Hexamine - hygroscopic or not?

[Potassiumchlorate]

What do you think about it? I have trouble consolidating parlon bound stars containing hexamine. It seems like they are "swelling".

[dagabu]

Straight from a manufacturers website:

 

"Hexamine is not hygroscopic. However, it

is sensitive to humidity and absorbs

moisture at a relative humidity above 65%,

causing binding or clogging.

P r e s s u r e a n d wa rmt h i n c r e a s e t h e

likelihood of the product forming lumps.

This effect is more pronounced with fine

grained products.

Above all, this has a negative effect on the

flow properties of the ground product. The

product should therefore be best stored in

a room with a constant temperature and a

relative humidity below 60%. Likewise,

there should be as little pressure on the

product as possible (i.e. do not stack

pallets on top of each other)"

 

-dag

[pyrojig]

sounds like a oxymoron of a statement ...

 

Not hygorscopic , but absorbs water, and sensitive to humidity .....,,,,,Huh,,,,,,,,sounds hygroscopic if you ask me...

[Potassiumchlorate]

sounds like a oxymoron of a statement ...../../public/style_emoticons/default/whistle.gif

 

Not hygorscopic , but absorbs water, and sensitive to humidity .....,,,,,Huh,,,,,,,,sounds hygroscopic if you ask me...../../public/style_emoticons/default/dry2.gif

 

I agree, but it should be pretty easy to drive the water out of it, shouldn't it? It's an excellent fuel and flame enlarger.

 

The relative air humidity here is very high most of the year, but I keep it in a plastic can. Maybe the lid isn't tight enough. It's the kind of hexamine with a slight smell of "fish".

Edited February 17, 2012 by Potassiumchlorate

[dagabu]

sounds like a oxymoron of a statement ...

 

Not hygorscopic , but absorbs water, and sensitive to humidity .....,,,,,Huh,,,,,,,,sounds hygroscopic if you ask me...

 

Strange ins't it? One better: Deliquescent

-dag

[Potassiumchlorate]

Deliquescent is when something is very hygroscopic, like strontium chlorate (and that is a shame for sure) or calcium chloride. Edited February 17, 2012 by Potassiumchlorate

[dagabu]

Deliquescent is when something is very hygroscopic, like strontium chlorate (and that is a shame for sure) or calcium chloride.

 

Yes it is a shame. Imagine what you could do with Sr(ClO₃)₂ if it would stay dry?

Edited February 17, 2012 by dagabu

[Potassiumchlorate]

Yes it is a shame. Imagine what you could do with Sr(ClO₃)₂ if it would stay dry?

 

The most lovely red without any metal fuels.

[50AE]

If it's possible for some of you, you should try Sr(BrO3)2 red. It's the deepest I've seen, done bu chemistry students that can get bromate for free.

 

Anyway, it's much more expensive and... quite reactive.

[Potassiumchlorate]

I think that I could get hold of potassium bromate. Can I react it with any strontium salt to make strontium bromate?

[warthog]

The only time the relative humidity is above 60% around here is in the summertime. The rest f the time our air is quite dry relatively. As for this statement being oxymoronic, it really isn't if you look at it closely. A hygroscopic chemical will draw moisture from even relatively dry air, it just has more affinity for the water than the air does so it moves where it is drawn. High humidity however is what drives this reaction. In dry conditions this isn't going to happen apparently.

 

I haven't used Hexamine much yet but I do plan on doing so this year. There are a number of formulae I have been looking at that either call for it or something I can no longer find but Hexamine is a good replacement for so I have some on hand now. No matter what the hygrosopicity of a given chemical that I keep around, I store it in a controlled environment and within a sealed bucket (the buckets have Gamma Seals for lids). Each chemical is then stored within its own "Tupperware" type tub inside which it is contained in a zip lock type plastic bag. Each bucket has a large moisture absorbing sachet in it which has a rechargeable desiccant in it. If it is something extremely hygroscopic, I also place a smaller packet of the desiccant into the smaller tub outside of the zip lock baggie.

 

Was a PITA at first to get it all in order but since doing it I don't have trouble with moisture in any chemicals. Any sorts of items to be stored, should they be hygroscopic like a Strontium Nitrate star or whatever, I store in a similar manner, though outdoors in a magazine (a friend's for now).

[50AE]

I think that I could get hold of potassium bromate. Can I react it with any strontium salt to make strontium bromate?

 

The problem is KBrO3 is less soluble than Sr(BrO3)2. You must use another, more soluble bromate, magnesium for example.

Or you can try to electrolyse SrBr2 solution

Edited February 17, 2012 by 50AE

[Potassiumchlorate]

The problem is KBrO3 is less soluble than Sr(BrO3)2. You must use another, more soluble bromate, magnesium for example.

Or you can try to electrolyse SrBr2 solution

 

Oh, typical.

 

My ideal would be to make red and green stars with barium perchlorate and strontium perchlorate and hexamine as the fuel. As long as there is no possibility to "seal" every star individually, that would be impossible to do, though.

[pyrojig]

Not to steer off topic, but I have som strontium perch. that may make for some amazing reds...

So what is the diif between the chlorate v.s. perch of this salt?

[Potassiumchlorate]

Not to steer off topic, but I have som strontium perch. that may make for some amazing reds...

So what is the diif between the chlorate v.s. perch of this salt?

 

Not much what the colour concerns. The problem is that both are highly hygroscopic (as far as I know; the chlorate is for sure), but if you could make something useful of the strontium perchlorate, it would be terrific.

