Adding Antimony Trisulfide for star tails?

[richardh08]

just vent the jar every hour

Yes, good advice when milling metals - especially aluminium.

A thin surface layer of oxide usually protects aluminium from attack by atmospheric oxygen. Reducing the particle size means that you are exposing vastly more surface area and you need to make sure that the oxide layer can reform. Opening the jar to the air every hour or so allows this to happen.

If you mill for a long time before opening the jar, the heat of oxidation of the enormously increased surface area can easily be enough to ignite the whole mass.

[Pyro-Gear]

Red-Relay-Blue-Relay......... Glitter?!

All rolled beautifully, like bearings.. up until the glitter. My lord that stuff didn't want to roll properly. 3 hours later and I have some pretty horrible stars What a waste of time/resources. Not sure where it went wrong.

Don’t worry if they look like raspberry’s Sam its quite common with this type of mix, let them dry for a while the put them back in the roller they will start to even up, spritz with a fine mist of 50/50.

[Niall]

Quote:
the carbonate in the formula should be fine to keep the acidity of the comp high

Err... my chemistry tells me that carbonates react with acids and so tend to remove any acid that may be present.

At best this mix will be neutral, and may be slightly alkaline from the charcoal. There's little point adding boric acid as it will just get neutralised by the carbonate.

Having said that, I'm sure this mix will be fine to roll (or pump) as it won't ever get really wet and, once rolled, will dry out fairly quickly. This kind of composition would normally only tend to cause problems if left very wet for a reasonably long period of time or get too hot while drying. I would worry if it contained finer (eg pyro grade) Al, and in any case I would think twice before wetting it enough to make cut stars with it.

It is similar in terms of ingredients to several of Winokur's glitter formulae and they all use a few percent of water to activate the binder. I've never heard of them causing problems.

In terms of compatibility, it is fine to roll it over a perchlorate-based mix.

It's good to ask, and it pays to worry about things that are unlikely to happen, especially when chemistry is involved.

Buffering? Oops....too quick to answer!!! Thanks for sorting that out, might explain my indigestion!

I just added carbonic acid to neutral water in my head and got acidity, not even sure how I got 'high acidity'!!!! I have also misplaced the two pints of milk I bought!

I thought that might be a reason for the barium carbonate being in the formula, perhaps it is for the neutrality it offers?

Would a bicarb work against this or cancel the effect of the carb, or do they just donate to become the other depending on pH? Just a random 0330hrs question because my brain has dumped.

I think I might have got myself wrapped in my own hoover cord over this and need help!

[richardh08]

I thought that might be a reason for the barium carbonate being in the formula, perhaps it is for the neutrality it offers?

The barium carbonate is there to act as a 'glitter enhancer'. Winokur, in his extensive investigation of glitter, found several such compounds. He thought they might act by slowing and/or cooling the reaction but, as far as I know, the mechanism is still not fully understood.

As well as barium carbonate, he found that sodium bicarbonate and sodium oxalate appeared to work well, but calcium carbonate and lead carbonate didn't.

To avoid taking this thread too far off topic, I'll start a separate thread on acids, alkalis and carbonates for anyone who is interested.

[Niall]

That would be excellent.