Uncured linseed oil

[Pernicious Atavist]

the bioled linseed oil on my thwart is tacky and has been for over a week now. i've scrubbing it with ooo steel wool and mineral spirits, but am not sure if it's working.

ideas? :confused:

[pcford]

don't use steel wool on a boat.

[Paulyboy]

Steel wool becomes rust wool. Use nylon scrubbers, available in woodworking stores near you! Are you sure you used boiled linseed oil?

[Pernicious Atavist]

yup, i'm sure it's boiled.

[Wild Wassa]

... and did you add a bit of turps to the mix? Boiling is only one stage.

Linseed oil will not dry ... it might after 600 years but it doesn't actually dry.

Warren.

[ 10-08-2005, 06:12 PM: Message edited by: Wild Wassa ]

[Jay Greer]

If the wood was bleached with oxolic acid prior to putting on the oil with out first nuetralizing the acid the oil or varnish won't dry.

[Pernicious Atavist]

the oil on the foredeck and sternshhets is, uh--cured--if not 'dry.' i think i should add a couple thin coats of varnish at this point. i don't want it too shiney, or slippery, just sealed

what say we?

[Pernicious Atavist]

oh--and i reckon my only recourse now is to keep with the spirits and elbow grease, right?

[Spissgatter W-9]

So, what would be there be any ill effects of applying a coat of varnish over this tacky linseed oil?

[Pernicious Atavist]

no--i was thinking about removing the tacky and then varnishing. the rest of the wood is newer, and hasn't had the amount of oil the thwart has. if tacky is what i'm bound for, then i reckon i should stop now and varnish.

[Bob Smalser]

Varnish over it now, and your varnish may take forever to dry. It's got enuf driers in it to cure itself, but likely not itself plus a heavy wet spot beneath.

I'd add a heavy dash of Japan Drier to your wiping rag with turps and it'll cure your wet spot in a day to where you can varnish over it. Those heavy metal salts gel resins up like nothing else I know of.

Next time add some Japan Drier to your boiled linseed....yeah, it's already got driers in it, but not enuf for damp weather conditions.

[ 10-08-2005, 11:03 PM: Message edited by: Bob Smalser ]

[Spissgatter W-9]

I don't know. Just wondering if the varnish would facilitate curing. About 60 days ago I treated the inside of my boat with linseed oil, turps, pine tar and japan dryer. It doesn't come off on my hand but seems a little tacky. I would like to give it a coat of varnish.

Short of that, I wonder if a solution with japan dryer would faciilitate drying? Would be counterproductive stripping it off as you seem to be conemplating. Too bad the chemist isn't participating on formum any more. He would know.

[Spissgatter W-9]

I see Bob has posted while I was busy with my questions. Thanks Bob, will give that a try myself.

[Pernicious Atavist]

thanks bob (and w-9). it's been rainiong like hell lately and very humid, well, it's central florida, so duhhhhh.... :rolleyes: and i didn't consider humidity. i'll look for japan drier. i had thought of that, but didn't know if it was too late.

[LazyJack]

People often site humiity and moisture as inhibiting the drying of varnish...but I don't get it. If the varnish were water based, this would make sense: the greater the water vapor partial pressure in the air, lower the rate of water evaporation from the finish. But in the case of Oil based finishes the rate of solvent evaporation should have nothing do with the partial pressure of water vapor (humidity), it would have to do with the partial pressure of solvent vapor which, assuming good ventilation, would be next to nil. I've never really noticed any difference between varnishing on dry days and on humid days. Temperature seems to have a far more significant impact on drying characteristics than humidity. Thats why I don't hesitate to wet down the shop floors before applying the finish coat.

[Bob Smalser]

Humidity is merely water vapor, and vapor is vapor, if I remember my physics correctly.

Dry air absorbs more vapor, faster that humid air because of greater capacity to do so. Doesn't matter what flavor the vapor is, whether solvent or water. When it can't absorb any more, it rains.

