wax or PVA, then just grind off the sticky.

If you use a 6 inch wide air roller, and are careful to follow the contours you should be able to grind in 40 minutes or so. Once your polyester reaches its peak exo-therm temp and starts coming back down, its done shrinking for the most part. Unless you paint it black and sit it outside...

I have a grinder that normally has a disc on it pad just for this so I don't throw them away when boogered... Tip the grinder up just a touch, and grab material from under the sticky. Sort of like grinding tar off a deck... don't grind the sticky stuff, grind the stuff under the sticky stuff.

Grind down till fair.

Depending on how close the rest of the area is, a layer of finish cloth over the mat and gone over with a body spreader makes things fair enough that when you grind back there are no lows to fill. The finish cloth gets ground off because it is already high, it just proofs out that you've got an even surface. Grind back till you see what it is supposed to look like, and stop... DA with 80 grit until you have a feather edge.

I use a paint stir stick for fairness guide on those type repairs, once it makes contact the whole way across from the good into the bad you can kiss it with a 16 inch board and 80 grit and see if you have contact everywhere. Make the inside edge just a touch low, basically just tip the grinder in ever so slightly to take off enough to leave a slight low, say a 64th or a split in two sharp pencil line of a low to your stir stick. That way when you DA it there is no way to burn off your gelcoat on the inside corners.

Change the pad on your DA. They curl up with use. Once you start thinking 220 grit, you want a flat pad. You want a flat pad from the start, but they wear out. One day you'll be working up to a fillet or raised portion of the deck with a worn out pad and it digs a trough in before you get rid of your guide coat. That is just enough to put a halo around things 3/4 of an inch away from the edge. Hmm, must be low... looks low, looks low, burn through... 220 doesn't cut that much slower than 80, so if it is fair to your block or board and the DA disagrees, change the pad!

Cheers,

Zach

Freakin hilarious! Great minds do think alike.However I'm pretty sure you're speaking a langauge that the non pro's around here are only picking up part of. Pulling 24 oz tows, torn matt, etc etc etc. It's all EXACTLY how we do it up here! For the most part...

[minaret]

Originally Posted by Suijin

So I've been going back and investigating cracks more carefully. As suspected, many of them do go into the glass. In many cases the top level of resin appears intact, but a bit more grinding and as soon as you're into the CSM you can see it. None of the cracks appear to go deeper into the first layer of cloth.

So I'm wondering how to approach this. The cracks is around the forward salon hatch and on both sides of the cockpit combing, primarily. There are some around the galley hatch, and a couple that extend forward along the cabin side a short ways at the turn from the deck to the cabin side.

With respect to the hatch, I'm wondering if it's not ultimately easier to just grind out a picture frame square around the whole thing and lay down new glass, instead of trying to do a patchwork, then fair and gel the whole thing back up. Seems a bit daunting but perhaps less work and easier to manage. The same question applies to the cockpit, although some of the cracks are more distributed.





I guess one question is whether with the cracks only going into the CSM whether reglassing is necessary. In a few spots I know it is, but wondering if I can get away with just new gel on the shallower grinds.

That is a ton of cracking. Yes, if it goes into the CSM it needs glass, unlesss you want it to reappear. At the very least use a fiber reinforced filler like 3M High Strength. But really, glass. There is no substitute.

[jhulmer]

Originally Posted by Zach

Good thread.

They make 5/8-11 roloc adapters, I've bought a few on Ebay as that seems to be the only place they exist... Lets you mount a roloc on a mini-grinder.

3M 4" Roloc scotch brite rubber pad holder backer 5/8"-11 arbor grinder TS TSM | eBay

Something I'd throw out there, is that it is worth your time to fair in the 6 inches or so to each side of the cabin and toe rail.

Reason being, you can sand from that area up into the fillets. If the non-skid area is still high and low, you have to use a wee-baby block and keep a careful touch not to ride up on the high and dig in to the round. That isn't so bad with paint, as you don't run through the grits or buff.

