About to paint my Hobie 16, in an effort to show the property oweners that allow me mast up storage I take good care of her. I have her sanded with 80 grit, about to go to 120 and then scrub, acetone and start painting. Any last minute suggestions?

Prime first - use the matching interlux epoxy "Kote". It actually sprays REALLY nicely, but be prepared when you open it: it looks like some kind of white jelly. You HAVE to reduce it with matching reducer at the recommended rate and stir FOREVER. I mean, you stir for a solid 10 minutes to get it to mix. I can't remember if I catalyzed first, then reduced (I think that's the right way), or what, but you also need to let it sit for 30 minutes to start reacting before you put in the gun.

Why primer? It'll cover way better, stick better and the primer is really the waterproofing before the paint. Good luck, and pictures please! Which Interlux you going to use?

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Chuck C
NACRA 500 Mk2
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but you also need to let it sit for 30 minutes to start reacting before you put in the gun.

I am just going to roll and tip, I do have a compressor but not a gun and I don't really have a good place to spray regardless.

I was hoping to avoid primer as I am trying to keep costs down on an 35 year old boat but if I am going through the effort, what another $100

If it gets much more expensive I may just go to the guy that paints mullet boats in the area and see how he does

Ha! Gotcha. - That 30 minutes is called "induction time" - couldn't think of it earlier, but it's important. Then, I'd certainly clean it really, really good first. You can get cheaper compatible primers, I think.

I got it for about $50/quart:
https://www.jamestowndistributors.com/userportal/show_product.do?pid=122

A quart (should be more when thinned) should do the boat if you spray (I think-check instructions). Don't know how well straight up paint would hold. It may end up peeling pretty quick. Want it to only last a year? Then I'd two-part polyurethane or epoxy without prime. Maybe 3-4 years more? Then I'd prime it. Plus, it'll look a lot better.

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Chuck C
NACRA 500 Mk2
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A common problem is embedded wax, or even on an older boat, mold release from the original production. The wax causes bullseyes that you just can't get rid of.

After sanding you should wipe down with something like this: https://www.amazon.com/Kleanstrip-Prep-All-Grease-Remover-KLE-GSW362/dp/B008QDSVPE/ref=asc_df_B008QDSVPE/?tag=hyprod-20&linkCode=df0&hvadid=312089957955&hvpos=1o1&hvnetw=g&hvrand=13705138459387963448&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003941&hvtargid=aud-829758849484:pla-569618139042&psc=1

Actually, they say to use it before sanding, so you don't rub wax into the sand scratches.

I painted a Dart 20 with Interlux single part, using a small roller and a brush for tipping, and it came out fine except a few small blisters below the water line, where water from the inside pushed out on the paint. My hulls were pretty dry, but that little bit of water or condensation kept messing up the small area. Bullseyes were a problem for me until a friend from an auto body shop gave me some of that cleaner.

My Tornado was painted by an auto body shop with ordinary 2 part PPG white auto paint. It has been outside for 20 years and still shines.



Edited by malcs on Sep 10, 2019 - 10:17 AM.

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or even on an older boat, mold release from the original production

wow ! i would have never thought that could still be on the boat

Yes I realize I already screwed up doing some sanding before I dewaxed.

Conventional wisdom is painting is the easy part; prep is the hard part. Without getting too far in the weeds prep is a multi step process. The boat needs to be clean to start. Often times the first step is use something like dish washing liquid to get rid of grease, oil, dirt, mold, and what else is on the boat. I tend to use an acetone wipe next. Then sanding; sometimes with multiple grit paper in stages. For best results primer is a must. Only then do you get to the painting part.

Unless you have an indoor place to paint it is not easy to get the results a pro shop can provide. On the other hand a shade tree mechanic setup can greatly improve not only the boat's look but add significantly to the boat's life.

