Repainting Cal 21

rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
First Post! Hello, relatively new to sailing and boat repair but I am thinking of repainting my 1971 Cal 21 sailboat this year and wondering what the benefits/cost/method would be of doing so. My boat stays in a rather murky freshwater from May-October on a lake in central PA. Last year I spent a good bit of time de-oxidizing, polishing, and waxing the hull before I put it in the water to remove some of grime that the pressure washer did not get in the fall. Now I am considering painting the whole boat to continue my restoration of it. Keep in mind I'm a college student working with a smaller budget. The boat has no leaks or cracks in the hull, and no blisters, although the gel coat is long gone. I thought of maybe the rustoleum brand boat paint and painting it myself with roller and brush in a large shed I have access to. Any help is greatly appreciated and I look forward to being a part of this forum.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Painting on a limited budget should be the LAST option. You will not get lasting results.
Have you completed Boat Shine 101 class. Quiz on Friday!
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
Welcome to wonderful world of DIY boat maintenance.

When you say, the gel coat is long gone, what does that mean? Gelcoat has the ability with some love and elbow grease to come back along way. If long gone means you can see the underlying fiberglass, then you will be painting soon. If you mean all your hard work didn't you where you wanted to be, don't give up yet.

Once you start painting with a paint like Rustoleum, you will be repainting every few years. Not to knock the rustoleum product, but one part polyurethane paints will last longer and shine brighter, but they are expensive and a lot more work.

Beg, borrow, steal, or buy a decent 7" buffer/sander. If money is an issue Harbor Freight sells one for about $30 that is just this side of junk. Do get a good buffing pad. Read the post Gunni suggested and go to work.

To save a few dollars, Defender.com has its annual sale going on this weekend. Usually the best prices of the year.
 

rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
Thanks for the input, and I should've specified that by "limited budget" I am not completely broke and willing to spend money on something that, in the long run, will benefit my boat. The gel coat is just chalky in texture but actually shined rather nicely with the wax and polish last year. Below the waterline is a greenish black color on the bottom, I'm not sure what that is exactly but it is not removed by sandpaper. As far as tools go I'm in good shape, have a good buffer and a decent sander as well as many other tools that I can borrow from the family business as I need it. I'm also not opposed to buying tools, but buying junk is not my thing, I'd rather get something decent that will last and do what I need it to do. I have heard that painting for use in freshwater is both a waste of time and money, but I'm not sure of the validity of this. I'm just looking to liven up the color of the hull as well as protect it both above and below the water. I'll start by checking out the link Gunni mentioned.
 
Jan 1, 2006
6,166
Slickcraft 26 Greenport, NY
The barn is a big asset. Painting outside in the spring is made way more difficult by all the pollen falling and tree detritus. I painted a boat, only 15', with the Interlux line of one part epoxy paint with good results. Also a mast. I don't think I even knew about the roll and tip method. As you probably know there's a lot of prep work. So you'll want a high quality paint.
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
T
Below the waterline is a greenish black color on the bottom, I'm not sure what that is exactly but it is not removed by sandpaper.
Try a little acetone on a rag. VC17 is a popular freshwater bottom paint. It turns a brown color in water, however, when you wipe it with acetone it should smear and you may see some copper colored stuff appear. Sanding VC17 to remove it is a PITA. It is copper powder suspended in a teflon based solvent. Smooth, fast, easy to apply and a challenge to remove.

If you do have VC 17 on the bottom, lightly sand and apply a single coat. On 21 foot boat, one can should get you through 2 seasons.
 
Aug 2, 2009
474
Catalina 315 Muskegon
I would also recommend avoiding painting (other than the bottom). By the way, I used to have a Cal 21.

The link you were given for compounding and polishing is the holy grail for bringing gelcoat back to life. I've used MaineSail's (the author) methods on a couple of boats and have gotten spectacular results. On the boats where I didn't use his techniques (pre-internet), my results were not good. Got a little shine, and it didn't last very long. If you use the right tools, pads, and wet sandpaper, and compounds, per MaineSail, you'll get great results. If you vary the recipe....best of luck to you.

The biggest challenge with using MS's techniques is knowing what grit to start with. On a boat of that age, with good, but chalky gelcoat, it's unlikely you'll want to start to with compounding. More likely that wet sanding (by hand) will be appropriate. Maybe 800 grit, and possibly as low as 600, but I'd start with 800. He'll describe the process, and the "grit increments" to use. Good luck with your project.
 
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Joe

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Jun 1, 2004
7,503
Catalina 27 Mission Bay, San Diego
If the bottom has a lot of algae on it.... green or brown.... try an inexpensive acid based toilet bowl cleaner. Smart & Final sells it in their janitorial supplies section. Active ingredient is Hydrochloric acid and the algae (pond scum) will come off easily. After that, wash and rinse with soap and water.... now... what's left... does it look like paint over the gel coat.. is it flaking off anywhere? How smooth is it? Do you have a boot stripe (water line) ? Do some quick research to learn about the different types of bottom paints. Essentially, the hard shell type is for boats that are stored in the water year round... the ablatives are most popular for trailer sailors, and those that take their boat out of the water on a regular basis.

