Author Topic: Making smoke testing fluid -- for my DIY smoke machine  (Read 2697 times)

Offline goodfellow

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Making smoke testing fluid -- for my DIY smoke machine
« on: March 15, 2019, 09:01:14 AM »
I've done some experimenting with my DIY smoke machine over the past few days and have made a few adjustments.

The smoke machine works well using the small venturi to get rid of some of the moisture in the smoke, but I wanted to see if I could get even better results mixing my own fluid vs. buying the generic stuff at Walmart.

Commercial fog fluid is mostly water mixed with a little bit of glycerin, and is designed to produce clouds of steamy fog very quickly, and dissipate just as quickly because these machines are often used indoors. The high water content in the mix (usually 10-20% glycerin and 90-80% water) facilitates the dissipation rate.

For smoke testing a reduced water mix is preferable. Hence I experimented with solutions ranging from 25-40% glycerin (increasing the content by 5-part increments each batch). For really dense smoke the 35-40% solution work very well and doesn't gum up the boiler tubing in the unit. At that level, the venturi is still reducing some moisture at the orifice and the smoke is so thick that it can quickly fill an intake system with long lasting vapors.

Going over 40% is not probably good for these small fog machines because the small diameter heating coil in the boiler can get clogged. At around 50% glycerin the boiler started to release a burning smell -- meaning the mix was carbonizing (starting to burn). Clearly not enough water in the mix to generate the steam necessary to keep the coil clean, and to generate the steam pressure necessary for efficient venting.

The mix I used was about 35-40% glycerin mixed with 65-60% distilled water. The ingredients were purchase for less than $15 at the drug store. Generic drug store glycerin is pure enough for this purpose. The smoke is awesome --- for testing purposes.

I would speculate that for smaller machines (smaller heating coil diameter) the glycerin mix will have to be reduced to 25% or below, while for very large machines (large diameter coils) the glycerin content could be slightly increased .


IMPORTANT:

LAST NOTE -- If you plan on setting up a similar machine, please make a note to drain and flush it after every use. Drain and flush the tank with distilled water, and then run the machine with clean distilled water for several cycles to flush out the glycerin residue in the boiler tubes.

DO NOT .....let the water/glycerin smoke solution sit in the tank -- it will separate and clog up your pump and your boiler tubes.
« Last Edit: March 17, 2019, 01:35:44 PM by goodfellow »