That Interlux stuff is good, but nothing beats 2 part auto paint, other than really expensive Awlgrip and Imron. Think about it, your car paint is designed to sit in the Texas sun and make it through winters in Alaska. My boat has been covered some winters, and not the others, and the paint is still good after 20 years. The paint mfg will suggest a different primer for fiberglass than metal, and sometimes epoxy needs its own primer. Baking it at a temperature that is compatible with the boat's structure works out best. Boats can get pretty hot out in the sun so I doubt a few hours in an autobody shop oven is a problem. This only applies to a boat that you intend to keep, not one you are just making pretty for the neighbors.

And, one further point. I've painted repairs on my (white) boat with the newer Rustoleum premium spray paint, which does not need primer. That paint has a number of years on it and is still looking good. Consumer stuff is pretty good these days.



Edited by malcs on Sep 10, 2019 - 03:33 PM.

I can attest to the bulls eye business - a friend built a hollow wood surfboard and because he sanded before washing off the amine blush, we chased them for about 3 months worth of weekends. Finally sanded and clear coated with polyurethane automotive clear coat. That came out absolutely awesome. He's been surfing on it for 3+ years.

I was waffling between the interlux perfection and auto poly single stage. Came to the conclusion, to prevent blisters, you pretty much have to keep hulls dry and have to epoxy prime first. The interlux perfection is actually a close formulation to the automotive stuff, near as I can tell. When you add up the costs of matching reducers, activators, etc. you're fairly close in price between the two, assuming you buy the Interlux off the web.

Malcs - how well is the poly holding up on the bottom from abrasion? I'd LOVE to do automotive as I'm very familiar with that, if I can get a bead on a reasonable price on a couple quarts of the stuff and it's very repairable.

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Chuck C
NACRA 500 Mk2
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Chuck C., the auto paint is VERY scratch resistant on my Reg White Tornado. I just looked and it was actually painted 17 years ago. Mine was baked in an oven after spraying, and we did use the correct primer. The owner of the shop races those motor catamarans, so he's familiar with painting boats.

The one part Interlux paint that I did years back was OK, but not spectacular. I seem to remember it had a very long cure time, perhaps months, before it reached full hardness. It was usable after a few days, but not fully cured to fingernail proof. The paint mostly leveled during the rolling and tipping process, but I'd say in auto terms I had a 5 footer. Looked great from 5 feet away. Auto paint on the other boat made it look new, and I still get comments when I tell people my boat is from 1986. It was fully cured within a few days after. You kind of know when you tap your finger nails on it and it makes a click, rather than a dead sounding tap.

So, you just can't beat 2 part paints, and oven curing. I'm guessing that paint technology is much the same across all of the two part paints, whether auto or marine. Exceptions are probably AwlGrip, and the extremely high toxicity of that stuff is probably why. Awlgrip will send you to the hospital and cause permanent nerve damage if you don't follow the safety precautions. I painted the topside of my monohull with that stuff and even outside with respirators you can tell you are dealing with something really toxic.

In my opinion this is only worth it on a specialty boat, not so much on something of lesser value. Most boats look OK at the beach, especially when wet, even if the gelcoat is skectchy.

charlescarlis the Amine Blush is a characteristic of some of the older epoxy formulations. Some of the new epoxies don't do that, but perhaps they are not as strong.

Here is what West System has to say about it:

Amine blush, sometimes referred to as bloom, forms when amines in the hardener react with carbon dioxide and moisture in the air. We have found that the same components that promote our epoxy’s strength and toughness also contribute to the formation of blush. Balancing an epoxy’s physical strength, mechanical properties and handling characteristics is a difficult task when formulating for the marine market. A slight change in chemical formulation can have a dramatic affect on the overall characteristics. Components used in WEST SYSTEM® Epoxy have been carefully selected to achieve the long-term, high-strength performance WEST SYSTEM Epoxy is known for.

Blush is water soluble and can be removed with an abrasive pad and water, after the epoxy has cured hard. 3-M Scotch-Brite® General Purpose Hand Pads or similar abrasive scrunge pads work well for abrading and dulling the shiny surface. Detergents and solvents are not required or recommended for removing blush.

