WARNING: There are many kinds of glycols, most of them poisonous. If you are tempted to make your own fog fluid, please read our section on that topic.
![[photo]](fogmac_vaporizer.jpg)
This picture shows a Fog Hog Vaporizer, slightly better than the typical inexpensive unit.
It has a 1,000W Heater and is rated for 4,500 cubic feet per minute fog output.
These units are very easy to use: pour the "fog juice" in the tank; let the fogger heat up; and press the button to get fog.
Glycol foggers are primarily rated by the power of their heaters, the common inexpensive units being rated 700 Watts. This number is important, because the more power that the heater draws, the better the job it can do of keeping the "heat exchanger" chamber hot and ready to vaporize the fluid to make fog.
Foggers are also rated as to the volume of fog that they put out. This number is expressed in cubic feet per minute (CFM), and one might think that it has meaning, a 20,000 CFM unit being able to belch more fog than a 15,000 CFM unit. Unfortunately, different companies measure this parameter differently, so it doesn't allow you to do an apples-to-apples comparison from one vendor to another.
![[photo]](fogmac_HogOutside.jpg)
This is an American DJ Fog Hog - one of their earliest foggers.
It has a removable tank, visible in back. The remote, not show, has a single light on it and a button. When the fogger is hot and ready, the light comes on. Press the button and you get fog.
The fog comes out of the nozzle that you think you see on the left.
But things are not always as they appear - the actual nozzle is a tiny pinhole in a piece of metal hidden within this
relatively large nozzle-looking thing.
![[photo]](fogmac_HogInside.jpg)
This is the inside.
The big silvery thing in the forground is the heat exchanger. It is wrapped in insulating fiberglass wool and foil.
Behind is the pump. When you press the button, if the heat exchanger is hot enough, the
control circuitry turns on the pump. The pump squirts small quantities of the fog juice into the heat exchanger,
which flash-evaporates into large clouds of fog
![[photo]](fogmac_HogBrain.jpg)
This is the control logic of the fogger - its "brain".
This circuit takes input from the thermostat and uses it to light the "ready" light.
It waits for the remote to "push the button", and uses that to turn on the pump.
The control logic also disables the pump unless the heat exchanger is hot;
there's no reason to squirt fog juice into a cold heat exchanger.
The new crop of ultra-cheap foggers saves money by using a less fancy control circuit
which routes line-voltage through the remote. I rather prefer the additional safety provided by a low-voltage remote.
Fog juice always consists of a mixture of more than one component, and they all have different boiling points. Here are a few chemicals that one might find in fog juice:
| material | boiling point |
| Distilled Water | 100 deg C |
| Propylene Glycol | 188 deg C |
| Glycerine | 290 deg C |
In general, heating a mixture causes the component with the lowest boiling point to boil off first, followed by the component with the next highest boiling point, etc. This principle is used in distillation to separate mixed liquids.
If this held true for a fogger fueled with such a fluid, you would first get water, then Propylene Glycol, then Glycerine.
I suspect it's a little more complex, involving azotropes and steam distillation...
An azeotrope is a constant-boiling point mixture. It works as if two or more different molecules hook together, producing something that exhibits a different uniform boiling point. This is the case with ethanol and water. You can distill it all day, and won't be able to get better than 50% alcohol. Perhaps something of this kind is happening with the fog juice.
Steam distillation is a process whereby the easily-boiled water vapor carries with it some of the component that would normally require a much higher temperature. This probably explains how scented fog juice works.
And maybe there are other factors, because when you squirt the fog juice into the hot heat exchanger, the resulting high pressure is almost like an explosion wherein things can happen that aren't quite obvious.
Some brave souls have built their own glycol foggers by dripping fog juice on inverted clothes irons. In the early days of Halloween-L, some folks made foggers by wrapping copper tubing around soldering irons. These heroic measures are seldom justified nowadays - glycol foggers are now easy and inexpensive to obtain.
![[photo]](fogmac_RS.jpg)
Cat.#: 42-3058
700 Watt Fogger (2500 cu./ft. per minute), with timer/remote
Regular price $99.99
This is one of the best low-end foggers on the market. I don't have one of these particular foggers, but numerous people on the Halloween e-mail list have bought them, and they all like them. The thing that makes it such a good deal is that it comes with a quart of fog fluid and the remote with timer. The remote/timer allows you to set periodic small bursts of fog to keep an area covered. Sooner or later, you will want a timer; pressing the "fog" button every minute or two gets tiring. For most foggers, the timer as an accessory that costs another $40.
It might help that this fogger is carried in-stock by Radio Shack stores across the country.
This package is usually on sale for ~$90 in September.
WARNING - The instructions packed with the fogger recommend cleaning with vinegar solution after use. Several contributors to Halloween-L report that they have damaged the pumps in their foggers by following these instructions. This is one case where I recommend ignoring the manufacturer's instructions - don't use the vinegar flush as a part of routine maintenance.
