16 replies to this topic

[bigtonyicu]

I'm in the process of building a dedicated firework workshop, so to keep busy I've been performing a few experiment.

I hade a length of CPVC pipe laying around and stopped to think:

-PVC contains 56% chlorine

-CPVC (=Chlorinated Polyvinyl Chloride) contains up to 74%

So I had to play.

Last night

I tried to remove the filler and was very surprise to find none (at least none that aren’t soluble in MEK). I dissolved the pipe in MEK (Butanone) and thinned it to the point were is would flowed like water, then I ran it through a filter (with the aid of a vacuum flask. Yes... I'm inpatient lol) and let the solvent evaporate to the point where it was a relatively thick liquid (thank god MEK evaporates very fast).

Tonight I mixed in a batch of Green KNO3 based nitrate star to make sure I wasn't getting chloride form my usual KClO3 that would give me hints of washed out green, I mixed 3 star composition and let them dry for 4 hours. Based on the percentage of chlorine in CPVC (assuming 74%) and the damp vs dry weight I ended with a percentage of 9%, 11.5%, 14% chlorine by weight.

I lit the first star (9%) and thought I was imagining very washed out green, then I lit the second star (11.5%) to my surprise that green was un mistakable, and with the 14% no difference.

If anyone wants to play I'm sure I could produce a more precise formula and come out with my own star system, but one thing at a time. The biggest advantage was production time (drying time); these star dried in only a few hours, they were pressed from a relatively dry mix but the use of MEK played the biggest factor in that. I will admit that the star didn't burn very fast the center of the stars must of still been damp, but definitely a great start.



I know it's not very precise yet but I had to share with someone, the wife just looked at me with the usual unimpressed “woohoo it's a green star, what’s the big deal” look so I had to share with someone that would get it.



So now I’m working on a way to dry and powder the left over paste/liquid so that I can get more precise weight and perfect a formula. Might try to dry it in thin sheets and run it through my hammer mill (once I actually build it), any other thought on how I could powder it would be greatly appreciated.

Edited by bigtonyicu, 30 July 2008 - 02:49 AM.

[Mortartube]

I am very interested in this. Can you post the green formulae that you used please and any further details.

Edited by Mortartube, 30 July 2008 - 09:59 AM.

[digger]

So now I’m working on a way to dry and powder the left over paste/liquid so that I can get more precise weight and perfect a formula. Might try to dry it in thin sheets and run it through my hammer mill (once I actually build it), any other thought on how I could powder it would be greatly appreciated.

Just a complete guess, but could it be precipitated out with the addition of another solvent such as water to change the plastics solubility?

Edited by digger, 30 July 2008 - 10:29 AM.

[bigtonyicu]

I'll post the formulas as soon as I get home, for some reason i can't log on to my FTP server from work today.

Just a complete guess, but could it be precipitated out with the addition of another solvent such as water to change the plastics solubility?

I'm affraid adding water wouldn't cause it to fall out of solution by simply adding it, It would just dilute the solution; but adding water to it and agitating it on a stirring hot plate under slight heat the exelerate the MEK evaporation, just might do the trick. I'll give that a shot over the next few days.

[Mumbles]

Actually adding water would force it out of solution. CPVC isn't soluble in water, so therefore it would push the solublility in MEK down greatly and it will fall out eventually. I don't know how well water would work as MEK isn't completely miscible with water. An alcohol would probably work better. Otherwise a large amount of water should do the trick.

Completely chlorinated PVC should behave pretty similarly to Saran. They have the same molecular mass, so it should be a 1:1 sub. Chances are its not perfectly chlorinated though, so some experimentation may be needed.

[Mortartube]

Hi,

Have you progressed any further with this, and could you post the formulas. If you have done so, I seem to have missed them.

[bigtonyicu]

Hi,

Have you progressed any further with this, and could you post the formulas. If you have done so, I seem to have missed them.

I'm working at expanding my workshop (before the nasty Canadian winter hits) and haven't had the chance to play around with CPVC since these preliminary tests (when are the extending the day to 36 hours?).

But this is the formulas that was used

KNO3 28
BaCO3 22
MaAl 38
CPCV 12

Easiest way to work with this would be to first test you CPVC to see if it contains any fillers.. if not the mix every thing by weight and flood with MEK end let it evaporate, when it gets the consistency of a thick paste cut into starts (N.B. do the drying process is a well ventilated area MEK can give you a nasty headache)

[seymour]

Bigtonyicu, Why dont you make Barium nitrate? It will make an excellent green with MgAl, CPVC and perhaps another organic fuel.

[bigtonyicu]

Bigtonyicu, Why dont you make Barium nitrate? It will make an excellent green with MgAl, CPVC and perhaps another organic fuel.

Make Barium nitrate? I can't think of an easy way of making Barium nitrate from barium carbonate, can anyone come up with something?

Edited by bigtonyicu, 05 October 2008 - 06:45 PM.

[digger]

Make Barium nitrate? I can't think of an easy way of making Barium nitrate from barium carbonate, can anyone come up with something?

The easy way using nitric acid?

[bigtonyicu]

The easy way using nitric acid?

The problem is finding a cheap source of nitric acid... It would make for some very expensive BA(NO3)2.

The only affordable way would be double sub and I can't think of a suitable nitrate to do so.

[seymour]

If you can find an agricultural place that sells nitric, you should be able to get 20L of roughly 70% for under $100. It is used as a cleaning agent. However, if it just isn't available, then you can dissolve Barium carb in vinegar to get the soluable Barium acetate, which you double decomp with Potassium nitrate. Luckily, Barium nitrate is the least soluable of all the species present in the solution, so it should crystalise first.

[bigtonyicu]

If you can find an agricultural place that sells nitric, you should be able to get 20L of roughly 70% for under $100. It is used as a cleaning agent. However, if it just isn't available, then you can dissolve Barium carb in vinegar to get the soluable Barium acetate, which you double decomp with Potassium nitrate. Luckily, Barium nitrate is the least soluable of all the species present in the solution, so it should crystalise first.

Cleaning agent? for gleaning what?

[digger]

Cleaning agent? for gleaning what?

It is used in the agricultural industry for pH adjustment in nutrient tanks for these big glass house soil-less growing affairs.

They don't use a great deal of it though. My next door neighbor runs one of these multi hectare glass houses and they buy it in 25l drums (they buy kno3 20 tonnes at a time). The stuff that they use is 30% as a little goes a long way for pH adjustment.

It is also used in the metal treatment industry as a pretreatment before electro plating to remove surface rust etc. Be wary of stainless weld cleaner as this may also contain hydrofloric acid.

Edited by digger, 06 October 2008 - 03:21 PM.

[pyrotrev]

then you can dissolve Barium carb in vinegar to get the soluble Barium acetate, which you double decomp with Potassium nitrate. Luckily, Barium nitrate is the least soluable of all the species present in the solution, so it should crystalise first.

This would likely be better done with a warm solution, since the solubility of KNO3 increases quite a bit at high temperatures.