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Dealing with the polyurethane smell?

6K views 31 replies 21 participants last post by  tvrgeek 
#1 · (Edited by Moderator)
I'm finishing some children's furniture (bunk bed) with Varathane Spar Urethane.
Wiping it on with a 50/50 mix with mineral spirits.
They'll want it in their room the moment it's dry to the touch, but I suspect I should leave it in the garage for a few days first to let the smell dissipate. Does anyone have tips on this?
Would paste wax slow down the smell release, so that it's not as noticeable?
How long should I expect to have to ventillate it before putting it in the kids' room?
Thanks all!
 
#2 · (Edited by Moderator)
It takes an amazing amount of time for varnish to fully cure, it will outgassing for some time. Putting a fan to blow on it will help some, that will (slightly) accelerate the curing process. It would be a guess how long it takes, and some folks are more sensitive to the odor adding to the variables. In most cases I'll take something in after a week or so.
 
#3 ·
It takes a while. And "while" will be different for different people. My wife is sensitive to the smell and I must leave completed pieces in the shop or elsewhere for a week or more. The only solution I know is to change to a less odorous finish. Most water based finishes have less offensive odor. I have not used all paste waxes but I know that Johnson's paste wax would not help. It has it's own odor that my wife doesn't like.
 
#5 ·
I know it is too late but I would not have used a spar finish. They are generally intended for outdoor use so Tony's suggestion about setting it outside for a while may be your best way to accelerate the process. As to the paste wax, it will actually add another delay to let that smell dissipate, depending upon what type you use. Some are largely petroleum based so you would add a whole new set of chemicals into the air while it dries.
 
#7 ·
I'm trying to buy low/no VOC products, not just for the smell, but for the dangers of VOCs, especially in kids rooms. It can be 1-6 months before most of the VOCs have off-gassed. If you do move it in early i would at least try and keep windows open as mich as possible and fans going to lessen the concentration.
 
#9 ·
I'm with the crew questioning the use of a spar urethane. That's an oil based product that will take forever to cure and will definitely out-gas quite a lot. No way I'd take that right from initial drying into a kid's room. The amount of VOCs that still have to go somewhere is going to be insane.

Water-based finish or shellac for kid's furniture unless you have a few weeks to wait for it to cure before moving it inside. Definitely not an outdoor finish like a spar urethane.
 
#11 ·
Thank you all. It seems I made a poor choice and should have researched (asked you guys) first. Unfortunately much of the project is already finished and I don't think I should use a different finish on the remaining portions. I'll choose better next time.
I did see a brushable lacquer, guessing that would dry very fast, what do y'all think of that?
 
#13 ·
One other thing to consider if you're using oil-based varnishes in the house: If you have a gas clothes dryer, your laundry will smell like burnt tires during the outgassing period. This is due to the clothes in the dryer subjected directly to the combusted air in the chamber and drum. Air that has carried the fumes passing directly in contact with the flames in the dryer. You will reek of a burnt rubber smell if you wear these clothes, but fortunately the smell is gone if you wash them again. If you smell the fumes of the varnish, that's an indication that you will have stinky laundry.

I'm not sure if this is a problem with electric dryers. And don't ask how I know this!
 
#14 ·
I used spar varnish on a mail box I installed in nov '17. It still smells inside. It is uncovered and south facing, but I can still spell it when I get the mail. So it may take a lot longer.
 
#17 ·
Lacquer stinks for a long time, it takes 4-6 weeks to fully cure. I did an experiment with a lacquered wood cup turned upside down and every few days flipped it over and sniffed, it was a little over 6 weeks before I couldn't smell the lacquer thinner. It also had very little water resistance, which was the real point of the test.
 
#18 ·
Great information guys. FWIW since I had already started with the spar urethane, I did as some suggested and left it in the garage for 3 days with the door cracked and a fan blowing. The smell was not noticeable even by my wife, who 8s typically very sensitive to such things.
 
#21 ·
I agree water-based polys have far less odor, I know shellac will seal in odors but I don't think a coat of it is a good way to go unless your finish is already dry, in addition, according to some people some of the new poly's are not compatible with shellac.
 
#23 ·
Lacquer stinks for a long time, it takes 4-6 weeks to fully cure. I did an experiment with a lacquered wood cup turned upside down and every few days flipped it over and sniffed, it was a little over 6 weeks before I couldn t smell the lacquer thinner. It also had very little water resistance, which was the real point of the test.

- Woodknack
Hmm. Sniffing the lacquer, were we? I keed, I keed! I know what you mean, with lacquer though. I made a knotty pine bookshelf that sat in the garage for a long time before it went into our bedroom. I love the smell of nitrocellulose lacquer. The wife ain't so happy about it, though.
 
#25 ·
I'm in the process of building book shelves and I made the mistake of finishing with Exterior spar urethane…bad idea! I'm in the process of trying to cure them (outside in the sun) hoping the smell goes away soon but I think I will have a long wait. I have 2 coats on them and I will probably need 1 to 2 more coats, just thinking making the last coats with Water based Urethane…...thinking that might seal the smell in…..sound like it might work or am I about to FIU….......HELP !
 
#26 ·
I've never tried it but if the spar still smells it is probably still out gassing and curing. It's probably not a good idea to put a water base finish on top of it. It is probably just going to take some time.

Personally, I would not leave it in the sun for very long. . Bad things can happen. Low humidity and a fan are the best option, IMO.
 
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