Polyurethane safety question

  • Advertise with us

« back to Safety in the Woodworking Shop forum

Forum topic by TJ65 posted 01-04-2011 11:56 AM 4030 views 0 times favorited 11 replies Add to Favorites Watch
View TJ65's profile


1378 posts in 3074 days

01-04-2011 11:56 AM

Topic tags/keywords: question polyurethane

Recently one of the Lj’s posted a question about the saftey of oils, varnish and Polyurethane and it got me to thinking-
If I use rags, paper, or anything else that gets saturated with Polyurethane they must be drowned in a tin of water and disposed of in the correct manner. But what about gloves ?
I always make a mess with the stuff all over my hands and it is a real pain to clean off so I have these heavy duty rubber/plastic gloves. I leave them to dry in the open but they do get a coating.
What is the catalyst in the poly to make it do such a thing heat, cold, oxidisation ???

Also I recently bought a new tin of Gloss Poly that has most of the same lables and wording, however the ‘DANGER of combustion’ warning is not there. Is there such a major difference between Satin and Gloss or is it that now (since it is a brand new tin) that they have had a rethink over the matter and it has been deemed not to be such a danger??

-- Theresa,

11 replies so far

View jackass's profile


350 posts in 3738 days

#1 posted 01-04-2011 02:08 PM

Hi TJ65 I have never had first hand information with this question, (no fires) so don’t take this statement as reliable. I treat all oilbase products the same, in that when I have used them I set them aside to dry away from anything combustable. The baddie is linseed oil, I have been known to burn a soaked with linseed oil rag in a safe environment ie: metal can, just to satisfy myself that it isn’t a worry any more. Exercising any precaution leads to a safe use of these products.

-- Jack Keefe Shediac NB Canada

View DonH's profile


495 posts in 2842 days

#2 posted 01-04-2011 02:56 PM


For most finishing products I wear vinyl surgical or examination gloves. Some products require other materials rather than vinyl.

Check the Lee Valley catalog for gloves – they provide an explanation about what differant finishes, glues etc for which each type of glove protects you. It is essential for your health that you protect yourself from contact with these materials as well as properly ventilate the area you are working in.

I agree with jack above on his points as well, I dry out anything used to apply oil based finishes before disposing of them.

-- DonH Orleans Ontario

View Gregn's profile


1642 posts in 3008 days

#3 posted 01-04-2011 03:33 PM

I treat all rags as combustible and hang them on a rack to throughly dry before disposing of them. I feel its better to err on the side of caution when using finishes and solvents.
As for the catalyst its the petroleum in a finish that can have a chemical reaction to air an other solvents that can create heat to cause combustion. A good example of chemical reaction is plaster of Paris and water both in themselves are fairly harmless but when you add the 2 together they create heat until cured. While the plaster isn’t combustible its the chemical reaction that is similar to oil based products. Hope this helps.

-- I don't make mistakes, I have great learning lessons, Greg

View GregD's profile


788 posts in 3161 days

#4 posted 01-04-2011 04:07 PM

I don’t think the finish-soaked rags and paper really need to be drowned in a tin of water. I always thought it is sufficient to spread the rags out to dry and harden. A lot of hydrocarbon liquids (gasoline, oil, finish) oxidize very slowly even at room temperature, and this generates a little bit of heat – not a problem if the heat can dissipate but it can start a fire if the rags are in a pile with only a little ventilation so that the heat is able to accumulate. Since finish-related products evaporate and harden the usual practice is to spread them out to dry. Once dry they will burn if ignitied, but I don’t think there is much risk of them igniting themselves. For oily rags that aren’t going to dry out, the standard practice is to put them in metal pails with lids that limit the supply of oxygen to the rags.

I agree with DonH that it is worth the effort to avoid skin contact with finishing products – and chemicals in general – as much as practical. So by all means keep using gloves and let them dry out

-- Greg D.

View ajosephg's profile


1880 posts in 3586 days

#5 posted 01-04-2011 04:14 PM

Me thinks your new can of poly is probably water based. Polyurethane in and of itself isn’t particularly flammable – it’s the solvent that makes it so.

-- Joe

View 8iowa's profile


1580 posts in 3786 days

#6 posted 01-04-2011 04:45 PM

Another twist on this polyurethane safety issue is breathing the fumes. Last year on a cold day I was doing my finishing in a closed room without any windows open. I began to feel light headed and had a slight headache.

This experience was a wake up call. I now mostly use water based polyurethane and provide ventilation when finishing.

-- "Heaven is North of the Bridge"

View SnowyRiver's profile


51457 posts in 3505 days

#7 posted 01-04-2011 04:50 PM

Hi Theresa,

I checked a can of Minwax clear gloss oil poly that I have and there is a comment about the vapors being combustable. I usually put the rags in a steel can with a lid. There is no comment about combustion on the water based poly that I have, but it does say the vapors can be harmful. I use latex gloves and generally just throw them in the can with the rags after I use them and use a new pair the next time.

-- Wayne - Plymouth MN

View jackass's profile


350 posts in 3738 days

#8 posted 01-04-2011 05:28 PM

Hi All,
I once rented an apartment to a family that volunteerd to paint the unit in a triplex that we owned. He used oil based paint in the kitchen, the power was not hooked up when the painting began. The kitchen was not quite finished when darkness began began to set in. The man had a Coleman lantern that he started to be able to see to finish the job. As soon as it was lit, it erupted a fire that engulfed all the walls in the kitchen instantly. They just barely escaped with their lives, as did the other tenants. The fire department did their job and all was extinguished. Caused a major clean up but not much structural damage. Everyone was very lucky.

-- Jack Keefe Shediac NB Canada

View TJ65's profile


1378 posts in 3074 days

#9 posted 01-04-2011 10:45 PM

Well thanks all
By the looks of all that I will continue to err on the side of caution with it and be careful with the gloves I am using and dry them out.
In regard to the gloss poly, maybe it is water based! I will have to check that out. I assumed that it was the same as it was from the same company.

-- Theresa,

View TopamaxSurvivor's profile


18288 posts in 3701 days

#10 posted 01-05-2011 10:22 AM

It should be easy to tell from the clean up directions.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View Russ's profile


357 posts in 3102 days

#11 posted 01-05-2011 04:53 PM

I always where gloves with that stuff and I have a good MSA mask I where. They can be gotten for around 30-40 from HD, Lowes and Woodcraft. I tried it with a something more basic and felt sick sick sick. I also place the finished rags on the driveway about 4 feet from the house and 3-4 from the cars until crusty.

-- Russ

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics