Hi,
I recently had to move my wood shop from my basement to my garage… (sad, isn’t it?) My basement had NO ignition sources at all and several nice windows that opened for ventilation.
The garage has the furnace and water heater (both propane) and no windows – just those big doors. I’ve read that fans used to vent some finishes need to be “spark free” to prevent an explosion.
Where the heck do you find these fans? I’ve been to several hardware stores and none of them have these – or even say they can order them. I contacted one “Safety Equipment” company in town and they had one that was 24″ in diameter and cost $1800!!!! I don’t think I need a 24″ fan, and I sure don’t want to spend almost two grand to get one… But I don’t want an explosion in my garage, either.
Any wise minds out there that can point me to some sources?
Thanks!
BTW, started woodworking about two years ago. Built a game table and a few other items… I have pictures on my website if you’re interested.
http://home.earthlink.net/~sambelcher/woodwork.htm
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Replies
Sam,
The source for just about any fan manufactured in Grainger (www.grainger.com), including fans for environments like you describe. The trick is that it's a business to business company that doesn't do retail counter sales. If you have a business or even a friend with a business then it's no problem.
These fans are expensive but certainly less at smaller prices. What kind of finishing are you doing that you're so concerned about? If you're spraying solvent based finishes this may be a consideration, but most hobbyist woodworkers really don't need such a system.
Best,
Seth
mistake. There is no win
and there is no fail . . . there is only
make."
John Cage
I'm not doing any spraying at all, but I've been reading the labels on some of the cans of finish that I've accumulated.
I guess you're saying a fire or explosion is not very likely?
I do have a friend with a business, so I'm sure I should be able to order through him. Thanks for the info.
Sam
Sam,
I don't know your garage or equipment but it sure seems that some plain and simple circulation (opening the garage door and a box fan) would do the trick. Explosion proof fans (and don't forget lighting as well) are WAY over kill for a garage woodworking shop with low volume hand applied finishes.
If you're looking to spend some money for safety you may consider a proper paint storage cabinet (also at Grainger) for all your finishes. Also some combustibile materials trash cans for rags and such. I'm sure there are others with hard data, but probably the most common finishing combustion scenario is wet linseed oil rags (self combusting!!). Make sure to soak your rags in water after use and lay them spaced apart flat to dry before tossing them.
Have fun!
Seth"Nothing is a
mistake. There is no win
and there is no fail . . . there is only
make."
John Cage
Sam,
If you are not spraying, the chance of creating an explosive situation by volatiles in your garage is nil. The problem is keeping the air fresh enough for the safety of your brain cells. And ordinary fans and an open door can take care of that.
In any case, an ordinary fan, mounted with its motor OUTSIDE the wall, rotating to bring outside air INTO the shop just about eliminates the chance that a volatile mist inside the garage could ignite.
Any induction motor, the kind used to drive all our larger power tools is safe as long as the capacitors across its power switch are intact. Low hp induction motors are inexpensive and can be used to drive a fan with a belt. It's the AC/DC motors such as are found on smaller tools - routers, hand drills, sanders - that are the problem. These motors have brush/armature assemblies that create a constant electrical arcing and could ignite a combustable atmosphere.
Rich
Keep in mind that you probably store gasoline for the mower in the same area. It's explosive range is 5-95% if memory serves right. The range for these coating are much more stable but, need just a little care to prevent the problems.
I once saw a fan mounted in the side wall. Nothing special, just a gable fan. fresh air is the key! You need it and so does the gas fired equipment for the house.
As far as I know, the only finish you might have to worry about would be laquer or laquer based. If you are spraying and doing that in a closed garage, well, good luck. You'd best keep your door open and some portable fans going.
I wouldh't think any kind of brush work would result in sufficient accumulation of vapors unless you are really closed up tight. Note that solvent vapors have to accumulate to a high level before becoming explosive. That level is more than a human can withstand without being sickened. before it reaches that level. Natural and LP gases are heavier than air and accumulate in low spots and so are more dangerous than most volitiles that are lighter than air and dissipate quickly.
If you want to ventilate in cold weather without reducing the inside temperture below tolerance for most finishes, a small fan, say 10-12" should move enough air to keep vapors from accumulating to explosive levels and not need to be ignition protected.
However, you might try doing a search on fans + ignition protected. All this means is sealed motors, which should not be that much more expensive than ordinary fans.
I'm not sure that it matters here but but when you look at the molecular structure you will see that all of the volitiles are heavier than natural gas (methane).
BJ Gardening, cooking and woodworking in Southern Maryland
While the volatiles are a concern, they are of very little concern if you are not spraying. The small amount of fumes that occur during the drying process are not likely to cause you a problem and a normal fan can be used to clear the space nicely. Spraying with HVHP will be a problem since you are atomizing the volatiles. HVLP is less of a problem but still has a potential though not as great.
Steve - in Northern California
First, my disclaimer: I am not a licensed electrician, nor a professional power engineer, nor do I recommend anything I am about to say!
Having worked in the power industry, I knew several design engineers to whom I brought this same question. They reminded me that induction motors (exclusively those WITHOUT capacitor starters or starter windings) have no brushes and do not create sparks while running. I created a spray booth using an attic exhaust fan which I have since used for spraying lacquer, shellac, and other volatile finishes. I still live to tell about it. I ELIMINATED all sparks in that room by turning on the fan before starting to spray, and leaving it on long after I had stopped (I do not use a spark free switch). (I used a furnace filter to reduce the finish buildup on the fan.)
Having said this, you can buy an explosion proof fan from companies like Grainger for roughly $300. This would be the safest way to go, and way most people would recommend.
Good luck.
Bert,
The capacitors in most small induction motors eliminate sparking. They don't create it. Their function is to absorb the voltage surge that occurs both on starting the motor (closing the power switch) and stopping the motor (opening the switch). Without the capacitor a spark almost always jumps between the switch electrodes. That spark eventually destroys the electrodes. In an explosive atmosphere, the spark also causes another nasty consequence.
Motors and their switches designed for explosive environments have extensive seals around the switch circuits so that any electrical discharges can't come in contact with the outside air. It's the extra attention to seals and other construction methods that make the equipment expensive. And the cost to the customer is usually far in excess of the added manufacture costs.
It's easy enough for anyone to do away with the switch at the motor altogether. The motor can be direct-wired, bypassing its switch so that no arcing can occur. The power switch can then be at a completely different location in the line feeding the motor. It could be outside the garage, in the house, etc.
Rich