Association Forum - Removing my ablative paint

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Removing my ablative paint

New Topic

Topic Locked

Printer Friendly

Author

Topic

Page: of 2

Steve Blackburn
Master Marine Consultant

Member Avatar

Canada
1091 Posts

Initially Posted - 03/09/2008 : 18:23:06

After 1 hour of work with 80 grit paper on a 5" sander I got this done:

When one removes ablative paint is it normal to have a black underlayer or is that possibly some type of tar product?

Also tried the RemoveAll 620 paint stripper I discussed earlier. Not too impressed so far as scraping was not easy at all. The paint was still quit thick and didn't go all the way to the gelcoat. However to be fair the product instructions say to apply at over 13 ºC (55.4 ºF). It was barely 11-13. I'll try again when it's hotter.

Steve Blackburn, Calgary, AB
C250WB - 1999 - Hull 396

Edited by - Steve Blackburn on 03/09/2008 18:26:33

dmpilc
Master Marine Consultant

Members Avatar

USA
4593 Posts

Response Posted - 03/09/2008 : 18:42:24

I may be wrong, but I think you are looking at the underlayers of the bottom paint that have not yet oxidized to the light blue color. Freshly applied blue bottom paint dries fairly dark. Then again, it may just be a darker undercoat. Can't tell without looking at it up close.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/09/2008 : 18:46:56

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Blackburn
 When one removes ablative paint is it normal to have a black underlayer or is that possibly some type of tar product?
<hr height="1" noshade id="quote"></blockquote id="quote">

Barrier coat?

Edited by - on

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 03/09/2008 : 20:16:41

Looks to me like hard paint, probably two coats or more. No barrier coat.
When I did mine, there were distinct layers, I had ablative over several layers of hard paint over barrier coat.
Was there much dust when you sanded? If not, then its just hard paint. If it's very dusty, you've got ablative.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/09/2008 : 20:28:44

Yes lots of dust. I came back looking like a smurf. Had a good respirator, gogles and gloves. I think dmpilc is right, it feels like its the same stuff throughout so must be darker unoxydized ablative. Not that thick I may add, looks like 1-2 coats no more. Can anyone attest to this, or is your ablative paint this light blue throughout?

I checked out Removall's web site and they state there that the surface temperature should be about 20C. Nothing on the packaging that says so, only a min temp of 13C stating that it takes longer when colder. I waited the maximum of 6 hours, and have never seen the paint crack or partially peel away as they say it would.

Edited by - Steve Blackburn on 03/09/2008 20:37:17

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 03/09/2008 : 20:36:38

I think the act of sanding causes it to change color.
It took me about 8* hours of sanding to get my bottom clean.

*8 hours= 1 hour of sanding. stop, complain, drink a beer.
1 hour of sanding. stop, complain, talk to passersby. 1 hour of sanding.stop, complain drink 2 more beer.
8 hours of sanding took me three days.
That's why I volunteered to come over and help - I'd be the guy complaining and drinking the beer and you wouldn't have to stop sanding, therefore getting it done faster.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/09/2008 : 20:39:17

LOL. You're too kind. Really hard on the arms too! When should it be 20C around here?

I too thought that the sanding might heat it up and force it to change color. But then I remembered that the aft bottom I did with the Removall and it too has that black underlayer.

Edited by - Steve Blackburn on 03/09/2008 20:41:23

Gloss
Master Marine Consultant

Members Avatar

USA
1916 Posts

Response Posted - 03/09/2008 : 20:40:09

when I sanded down my old Catalina 22 it had a blue ablative layer, with a hard black layer underneath. The ablative came off easily, but really had to sand the black off. In retrospect I figured that the black may have been a primer coat. I believe interlux primecon is black in color, and is very hard. I should have left it on. VC tar is black, but I don't believe that it is suitable for an undercoat to ablative.
Check out the interlux website, or get one of their bottom painting guides. It will tell you more than you want to know
Good luck.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/09/2008 : 20:42:50

Frank, you're right. The light blue comes off pretty darn easy and blue dust everywhere. When I get to the dark layer the "fun" begins and no dust.

Edited by - Steve Blackburn on 03/09/2008 20:44:03

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/09/2008 : 21:13:03

I'm guessing the factory put on a coat of hard paint (common if you order bottom paint without specifying), and later an ablative was added over it. Also, a good practice with ablatives is to put on 1-2 coats and then add coats of a contrasting color so that the first coat is your "signal" coat that you need to add some. If you see none of the signal coat, you have the option of going another season without painting, or just painting areas where you see the color.