[ 10-09-2005, 04:10 PM: Message edited by: Bob Smalser ]

[LazyJack]

Ah, thats just it Bob, Vapor ain't just vapor any more than a liquid is just a liquid. If you're still interested in physics, check out Raoults Law. BTW, remember those stupid pumps they used to sell that you screw onto the top of an open plastic soda bottle to pump them up with air pressure to try to keep the remaining soda from going flat? If they pumped it up with CO2 it would have worked great...in fact I think thats how they carbonate beverages in the first place

[Bob Smalser]

If you're trying to convince me that oil paints dry just as well in humid weather as dry, you might as well be selling bridges, Raoule's Law or no Raoule's Law. ;)

[Pernicious Atavist]

well, fellas, i gavce up on the oil, :( sanded off the tacky and applied a thin coat of vahnish. i'll add maybe two more coats; i don't want it to be too slippery nor do i want a yacht finish.
ain't this fun? :cool:

[LazyJack]

I'm not arguing against the phenominon, I've just not run into it and I'm just questioning the logic that people put forth as an explaination for the phenominon.
Not that there ain't more important things to think about... ;)

Speaking of bridges...interested in buying a handy pump gadget to keep your soda fizzy? :D

[Dan Lindberg]

Some years ago I had a canoe that the varnish wouldn't dry in the normal time, maybe this is why. I know I bleached the canoe, don't remember with what anymore.

But, leaving it in the warm sun for a week or so did get it to dry, finally.

"If the wood was bleached with oxolic acid prior to putting on the oil with out first nuetralizing the acid, the oil or varnish won't dry."

Dan

[Bruce Taylor]

LazyJack -- Apparently, while every solvent has a fixed, theoretical evaporation rate, solvents that are miscible in water evaporate more slowly as humidity rises. See here: http://www.woodfinishingsupplies.com/Sol vents%20for%20wood%20finishing.pdf (http://www.woodfinishingsupplies.com/Solvents%20for%20wood%20finishing.pdf)

In any case, oil varnishes are not really evaporative finishes; they cure when the molecules in their oils and resins crosslink to create big, fat polymers. Even raw linseed oil will crosslink, in the fullness of time. However, all sorts of environmental variables (such as exposure to light and various chemical catalysts) will affect the rate at which that miracle occurs. I don't pretend to understand the process (and where the hell is The Chemist, these days?!), but I can tell you from personal experience that Bob is exactly right: the stuff dries more slowly as RH goes up!

[ 10-10-2005, 07:18 PM: Message edited by: Bruce Taylor ]

[LazyJack]

Well humph!
I'm still puzzled...but not so much so when I remember as you point out, that a film finish is a polimerization rxn for the most part which may indeed be effected by ambient water vapor. Ah well, Captains Z-spar and plain ol alkyd enamel...it's never let me down!

Didn't mean to side-track this thread by the way

[ 10-10-2005, 11:37 PM: Message edited by: LazyJack ]

[Pernicious Atavist]

hi, all. well, reading all this input had been illuminating. i applied the first coat of z-spar cptn's yesterday and the second, maybe third will goon today. i think that will be plenty since there's plenty oil under the vahnish. and it all seems to cure better on drier days, of course, cross-link polymerization and all.... ;)

[didio]

Use scotchbrite pads or bronze wool for scrubbing. Wet the pad with some sort of solvent--turpentine, paint thinnner, alcohol. wipe up with solvent dampened rags.

[Alan D. Hyde]

When applying linseed oil, 50/50 boiled linseed oil & turpentine is a good mix.

Heat it as hot as you can stand to work with it, then apply generously.

After a while--- before it starts getting sticky*--- wipe off any excess with a clean rag. Repeat as needed.

Alan

* The time that this takes will vary with humidity, temperature (of the air and of the surface itself), absorbtiveness of the surface, sunlight/shade, and degree of air movement.

[ 10-12-2005, 10:10 AM: Message edited by: Alan D. Hyde ]

[Kermit]

I've used various oil soups through the years, and while japan drier is definitely a good idea, don't forget the sunshine. UV seems to help the stuff to kick off and get harder faster. I once used one of my favorite tar and oil soups on a dougfir door on the north side of a garage. Took all summer to get over being tacky.

[ 10-11-2005, 09:22 PM: Message edited by: Kermit ]