Glen-L.com

Ok, so I'm still kinda unclear on a few finishing topics...

1) Varnish vs. Automotive Urethane. What is the difference? Which one is typically considered better? Or which one is used for which situation, etc...

2) A little more specific here... I plan on painting the bottom of my malahini with supermarine paint, probably do a white bootstripe, very similar to what Iggy's doing. I know that the paint needs to have the work surface prepped by sanding up to 120 grit, but what about the brightsides surface for the varnish or Auto-urethane? Sand prep to 120 just like the painted surface? Or apply the finish right on top of the cured resin without sanding? How do I need to prep the sides prior to applying my finish?

3) After the bottom is painted, and I start to varnish or auto-urethane, how does that work as far as the paint that comes 4 inches or so up the side? Do I finish up to the bootstripe? Or finish over top the bootstripe? Just want to make sure everything is protected, but don't want to finish over the paint if that is unacceptable either...

Thanks
Charles

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If you use the auto clear,I would think you could go over the bootstripe if the paints are compatable.

The varnish will add yellow or amber to what ever paint.

You need to sand the epoxy.....not sure what grit,or wet or dry,I'll let someone else answer that

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Onplane if you go with automotive clear you will have to sand it up to atleast 600 or 800 grit or it wont be smooth enough and the sanding scratches will show you should be able to clear over all the paint youve already done as long as the paint is cured and not still gassing off to much.

Charles,

I only painted the blue bottom on my boat prior to flipping. I did the boot stripe just before I put the finish on the sides 8 months after flipping.

Yes, sand up through 120 for the bottom paint, I think I sanded through 220 on the sides, the grit is not as important and being sure you have a smooth, flat surface. I used at random orbit sander and then hand blocked with a 12" block.

The finish is all personal preference. I think varnish looks great but its time consuming to apply and likely requires the most maintenance every few years.
I saw one boat with urethane auto clear on it at the Gathering and it looks fantastic. It goes on perfectly clear and smooth, there is not really any warm amber glow like varnish, its truly clear just keep that in mind.
You can also get a urethane clear from SuperMarine, which is what I did. Its slightly easier to apply than varnish. It only takes 2-3 coats for full UV protection compared to 10 and it dries in 3-4 hours compared to 12 or more. It should hold up twice as long as varnish. The downsides of SM clear are, it will have slight orange peel unless you wet-sand and buff. It seems to scratch slightly easier than varnish and much easier than auto-clear. SM just seems to cure softer than the other finishes.

If you apply either varnish or SM clear, tape right at your boot stripe, you dont want either to go over paint or they will yellow, SM clear to a lesser degree than varnish. I overlapped 1/16" over my boot stripe with the SM clear and it does not show. As long as you cant see a gap between the clear and paint you will be fine as far as protection. Epoxy is enough protection from the water for your wood, you just are protecting the epoxy from UV with the finish.

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Chris,

Great info, but could you give me some more like...

- How often does it need to be reapplied? (I know you said twice as long as varnish, but I was thinking varnish is an every year thing...) Do you have to reapply every 2-3 years?

- How do you reapply? scuff/sanding required?

- When putting on initially do you allow each coat to dry then sand for mechanical bond, or just re-coat within a certain time limit for chemical bond (like epoxy/paint)?

- Is there a shelf life on the SM Clear?

- What is the cost difference between auto-urethane, varnish, & SM urethane clear?

thanks for the help, I'm a true rookie when it comes to this stuff... I obviously want something that is tough, looks good, and requires little effort in maintenance... (Doesn't everyone?! ) But I know you rarely get them all in one package. So I guess I can skimp on one or the other, but right now I just don't know much about any of them...

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I use Interlux 2-Part PU. After 2 years it still looks great. But, someone said they stopped making it.

As I remember, to refresh: 220 grit then recoat.

I always do a light 220 grit between coat pop any air bubbles and remove any bugs.

Bill

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Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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Interlux Perfection Plus
follow the directions EXACTLY as in the application guide and buy their thinning and cleaning product
-Billy

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Bill,
I don't know for a fact if they still make it or not, but I do know places still stock it. Got mine a couple of weeks ago.