Now if it were me, and I'm on a schoolboy budget... I would work on the topsides( hull between the waterline and deck) with a buffer and liquid polish first.... see how it progresses... then make a decision... painting would be my last choice. For the bottom.. assuming all biological growth and flaking paint have been removed...I would invest in a gallon of ablative type bottom paint.... follow the direction on the can for applying over existing paint. Look for sales.... West Marine, in particular, has a lot of sales this time of year. Be prepared to spend 90 to 150 for a gallon.... but that gallon will give you quite at least 2 coats and additional coats on leading edges... bow, keel, rudder.

Applying bottom paint is perhaps the easiest thing for a DIY'er to do..... A high quality topside finish is at another level... way more expensive because of prep, products and time... recovering the gel coat will look better, in the long run, than rustoleum.
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
Joe has a good thought about an acid wash. Just go to the nearest hardware store and get some muriatic acid brush it on and rinse it off. Should take any growth with it. A gallon of muriatic acid (aka 30% hydrochloric acid) is a lot cheaper than toilet bowl cleaner. Neutralize with baking soda and water.
 
Jul 27, 2011
4,552
Bavaria 38E Alamitos Bay
I've painted 1964 vintage Cal-20 topsides white with Brightside; works well; lasts a few years. Sand first, wash or wipe with tack cloth, then apply paint using a roller. Can get the stuff from WM as well as other places.

Otherwise, compound yourself into oblivion using this until it shines; then wax.
 
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rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
So after your guys advice I think I'm going to go with the acid wash the bottom and paint it using the CPP. As for the topside I think I'll skip painting and follow the instructions of the Boat Shine 101 article. Now for the deck, does anyone have any recommendations for improving the conditions of it? There are some hairline cracks where years of walking have produced stresses. I have used a product called "Captain Trolley's" for that purpose, which filled the cracks but left an ugly looking resin on a few of the small cracks I tested it on before I got the hang of it. Is there any method of just "sprucing up" the deck a bit?When I get a chance today I'll grab some pictures of the boat. Thanks again.
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
Before you buy the bottom paint, make sure you don't have VC17 on the hull now. No paint sticks to VC17 because it is teflon based.

There ain't no easy cure for gelcoat cracks short of grinding them out and filling them. Or learn to ignore them, they are probably cosmetic and not structural.
 

rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
Okay, and if it is VC17 then I will just have to use it to repaint the bottom? And the cracks are on the deck, is there a gelcoat on the deck? I was under the impression it was a fiberglass specifically for the deck?
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
If it is VC 17 then you either have to sand it off (ugh, just did that) or use VC17.

The deck is gelcoat over fiberglass. Decks usually get chalky and are harder to restore because they get direct overhead sunlight. The nonskid also gets worn and for obvious reasons you don't want to wax the surfaces that you walk on.

Check out Boatworks Today on YouTube. Andy has a lot of good videos on boat repair and maintenance including a couple on repairing nonskid.
 
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rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
Okay, will do. I'll check this all out tonight and see what route I'm going to go with.
 

Joe

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Jun 1, 2004
7,503
Catalina 27 Mission Bay, San Diego
Capt Tolley's is a penetrating epoxy that is not a cosmetic solution to gelcoat spider cracks. It works well in sealing the deck's wood core from water intrusion through damaged glass and gel. If you google search "gelcoat crack repair" you'll find lots of articles on the subject. Don't confuse "crazing" with "cracking".

Never used muriatic acid..... but I know this works.... Home depot... $4.49 qt is enough for many cleanings.... the deck brush is $7.99 Remember, acidic not bleach, cleaner.


 
Last edited:
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
Capt Tolley's is a penetrating epoxy that is not a cosmetic solution to gelcoat spider cracks. It works well in sealing the deck's wood core from water intrusion through damaged glass and gel. If you google search "gelcoat crack repair" you'll find lots of articles on the subject. Don't confuse "crazing" with "cracking".

Acid Bath?????? Not what I was thinking....but call it what you want. Never used muriatic acid..... but I know this works.... Home depot... $4.49 qt is enough for 4 or 5 cleanings.... the deck brush is $7.99
Zep Acidic Toilet Bowl Cleaner is Muriatic Acid, Sulfamic Acid and some other stuff. Check the MSDS.‎ content.rpgov.net/dpw/right_to_know/DPW/Zep%20Acidic%20Toilet%20Bowl%20Cleaner.pdf
 

rcw4

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Mar 29, 2017
8
Jenson Cal 21 Bald Eagle State Park
So to be clear the acid/toilet bowl cleaner is for removing stuck on grime below the waterline? To begin prepping for painting?
 
Jan 11, 2014
7,981
Sabre 362 113 Fair Haven, NY
Yes, test a small area first. Posting a good photo might also help.
Wear proper protective gear, eye protection, gloves and clothes that are not your Sunday best.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Don't sweat the gelcoat cracks on the deck. Scrub the deck well and often and the remove the dirt in those cracks - they will fade away.