Edited by - on

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 03/09/2008 : 23:02:57

I agree with Dave Bristle, my blue ablative is blue through and through and so was the very old stuff I removed first. As I said before, nearly all of my old ablative came off with a scrub brush and soapy water and I can scrub the new stuff off now. It sure sounds more like copolymer or modified epoxy self polishing bottom coat that leaves a residual carrier.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/10/2008 : 00:51:55

Once I'm done removing this paint from hell, do I need to put on a special undercoat before the VC17?

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/10/2008 : 04:51:41

VC TAR2

VC®Tar2 is a 2-component epoxy primer providing osmosis protection to GRP boats and anticorrosive protection to steel and alloy surfaces. For use below water only, key product features include:-

Self-leveling to give an excellent finish

Easy to apply and overcoatable within hours

No sanding required between coats

Offers excellent barrier to water for osmosis protection and treatment

Ideal primer base for VC 17m antifouling

Edited by - on

Steve Milby
Past Commodore

Members Avatar

USA
5895 Posts

Response Posted - 03/10/2008 : 07:37:26

If the black that you see is VC Tar, you can tell because the dust from it will roll up in little balls when you sand it heavily. I doubt that it's VC Tar, but it could be. The reason why it probably isn't VC Tar is because VC Tar is a barrier coat, and there should be no need to apply a barrier coat to a C250. Catalina applies a barrier coat to the bottom of C250s at the factory. The only reason why you should have to barrier coat a C250 is if someone sands through the factory barrier coat (like, what you're doing now).

What I don't understand is, why are you sanding down ablative antifouling paint? Ablative antifouling paints have only been around for a few years, so we might not have learned all it's eccentricities yet, but, so far as I know, it continues to provide protection as long as it's on the boat. If you take the boat out of the water at the end of the season, it'll be good next season, as long as it hasn't ablated away. Why do all that hard work to sand it off, when you can remove it just by sailing the boat, and having fun?

If you want to change to VC17 because you want to race the boat seriously, then I can understand doing all that work, but, if you just prefer VC17 generally, I'd suggest you let it erode in the ordinary course of sailing for a year or two, pressure washing it at the end of the season. It'll come off much easier. I stripped the antifouling on my C25 and also on my C&C 35, and it's a horrible job that nobody would do if there was a halfway reasonable alternative.

Edited by - Steve Milby on 03/10/2008 07:50:17

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/10/2008 : 10:24:56

Doesn't roll up in balls when I sand it. It's probably some type of barrier coat as you have suggested. The reason I wanted to take it off is that I'm going to have the boat in fresh water on a mooring ball all summer. I will be racing the boat but not all that serious. Already the Keel had some areas that was diretly on the gel coat. I have to admit that the rest of the boat seems fine.

Maybe the reason I'm thinking that my chemical stripper doesn't work is because this barrier coat is left intact? Don thanks for the VCTar2 tip, looks like an excellent product.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/10/2008 : 11:02:32

Although I went the VC Tar route, some here have also used Interprotect 2000, another Interlux product, as a primer/barrier coat for VC17m.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/10/2008 : 13:16:26

You think I could simply sand to the black layer and put VC17 over it? There are chances that it might not be a barrier coat after all. Also wanted to see the hull to apply repairs and see if I have any blisters. I really want to do a good job that will last.

Also as you can see from the picture you can see slight markings from the 80 grit sandpaper on the gelcoat. If I lightly sand over it with 150 grit it removes these markings and I'm not removing much gel coat. I was wondering if I should just leave the 80 grit markings leaving behind more gel coat?

How clean do I need to get the hull. There are some very faint ocassional blue spots that are left behind from the sanding. Even acetone won't remove them easily (sanding with 150 grit will). Wonder if I should just leave them there, I can't believe this would affect the VC-17 underlayer from bonding.

Edited by - Steve Blackburn on 03/10/2008 13:40:46

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 03/10/2008 : 14:03:42

How you proceed depends on what you're going to put on next.
I called the interlux 800# several times with questions and of course got some expert advice here.
Interlux told me to remove everything, then repair any holes or blisters, then add the primer, then the bottom paint.
I removed a miniscule amount of gel coat because I wanted to get it perfectly smooth. Thickness of gel coat varies.
The Interlux site and toll free technical assistance had the final say in how I proceeded. Keep in mind that Interlux will suggest paint based on your geography. What works in Florida will not necesarily work in Alberta.
Did your PO tell you what was on the bottom?

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/10/2008 : 15:13:33

I doubt the PO would know in my case. I'll email him tonight.

I think I'm just going to go ahead with removing the whole thing and lightly sand with 150-220 to make it smooth and remove the remaining faint blue areas.

