Flamable Rags - Any Simple Rules?

[Doug Hobkirk]

I am a novice refinisher. I have mostly used various Minwax or Cabots pre-mixed stains with a wipe-on poly finish, but I am interesting in experimenting more. I have done samples using Tung oil, BLO, and shellac. I do small pieces mostly - end tables, small drop-leaf tables, chairs, etc. I do about one piece a week for a charity. I work in my attached un-heated garage near Boston (i.e., it gets pretty cold) and I keep my water-based chemicals inside during the winter.

I don't want to burn the house down. I have never had a rag get warm but I believe there is a fire danger. I want to avoid using chemicals that have spontaneous combusion traits. Taking rags outside to air dry is impractical in the snow and ice.

I beleive BLO rags are dangerous. Are there others?

Does it help to seal rags in ZipLoc bags?

Thanks

[Brian Peters]

Store oily stain rags in a closed metal can filled with water. No ziplock or plastic cans. Metal are the best. Most of the time you will be safe with putting them in the garbage but all it takes is one time. I've seen the hot summer sun set blade to a dumpster and the box truck parked next to it because the rags were dumped in the dumpster. A lot of towns have companies that will pick them up for you for a small fee.

[Jason Whitaker]

I think it is a safe general practice to take the above precaution with ALL rags with finish on them. Even though there may be some more dangerous than others, it just builds a good "Safe Practice Standard" for you and will make it less likely you miss something.

Just this past summer I saw, firsthand, a family almost lose their house (if not for a wonderful fire dept) just a few blocks away from my home because they had been staining a bench and had thrown the rags bunched up in a box and left them on the deck. Maybe not the same scenario but certainly opened my eyes to the danger.

Be safe and have fun!

[Joe Jensen]

I take all rags that have been used with thinner or finish and spread them out on the gravel in the yard for several days until they are completely dry/cured. Then I toss them. I used to keep them in a closed metal can, but what do you do later? Eventually you have to dispose of them. That why I switched to drying them outside.

[Cody Colston]

I have a sink in my shop so I wash the rags with Dawn detergent, wring them out and then spread on top of a sawhorse to dry. The next day, I toss them in the trash.

[Jack Ellis]

Apparently oil-based finishes generate heat as they cure in the presence of oxugen (what's known as an exothermic reaction). When finish-soaked rags are bunched up in a confined space like a dumpster or trash can and in contact with other flammable materials, this exothermic reaction can lead to temperatures that are high enough to start a fire. If you put rags in a metal container and seal it, there's not enough oxygen to support combustion or the curing process. If the rags are in water, the curing process is also starved for oxygen.

Although the fumes will likely be a problem if you want to work in the room, I believe you can simply spread out the rags on a metal rack that is well away from anything flammable and allow them to dry out if you'd prefer not to spread them on concrete. The keys are a) to avoid bunching them up, and b) keep them away from anything else that burns easily. If the rags are spread out, natural circulation will keep them cooled.

This is one of the reasons I use water-based finishes when I can. Easy cleanup and very minimal fire danger.

[Steve Rozmiarek]

I just set them outside under a small rock or spear them with on of the wifes staked flower bed things until they dry, then they get tossed. ALL rags get this treatment. Don't want to mix up the BLO rag and the shelac mess rag.

[Ken Fitzgerald]

In the winter...I take all of my finishing rags and drape them over a metal ladder in the shop for a week or so. My shop thermostat is set to 64ºF and they dry in about a week.

In the summer I place them on a chain link gate next to the carport. A week later...into the trash.

[Robert Chapman]

My simple rule is - Dry them out in open air before you throw them out.

[Rob Luter]

A close call with BLO covered rags when I was a kid (basement full of smoke :eek:) has me paranoid. I use BLO and Danish Oil quite a bit. I use a brush on/wipe off process with coats thin enough that I never wind up with rags that are really soaked with finish. When I'm using these finishes and done with the rag I wash it in hot soapy water to remove all the oil. At that point it gets hung up to dry. After I accumulate a few they get run through the washing machine and returned for re-use. I hate to throw anything out that I don't have to. Stain rags and the like get thrown on the burn pile outside and go up in smoke with wood scraps, sticks, yard waste, etc.

[Brian D Anderson]

Yup. Put them outside away from flammables to dry. My employees apartment complex burned down a few months ago due to his neighbors throwing some oil soaked rags they were using to refinish furniture in the trash. I believe it was linseed oil . . .

http://www.whec.com/article/stories/S629768.shtml

-Brian

[Rod Sheridan]

Drying the rags is also a good way to prevent spontaneous combustion.

Spread the rags out so the air can dry the oil, and make sure that you don't layer them.

Spontaneous combustion occurs when the heat from oxidation can't escape because of the rags being balled up or placed in layers.

Once the rags are dry, the can be disposed of as normal refuse.

Washing the rags is not a good idea as you are then putting oil and solvent down the drain, where it eventually gets into the ground water.

Regards, Rod.