I like to mud hog the non-skid off, and use a steel straight edge about a foot long to bring it down to the same level as the area that needs to be shiny. I've got an old National Detroit that is a sweet heart, she'll freeze your hands off but makes beautiful surfaces. The good thing about a mud hog, is that you can guide coat a surface and jump grits. 80 to 320? No sweat if there is material that sands the same, it's going to be damn flat.

Pick on and fill the low spots around the deck drains and hawse pipes, as low spots where water gathers are your dirt spots when you are done. Awlgrip doesn't like to remain under-water for very long, which sadly can be a month of rainy days and standing water. If you are going to get blisters, they happen there. Or small puddles around stanchions.

Remember that you can trowel gelcoat.

Roll on a coat thick, wait for a it to tack up enough to start being sag-free, take a yard stick or sheet rock trowel and pull off the excess, remove the excess from the boat. Flatten out any drag lines, or over-fill with new. Then either spray or roll on enough that you get a full cure on the thin areas. It also helps a bit if you add just a touch of tint to the troweled coat so when you get to the low spot, you know its time to stop rather than sand in a new low spot. Don't tint the top coat.

I'm a fan of getting that sort of stuff fair, before spraying thinned. Mainly so that you get a feather edge around any repairs. It takes a fair bit of material to fill a holiday or a slight under-filled area that has left a hard edge. If you are thinned enough to spray nicely you can get solvent popping and porosity if you try to put a triple pass on around the same spot to fill/cover. Solvent popping really sucks to find when you start buffing, you see it when the buffing compound fills up the pits.

That is something else, to find, as by that point you've got taped and bleeding finger tips that are too sore to even pick up anything to throw across the boat yard...

So, going backward to fairing... Once you have a 6 inch wide pass around the cabin, you can push a 16 inch board around the boat with 80 grit. Once its flat, its flat and you can run through the grits in no-time. The shorter the board you have to use, the longer it takes to get an OCD quality job. Shiny isn't always fair, and fair isn't always shiny... but trying to buff low spots in inside corners hurts my soul just a little bit.

Hutchins makes a white 16 inch board, a speed file that is ever so slightly flexible, that works well for cutting down high spots with sticky 80. 3M makes a stiff vinyl padded 16 inch board that works very well in the 220-320 grits to make things flat. Once you get there, you can go back to a rubber block and go up the grits as high as you want. It helps a lot to be flat enough, that there are no low spots that a rubber block spans. Full-stop... If the rubber block spans them, then in order to get our your orange peel you have to sand for days and make a low spot the size of your rubber block.

If... everything is damn flat, you spray your thinned gel and sand with the 16 inch board until you have an even coat, then there are no low spots. Keep sanding till you have a haze of scratches in the bottom of the peel, and switch grits.

Once your corners are fair and flat, you can put an inch thick foam soft interface pad on your DA and power sand your fillets with 320-400 grit to remove orange peel and stipple before you hand sand.

Remember that the key to sanding fillets, is don't sand your fillets. If they look good now just sand for tooth and adhesion.

Dry guide coat, and slow speed take it off the orange peel. That makes life a bit easier once you can do that, as buffing them takes no time at all once everything is flat, as you can use a foam interface pad to help out with the buffing... Aqua buff 2000 is nice to work with as you can wet sand back at 800, and once you have contact everywhere buff till done.

If you have a lot of cracked areas tight together like around your hatch, remember that Mat is cheap and easy to work with, and adds a bit of stiffness. You can grind out a 5 inch wide stripe that takes almost all the cracking and lay in a torn layer of mat. Make the repair wide enough that it reaches into the non-skid area. If you over-fill the low spot so that it overlays over a blue masking tape line to border the area that is good... you can grind down to the tape, until you can peel it off and you have a feather edge that is a tape line over-filled.

If you want some extra strength, you can pull the roves out of woven roving and wrap it around your hatch frame. Dunk a strand into your resin and let it wet out fully, and then smash into your first layer of mat. Instant unidirectional-reinforcement. They also make good bulk for rebuilding the inside radius of a corner fillet. Fillets made of uni-fiber don't generally stress crack. Over-fill the low with mat, two layers above 75f gives enough thickness to damn near surface cure without any wax or PVA, then just grind off the sticky.

