Novice boatbuilder needs varnishing advice.

[Jimbo1490]

This little company down in Hialeah, Fl called Fasco makes one of the most UV resistant marine varnishes you can buy. Fasco is a mom & pop outfit that's been in business for quite a long time and the owner/formulator will talk to you if you ask for him (at least the last time I talked to them, but hey that's been a while). The UV inhibitor everybody is referring to is a pretty pricey chemical, (I forget the name) that costs several hundred dollars a gallon. The thing is Fasco dares to use more of this chemical in their varnish than any other manufacturer does. I had some brightwork (not on a boat, but the same stuff) down in Miami with the Fasco varnish on it, always outdoors and it went longer than a year between re-coats, which is pretty good for a conventional one-part varnish.

[alan white]

Originally Posted by LP

I'm buying my Captain's at the wrong location. Where are you purchasing yours for $23 Alan?

Hamilton Marine in Searsport, Maine. They have other locations, but all in Maine. They have an online catalog. Every spring, they run a special. You can even buy a gallon for $70.00 (last year's prices).

[Kaptin-Jer]

Thanks Jimbo, but I still don't have my passport

I go through about two quarts a week right now, I'm re-working the interior. I don't like to buy more than a quart at a time. I can keep a quart from starting to set, but I have a rough time with a Gallon, Yes I know all the tricks, but I still like buying a quart at a time, so a trip down south would not be worth it to me.

[PAR]

If you have a propane torch onboard when you varnish, you can keep an opened can fresh by filling the top of the can with the gas, which is heavier then air and sinks. This displaces the air, shoving it over the rim and fills the void above the used varnish with propane, then slap on the lid. No air, no skin, no problem and it works very well.

[alan white]

Interesting, Paul. I'd also remind those who buy a quart at a time that any Sherwin Williams (and I think, Home Depot) store has empty quart cans/lids for sale for two bucks. By the gallon, quarts cost $17.50 from my supplier. about half what a lot of marine supplies are selling the same exact brand and item number for.

[PAR]

Alan, I've also used argon, mapp gas or acetylene, depending one whatever is closest to me at the time. Those empty quart and gallon cans from the hardware store are great for storage of "mixtures" like dirty varnish (same trick works to prevent skinning) and solvents, stain mixes, resins with pigment, etc.

[Kaptin-Jer]

But when you buy a quart all you need to do is exhale into the can before snapping on the lid. Works great. I would burn myself with a torch, and I usually can't get the CFO (my wife) to spring for a whole gallon at one time.

[Jimbo1490]

PAR,
That's a really cool trick; one I'll remember. All the cans of urethane catalyst come packed with inert gas from the factory, which is why they have OK shelf life until you open them and pour some out. Then that dry gas sparge is replaced with ambient air with it's oxygen, which is usually very humid to boot.

I used to do quite a lot of rigid polyurethane casting for prototype parts. Those casting resins are VERY reactive. Some formulations will go from liquid to full hard in 5 minutes once mixed. They are also very moisture sensitive, so much so that if you just open the cans in ambient air, the shelf life would drop to no more than a week or so. So they came out with this little device that attaches to the can. It's a little air filter cannister containing silica gel. You puncture the lid with a little pipe on the bottom of the cannister and then this little cannister just sits there on top of the lid. Then you get this little spigot that punctures the bottom of the can. That's how you pour. Then all the air coming in at the top has to go through the little cannister filter at the top with the desiccant. Worked really well. I don't know off hand where you'd buy one; it came with a case of casting resin I bought. The drier is reusable too. You just put it in the oven for an hour and it's good as new.

But that just solves the moisture problem which is really only a problem with polyurethane, including the one-part types. PAR's trick addresses the oxygen problem, too.

[PAR]

I've gone to the trouble of installing Schrader valves on a few cans of stuff I use all the time, but not much of, like application specific stains. Trying to match a 60 year old Chris Craft stain can be a prick and once you've got it, then you don't want to lose the recipe, for example. Pump in something heavier then air that doesn't like moisture either and hold open the other (I use two valves per can, so the lid can be on tight)until you have a strong smell of whatever you're pumping in, coming out.

Also drawing a vacuum on an open cartridge of 5200 (or most other goo in a tube) in a bag with the same gasses will permit you to keep it for several months (okay maybe 6 months).

[the1much]

Originally Posted by Kaptin-Jer

But when you buy a quart all you need to do is exhale into the can before snapping on the lid. Works great. I would burn myself with a torch, and I usually can't get the CFO (my wife) to spring for a whole gallon at one time.

i knew i was doing it wrong,,,,EX-hale

[Kaptin-Jer]

Yes, Jim EXHALE! only inhale every 3rd can.

Paul, if my bread and butter depended on keeping formulas and expensive coatings fresh I would do what you are doing too. I can buy what I need in small enough quantities that if I should lose a 1/2 quart of something it won't break the bank.