Hull work and barrier coating

[laika]

I know this topic has been done before, but I was hoping for some thoughts on this particular situation and plan...

I had my hull peeled down to bare laminate last August in North Carolina (best boat money ever spent hiring the pro and his peeler). I spent the first two months washing the hull down with Ajax and a hard bristle brush twice a week. I then skirted the boat before I left for the winter to prevent any UV damage (tho already having been exposed for two months in late summer). All small blisters/delam zones (few dozen in total) have already been ground out.

Some pics attached below.

Here's my basic plan:

1. Take deep breath of mountain air before return to boatyard living
2. Wash hull laminate a few more times with Ajax and hard bristle brush
3. Fill and fair all divots (patch deeper ones with cloth)
4. Layer on one or two coats of unthickened West System epoxy
5. Layer on many, many coats of Interprotect 2000e in gray and white color
6. First coat of Pettit hard paint before last coat of 2000e is fully set
7. Drink (1) bottle of scotch

Is there a reason not to go as heavy as is practicable on the number of barrier coats? More chance of cracking? I have a small boat that I have sailed and love and am not overly concerned with cost. More with doing the job right.

I also plan on glassing a layer or two of biaxal cloth along the where the two halves of the hull were originally laid together. Once the gelcoat was removed, a tiny crack was discovered in this epoxy-like material (going all the way up to into the bilge). This is not a structural problem, but figure why not do this to preclude any future issues?

I also plan on reinforcing the leading edge below the waterline (cutaway full keel) with a few layers of biaxal. Again, why not..while I'm still staring at a bare hull? I had considered even using a V-shaped piece of G10 to lay down and glass in here, but think that might be a bit extreme and difficult to pull off. Kevlar is not a viable option, and biaxal cloth seems the next-best thing to try to make this area as puncture-proof as possible.

Any other suggestions or advice for someone in my position, staring at a bare hull which will hopefully never see the light of day again? Any barrier coating systems about these days that blow 2000e out of the water? I am not looking for needless work, but am willing to do anything within reason to make her as safe and reliable as possible.

Thank you for your time

Ryan

EDIT: having trouble with photo attachments..here's the link to the folder:
http://www.flickr.com/photos/116556741@N02/

http://www.flickr.com/photos/116556741@N02/12334676053/

[lancelot9898]

I went through the same thing last year having a peel done on the boat after blisters were discovered. A surveyor did a laminate profile to determine the extent of the blistering and also provided a breakdown of the laminate. The blisters were contained on the CSM(Chopped Strand Mat) and there were three seperate layers of CSM after the gelcoat before getting into the fiberglass laminate. Because of the heavy buildup of bottom paint over the past 25 years it took a double peel to get to a good layer of CSM. Numerous fresh water scrubbing and rinsing took place over a year while the boat was on the hard following detailed instructions for proper prep. I then used the interlux product line to do the entire project rather than switching from one manufacture to another. Epiglass was used to soak into the remaining CSM and then the first layer of 2000e was applied. (Epiglass leaves an amine blush which must be dealt with prior to applying 2000e) Next watertight epoxy was use to fill some of the small voids that were remained. And then 5 more coats of 2000e was put on allowing for a chemical bond between the final coat and the first bottom paint layer. If you go with the interlux product line there is a good website that will answer your detailed questions at www.yachtpaintforum.com

So I now have a total of seven epoxy layers of the boat bottom. The hardest part was the peel which I had the yard do and also they did the heavy sanding at the water line and on bottom of the keel. I still had to do a lot of sanding myself, but not as aggressive as they did.

I too am in the mountains of NC and the boat is sitting on the hard on the coast. Best of Luck.

[Anchors Away]

You're on the right track. Do check your hull with a moisture meter prior to applying the coatings. --Chris.

[minaret]

I've done hundreds of bottoms, and our yards method is depicted in the Nauticat 52 refit thread stickied in construction and maintenance. You are on the right track, just two points to make.


1. After epoxy coating and before barrier coating, we chemical bond a double pass of epoxy with filler over the bottom and sand it fair before barrier coating. This is a must if you want a pro job with a fair bottom. It will be obvious if you don't do this, especially at the waterline.



2. Don't use alternating colors of 2000e. The reason is that white 2000 costs a lot more than grey. It is also much thinner, meaning you get less millage per coat. It's a gimmick for DIYers. It's easy to get perfect coverage with just grey, it changes color a little when it dries. I don't know a single yard that uses white 2000. Using white also means you can't reuse leftover grey from the day before. I keep mine in the shop freezer over night, then mix it back in to the new batch the next day. Less waste.

