Inteprotect VC-17 Bottom Paint Questions

[Starscream]

Hi everyone,

I recently dropped out my centerboard and removed my rudders, sanded them down, and painted on some Interprotect2000E followed by several coats of VC-17 smooth anti-fouling paint. I posted about that adventure on another thread.

Now I'm moving on to removing the existing anti-fouling, which is at least a dozen years old. My boat already has a layer of grey Interprotect2000, also a dozen or so years old.

Sanding off the existing anti-fouling is a nightmare. There is a layer of greenish grey freshwater slime over the anti-fouling that powders up right away, then I have to work through a still-thick layer of light red powdery anti-fouling, then a thin layer of dark red hard anti-fouling before I reach the Interprotect. Once at the Interprotect layer, it is really hard to sand away all the anti-fouling. The Interprotect tech data says to apply the first coat of anti-foul while the last layer of Interprotect is still tacky. I guess that's how they did it, because the bond is amazing. Using 80 grit with a hand-sander, it is just so darn hard to get all the little red flecks removed.

Here's a photo of my progress:

You can see each layer: dried slime, light red powdery anti-fouling, dark-red bonded anti-fouling, grey interprotect. The dark red stuff is just about impossible to get off.

Couple of questions...

Is 80 grit followed by 180 grit the right plan of attack?

What if I don't get all of the small red flecks off before I re-coat with Interprotect? How much leftover red is ok?

There are a few good scratches and chips underneath the boat. Interprotect 2000E tech data says you can fill scratches with it, not sure if I should just overcoat a bunch of times or buy something else to fill them first?

Here's a photo of about the best I can do without sanding all the way through the old Interprotect layer:


It's not in great focus. It shows the scratches created by the 80-grit, this photo was before the 180 grit.

This is HARD. I've just about finished sanding the front half of the boat to the end of the centerboard trunk, still the entire bottom half to go. Blah. But I got nothing else to do so I'll just suck it up.

[Jimmyt]

I don't even own any 80 grit paper. I hear people talk about using 60 and 80 on their cars/boats and it makes my skin crawl. You wind up with the sanding marks that your photos show, that are often hard to get flat again. If I started with 180, on something that I was going for a gloss finish on, I would consider that aggressive. My go-to grit is 220. If I had a thick layer to take off, I'd probably go for a chemical strip - if it would work. I've stripped a whole car with 220 though.

Having said that, I keep my boat with the factory gelcoat gloss finish on the bottom. When I get a scratch, I use gelcoat, 220, 400, 600, and polish. So, you are out of my lane.

I'm interested to see the responses to this.

Whatever the case, you're making good headway. That's a big job, no matter how you do it (unless you just sign the check).

[Starscream]

I don't even own any 80 grit paper. I hear people talk about using 60 and 80 on their cars/boats and it makes my skin crawl. You wind up with the sanding marks that your photos show, that are often hard to get flat again. If I started with 180, on something that I was going for a gloss finish on, I would consider that aggressive. My go-to grit is 220. If I had a thick layer to take off, I'd probably go for a chemical strip - if it would work. I've stripped a whole car with 220 though.

Having said that, I keep my boat with the factory gelcoat gloss finish on the bottom. When I get a scratch, I use gelcoat, 220, 400, 600, and polish. So, you are out of my lane.

I'm interested to see the responses to this.

Whatever the case, you're making good headway. That's a big job, no matter how you do it (unless you just sign the check).

Thanks Jimmy,

I chose the 80 grit to get through the old ablative anti-foul and the slime layer. But yeah, it does leave those marks. I'm following up with 180, then I hope the new interprotect will smooth out any remaining imperfections. We'll see, but it can't be worse than the current finish, which is like 1-grit sandpaper. With the new VC-17, which is supposed to be super-smooth and non ablative, I am curious to see if I will notice any effect under sail or under power. It's hard to imagine that I wouldn't see an improvement; it's hard to describe how rough the old hull is.

Yeah, I could just sign the check. For a crap job like this, it's tempting tbh, but my philosophy is that if I have the skill and the time, then I'll do it myself thank you. One of my sons once asked me when he was about 8 why I am the only one in the neighborhood who changes his own tires, and brakes, and oil, is it because we are poor and everyone else is rich and just pays someone to do it? I explained my philosophy and I think all my sons appreciate it. Hopefully they'll adopt the same attitudes. I find that a lot of people who own Macgregors have a similar approach to life.

[Jimmyt]

I'm sure it will be fine. Like I wrote above, I'm the only one who doesn't believe in using those aggressive grits.

I grew up as a child of a depression era child. My Dad, Aunt, and Uncles, were all DIY types because they grew up doing it that way. They actually knew the struggle. When I came along, they were all doing well, but couldn't shake that DIY mentality.

So, I was brought up making what I wanted out of what I had, or stuff I could scrap up. The times I've had to write a check for things have often resulted in disappointment. Workmanship, and attention to detail are becoming things of the past. I hate paying for someone to do a job at a much lower quality than I would do myself...

I think it's great that you're doing it yourself. I do almost all of my own work. DIY will save you some serious coin on that job. Plus, you'll get a really good look at your hull while doing it.

[Starscream]

I sanded as much as I could, but there were still some tiny red flecks here and there. I sanded entirely through the barrier coat in several places, so my first pre-coat of interprotect yesterday was just a small batch applied with a mini-roller to the bare areas and damaged areas.

I applied the first full new coat of interprotect today (at least the front half). Rear end is another story.