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Perfection Plus is what replaced it
http://www.jamestowndistributors.com/userportal/show_product.do?pid=4245&familyName=Interlux+Perfection+Plus+Two+Part+Varnish#

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Perfection Plus is what I was referring to.

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That's the stuff! Stinks like hell when you apply it though!

Bill

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Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Charles,

I only have experience with the SM clear, so I can only really speak of my experience with it and pass on what I have observed with auto and varnish.

Hard telling how long the SM clear will last. None of us that used SM have had our boats done very long. I would guess on my garage kept boat it will last at least 5-10 years. I bet I redo it due to scratches and bumps and other damage long before the finish actually starts to deteriorate like old varnish does.

To re-apply you just scuff with 220 and roll another coat on.

To initially apply the SM clear you apply one coat at a time and scuff between after a days cure time. If you try two coats at once it crinkles. The can says only 2 coats required for complete UV protection.

Not sure about shelf life. (email the tech dept at SM) I put my blue bottom paint on a 10.5 months ago and just re-opened the same can and touched up a spot on the bottom and the paint was still good. I doubt it will be any good when it comes time to redo the bottom paint or the clear coat though.

The costs for the materials for each is pretty close and was only 2% of my total build costs. If you are going with auto clear and have no experience it might be a little pricey to have a body shop spray it. I'd be awfully tempted to go that route if doing all this again. It seems to be the smoothest finish of all of them and quite durable. With that said, on my Kayak kit I just bought I am planning to try varnish just to learn how to use it. I think with garage kept boats its going to last quite a while as well and varnish is smoother than SM1000 is. SM1000 will have slight orange peel unless you wetsand and buff the final finish. I did not wet sand and buff, its only necessary for a showroom smooth finish. I figure my not wet sanding and buffing I wont be too upset if I scratch the finish using the boat.

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"Nothing screams poor craftsmanship like wrinkles in your duct tape."

I used Imron ( by Dupont ) on my sailboat in 96. Itwas sprayed and I wasn't really impressed at first, but 2 hours later it looked incredible. The boat haas been in Europe for the last 6 years and still looks great.
I plan on using it on the Titan also.
Doug

Thanks for the replies.

Chris,

I checked out the SM-1000 on SM's website this weekend. I thought the price was quite reasonable really... pretty much comparable to their paint costs.

How much of the SM1000 did you end up using on the zip?

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I first finished my boat with Interlux Perfection Varnish. I rolled and tipped a couple coats and it looked pretty good, but not great. My brother, who has professional painting equipment and plenty of experience using it offered to spray it as long as I did all of the sanding, taping, and cleaning. That's an offer I couldn't resist, so we then sprayed the interlux on my boat. It looked sensational, with an ever so slight orange peel. This finish was on my boat for a little over a year and still looked good, although there were a couple scratches that I couldn't buff out.

Because I'd had some separation on a few of my decking boards (had nothing to do with the finish), I decided to sand back down to bare wood, correct the problem and use auto clearcoat for the finish this time.

At the risk of sounding boastful, I think the deck on my boat is quite striking, somewhat from wood selection and mixing, but largely because of the professional finish. But the finish looked equally as good with both the interlux and clearcoat. The difference is not in the product, but in the spraying. I appreciate the research and effort Interlux and SuperMarine have put into their products to allow them to be easily applied, and you can get a very nice finish with these products; but, I'm of the opinion if you want a professional sprayed on look; well, you'll have to spray it.

While I don't see a lot of difference in the appearance, between the two, I prefer the auto clear because it sprayed easier, scratches can generally be buffed out fairly easy, and it feels great (just like a new car) when you wax it. The way I applied it was to dry sand with 320 before the first coat, wet sand with 800 between coats (I applied seven), then wet sand the final coat with 2000 to take out any minor orange peel, then polish, buff, and wax. It sounds counter-intuitive to sand the final coat, but thats the way it's done, and it's truly amazing to watch the shine come back out as you begin applying the polish.

I researched this quite a bit before going with the clearcoat. The clearcoat can result in a little bit of a plastic looking finish, but I like it. From what I've read, there's no issues with the durability of clearcoat for topsides application.