Edited by - on

triley
Captain

Members Avatar

USA
251 Posts

Response Posted - 03/11/2008 : 17:00:41

I have an ablative paint on mine and keep the boat on a lift-- we have to because of where we are on the lake. The paint is slowly coming off. I will be in my third year.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/14/2008 : 20:13:32

Hey Guys,

Just wanted to let you know of a little discovery I made today. I bought a Briggs & Stratton 2,200 PSI Gas-Powered Pressure Washer for $299 on sale and using the maximum nozzle was able to remove nearly all of the paint layer. I call it a discovery because it takes nearly no effort and I was doing this sitting down. Half an hour later I was all clean and just washed my hands dirty from handling my garden hose!

Only a very thin blue layer subsides Im glad this thin layer stays behind this means my power washer isn't hurting the gel coat. Notice the part that was over the water line doesn't come off with the pressure washer (some of it, but I'll have to do this 3" strip the old fashion way).

This is the same area after about 10 strokes of a 3M heavy duty pad and finishing off with a light 220 Wet sanding. The gel coat is pristine unlike what I've done with 80 grit paper last week.

Close up. Looks pretty clear to me that these are brush marks from the first layer. Also good news is that I do not seem to have a barrier coat afterall. So this black underlayer has to be from the sanding itself.

Amazingly the part where I put on stripper last week and scraped off wasn't very responsive to the presure washer. Seems that the sripper made the paint even harder or something. I'm thinking of reapplying stripper which should soften it enough for me to get it pressure washed.

Edited by - Steve Blackburn on 03/14/2008 20:34:43

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/14/2008 : 21:34:04

A paint specialist once told me that I'd waste stripper trying to use it below about 60 degrees, and to also consider that the hull takes a while to warm up in the morning... The warmer the better.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/14/2008 : 21:38:14

BTW, since that's your backyard and not a boatyard, don't let kids or pets play in that grass for a while.

Edited by - on

Nautiduck
Master Marine Consultant

Members Avatar

USA
3704 Posts

Response Posted - 03/14/2008 : 21:41:23

This is why I use VC17M. Never any sanding. I am done with ablatives. Why are you considering the VC Tar? A C250 is modern enough that blistering is not going to be an issue. You don't need a barrier coat.

Edited by - Nautiduck on 03/14/2008 21:43:02

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/14/2008 : 23:16:15

Thanks Dave, I'll keep the kids away. The ablative paint falls in 2mm chips below the boat right underneath the trailer, so the surrounding area is not much of an issue. Nonetheless I'll tell them to keep away. It is also my conclusion that temperature has much to do with stripping. Once the temperature is good enough here I want my boat in the water, not working on it. So what I am doing is working a few hours once in a while on it and it will get eventualy done. The season here starts the 3rd week of May.

Randy, thanks...I thought I needed a barrier coat since it would serve as an extra protection. I'm really looking forward to VC17 and simply adding 1 coat per year without the need for sanding. I think I read somehwere that my first VC17 application (on a bare bottom) should be 3 coats?

Was also wondering that since VC17 will take its color once submerged in water, is it a problem that whatever is over the waterline will not be wet? Wouldn't want to have a different colored 3" strip over the waterline. But I imagine that waves will eventually take care of that? How fast do you need to put it in the water once it's applied and all new?

Edited by - Steve Blackburn on 03/14/2008 23:18:42

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 03/15/2008 : 00:05:19

I researched a little more and came up with this info from the Interlux web site:

BARE FIBERGLASS: Begin by scrubbing well using soap and water and a stiff brush. Rinse with fresh water. Wipe with Fiberglass Solvent Wash 202. Sand with 320 grade (grit) paper. Wipe clean.

Method Apply 2-3 coats on the area to be coated per season. Do not sand between coats of VC 17m.

So I'm guessing for my first time it would be advisalble to go with 3 coats. Now they say that the coverage is 313.5 (sq ft/Gal) by roller. Found out that a quick way to determine how many sq ft you have is to calculate .75 X length X beam. So for a C250 that is .75 * 25 * 8.25 = 158.68. So 3 coats = 476.04 (1.5 gallons). 2 coats = 317.36 (1 gallon, or 4 quarts). From your experience is my math about right? Where is the best place to buy it?

I think 2-3 coats a year is slightly excessive for my needs since I the boat will be in fresh water and only for 4-5 months per season. I think if I start with 3 coats, then 1 a year after that I should be fine.

Edited by - Steve Blackburn on 03/15/2008 00:18:26

Page: of 2

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.