magnesium and linseed oil.

[Dalle]

I have read that you should add linseed oil to magnesium powder so that it does not corrode. But how do you get fine powder from it? Doesn't it stick together?

[SharkWhisperer]

I have read that you should add linseed oil to magnesium powder so that it does not corrode. But how do you get fine powder from it? Doesn't it stick together?

 

"Boiled" linseed oil (quotes because it's not really boiled) forms a hard shell over the metal particles as it dries (actually, it's a polymerization reaction, not an evaporation/drying). Raw/unboiled linseed oil will stay gooey and doesn't work. Mg + boiled linseed oil clumps but is passed through a screen several times as it dries to break it apart and make the coating more uniform. You may need to add an organic solvent if the linseed oil is too viscous. It can take quite awhile to dry, too, after coating. Any comps subsequently made with coated Mg will also be screened again. A good ballpark estimate is 3% by weight of boiled linseed oil for Mg 100 mesh and bigger (not counting any extra solvent you might add), up to 5% for finer particles. Too much and you're going to have a mess.

 

As a new fireworker, why not just avoid crap like coating Mg until you have more experience? Except for very specialized purposes, there are few things that can be done with Mg that cannot be done with less-reactive MgAl that doesn't need a coating. It's a messy hassle & is just one reason my Mg rarely sees use and sits for years ignored on a shelf. I use a ton of MgAl, though.

 

Also, are you aware of the potential risks of spontaneous combustion of linseed oil-soaked rags and such that have been documented in woodshops and similar? The polymerization involves exothermic oxidation that can start fires. Unlikely relevant in small-batch Mg coating for fireworking but it's basic knowledge of the chems you're working with nonetheless. Relevant if you have a spill and mop it up with rags & toss them into a bucket.

 

p.s. Please read and review prior articles & threads on the topic. For instance: https://www.amateurpyro.com/forums/topic/3802-coating-mg/ , and here: https://www.amateurpyro.com/forums/topic/11706-coating-magnesium/ .

Edited July 21, 2023 by SharkWhisperer

[Dalle]

Thx for advise,

I tested different setup on flash powder today (1gr in a straw)

 

70/30 KClO₄ / german dark alu 96,3decibel

50/40/10 KClO₄ /German dark alu/sulfur 91,4decibel

50/40/10 KClO₄ (german dark alu/ blue alu 50/50)/ sulfur 93,1decibel

70/30 KClO₄ / (german dark alu/ blue alu 50/50) Fail

i am curious how the setup whith magnesium are.

Probably, you do not need to use linseed oil if you use the composition directly.

This is not my goal in pyrotecniks but I have to try it. :-)

Edited July 21, 2023 by Dalle