# curing oil based stains and urethane in high humidity?



## woodbutcher (Dec 29, 2006)

How can one best use oil based stains and poly in high humidity? I've been cutting the urethane with 50% mineral spirits , but with little success. The humidity is averaging between 75-85% with no let up in sight. The project requires the use of urethane for the finish, but 3days to cure is just too much! any suggestions, would be much appreciated.

Ken McGinnis


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## CharlieM1958 (Nov 7, 2006)

Ken, are you talking about fully curing, or just drying enough for a second coat?

Here in New Orleans the humidity is almost always over 75%. In general, I find I can recoat urethane or apply finish over a stain successfully with just an overnight wait.

Short of having the necessary equipment to regulate the temperature and humidity of your workspace, I can't think of any easy answers.


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## HokieMojo (Mar 11, 2008)

i feel your pain and will be interested to hear others thoughts. One idea is that after the coat loses some 95% of its tackiness, you could put a fan in the room (not blowing directly on it) to increase ciculation. This seems to save me a day of drying time. Then for the last coat, I go with no fan to get a smooth finish.


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## mmh (Mar 17, 2008)

Are you working indoors or outdoors? Can you move the piece indoors to an air-conditioned or dehumidified environment? A sealed area with a lightbulb constantly on would be a kiln like atmosphere.

I have tried to do my finishes during lower periods of humidity, but the time factor may not always allow for this. My workshop is in the basement and I we have central A/C and I run the system's fan constantly to keep the air flowing as it keeps the hot & cold air circulating around the house so the tempurature is even. I have found that running the fan constantly also keeps my wood collection dry and any green pieces are placed close to the fan unit and they dry quite nicely. I have a 100 watt light bulb kept *on* in that room to keep the humidity down, as I have a 150 gallon fish tank in the same room. This set up has not had any problems with mold or warping.

OR

Move to Arizona.


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## sbryan55 (Dec 8, 2007)

Ken, I am with Charlie on this. Here in Kentucky the humidity is only rarely below 75 percent but overnight is usually more than sufficient to let oil based stains and finishes to dry enough for topcoating with a sealer or application of a second coat. With wipe on finishes it will cure sufficiently so that I can usually apply a second coat within 4 to 6 hours.


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## stefang (Apr 9, 2009)

You should let it dry enough by whatever means to be able to sand lightly between coats just to knock off any nubs, hair or whatever encased in the last coat. It would probably be a good investment for you to buy a dehumidifier if you will running into this problem a lot. I did, and it makes all the difference.


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## woodbutcher (Dec 29, 2006)

Gentlemen,
Thank you all for your your input and help. I believe the consensus is that I either correct the conditions of high humidity or be patient. It seems the older I get the less patience I have, guess I'm some what short on this virtue! CharlieM1958, I was hoping for a pretty good cure, where I couldn't see finger prints, prior to using a second coat. I'm afraid if I put a second coat over a not fully cured first coat, that I'll just retard further the final hard cure. HokieMojo, mmh, Scott Bryan, stefang I thank you all again for your help. I'm just too accustomed to using tung oil I guess and wiping constantly, I know to be patient there-LOL.

Sincerely,
Ken McGinnis


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## CharlieM1958 (Nov 7, 2006)

I've fnally gotten used to the idea of building a project in weekend and taking three weks to get the finish done. It still ticks me off, though. :-


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## a1Jim (Aug 9, 2008)

The best way is to use water base instead.


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## woodbutcher (Dec 29, 2006)

bentlyj,
I've used the Japan Drier in the past. Pretty darn tricky with tung oil. Either I get too much drier and the top cures with the bottom left tacky, or I start fires with it-LOL. I guess I'll just learn to exhibit the same patience CharlieM1958 does now as long as I don't start getting that square corner twitch, he has! Thanks for your time and input.

Sincerely,
Ken McGinnis


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## woodbutcher (Dec 29, 2006)

a1Jim,
Hello buddy, you're probably right. I was just under the impression that the water based urethane was not as durable and resistant to as many things as the oil based product. If I'm wrong in this assumption and the water based product is just as durable, I could use this idea. Is it much less sensitive to humidity? Does it work well with oil based stain? I'm simply hooked on oil based stain, if I have to use a stain for a project. I'll investigate this idea further for future use. Thanks for your help, I new there was a darn good reason, you were on my buddy list-LOL

Sincerely,
Ken McGinnis


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## CharlieM1958 (Nov 7, 2006)

By the way, square corners dry faster.