[Tony Bilello]

We almost had a fire from Minwax stain. Fortunately, we were stilll in the shop when our eyes started burning. Looking for the source of the irritation, we saw the small pile of rags from the days staining. When we lifted the top few rags, the pile started smoking. We separated the rages and spread them out.
I have a concrete floor. I now spead the rags on the floor before I go home for the day. As long as they are not stacked up, they will not heat up. Usually the next morning they are dry and go into the dumpster.

[Brian W Evans]

As several creekers have said, ALL rags go outside to dry. Simply put, if they're not in your house/shop/garage, it'd be hard for them to burn anything down. Foam brushes go out, too.

I also don't see the point in washing them. Once the solvent/oil evaporates outside, the solids are relatively safe (i.e. non-toxic), if Bob Flexner (http://www.amazon.com/Understanding-Wood-Finishing-Select-Finish/dp/B001QFZLWA/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1234878554&sr=8-1) is to be believed. Why put the toxic stuff down the drain?

[Scott Vigder]

I use disposable surgical gloves whenever I finish.

When I am done, I tuck the rag into the palm of my surgical glove, then pull the glove off my hand and completely envelop the rag. The rag is now in a "baggie" and I squeeze as much air out of the glove as I can before knotting it at the wrist.

Then I place the squeezed-out glove in the palm of my other gloved hand, and pull it tight over the first glove. After squeezing any air out of the the second glove, I knot up the wrist and toss it in the trash.

As previously mentioned in this post, air is the necessary ingredient for the thermal properties to become dangerous. I've checked the gloves at various time intervals for heat, and have never had one heat up on me.

I use mostly BLO, wipe-on varnish and poly.

[Carlos Alden]

Doug:

I also live in a cold winter climate and see no problem with putting rags outside to dry. You won't be using them again, so it doesn't matter if they get rain/ice/snow on them, right?

It IS important to not bunch them up. I see that several people let them dry separately on the floor on on a rack, but having flammable vapors in the air makes me nervous, so after use I toss them in a little gravel area right outside my garage. After a day or so the solvent is gone and I put them in the garbage.

I would not wash rags and put solvent down the drain. We live right on top of our aquifer. I know it's a toss-up: solvent in the air or solvent in the water table, but it seems to make more sense to let things air-dry.

Additional note: although epoxy is not flammable, the curing process with two-part is exothermic, and a big glop of epoxy resin sitting in a cup can catch fire. I've had plastic cups melt and become too hot to touch. Take care with disposing of epoxy for the same reasons.

Carlos

[Tony Bilello]

When ever I mix epoxy, I always keep my mixing bowls on a metal tray so I can just move the whole tray onto the floor for it to finish exotherming (heating).

Another note on 'drying' oil and stain soaked rags. I agree with you in that the rags should be outside to dry, however, it is not always possible. I rent a 'mini-storage' space for my shop and "ouside" means trashing up their common area. I have also rented shops in warehouse districts which also meant that when you walked out the door yoiu were in a common parking lot. In my particular case, my only option is the concrete floor.

[Ben Franz]

I have a friend who builds custom spec houses (or used to before the housing meltdown). He finished a new rear deck with a wipe on stain/finish and piled the used rags up next to the garage on a hot day. The resulting fire gave him an opportunity to rebuild his brand new garage and taught him a lot about insurance claim processing. I've been a lot more careful about disposal ever since.

[Ed Hazel]

I have a retractable clothes line that I hang the rags on I generally leave them there until trash day then take them down and put out in the trash.

[Howard Acheson]

The dangerous rags are those wetted with a drying oil. Drying oils are linseed oil (both raw and "boiled") and linseed oil mixtures (Danish Oil, Scandinavian Oil and Tung Oil Finish) and tung oil. Non-drying oils like motor oil, mineral oil, vegetable oil, nut oils etc. are not a problem.

I do not recommend wetting rags as you then have created a hazardous waste with the contaminated water.

Putting rags in an airtight container will work as long as they remain in the container and the container remains airtight. But, once you open the container, oxygen is available and the rags, no matter how long they have been in the container) can begin to oxidize and create heat. I've even seen this happen with rags that have been soaked in water and later are allowed the dry out.

The easiest and safest practice is to hang them up on a cloths line or fence and lay them spread out on the lawn or driveway. Once they have dried, they are no longer dangerous and can be discarded in the regular trash. Some burn them but that can create an air pollution problem.

[Jim Eller]

I burn all paper towels, rags and etc that have come in contact with flammables.

I just have a metal pail setting on a couple of bricks in the back yard a burn them in that. I do it immediately after each use. I never keep them overnight.

Jim

[Anthony Whitesell]

Clothes pins and a tomato planter is what I use as I don't have a non-combustible place to lay them out.

I highly suggest that you go with the hang-to-dry opposed to the metal can route. In May 2008, I believe, maybe 2007, a garage was set ablaze a few towns over by oil soaked rags. According to the fire department, the rags had been disposed of in a metal flammable material trash can but got the can hot enough to either ignite the can itself or something nearby.

Take them outside and hang them to dry.