rickoman Posted March 7, 2011 Report Share Posted March 7, 2011 I applied my first ever coat of GF oil varnish last night. Very pleased with the ease of application and look. Spread my rags out to dry and packed it in for the night.... Just as I was about to drift off to sleep I got to wondering if the cardboard I had used to protect my workbench (that had gotten many drips of Oil/Varnish) could combust just like the rags? What about the gloves I was wearing that I tossed in the trash? I jolted out of bed, ran to the shop and promptly removed anything and everything that could possibly be a hazard outside to the driveway to dry. Could the cardboard have spontaneously combusted like rags can? What about butcher paper? Is plastic the only safe drop cloth material when working with volatile oil/varnishes? Are the latex gloves any concern? can they just be tossed in the trash or should they be laid out to dry too? Am I missing anything? or just being paranoid? Thanks for all your advice in advance, --Rick Quote Link to comment Share on other sites More sharing options...
Don Z. Posted March 7, 2011 Report Share Posted March 7, 2011 I will preface this by saying that I'm a history major, so not any type of engineer, but... My understanding is that when oil based finishes dry, they create an exothermic reaction. That is to say, they make heat. If rags are bundled, the vapors in the VOCs, as well as the heat, are trapped within the folds. Eventually, the vapor pressure is great enough that the heat generated (insulated by the dead spaces in the folds) exceeds the flash point of the VOCs, and you get fire. Cardboard laying flat? probably not an issue. Bundled/folded/spindled or mutilated? Probably. Ditto craft paper. Bundled up gloves? Same. Solutions: Lay things FLAT outside. vapors and exothermic heat are dispersed. Failing that, fireproof can. Quote Link to comment Share on other sites More sharing options...
Sac Posted March 7, 2011 Report Share Posted March 7, 2011 Hey Rick, I must say that I have thought about this myself. I think what makes the rags more likely to combust is the fact that there is a lot of finish left in them when you are finished. And I read this just recently, that oil finishes dry by creating heat. When the rags full of finish are left all balled up, that heat is more intense. That is why you are suppose to lay then out. This keeps them cool and allows them to dry. With the gloves, I don't think that there is enough finish on them when you are done to worry about, but I usually throw them on the concrete floor when I am done just to be safe. I wouldn't worry too much at all about the cardboard. It is wide open and has plenty of airflow. Your project has more finish on it than the cardboard does. I hope this makes sense. Quote Link to comment Share on other sites More sharing options...
BenMinshall Posted March 7, 2011 Report Share Posted March 7, 2011 It is certainly best to lay out anything that's been contaminated with finish in a single layer on a non-combustible surface until it's crispy dry. The gloves are probably not a big concern, but I would lay out the paper and cardboard and let it dry well before mixing it into the trash. I usually drape mine over the side of the metal trash can and when they are dry the next day, just shove them in. Quote Link to comment Share on other sites More sharing options...
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