If you use a 6 inch wide air roller, and are careful to follow the contours you should be able to grind in 40 minutes or so. Once your polyester reaches its peak exo-therm temp and starts coming back down, its done shrinking for the most part. Unless you paint it black and sit it outside...

I have a grinder that normally has a disc on it pad just for this so I don't throw them away when boogered... Tip the grinder up just a touch, and grab material from under the sticky. Sort of like grinding tar off a deck... don't grind the sticky stuff, grind the stuff under the sticky stuff.

Grind down till fair.

Depending on how close the rest of the area is, a layer of finish cloth over the mat and gone over with a body spreader makes things fair enough that when you grind back there are no lows to fill. The finish cloth gets ground off because it is already high, it just proofs out that you've got an even surface. Grind back till you see what it is supposed to look like, and stop... DA with 80 grit until you have a feather edge.

I use a paint stir stick for fairness guide on those type repairs, once it makes contact the whole way across from the good into the bad you can kiss it with a 16 inch board and 80 grit and see if you have contact everywhere. Make the inside edge just a touch low, basically just tip the grinder in ever so slightly to take off enough to leave a slight low, say a 64th or a split in two sharp pencil line of a low to your stir stick. That way when you DA it there is no way to burn off your gelcoat on the inside corners.

Change the pad on your DA. They curl up with use. Once you start thinking 220 grit, you want a flat pad. You want a flat pad from the start, but they wear out. One day you'll be working up to a fillet or raised portion of the deck with a worn out pad and it digs a trough in before you get rid of your guide coat. That is just enough to put a halo around things 3/4 of an inch away from the edge. Hmm, must be low... looks low, looks low, burn through... 220 doesn't cut that much slower than 80, so if it is fair to your block or board and the DA disagrees, change the pad!

Cheers,

Zach

Zach
Thanks for the input! but I have to agree with Minaret, I got about 2/3 of your explanation. But, what I got makes a lot of sense and I appreciate the advice. man! I love CF you guys are great!

However, I have to admit that reading this made my back, shoulders, and hands hurt! hum! This isn't going to be fun!

A friend of mine I use to sail with on his boat would always say if you can't see it from the cockpit it want bother you! Well that's out the window with the deck! Got-a-fix it!

[Suijin]

Originally Posted by minaret

That is a ton of cracking. Yes, if it goes into the CSM it needs glass, unlesss you want it to reappear. At the very least use a fiber reinforced filler like 3M High Strength. But really, glass. There is no substitute.

Yeah but would you just grind down the whole thing, or as large an area as possible to cover all the cracks and do as many of them as possible in one go, or individually? If the former I'd take it down pretty uniformly past the CSM, then CSM/cloth/CSM. The gel is thick enough that I can fit three layers in and still get the original profile or close when I go back over with gel.

I'm thinking the former is faster but the latter is easier to fair to the original profile.

[Suijin]

Originally Posted by Zach

Good thread.

They make 5/8-11 roloc adapters, I've bought a few on Ebay as that seems to be the only place they exist... Lets you mount a roloc on a mini-grinder.

3M 4" Roloc scotch brite rubber pad holder backer 5/8"-11 arbor grinder TS TSM | eBay

Something I'd throw out there, is that it is worth your time to fair in the 6 inches or so to each side of the cabin and toe rail.

Reason being, you can sand from that area up into the fillets. If the non-skid area is still high and low, you have to use a wee-baby block and keep a careful touch not to ride up on the high and dig in to the round. That isn't so bad with paint, as you don't run through the grits or buff.

I like to mud hog the non-skid off, and use a steel straight edge about a foot long to bring it down to the same level as the area that needs to be shiny. I've got an old National Detroit that is a sweet heart, she'll freeze your hands off but makes beautiful surfaces. The good thing about a mud hog, is that you can guide coat a surface and jump grits. 80 to 320? No sweat if there is material that sands the same, it's going to be damn flat.

Pick on and fill the low spots around the deck drains and hawse pipes, as low spots where water gathers are your dirt spots when you are done. Awlgrip doesn't like to remain under-water for very long, which sadly can be a month of rainy days and standing water. If you are going to get blisters, they happen there. Or small puddles around stanchions.

Remember that you can trowel gelcoat.

Roll on a coat thick, wait for a it to tack up enough to start being sag-free, take a yard stick or sheet rock trowel and pull off the excess, remove the excess from the boat. Flatten out any drag lines, or over-fill with new. Then either spray or roll on enough that you get a full cure on the thin areas. It also helps a bit if you add just a touch of tint to the troweled coat so when you get to the low spot, you know its time to stop rather than sand in a new low spot. Don't tint the top coat.

I'm a fan of getting that sort of stuff fair, before spraying thinned. Mainly so that you get a feather edge around any repairs. It takes a fair bit of material to fill a holiday or a slight under-filled area that has left a hard edge. If you are thinned enough to spray nicely you can get solvent popping and porosity if you try to put a triple pass on around the same spot to fill/cover. Solvent popping really sucks to find when you start buffing, you see it when the buffing compound fills up the pits.

That is something else, to find, as by that point you've got taped and bleeding finger tips that are too sore to even pick up anything to throw across the boat yard...

So, going backward to fairing... Once you have a 6 inch wide pass around the cabin, you can push a 16 inch board around the boat with 80 grit. Once its flat, its flat and you can run through the grits in no-time. The shorter the board you have to use, the longer it takes to get an OCD quality job. Shiny isn't always fair, and fair isn't always shiny... but trying to buff low spots in inside corners hurts my soul just a little bit.

Hutchins makes a white 16 inch board, a speed file that is ever so slightly flexible, that works well for cutting down high spots with sticky 80. 3M makes a stiff vinyl padded 16 inch board that works very well in the 220-320 grits to make things flat. Once you get there, you can go back to a rubber block and go up the grits as high as you want. It helps a lot to be flat enough, that there are no low spots that a rubber block spans. Full-stop... If the rubber block spans them, then in order to get our your orange peel you have to sand for days and make a low spot the size of your rubber block.

If... everything is damn flat, you spray your thinned gel and sand with the 16 inch board until you have an even coat, then there are no low spots. Keep sanding till you have a haze of scratches in the bottom of the peel, and switch grits.

Once your corners are fair and flat, you can put an inch thick foam soft interface pad on your DA and power sand your fillets with 320-400 grit to remove orange peel and stipple before you hand sand.

Remember that the key to sanding fillets, is don't sand your fillets. If they look good now just sand for tooth and adhesion.

Dry guide coat, and slow speed take it off the orange peel. That makes life a bit easier once you can do that, as buffing them takes no time at all once everything is flat, as you can use a foam interface pad to help out with the buffing... Aqua buff 2000 is nice to work with as you can wet sand back at 800, and once you have contact everywhere buff till done.

If you have a lot of cracked areas tight together like around your hatch, remember that Mat is cheap and easy to work with, and adds a bit of stiffness. You can grind out a 5 inch wide stripe that takes almost all the cracking and lay in a torn layer of mat. Make the repair wide enough that it reaches into the non-skid area. If you over-fill the low spot so that it overlays over a blue masking tape line to border the area that is good... you can grind down to the tape, until you can peel it off and you have a feather edge that is a tape line over-filled.

If you want some extra strength, you can pull the roves out of woven roving and wrap it around your hatch frame. Dunk a strand into your resin and let it wet out fully, and then smash into your first layer of mat. Instant unidirectional-reinforcement. They also make good bulk for rebuilding the inside radius of a corner fillet. Fillets made of uni-fiber don't generally stress crack. Over-fill the low with mat, two layers above 75f gives enough thickness to damn near surface cure without any wax or PVA, then just grind off the sticky.

If you use a 6 inch wide air roller, and are careful to follow the contours you should be able to grind in 40 minutes or so. Once your polyester reaches its peak exo-therm temp and starts coming back down, its done shrinking for the most part. Unless you paint it black and sit it outside...