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## Karson (May 9, 2006)

I was going to suggest japan Drier also.

I've only used it a few times and in my Danish Oil Blend that I make. 1/3 BLO, 1/3 Urathane, 1/3 Mineral Spirits. I use a part of a capful in a cup of finish.


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## woodbutcher (Dec 29, 2006)

bentlyj,
You got the idea allright. Two sealed containers one tung oil and the other Japan Drier, should be on every survivalists' list of things to have on hand. Niether wind nor rain will stop the action I can get with these two combined in the proper amounts! Thanks again.

Sincerely,
Ken McGinnis

p.s. If I didn't have to provide for a bullet proof finish on this particular project, I'd consider lacquer also!


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## tenontim (Feb 24, 2008)

I use Japan Dryer and Naptha, with my varnish mixes. You can use one or the other to speed up the drying time. I've found that if you use too much Japan Dryer, it will cause your finish to not dry at all and be sticky. Mix your tung oil with Naptha instead of mineral spirits and it will speed your cure time. I'm sure you know to start weak and increase the amount of tung oil in your mix, until your last coat is pure tung oil. As for the constantly wiping the beads: I start my finishing process with the shop on the warm side and before I finish, I will either turn on the air conditioner (in summer) or open a window and put on my exhaust fan (winter). If the surface of the piece cools off after applying the finish, it won't bead up as much, if at all.


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## woodbutcher (Dec 29, 2006)

Karson,
Thank you sir! Hows the bionics going? It didn't appear to slow things down in the deck building venue I noticed. The amount of Japan Drier you suggested, seems much more reasonable and I may just give it a try again. Thanks again Karson and keep those EveryReady batteries charged!

Sincerely,
Ken McGinnis


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## Karson (May 9, 2006)

I went to the cardioligist who installed the pacemaker today. he asked me how i was doing. I told him fine that I had built a deck last week. You should have seen the look on his face. He then said I've got a deck that needs work also.


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## woodbutcher (Dec 29, 2006)

tenontim,
Thank you friend. I've not played with the Naptha before in the tung oil, still using mineral spirits in varying amounts between coats and finishing with pure tung oil as you mentioned above. What kind of flash point am I dealing with when using Naptha? Is it as sensitive as Japan Drier?

Sincerely,
Ken McGinnis


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## TopamaxSurvivor (May 2, 2008)

A room air conditioner should lower the humidity quite a bit. All dehumidifiers are are refrigeration coils that condense the humidity to water and drain it off.


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## woodbutcher (Dec 29, 2006)

CharleM1958,
Doesn't my slower curing finishes tend to run towards the sharp square corners and then drip! Seems like the finish flows more smoothly around all my round corners, disperseing the finish more evenly? I appreciate the opinion, regarding those square things as always though!-Take care Friend.
Sincerely,
Ken McGinnis


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## woodbutcher (Dec 29, 2006)

TopamaxSurvivor,
You're right as rain! I'm thinking it might be cheaper to chemically change my finish as opposed to running my air conditioner so much though! Thanks for your time and help, Sir.

Sincerely,
Ken McGinnis


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## tenontim (Feb 24, 2008)

The MSDS says flash point for Japan drier is 114 degrees f, for Naptha is 50 degrees f, and mineral spirits is 104 degrees f. So if you light your shop with kerosene lamps or other open flames, the Naptha would be a little more flammable.


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## woodbutcher (Dec 29, 2006)

tenontim,
I believe, I asked the wrong question actually. Thank you for the answer to my question though. I'm actually concerned about the interaction of Naptha and tung oil. Is Naptha going to be more likely to cause combustion in conjunction with tung oil, than Japan Drier would be? I don't use a sealed fire resistant container in my shop right now for disposal of rags and such, maybe I better though! 
Sincerely,
Ken McGinnis


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## tenontim (Feb 24, 2008)

I'm not sure about the combustion factor, I'd have to check. Japan drier is made from a combination of about 7 or 8 chemicals, mineral spirits being one. Can't rem I make it a habit of putting all of my rags in a water bucket outside when I get through with them. In my younger days, I was always told to get rid of oily rags, no matter what kind of oil was on them. Better to be safe than sorry, I guess. Here's the MSDS for Japan Drier and Naptha
http://siri.org/msds/f2/blt/bltqv.html
http://siri.org/msds/f2/bsh/bshcj.html


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