Radio Shack also sells:
1,000 Watt Fogger (5,000 cu.ft. fog/min), with remote Regular price $199.99 Cat.#: 970-1267
In spring of 2001, the price went up to $70, but it might come on sale again.
The fogger that crashed through the price barrier is:
| company: | MCM Electronics |
| part number: | 555-3210 |
| description: | $49.00 Party Fogger 700W 2500 Cubic Ft/min, manual (push-button) remote control, fluid not included |
| company: | Antari Lighting Ltd. |
| model number: | F-80 |
The Antari FC 4 timer remote should work with this fogger. Rumor has it that this remote is available for $29.99 from http://www.coolstuffcheap.com/coolstuff/adjshadfogma.html
This unit is a very basic 700 Watt fogger, with dumb remote. The thing that makes it exciting is the low cost. All of a sudden, haunters who were kludging up foggers out of clothes irons, Mr. Coffee machines, and soldering irons had a cost-compatible alternative, of commercial quality.
There is no guarantee that, at the time you read this, MCM will still be offering this deal. But it does prove that glycol foggers can be made and sold at a very attractive price-performance point. And if you look hard enough, you will find them.
Note - When the $50 fogger went up to $70 in spring of 2001, purchaser Robert Benfield reported that he was shipped a model other than the Antari. He reported getting the MBT Brute II Fogger (MSRP $172). So, you better see what you get before buying accessories for it!
The year 2001 saw increased emphasis on higher-budget Halloween props and effects.
Is a $40 fogger good enough to be worth buying? Foggers are extremely variable in price. I have three of them. I paid $500 for the nicest one, about one third the MSRP. It is equipped with DMX control, a timer, and 1500W heater. It is the size of a duffel-bag, and heavy. It pumps out fog like there is no tomorrow. You are not coming near that for $40. The question is, "do you need to?" I think that many of the low-end foggers will be "good enough".
There's a down-side to this, though...
A glycol fogger isn't the same as a plastic skeleton. With simple props, even a novice knows what to expect - "hang skeleton in window". But foggers are more complex. People won't read enough of the instructions, and the instructions probably won't cover all their questions.
I predict a large number of disappointed newbies. Sad, really.
There are some fog juices with scent added, and some companies sell scent additives for fog juice. If you absolutely have to have scented fog, use those products, in the manner indicated by their manufacturer. Do not attempt to brew your own scents; you are likely to clog or damage the fog machine.
Any scented fog juice will require that you clean the machine more frequently, and may cause premature failure.
No - The flash-evaporatrion process used to make the fog produces a warm fog. Warm gasses and liquids rise above their cooler counterparts, so fog from a glycol fogger tends to rise up, for a "London pea-soup fog" effect.
If you want the glycol fog to stay close to the ground, you must chill the fog after it exist from the fog machine, so it is cooler than the surrounding air.
Not really. The fog juice is mostly water, with some simple chemicals mixed in. The chemicals would be slippery in quantity - if you spilled a puddle on the floor. But in operation, the fog tends to float away, and you don't need much juice to make a lot of fog. So, it's hard to get enough vapor to condense in one place to make a mess.
But, just in case, don't shoot it close to stain-prone surfaces, or slick walking surfaces.
It depends on the type of smoke alarm you have. We have additional information on fog and smoke alarms.
The real problem with glycol fog is that the glycol is hygroscopic - it has an affinity for water, and soaks it up. In the lungs, glycol fog has a slight drying effect. This isn't dangerous, but can be irritating, especially for those with sensitive lungs. Prolonged or dense exposure can cause coughing.
Health effects of glycol foggers have been studied for a long time, and continue to be studied. So far, there have been no findings of permanent damage, but some reports of temporary discomfort.
Here are some reports on the safety of glycol foggers:
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After filling the unit with the correct fog juice, plug it in, turn it on, and let it warm up. The remote-control should have (at the least) a button and a light on it. The usual drill is for the light to go on when the unit is hot and ready to operate. Be prepared to wait a good, long time for the machine to get hot. Some machines require as long as 10 or 15 minutes. If it isn't ready by that time, I guess you do have problems.
But as soon as you press the button, generating fog, that heat is used up, and the heat exchanger cools down. If you have a low-wattage machine, a good long fog burst will cool the machine enough that it will have to stop and reheat.
Inexpensive glycol foggers are not capable of continuous fogging!
That doesn't make them bad machines. You just have to know how to use them.
Your best friend for this is a timer on the fogger that allows you to program the fogger for little regular bursts.
High-end foggers ususlly come with such a timer.
For cheaper foggers, a timer is usually available as an add-on.
And it's a really good thing to get!
The machine will cycle on and off, blasting out fog and shutting off.
The only real danger to the fogger is running it dry.
