Ned makes KNO3-glitter without Boric Acid, and seems to be very relaxed about it.

[Ubehage]

I have noticed in the video below, where Ned Gorski makes a batch of glitter stars, he does not use any Boric Acid.

He even mentions it, and talks about drying the stars quickly and far away from everything in case of a reaction.

 

This makes me think, what will happen to the stars in case of a reaction?

Can you just "wait it out", and use the stars anyway?

 

What do the experienced people have to say?

Personally, I wouldn't risk it. Adding a bit of Boric Acid is so easy. But I'd like to know anyway.

 

https://www.youtube.com/watch?v=lnYCeabgy88

[OldMarine]

I wet my glitters with a solution of boric acid just to be safe. I've read they can heat up enough to ignite or can swell and crack. Like you said it's cheap insurance.

[Arthur]

The chance of a dryer full of stars igniting while drying doesn't meet my idea of a nice quiet hobby.

[Mumbles]

It should be noted that boric acid is incompatible with MgAl glitters. Dichromate solution can be used assuming the star doesn't also have barium nitrate.

 

In my experience it's only absolutely necessary when using compositions containing a nitrate, flake Al, and a basic component such as sodium oxalate. That said I do use it in all of my aluminum glitters.

 

If a reaction starts, you can quench it quickly with boric acid without much harm. If it goes on too long the effect is greatly diminished and the stars are basically ruined.

[WSM]

I see that adding boric acid to glitter mix is advisable if it reacts when wetted for making stars. The main problem appears to be the potassium nitrate and aluminum, especially if the nitrate is alkaline (aluminum breaks down in an alkaline environment, often exothermically). A main contaminant of potassium nitrate is alkaline carbonate (potash or potassium carbonate), due to improper purification during manufacture.

 

This suggests it would be prudent to test the pH of our KNO₃ before use in water-bound, aluminum containing mixtures.

 

Make a solution of potassium nitrate and distilled water and test it with a pH pen or narrow range pH paper. A range of 7.0 to slightly lower is good. anything much higher than that is cause for concern. The higher the pH number, the greater the alkalinity and the faster aluminum will degrade and generate heat.

 

If you find your nitrate is alkaline, maybe spending a little more for a better grade of KNO₃, unless you're up for treating yours with dilute nitric acid, would solve the problem.

 

WSM

Edited January 7, 2018 by WSM

[Ubehage]

I see that adding boric acid to glitter mix is advisable if it reacts when wetted for making stars. The main problem appears to be the potassium nitrate and aluminum, especially if the nitrate is alkaline (aluminum breaks down in an alkaline environment, often exothermically). A main contaminant of potassium nitrate is alkaline carbonate (potash or potassium carbonate), due to improper purification during manufacture.

 

This suggests it would be prudent to test the pH of our KNO₃ before use in water-bound, aluminum containing mixtures.

 

Make a solution of potassium nitrate and distilled water and test it with a pH pen or narrow range pH paper. A range of 7.0 to slightly lower is good. anything much higher than that is cause for concern. The higher the pH number, the greater the alkalinity and the faster aluminum will degrade and generate heat.

 

If you find your nitrate is alkaline, maybe spending a little more for a better grade of KNO₃, unless you're up for treating yours with dilute nitric acid, would solve the problem.

 

WSM

Awesome info, thanks!

[NeighborJ]

It is a good idea to test the ph of all chemicals used. Most notably is charcoal, following Neds lead has caused me to find yet another way to screw up a glitter. Some types of charcoal are used to make lye, and as we all know it cannot be mixed with Aluminum or MgAl without a reaction. Neds method can be used if you are familiar with your chems already and they are much less likely to have a reaction if the stars are pressed with very minimal moisture. The boric acid is just good insurance but even still, it won't be able to neutralize lye.

[Mumbles]

I'm curious what charcoals are used to make lye.

[NeighborJ]

Oh, the charcoal I had problems with was Red oak, ive been told that hemp stalks also make it,there shouldn't be any issues using any type of evergreen. I would be leery of the ph in mixed hardwoods.

 

I've read articles for DIY soap making where the lye used was derived from the ashes of oak trees by running water thru the coals several times. The process was repeated until the resulting solution was strong enough to dissolve a feather. If I recall the article also provided a list of woods suitable for the task.

 

Jason

[Arthur]

Wood ashes were the original washing powder, the white powder was removed from the charred wood and clinker keeping the oxides/hydroxides/carbonates of (largely) potassium, by screening in water.

 

BUT this was the use of wood ASH not charcoal, and may actually yield clean charcoal!

 

HOWEVER retort cooked charcoal should contain no ash, but TLUD cooked charcoal will contain some ash -sometimes visible as white dust.

I am aware of one user of a huge TLUD (45 gallon drum) who used to crush the charcoal to about 2 mesh then screen it over 600 mesh to remove the visible fine white ash dust, which would have been strongly basic.

 

Old fashioned charcoal may well have also contained bases/alkalis but modern pure charcoal should contain none.

 

TLUD users should be aware that strongly basic ash is also a possibility. Could the TLUD process need a cleanup stage? Personally I think it might, for some applications.

 

Remember the the "nitre beds" of old literature made Sodium Nitrate, this was mixed with wood ash to form the dryable Potassium Nitrate.