[silverp40]

Agreed with many coats of 2000. Supposedly the product is less water absorbent than standard epoxy (as per Interlux website).

After sanding our bottom to gelocoat (grinder with 24 grit sanding attachment), I applied 15 coats of 2000. Also rolled opposite ways each coat (vertical then horizontal then vertical, etc). An old pro turned me to this one.

No blisters or any water in the hull for 7 years.

[wingless]

Ensure the barrier coat layer is properly cured prior to application of the next coat.

The wet thumb print test must be followed.

Different spots on the hull will dry at different rates. Test the hull during the process to ensure the application is correct.

Follow all the instructions for all the products.

More layers of properly-applied barrier coat is better.

[Kestrahl]

Saw one done in the yard next to us. He was basically up to where you are now. The boat builders brought over a cloth wet out machine and in half a day had the entire bottom done with glass and epoxy to the orginial thickness. Don't think that boat will be getting blisters again!

Sent from my GT-I9500 using Cruisers Sailing Forum mobile app

[laika]

A hearty thanks to all for all the excellent advice and knowledge dropping. Really nice to have this sounding board to ensure I'm not overlooking anything.

The yard I'm at does a lot of barrier jobs with 2000E and they said they'd cut me a square deal on as much as I need. As it still seems the go-to brand for most everyone else, a couple gallons of grey it is

And thanks Chris, forgot it on the list, but I definitely plan on getting a hull moisture reading before the epoxy goes on. Easy enough and certainly don't need to be doing this twice!

[laika]

Originally Posted by lancelot9898

I went through the same thing last year having a peel done on the boat after blisters were discovered. A surveyor did a laminate profile to determine the extent of the blistering and also provided a breakdown of the laminate. The blisters were contained on the CSM(Chopped Strand Mat) and there were three seperate layers of CSM after the gelcoat before getting into the fiberglass laminate. Because of the heavy buildup of bottom paint over the past 25 years it took a double peel to get to a good layer of CSM. Numerous fresh water scrubbing and rinsing took place over a year while the boat was on the hard following detailed instructions for proper prep. I then used the interlux product line to do the entire project rather than switching from one manufacture to another. Epiglass was used to soak into the remaining CSM and then the first layer of 2000e was applied. (Epiglass leaves an amine blush which must be dealt with prior to applying 2000e) Next watertight epoxy was use to fill some of the small voids that were remained. And then 5 more coats of 2000e was put on allowing for a chemical bond between the final coat and the first bottom paint layer. If you go with the interlux product line there is a good website that will answer your detailed questions at www.yachtpaintforum.com

So I now have a total of seven epoxy layers of the boat bottom. The hardest part was the peel which I had the yard do and also they did the heavy sanding at the water line and on bottom of the keel. I still had to do a lot of sanding myself, but not as aggressive as they did.

I too am in the mountains of NC and the boat is sitting on the hard on the coast. Best of Luck.

Lancelot, thanks for the breakdown and the link to the Interlux forum. I read through many of the 'boatcare' posts and there is a lot of good info there. And come to find most of the questions I had you had already asked! Will definitely be leveraging the deep product knowledge there as things progress. Probably going to stick with West System over Epiglass though if for no other reason than familiarity.

To be sure, hiring out the peel was the best money I've ever spent. The alternative would have been two weeks of terror and pain.

[laika]

Originally Posted by minaret

I've done hundreds of bottoms, and our yards method is depicted in the Nauticat 52 refit thread stickied in construction and maintenance. You are on the right track, just two points to make.

1. After epoxy coating and before barrier coating, we chemical bond a double pass of epoxy with filler over the bottom and sand it fair before barrier coating. This is a must if you want a pro job with a fair bottom. It will be obvious if you don't do this, especially at the waterline.

2. Don't use alternating colors of 2000e. The reason is that white 2000 costs a lot more than grey. It is also much thinner, meaning you get less millage per coat. It's a gimmick for DIYers. It's easy to get perfect coverage with just grey, it changes color a little when it dries. I don't know a single yard that uses white 2000. Using white also means you can't reuse leftover grey from the day before. I keep mine in the shop freezer over night, then mix it back in to the new batch the next day. Less waste.

