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I'm ready to apply the final coat of international "schooner" varnish to my deck, but I've been getting some dust in the previous coats which required sanding in between...and this is despite wetting down most of the work area with water and wiping the deck with a thinners-dampened cloth.

Anyone got any tips / procedures for getting a perfect finish?

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David McAdam
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Dust and suicidal flies are a fact of life when you're varnishing David! I closed in the sides of my covered building area with polythene sheeting, I thought it was pretty airtight, but some little moth-like things still got in and decided to reenact the war in the Pacific by diving kamikaze style into my fresh varnish.
All you can really do is to wait until it's properly dry and hard then cut and polish the buggers out.

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Graham in Shepperton, England

Good, Quick, Cheap, pick any two.

Luckily kamikaze flies haven't been a problem since I've been able to distract them with a big light before they can acquire the target. Its more a matter of microscopic dust that seems to appear out of nowhere. The shed that I'm working in has a very high ceiling so its not possible to spray it with water...I might try to find a different place to apply the final coat....

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David McAdam
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I used to paint cars for a living in a former life. I was always fighting dust. I finally found the biggest offender was my own clothes. (remember I was spraying) I put on one of those white 'bunny suits', I looked like a Atomic Lab worker. But it worked. I also had to put on a head cover.
A TACK cloth is better than a solvent rag. TACK cloth is made for just this purpode, to pick up dust. Remember that rags are cloth, and cloth has lint, so your solvent rag is likelt leaving as much lint behind as it is picking up. I quit using solvents on the surface of any kind, solvents will dissolve impurities, and just smear them around. If the surface is properly sanded, then it is in the best possible state for application of a coating. Using an solvent endangers introduction of impurities.
Wetsanding is still the best. Dry it off with a baby diaper (old cloth type), blow it off, and tackrag it. No solvent , no fuss.

Kens, by solvent, are you referring to something that you would use to clean up your spray equipment such as lacquer thinner? ...or something along the lines of DuPont's PrepSol? I was thinking that I would use PreSol, right before tacking, to clean away silicons or waxes or anything else that would cause the paint to fisheye or react when applied to the boat.

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

The ONLY thing Prep-Sol is made for is removing wax from a waxed painted surface.
Unless you are working on a waxed boat on this building forum, STAY AWAY FROM IT.
Prep-Sol is evil and has no purpose as far as I am concerned.
When I said solvents, I mean ALL solvents based from petroleum product.
This includes paint thinner, lacquer thinner, mineral spirtits, enamel reducer, turpinetine, whatever you got, and especially, Prep Sol.
PrepSol is the absolute WORST.
I know some guys wipe with some solvent and get by with that. If you wipe with 'PrepSol', and do not get it all wiped off before it dries, the paint will not stick to dried PrepSol.
The place for PrepSol, is to remove wax BEFORE you start the re-painting process on cars. If you are already working with a primer, or, sandpaper, then there is NO use for PrepSol in your shop, get rid of it, throw the crap out, kill weeds with it.
The deal with solvents is that they do NOT dry without some amount of residue. PrepSol dries with the MOST residue.
Even something as highly refined as Methyl-Ethyl-Ketone (MEK) dries with residue. Not only that, a solvent will not evaporate any impurities, it only dissolves impurities and spreads them around with your rag.
The best way to work the paint project (assuming this is never waxed & never introduced to silicone):
1. sand off the material
2. dry sand preferred
3. wet sand if the dust bothers you.
This way, you NEVER dissolve any impurities, you blow them away with the dust. Not only that, raw sanded paint will absorb solvents, and if that solvent is contaminated, then you just contaminated your project..
Use your solvents for thinning the paint and cleaning up, and that's it.
No more! No how.
I dont care what kind of solvent it is.
P.S.
You can buy cheaper weed killer than PrepSol.

Dave - There is an excellent article on what it takes to get that super varnish finish. Here's the web site: http://www.vintagehydroplanes.com/buffing.html
I'm thinking of going in that direction - - but lots of work.

Robert A

Thanx Kens. I'm glad you told me that because this is all stuff I didn't know. You may have just saved me a considerable amount of heartache and discouragement.

I will say this, I've had some experience wet sanding automotive urethanes that were shot with a hardener. I got good results each time. It is a lot of work but the end results are worth the extra effort. The hot rod guys do it on every machine as a matter of rote.

Robert A, that's a really good article on varnishing "Moonshine Baby." I skimmed over it and will go back and reread it in deeper detail when I have a little more time.

Good stuff. That's why we have forums.

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Notice that that article didnt use solvents on the sanded surface to remove any dust nor for preparation.
He used a vacuum to remove dust. I like vacuums too. I havent tried the naptha on raw wood, and suspect that I never will either.
His process for the final sanding/blocking/polishing of the surface is correct for a fine finish. The 'show' quality finishes are obtained by blocking and polishing.
In some ways this can save work because defects in the finish are sanded out and polished, such as dirt and those pesky mosquitos. You wait for the paint to dry and block out the bugs & polish them. The thing you must know is the window of time you have for recoating the paint product. Nowadays there are just so many types of paint out there that one cannot speak for them all. You must read your label and abide by that.
I really liked the two-part polyurethanes (isocyanates activated) because you could recoat at any time, block it out the day after, and polish it a week later. Wow! You could polish that to a glass finish.

Is Imron an example of that type of finish or is it something else?

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Yes, Dupont Imron is the 2-part polyurethane. It has isocyanates and is hazardous to breath the overspray. You need the best expensive charcoal filtered respirator to spray it.
Imron was one of the first polyurethanes to come out, and that was around the mid 70's or so.

My personal favorites were the products from PPG (formerly Ditzler).
Some shops liked DuPont stuff, and myself, I liked PPG. Personal preference on that one. All the paint manufacturers have "improved" and renamed their products since I was painting cars. Perhaps the exception is Imron, I believe they still sell it under that name.

The thing that I watch out for is the so-called one-part polyurethane. There is no such thing. If it is a polyurethane, then it becomes the 'poly' part of its name by adding the activator. When you add that activator that stuff will setup by chemical reaction, even if you put the lid back on it. This chemically drying paint is what gives this stuff the workability that I like so well. It is predictable in its drying properties. Kinda like epoxy, it has a pot-life, and a drying schedule depending upon the temperature. If you go out to buy the real polyurethane, bring your checkbook, it aint cheap. It might even scare you.