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Blush is water soluble and can be removed with an abrasive pad and water, after the epoxy has cured hard. 3-M Scotch-Brite® General Purpose Hand Pads or similar abrasive scrunge pads work well for abrading and dulling the shiny surface. Detergents and solvents are not required or recommended for removing blush.

West system recommends using peel ply too
the amine blush forms on the top of the tape and is removed when the tape is removed

Done the peel-ply trick myself (my buddy's was a first foray at epoxies). As a note, you can get the same "peel-ply" material at fabric stores MUCH cheaper by using an ultra-light polyester fabric. The up-sides, besides the removal of amine blush is that it leaves a wonderful texture that makes it sand WAY quicker to accept paint.

So - back to the topic of how abrasion-resistant a finish is: Is the single stage, 2-part urethane used for autos good enough for our boats? I'll be painting this winter as well. My boat is OLD, in fairly good shape and I'm thinking of a 5 year finish (target). I try not to be too tough on it.

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Chuck C
NACRA 500 Mk2
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I appreciate all the detailed responses. I actually got a good quote from an auto body shop and am going to move that direction. One of the main reasons is that I’m getting ants in my pants and am afraid I will rush the process and won’t get the results I want out of the paint/primer costs. I will let you know how it works out

Just an update for those interested.

I took my Hobie 16 to an autobody shop on Saturday and picked it up today. I am quite pleased. Looks fantastic although only time will tell. $400 dollars out the door which was more than I was planing on spending on the project but my material costs were already going to be close to $200, maybe a little more and I really am only able to work on it on weekends when I would rather be sailing. I do not think I could have done half as good a job in 3 times the amount of time, but I don't do it for a living so no surprise there.

Dude! That's actually not bad... Yup - by the time you add up sandpaper, paper supplies, masking, solvent prep, paint, reducer, activator, etc. THEN time - $400 looks cheap, REAL cheap. And you had it done in a real paint booth. Good call, I think. Do you know what brand auto paint they used?

How about some pictures?

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Chuck C
NACRA 500 Mk2
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awesome sauce!
yea, lets see the proof . :)

That is a great price! And you don't have nearly full cans of thinners sitting around, waiting to be disposed of 10 years from now. Make sure you have the shop write down the exact formula/color for future touch ups and repairs. Let's see some pictures.

I struggle posting photos here



Edited by jalex on Sep 17, 2019 - 01:33 PM.

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I struggle posting photos here

you can email them to me and i will post if you want andrew at asn studios . dot com

looks great but a lot less "shiny" than i would expect - perhaps that comes with wax?

i say that because i can see a reflection in my gelcoat when freshly polished
and i can see a reflection in my painted boat as well

Looks good - might just be the lighting. I'd clean all the paint over spray off the stainless sooner than later as you're likely to be chipping it off, if you do. If you just want to, you could easily buff it out, especially if the paint was cured in an oven. In fact, if cured in an oven, the pros usually like to buff within about 12 hours (at least clear coat) as the paint gets real hard after that and is a bear to buff properly.

I like it! - for what it is (an old Hobie 16, refreshed). Now, clean the aluminum of all dirt, get some Penetrol from the paint department and wipe the aluminum and you'll have a crisp, detailed boat. The stuff helps, even if it's very temporary.

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Chuck C
NACRA 500 Mk2
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Is it true that a dull finish is faster (in the water) than a glossy one?

(besides being faster to prep and apply)

It is not a mirror finish but the money/job time/quality ratio was a good one. She’s on the beach 365 days a year so keeping her shiny is almost futile.

I guess I do need to wax her, and I guess I will be using a different product now she is no longer gel coat?

I read somewhere - can't remember, maybe hearsay, that axing a sailboat hull, like a jet ski hull isn't a good idea. Have no idea if that's true, but something about detaching the boundary layer between the hull and the water is good. Waxing makes it "stick" - I think the same applies for surf boards (???). The reason why they keep their boards clean on the bottom; control and speed.

Dunno - but I'd sure wax above the waterline for UV protection, at least. Perhaps it makes no difference or not a substantial difference for the entire hull.

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Chuck C
NACRA 500 Mk2
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