[Arthur]

Remember that there can be huge differences between bottled lab reagents with purities measured and impurities specified in ppm and old fashioned materials salvaged from domestic waste.

[NeighborJ]

Thank you Arthur, you have confirmed my suspicions and brought them full circle.

 

The comp I was making when I discovered the charcoal I had was contaminated with lye is the pyrotec gold glitter. At first I was baffled when, as they dried, it turned to a pile of dust. After checking the Ph I discovered the lye contamination. I conferred with David F about this and he had not experienced the issue on that comp. Looking back I did use a TLUD and he uses a retort. This was the only difference in the preparation of the oak charcoal.

 

I do pour my cooked charcoal from a ladder onto a tarp in order to allow the ash to blow away in the wind however this apparently wasn't enough to remove all the lye.

Edited January 10, 2018 by NeighborJ

[Mumbles]

I would say Arthur actually said the complete opposite of what you want confirmed. If you have lye in your charcoal, you contaminated it somehow. It does not naturally exist in charcoal. Saying it is made from charcoal, when in reality it can be made somewhat laboriously from ash, the burned, highly chemically and thermally remnants of charcoal is a huge stretch I think you're mistakenly using to try to explain away something you don't understand.

[NeighborJ]

Ok, you may be right.

[Arthur]

TLUD gives you the opportunity to burn the wood to ash after you have cooked off the volatiles. You need charcoal, NOT wood ash. Wood ash is a serious alkali/base (potassium oxide acquiring water and CO₂ from the air rather quickly to for K hydroxide and K Carbonate.

 

Better control of your charcoal process is essential. OR you need to break up the lumps and sieve off the fine (ash) dust. OR you need to wash the charcoal in water to remove anything soluble, but then you have to dry the charcoal properly before you can weigh it for use.

[Mumbles]

Dang, that last post came off way too sharp and harsh. I apologize NeighborJ. I gotta stop posting before having coffee in the morning.

 

I didn't notice the glitter you said you were using. It contains a heck of a lot more charcoal than a normal glitter. I still think it's unlikely, but could in theory be possible for some of the basic materials to started to affect things. Another possibility you may want to consider is the purity or pH of the sodium nitrate. If you have something more on the order of fertilizer grade that may be part of the issue as well. Besides basic impurities, chloride and some other anions can be quite corrosive.

 

Most charcoals have some native amount of ash. This is just the ultimate fate of minerals from the soil and life cycle of the tree. Very clean woods will have ash contents in the realm of 3-5% by mass. Very "dirty" woods will have ash contents in the 20-30% realm. Commercial airfloat charcoal is probably right around 15-20%. There is a general relationship between ash content and speed. Lower the ash content, the faster the burn.

 

Two random thoughts related to this. While low ash content is correlated with a faster burn, I've wondered if a high ash content is correlated with a long hangtime. The components of ash really aren't that different that the carbonates, bicarbonates, and oxalates we already use to slow burn rates and add delays to glitters. There are some instances, the firefly effect specifically, where addition of sulfate greatly extends the delay effect as well.

 

If you really want to lower the ash content, wash your charcoal with a dilute acid like nitric or perhaps acetic. 50% or more of the ash is very poorly soluble in water. That said, crappy charcoal is not magically made significantly better by this treatment. There's more to speed than ash content.

[Sparx88]

If I may, I'll contribute my experiences with this topic. To anyone reading that don't already know, most of the fella's that have shared experience and knowledge on the topic here in this thread are to be trusted. Seriously, heed they're advice.

 

Me however, am no expert but have learned from these guys a lot over the years. With glitter comps I have experience with winokur 19 and 20. W19 uses magnal, W20 uses aluminum. With w19 having magnal it is important to NOT over wet. This is true for most star comps. W19 is best rolled. I've done cut, pump and plate, which do work but not as righteous, with cut the next best. Easier to control moisture, and is less dense, which translates into more flashes and longer tail. Do not force dry these, no heat, no outside in the sun. Use a fan. They will react with heat, and will start to smell bad like hot sulfur and heat up even more on they're own. If this happens you have ruined stars. Toss'em into the burn pile. With w20, you can use boric acid 2-3% because it's aluminum and will help against the reaction. And again rolling is best imo, and cut is next best as long as you add only the bare minimum of water needed to have a consolidated patty that won't crumble or become mud like. Swelling and cracking like oldmarine said is almost a certainty with the reaction.

Edited January 13, 2018 by Sparx88

[dynomike1]

Why not use bakeing soda? thats what N1 calls for ani i never had any problems.

Edited January 14, 2018 by dynomike1

[Mumbles]

Mike, what are you suggesting using baking soda for?

[dynomike1]

In place of Boric acid

[Mumbles]

I wish it were that easy. Baking soda is not going to offer any protective benefits like boric acid. If anything, by being a base, it makes things slightly worse. It does make a great delay agent though.

[dynomike1]

I thought it added protection also. I only make N1 anyway, never had any problem storing it. Now i know

[Scorpion812]

Try this formula, ity doesn't require boric acid to be safe:

50% black CuO

50% Al

Bound with nc and primed with bp

[Mumbles]

Also not a glitter.

[starxplor]

Also not a glitter.

 

Also pretty expensive.