You must always have enough fluid in the tank.
If you tape down the fog button, make regular checks on the fluid level.
It is important to follow manufacturer instructions,
because some foggers are intended to be stored with fluid in them (to keep the seals moist)
and others need to be stored dry.
Some are made easy to clean, and others require special tools or cleaning fluids.
Sticking to manufacture's instructions may extend the life of your equipment and
will preserve the warranty.
WARNING - Some fogger manufacturers recommend flushing out the fogger with a solution of vinegar and water after use.
Some people have damaged their machines by following these instructions.
This is especially tricky, because haunters who only use their machines in October, don't know that they have been
damaged until the warranty runs out next year!
We recommend that vinegar flushing not be used as a part of normal maintenance.
Use it only when you suspect that the fogger has been clogged by mineral buildup,
and then flush out the vinegar with generous amounts of distilled water.
If you lack manufacturer's cleaning instructions, you might want to consider doing what we do.
Depending on the amount of buildup, we work our way up through three levels of cleaning:
nozzle cleaning; distilled water flush; vinegar flush.
This type of cleaning is open to debate. Some people do it regularly;
others avoid it completely, saying that it damages the fogger.
In our opinion, it is a valid part of fogger maintenance,
but should be only used when you really need it and you must thoroughly
rinse the vinegar from the machine after it does its job.
Here is how we do a vinegar flush:
The short answer is "No".
There is no known material that will color the fog without clogging the machine.
Heck, there isn't even anything that will color the fog and clog the machine.
Normally, the fog is white.
You can give it the illusion of color by shining colored light on it.
This actually works very well, and you can change colors on a moment's notice.
You can color the fog from an ultrasonic mister.
In theory, one could have an additive that has a boiling point near the fog juice;
has a good color; keeps the color when evaporated; gives a enough color without too much additive;
isn't prohibitively expensive; is nontoxic; does not decompose to toxic byproducts;
does not damage the seals in the pump; does not corrode or clog the heat exchanger, etc.
Rosco says that they have spent a lot of time looking for such a material, and haven't found it yet.
Given the frequency with which the question comes up, there's probably money in a solution, and
if the chemists at Rosco can't find an answer, it is unlikely that you will.
Sorry.
If you really want this, buy it commercially from a dealer in fog machines,
and use only a tiny amount.
You can also buy pre-scented fog juice.
For that you need a fog chiller.
Thank you for visiting. Your comments are welcome.
I Want Continuous Fog From My Machine!
In order to keep the fog coming, you have to ration the heat stored in the fogger's heat-exchanger.
You do this by making many small bursts of fog, with resting in between.
It is the long uninterrupted blasts that cool down the fogger so much that it must stop to reheat.
I Want Maximum Fog From My Machine!
If you want the most total fog from your machine, you might be tempted to tape down the "fog" button on the remote control.
This actually works.
The machine will heat up, get hot enough, start the pump, make some fog, cool down, and shut off the pump until
it gets hot again.
It Fogs, But Not As Much Or As Long As It Did Before
It probably needs cleaning. We have a section for that.
Other Helpful Sites
Cleaning glycol foggers
All glycol foggers require periodic internal cleaning.
You should have received cleaning and storage instructions with your unit;
follow them.
If you didn't receive cleaning and storage instructions specific to your fogger, try to get them by contacting the manufacturer.
Nozzle Cleaning
Distilled Water Flush
If you have no hope of cleaning your fogger according to manufacturer's directions, you might consider this protocol:
Vinegar Flush
If your fogger seems especially dirty, slow to fog, or fast to reheat,
you may have mineral deposits in the heat exchanger.
Flushing the fog machine with vinegar dissolves mineral deposits.
Making your own fog fluid
A lot of people are curious about making your own for fluid,
so we added a page on the subject.
Fog Additives
Glycol foggers don't work well with additives in the fog juice,
but a lot of people try.
This is a great way to ruin your fogger.
Coloring the fog
A frequently-asked question is "Can I add something to the fog to make it colored, or glow in the dark?"
I suspect that a lot of people have ruined their foggers trying to add stuff to the fog juice.
The longer answer is:
Certain kinds of additives can be put in glycol fogger juice.
Commercial fog juice is available in numerous scents.
Scented fog
There are materials that can be added to fog fluid to give it a nice smell.
They tend to be fruity.
The most common fragrances are apple, citrus, strawberry, pina colada, and vanilla.
Flavored fog
There's a horror story in the Halloween-L archives about rental foggers that come back completely
ruined by users who add sugar to the fog juice in order to get "sweet fog".
Making the fog hug the ground
The first time that you use a glycol fogger, you will notice that the fog billows out of the nozzle,
out and up - giving a "pea soup" effect.
A frequently-asked question is "Can I make the fog hug the ground, like in movie graveyards and swamps?"
Related Pages
Please see our related pages on glycol foggers.
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