It depends on what makes the fog, not on the fog itself. Three quite different things get sold as fog for model cars - a glycol-based fluid vaporised by a heater, an oil vaporised by a heater, and plain water turned into mist by an ultrasonic plate - and each one does something different to paint, printed tampos and bare metal.
The three kinds of fog
| Made from | How | What reaches the car | The risk |
|---|---|---|---|
| Propylene glycol and glycerin in water | Heated into vapour | Fine vapour that disperses | Low, if the fluid is pH-neutral and residue-free. A light film can build up on surfaces over many sessions |
| Mineral oil, including baby oil | Heated into vapour | An oil mist | Settles as an oily film on paint, tampos and clear parts, and holds dust |
| Water | Ultrasonic plate, no heat | Liquid water droplets | Moisture on bare metal - steel axles are what rust |
Worth knowing: baby oil is mineral oil with fragrance added. "Harmless" on skin is not the same claim as harmless on printed decals.
Five questions to ask before running fog over a car
- What is in the fluid? A seller who will not name the ingredients has not given you enough to decide.
- What is its pH? Neutral is what you want near paint, decals and chrome.
- Does it state a residue? "Zero residue" is a claim you can hold a seller to; silence is not.
- Does the maker forbid substitutes? If a heated fogger lists fluids that damage it, that tells you the element is sensitive to what goes through it.
- If it is water mist, how will the car dry? Droplets sitting on a chassis are the start of rusty axles.
What not to put in a heated fogger
- Mineral oil or baby oil - the film problem above.
- E-cigarette liquid - flavourings and additives you did not choose, and not what the heating element was made for.
- Plain water - it will not fog properly in a heated unit; mist from water is a different mechanism.
- Scented stage haze or anything unlabelled.
Protecting the car either way
- Use a duplicate for long sessions. Save the grail for a short final shot.
- Soft-brush the car afterwards, dry, and every few sessions look at the clear parts in raking light for a film.
- Dry anything exposed to water mist, paying attention to the wheels - what corrodes and what cannot is in do diecast cars rust.
- Do not store the car in the tunnel. Take it out between sessions.
- Keep the chamber clean. A hazy chamber is condensed fluid, not a dying fogger - fog display maintenance.
- Ventilate the room, and do not breathe the fog directly.
What is in ours
Stated plainly, so you can compare it with anything else. The fluid for our WindChaser is:
| Property | Published figure |
|---|---|
| Ingredients | Propylene glycol (USP pharma-grade), vegetable glycerin (food-grade), distilled water |
| pH | 7.0 neutral |
| Residue | Zero - evaporates clean |
| Ingredient rating | FDA GRAS-rated ingredients |
| Do not substitute | Mineral oil or e-cigarette liquid - they damage the heating element |
| Handling | Well-ventilated rooms; not for direct inhalation |
Refills are here, and every published figure for the unit is on the specs page. What the fog can and cannot tell you about aerodynamics is in can a 1:64 wind tunnel show real aerodynamics.
FAQ
Is fog fluid safe for diecast cars?
It depends on the fluid. A pH-neutral, residue-free propylene glycol and glycerin fluid is low-risk for paint, decals and chrome. Oil-based fog can leave a film, and ultrasonic water mist leaves moisture that can rust steel axles if the car is not dried.
Can I use baby oil in a fog machine for model cars?
Baby oil is mineral oil with fragrance. Oil vapour settles as an oily film on paint, printed tampos and clear parts, and some heated foggers are damaged by it - check what the maker specifies before using anything.
Can ultrasonic water mist damage diecast cars?
The mist is liquid water, so it wets the car. Painted zinc bodies are fairly tolerant, but steel axles and bare metal can rust if left damp. Dry the car, especially around the wheels, after each session.
Does fog leave residue on a display?
Some fluid condenses on nearby surfaces over time, which shows up first as haze on a clear chamber. Soft-brush the car and wipe the chamber periodically; a residue-free fluid keeps that film minimal.
Is desktop fog safe to breathe?
Follow the fluid's own label. Use it in a well-ventilated room and do not inhale the fog directly.