Powderman Posted April 17, 2021 Posted April 17, 2021 I am having hard times finding any info how to apply linseed oil or stearic acid. I have found some study where linseed oil was failing in water presence, but stearic acid not. I have stearic acid (with some other fatty acids content), but I would like to know if there is some proven way to use it... Two possible ways come to my mind - mixing at elevated temperature or using some solvent...
kingkama Posted April 17, 2021 Posted April 17, 2021 The common way I know is the use of solvents like varnish thinners. I see someone using the siliconic wax used in car polishing dissolved in acetone, which is better in treatment of metals like MgAl or magnesium.
Powderman Posted April 18, 2021 Author Posted April 18, 2021 (edited) So I am going to try something I have at hand, because I am candlemaker/candle supplies seller I have variety of paraffins, waxes and also stearic acid... I have added 0,5% of paraffin to my Mg flakes with the help of alkane mix C4-C11, after drying it pours nicely but it lacks the tendency to go airborn. Seems OK, will make some tests in KNO3/water/heat environment... Edited April 18, 2021 by Powderman 1
SharkWhisperer Posted April 18, 2021 Posted April 18, 2021 (edited) I am having hard times finding any info how to apply linseed oil or stearic acid. I have found some study where linseed oil was failing in water presence, but stearic acid not. I have stearic acid (with some other fatty acids content), but I would like to know if there is some proven way to use it... Two possible ways come to my mind - mixing at elevated temperature or using some solvent...Mg typically either gets the linseed treatment or (probably more durable) dichromate treatment. Never heard of anybody using stearic acid for Mg protection in fireworking, though it's not unusual for Al. But the reactivity issues are greater with Mg than Al, particularly if it's manipulated much (which could compromise a simple stearic acid layer) or for long-term storage. I've attached a very useful article that details the methods, limitations, and nuances of passivating Mg powder for pyro with dichromate treatment. If you haven't located it, there's an older APC thread on coating with boiled linseed oil--this will not protect it from ammonium perc, and wondering if your stearic acid will? https://www.amateurpyro.com/forums/topic/3802-coating-mg/Coating Magnesium.pdf Edited April 18, 2021 by SharkWhisperer
Powderman Posted April 19, 2021 Author Posted April 19, 2021 Thank You very much SharkWhisperer, at the moment I do not have ammonium perchlorate so I will buy linseed oil and until then I will use paraffin for tests/immediate use so no storage/deterioration problems...
Mumbles Posted April 19, 2021 Posted April 19, 2021 I'm more familiar with treating iron or steel with paraffin. I'd imagine the treatment could be done the same way for Mg or other metals, but I haven't heard of any real tests with it. For iron or steel, the it's usually done by heating up the metal turnings or whatever you have in a metal pan and adding the wax to the hot pan and metal. The wax should melt and it can be stirred in to coat it. There can be clumping problems as the wax cools and solidifies. Generally the coated material is passed through a coarser screen once it's cooled to break everything apart. As I mentioned, this is generally used in for iron or steel, which just happens to often be coarser for use in sparks. Using a fine material might make this difficult when using Mg or something similar. It'd be hard to get it all to break apart, or would probably require a much finer screen which I could see being a mess or a big pain. I'll have to go searching, but a few members here had success using parlon dissolved in acetone for coating more reactive metals like Mg. It seemed very efficient, to the point of making the metal resistant to dilute HCl.
YourBoiPyro Posted May 25, 2021 Posted May 25, 2021 Why does one need to treat magnesium? Pardon my stupidity, but I'm new to this type of stuff.
MadMat Posted May 26, 2021 Posted May 26, 2021 (edited) Finely powdered magnesium is VERY reactive. There are a number of chemicals that can spontaneously start highly energetic reactions with magnesium. Under the right conditions, magnesium can even become pyrophoric; that is, it will ignite upon contact with air. Treating magnesium is done for safety reasons. Edited May 26, 2021 by MadMat
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