I have a grinder that normally has a disc on it pad just for this so I don't throw them away when boogered... Tip the grinder up just a touch, and grab material from under the sticky. Sort of like grinding tar off a deck... don't grind the sticky stuff, grind the stuff under the sticky stuff.

Grind down till fair.

Depending on how close the rest of the area is, a layer of finish cloth over the mat and gone over with a body spreader makes things fair enough that when you grind back there are no lows to fill. The finish cloth gets ground off because it is already high, it just proofs out that you've got an even surface. Grind back till you see what it is supposed to look like, and stop... DA with 80 grit until you have a feather edge.

I use a paint stir stick for fairness guide on those type repairs, once it makes contact the whole way across from the good into the bad you can kiss it with a 16 inch board and 80 grit and see if you have contact everywhere. Make the inside edge just a touch low, basically just tip the grinder in ever so slightly to take off enough to leave a slight low, say a 64th or a split in two sharp pencil line of a low to your stir stick. That way when you DA it there is no way to burn off your gelcoat on the inside corners.

Change the pad on your DA. They curl up with use. Once you start thinking 220 grit, you want a flat pad. You want a flat pad from the start, but they wear out. One day you'll be working up to a fillet or raised portion of the deck with a worn out pad and it digs a trough in before you get rid of your guide coat. That is just enough to put a halo around things 3/4 of an inch away from the edge. Hmm, must be low... looks low, looks low, burn through... 220 doesn't cut that much slower than 80, so if it is fair to your block or board and the DA disagrees, change the pad!

Cheers,

Zach

This all makes a vast amount of sense to me and I get it. A few things...

First, I'm not going to re-gel the nonskid areas for three reasons; they're getting paint, ultimately, they cover 90% of the deck surface area, and over 85% of that, I got the nonskid off and got it flat without burning through the gelcoat.

Since it's getting painted nonskid, I'm not going to kill myself getting it absolutely fair. I'll go over it once or twice and fill any obvious low spots...anything that might show when it's painted in evening light, and any areas around the edge where it got low as I was feathering the edge during grinding/sanding. I'll be filling with fairing epoxy since it's going to be under paint.

The molded in non-skid was raised up about 1/8" from the level areas, with a curve up to it. If I take it down flat with the existing smooth areas, I'm going to be taking off a fair amount of glass. Not gonna do that. That leaves a different problem, which is that the edge where the molded non-skid and the smooth met is, and never was, perfect. It goes up, it goes down, you never saw that because it was all uniform color/reflectivity, and now it's a little wavy in spots from the grinding off as well. The issue is deviation of the formed edge from the painted edge, since the painted edge will be perfect. I'm going to go back and fill/shape/fair with gel to address that as best I can, but making it perfect would take months.

I agree on the approach around the hatch, and I'll use that for the fillets along the coaming as well. Just the idea of grinding all that out had me depressed but it's ultimately the right way to do it.

I'm only going to put new gel down where I'm doing repairs. 95% of the existing gel is in good shape, or rather it's thick enough, easily 1/8" on much of the surface, to take it down to good. If I applied yet more gel on top of that I'd be asking for more trouble down the road. I'd really have to take the whole boat down to glass or close to it if I wanted to regel the whole thing.

Thanks to everyone for their advice and input...seriously appreciated.

[UNCIVILIZED]

Originally Posted by Suijin

Yeah but would you just grind down the whole thing, or as large an area as possible to cover all the cracks and do as many of them as possible in one go, or individually? If the former I'd take it down pretty uniformly past the CSM, then CSM/cloth/CSM. The gel is thick enough that I can fit three layers in and still get the original profile or close when I go back over with gel.

I'm thinking the former is faster but the latter is easier to fair to the original profile.

Given the cracking, along with having that much room for reinforcements, how about a layer or two of an axial, along with some mat? Wouldn't that make things a good bit stronger than a joint maed mostly of CSM?

On the sanding, why a 16" or 18" board? The temptation for me is to build a custom "longboard", 21" long, & attach a piece of belt sander paper to it. Since said sandpaper seems to have a fairly impessive lifespan as compared to other varities.