Minaret, that thread is superb. Thanks for taking the time to do it.

I'm partial to your conservative methodologies and overall refit philosophy and I was particularly interested in your choice of carbon fiber and Proset epoxy underneath the layers of biaxal 1708. I've got some more homework to do on this, but..

Say I were to beef up the bottom leading edge of my cutaway full keel (encapsulated) in order to further protect from hard groundings, would you recommend the 13.75 oz. carbon unidirectional fiber and Proset as you used on your skeg and rudder with some West System and biaxal after?

Would you advise the same choice of materials if I were to reinforce the top of the leading edge at the waterline (in order to protect from submerged objects)?

Is carbon fiber and Proset notably more difficult to use? I have a fair deal of experience with glass work. Have heard it's a bit trickier, but imagine it can't be that drastically different?

Some of the folks around the yard last fall thought I was crazy and a bit daft to be considering reinforcing the hull like this. Just seems like such cheap insurance to mitigate the potential for catastrophic collision damage.

[laika]

Originally Posted by Kestrahl

Saw one done in the yard next to us. He was basically up to where you are now. The boat builders brought over a cloth wet out machine and in half a day had the entire bottom done with glass and epoxy to the orginial thickness. Don't think that boat will be getting blisters again!

Sent from my GT-I9500 using Cruisers Sailing Forum mobile app

I have actually been considering doing this myself! Feel like a got a boat small enough to pull it off and an soothing voice whispering in my ear, "You'll never have to worry, never have to worry..."

[minaret]

Originally Posted by laika

Minaret, that thread is superb. Thanks for taking the time to do it.

I'm partial to your conservative methodologies and overall refit philosophy and I was particularly interested in your choice of carbon fiber and Proset epoxy underneath the layers of biaxal 1708. I've got some more homework to do on this, but..

Say I were to beef up the bottom leading edge of my cutaway full keel (encapsulated) in order to further protect from hard groundings, would you recommend the 13.75 oz. carbon unidirectional fiber and Proset as you used on your skeg and rudder with some West System and biaxal after?

Would you advise the same choice of materials if I were to reinforce the top of the leading edge at the waterline (in order to protect from submerged objects)?

Is carbon fiber and Proset notably more difficult to use? I have a fair deal of experience with glass work. Have heard it's a bit trickier, but imagine it can't be that drastically different?

Some of the folks around the yard last fall thought I was crazy and a bit daft to be considering reinforcing the hull like this. Just seems like such cheap insurance to mitigate the potential for catastrophic collision damage.

Sure, it's easy enough to do. If you don't want to get into Kevlar or hybrids, a bit of carbon uni would really stiffen your stem. I always bury it under S-glass, so as not to have to grind on it. The materials complement each other anyway, stronger that way. Proset is a dream to glass with. If you are used to any other epoxy for laminating, you will be blown away. It's very expensive, about $100 a gallon. But you use so much less resin for a layup that it really does pay for itself. No post cure required, but I do it anyway. You can hand lam real nice with it, just be sure to peel ply. Even I might think you are a bit daft if you do the whole waterline like that! If you do glass the bottom, I can't imagine how an impregnator would help. If you wet out the glass before applying it to the hull, it's a nightmare. You'll have a huge wet layup fall on your head (been that guy, don't do it!). You apply a coat to the surface and let it solvent flash so it's a little tacky, then carefully place the dry glass. The sealer coat holds it in place while you wet out and squeegee. Glassing overhead sucks!


13.75 might be a bit much for a boat that size, I would use something lighter or it will be a pain to fair.

[wingless]

Originally Posted by wingless

Ensure the barrier coat layer is properly cured prior to application of the next coat.

The wet thumb print test must be followed.

Different spots on the hull will dry at different rates. Test the hull during the process to ensure the application is correct.

Follow all the instructions for all the products.

More layers of properly-applied barrier coat is better.

Good information.

Here is the Interprotect Technical Manual and the 2000E Product Data Sheet.

[wingless]

Originally Posted by laika

EDIT: having trouble with photo attachments..here's the link to the folder:
Flickr: ryankieffer's Photostream

1_peeling | Flickr - Photo Sharing!

Click save...

Surround the URL of the image link w/ [IMG] followed by [/IMG], w/o spaces.

[laika]

Wingless, you're making this too easy for me! Many thanks for all the help and links. I'm in IT by day, so you'd think I'd be able to figure this stuff out