[allrocketspsl]

your adding water or alcahol anyway to the comp.I have made many parlon bound just have to work fast.Screen slice is best i feel.All

[Potassiumchlorate]

Kind of the point to bind with parlon is to make the stars waterproof. If hexamine is hygroscopic, which it seems to be, it would be better to dry it thorougly and then bind the stars with parlon. I know a guy who has parlon stars from 1994. He can hold them under the water hose for several minutes and then just wipe them dry with paper and use them immediately - 18 year old stars!

 

If one should bind with dextrin or SGRS, though, it'd be needed to cut some parlon. If just adding +4% binder, the composition would be (rounded off to half percents):

 

Potassium perchlorate 59.5

Copper(II)oxide 12.5

Hexamine 9.5

Parlon 14.5

Dextrin or SGRS 4

 

That is by far too little potassium perchlorate for me. You can't cut away much copper(II)oxide, since the copper content is just about right (it should be between 7 and 14% all in all and it is 10.4%). You can't cut away much hexamine, because the whole point with the use of hexamine is to have an energetic oxygen-free fuel and flame enlarger. You can however cut away some parlon without starving the composition on chlorine:

 

Potassium perchlorate 62

Copper(II)oxide 13

Hexamine 10

Parlon 11

Dextrin or SGRS 4

Edited February 18, 2012 by Potassiumchlorate

[dagabu]

Kind of the point to bind with parlon is to make the stars waterproof. If hexamine is hygroscopic, which it seems to be, it would be better to dry it thorougly and then bind the stars with parlon. I know a guy who has parlon stars from 1994. He can hold them under the water hose for several minutes and then just wipe them dry with paper and use them immediately - 18 year old stars!

 

If one should bind with dextrin or SGRS, though, it'd be needed to cut some parlon. If just adding +4% binder, the composition would be (rounded off to half percents):

 

Potassium perchlorate 59.5

Copper(II)oxide 12.5

Hexamine 9.5

Parlon 14.5

Dextrin or SGRS 4

 

That is by far too little potassium perchlorate for me. You can't cut away much copper(II)oxide, since the copper content is just about right (it should be between 7 and 14% all in all and it is 10.4%). You can't cut away much hexamine, because the whole point with the use of hexamine is to have an energetic oxygen-free fuel and flame enlarger. You can however cut away some parlon without starving the composition on chlorine:

 

Potassium perchlorate 62

Copper(II)oxide 13

Hexamine 10

Parlon 11

Dextrin or SGRS 4

 

Looks like we got hung up on hygroscopy v.s. a tendency to hold water, moot is the point so lets move on to the parlon idea. Parlon, is a plastic of sorts, if you were to use fresh acetone in a very dry environment to dissolve the parlon, the resulting coating on the star would essentially make it waterproof and thus encapsulating the hexamine making any concerns of water v.s. hexamine disappear.

 

-dag

[Potassiumchlorate]

Looks like we got hung up on hygroscopy v.s. a tendency to hold water, moot is the point so lets move on to the parlon idea. Parlon, is a plastic of sorts, if you were to use fresh acetone in a very dry environment to dissolve the parlon, the resulting coating on the star would essentially make it waterproof and thus encapsulating the hexamine making any concerns of water v.s. hexamine disappear.

 

-dag

 

I know. The thing is that if it is hygroscopic, I most dry it first. I have had it for at least seven years in a plastic can with a not so very tight lid. It sublimes at 280^oC, so I'd guess that it can be dried in the oven.

[allrocketspsl]

your using acetone dried out to bind the parlon

[dagabu]

I know. The thing is that if it is hygroscopic, I most dry it first. I have had it for at least seven years in a plastic can with a not so very tight lid. It sublimes at 280^oC, so I'd guess that it can be dried in the oven.

 

Have you ever used an oven to dry out Hexamine? If not, you are in for a surprise! The stink it makes will stay around the house for weeks, it smells like cat pee to me others have a different nose but most everyone agrees that it stinks!

 

-dag

[Potassiumchlorate]

Have you ever used an oven to dry out Hexamine? If not, you are in for a surprise! The stink it makes will stay around the house for weeks, it smells like cat pee to me others have a different nose but most everyone agrees that it stinks!

 

-dag

 

I know the smell. I have extracted it from Esbit tablets before I had the pure chemical. That's OK. What's important is that it works.

 

Hm, there are many lumps in it, but the powder that isn't lumped is airfloat. Could a powder be airfloat if it had absorbed any considerable amount of water?

Edited February 18, 2012 by Potassiumchlorate

[pyrojig]

I know the smell. I have extracted it from Esbit tablets before I had the pure chemical. That's OK. What's important is that it works.

 

Hm, there are many lumps in it, but the powder that isn't lumped is airfloat. Could a powder be airfloat if it had absorbed any considerable amount of water?

 

Sounds like you have it. It will turn to a sludge if it gets water logged. So if it is powder still, your set, just keep it in a very well sealed container.

[dagabu]

I know the smell. I have extracted it from Esbit tablets before I had the pure chemical. That's OK. What's important is that it works.

 

Hm, there are many lumps in it, but the powder that isn't lumped is airfloat. Could a powder be airfloat if it had absorbed any considerable amount of water?

 

Pressure, heat and moisture are the culprits. Dry it out and mill it before use. I have a 3k lump of hex that I was given and it is as hard as a salt lick!

 

-dag

[Potassiumchlorate]

One reason that it might be hard to consolidate is due to the paradoxical fact that parlon stars with high metal content are easy to consolidate, while parlon stars with little or no metal are hard to consolidate. Dextrin stars are usually the opposite.