While I am under there, if the boat falls somehow, to get me it's gonna have to make it through three jack-stands and two drive-on ramps that I use for wheel stoppers in the driveway. The butt end is on blocks right now, but I'm gonna have to get it up higher to do that end. Not looking forward to more sanding.

[Starscream]

Second coat done today.

I had a little left over so...this:


I will revise a previous statement on the paint coverage: a gallon of 2000E will do more than one coat. I'd say that it takes a bit more than half a gallon for a single coat, maybe 2/3 of a gallon for a generous coat. I ordered two more gallons so I'll get a good four coats on top of the old barrier coat, and I'll probably do some of the bilges and other bits.

The deep scratch is gone. The divots are filling in nicely.

It ain't fun crawling under there.

[Russ]

Second coat done today.

I had a little left over so...this:


I will revise a previous statement on the paint coverage: a gallon of 2000E will do more than one coat. I'd say that it takes a bit more than half a gallon for a single coat, maybe 2/3 of a gallon for a generous coat. I ordered two more gallons so I'll get a good four coats on top of the old barrier coat, and I'll probably do some of the bilges and other bits.

The deep scratch is gone. The divots are filling in nicely.

It ain't fun crawling under there.

Good info.

So what would you say is required for a Ma 26 bottom paint job?

[Starscream]

Good question Russ. I'll summarize the whole operation in a couple of weeks when I'm done the whole thing.

For a barrier coat, I would say two gallons of Interprotect 2000E would be enough for three good coats, or just possibly 4 coats with care, on a 26X, and the literature says 4-5 coats is recommended. I'd say 3 gallons is the right quantity of Interprotect, which would leave some over for other things. Interprotect is an excellent metal primer as well, so any leftovers can go to good use. My outer layer will be white, so that if I ever sand the hull again (never, please, never again) I can see when I get to the first barrier coat and when I get through it to the second barrier coat. Plus, I'll use the leftover white in the bilges. I tried some anti-microbial Kilz paint in there, but after a couple of years it's all flaking up.

Not sure on the VC 17 yet. I did about five coats on the rudder and centerboard, and that took up most of a quart. I have 2 new quarts, and I'm thinking that probably won't be enough. We'll see. From what I can tell, the VC-17 is the freshwater sailor's go-to product to create a slick finish on the hull, but it can only be applied on a well prepared surface. That means all previous anti-fouling has to be removed. That part was an absolute nightmare of sanding. Getting the boat up off the trailer was not easy either. I'm not professionally equipped: maybe better than the average suburban household, and I am doing this whole thing with the material I have in-house because, you know, covid.

[Starscream]

I got the second-to-last coat of interprotect on yesterday, using white instead of grey this time.

I should revise my quantity estimates. I used about 90% of the full gallon to get one coat of white on, likely because I was putting it on over grey and could see poorly covered areas. When painting grey over grey, I used around two-thirds of a gallon and thought I had a good coat when it probably wasn't so good. So the practice of alternating colors seems to be a smart one.

I had just enough to give the cooler box a second coat in white and the bilge under the cooler box, then the gallon was gone.

I'm getting worried about taking the masking tape off. There is a nice layer of interprotect built up now, and one more coat coming.

[Jimmyt]

Razor blade along tape edge first...

Nice job! Thanks for all of the info!

[Starscream]

Almost done. Just have to take care of the three support spots.

Four quarts of VC-17 did 3 coats, plus an additional 2/3 quart for the rudders and centerboard. Three gallons of Interprotect 2000E did 4 coats.

So, a good job takes: 3 gallons of Interprotect 2000E alternating colors for four coats, 5 quarts of VC17m, 40 grit, 80 grit, 120 and 240 sandpaper, a quart of Interlux 216 special thinner/solvent. A bunch of small paintbrushes to do around the bits attached to the stern, and the centerboard trunk. Maybe half a dozen rollers, 3/8" or 1/4" nap, solvent resistant, and MUST use the quality rollers. A roll of good quality masking tape. I guess I spent about $700 CDN on the job. I wonder how much that would cost at a yard?

It looks awesome. The masking tape was 3M quality stuff, and it came off just perfectly, with absolutely no creep and, thankfully, no need to razor-cut the whole perimeter.

All the minor scratches and dings were completely filled by the 2000E and are gone. A couple of major divots are still visible, but well enough protected that I am not going to do anything else about them.



One of the hard parts was raising the anti-fouling up about half the distance to the bootstripe, but near the stern only. The old barrier coat was pretty thick, so I had to fill the valley between the old barrier coat and the new top-line of the anti-foul. That took several extra trips out with some saved 2000E and a paintbrush to overfill, then sand down to level. Looks pretty good now.


Some work remains...not looking forward to it, but gotta get it done.

[Jimmyt]

What you have finished looks fantastic!

[Starscream]

FINISHED!

hahahahahaha
*runs away laughing hysterically, with a mix of copper coat and epoxy sticking his hair up in wild directions, coughing up solvent-laden aerosols, and squinting through the sanding dust built up under his eyelids as he tries to rub the epoxy from his skin.


I never want to do THAT again. But I'm happy I did. Thanks for the support and advice.

[Jimmyt]

FINISHED!

hahahahahaha
*runs away laughing hysterically, with a mix of copper coat and epoxy sticking his hair up in wild directions, coughing up solvent-laden aerosols, and squinting through the sanding dust built up under his eyelids as he tries to rub the epoxy from his skin.


I never want to do THAT again. But I'm happy I did. Thanks for the support and advice.

Congratulations!

[Tomfoolery]

Phew! I feel tired and dirty just from reading this thread.

Looks real nice, though. Should be easy to recoat next year, too.