Binder systems question

[cogbarry]

Hopefully I'll soon be ready to start answering more questions here soon. For now I appreciate all the help I've received on this forum and will try to ask good questions. So here goes.....

 

When I started making shells I avoided comps that called for binding systems with acetone or NC laquer as I was more comfortable with water/dextrin. However, I have found that I get much better results rolling stars with acetone/red gum. My question is, is 5% redgum and acetone pretty much interchangable with water/dextrin accross most comps? Also, if a comp calls for red gum apart from the binder system (as part of a formula that doesn't specify binding system) should I still add 5% red gum?

[Potassiumchlorate]

5% red gum seems too weak. Red gum isn't a very strong binder.

 

Yes, you should still add red gum. Red gum+dextrin make the stars very easy to roll. The alcohol that you add to the water to decrease the surface tension activates the red gum, so it works like a binder. With parlon as the main binder red gum helps in making it less sticky.

Edited September 30, 2011 by Potassiumchlorate

[cogbarry]

5% red gum seems too weak. Red gum isn't a very strong binder.

 

Yes, you should still add red gum. Red gum+dextrin make the stars very easy to roll. The alcohol that you add to the water to decrease the surface tension activates the red gum, so it works like a binder. With parlon as the main binder red gum helps in making it less sticky.

 

What would you recommend? 7%? ..or what the the numbers be with red gum and dextrin? Lately, I've been using red gum and acetone (a bit fumey though) as the stars roll nice and round, no spiking issues although I might not like going outside to roll stars in the winter. The other reason I had used this system is because I thought it would mitigate any potential "drivin in" issues as there is never any water in the stars.

[Potassiumchlorate]

I'm not the most experienced here, but personally I'd use something like 7% red gum or more if that was the only binder.

 

I have seen 3% red gum in one composition, but that was pumped golden stars based on mealpowder, Sb₂S₃ and lampblack.

 

If you use dextrin as a binder, that is the main binder and red gum is a secondary binder so to speak; it's main purpose in such compositions is to work as an organic fuel.

 

But I think you should ask Mumbles or someone else really experienced. I've just been into this for 3-4 years.

[cogbarry]

I'm not the most experienced here, but personally I'd use something like 7% red gum or more if that was the only binder.

 

I have seen 3% red gum in one composition, but that was pumped golden stars based on mealpowder, Sb₂S₃ and lampblack.

 

If you use dextrin as a binder, that is the main binder and red gum is a secondary binder so to speak; it's main purpose in such compositions is to work as an organic fuel.

 

But I think you should ask Mumbles or someone else really experienced. I've just been into this for 3-4 years.

 

Well thanks for sharing the knowledge you do have. I may try the red gum/dextrin system at some point just to get away from the fumy and flammable acetone.

[Mumbles]

5% red gum seems too weak. Red gum isn't a very strong binder.

 

Yes, you should still add red gum. Red gum+dextrin make the stars very easy to roll. The alcohol that you add to the water to decrease the surface tension activates the red gum, so it works like a binder. With parlon as the main binder red gum helps in making it less sticky.

 

I'm going to have to disagree with you here. Lets say you use 10% alcohol in water as your wetting solution. That 10% alcohol does not function separately from the water. They're mixed, and have different properties than pure isolated liquids. If you fully dissolve redgum in say 10mL of alcohol, and add 90mL of water to it (approximating the wetting solution), I can guarantee you that the red gum is not going to stay dissolved. If it's not dissolved, it can't bind.

 

Most stars have some binding system inferred (as with the presence of dextrin), or stated. Whether those instructions, if not stated within the formula, get lost along the way from transcription from books or other sources get lost is another thing. I typically try to leave the formula as is when binding it if it is not explicitly stated. Red gum stars are not as hard as dextrin, and I don't particularly like it as a binder, but that doesn't mean it's totally unusable. I like the suggestion that a formula should have at least 7% red gum if you're going to try to bind with it. There are certain formulas where it will at least change the effect. A very notable example is aluminum streamers. Most are bound with dextrin alone, or a combination of dextrin and wheat paste. Adding red gum to the mix enhances the length of the tail noticeably. It gets burned up in the star, and leaves more aluminum to burn in the air. I don't know how it'd work for instance in a glitter or charcoal streamer.

 

It should be noted that most any solvent can get driven in, not just water. Red gum is actually notorious for holding onto some alcohol, as is shellac.

[Potassiumchlorate]

Well, I told you that I'm not the most experienced here. ;)

[cogbarry]

I'm going to have to disagree with you here. Lets say you use 10% alcohol in water as your wetting solution. That 10% alcohol does not function separately from the water. They're mixed, and have different properties than pure isolated liquids. If you fully dissolve redgum in say 10mL of alcohol, and add 90mL of water to it (approximating the wetting solution), I can guarantee you that the red gum is not going to stay dissolved. If it's not dissolved, it can't bind.

 

Most stars have some binding system inferred (as with the presence of dextrin), or stated. Whether those instructions, if not stated within the formula, get lost along the way from transcription from books or other sources get lost is another thing. I typically try to leave the formula as is when binding it if it is not explicitly stated. Red gum stars are not as hard as dextrin, and I don't particularly like it as a binder, but that doesn't mean it's totally unusable. I like the suggestion that a formula should have at least 7% red gum if you're going to try to bind with it. There are certain formulas where it will at least change the effect. A very notable example is aluminum streamers. Most are bound with dextrin alone, or a combination of dextrin and wheat paste. Adding red gum to the mix enhances the length of the tail noticeably. It gets burned up in the star, and leaves more aluminum to burn in the air. I don't know how it'd work for instance in a glitter or charcoal streamer.

 

It should be noted that most any solvent can get driven in, not just water. Red gum is actually notorious for holding onto some alcohol, as is shellac.

 

Hmn,

I was wondering if other solvents were prone to the driven in issue. I guess if the comp is prone to sealing in gases when it drys/cures, this can be an issue. If in doubt, let rolled stars dry in thin layers?

 

I find that many star formulas don't specify the binding system. Seems in some cases that some knowledge is assumed of the reader. If I knew I was going to be a pyro, I'd have taken more chemistry and even paid attention in class. Unfortunately, my backround here is weak. This is why I asked if there were some general (global if you will) rules. Then I wondered if there might be effect changing issues in certain comps. You've answered that, thanks.

 

Well, I told you that I'm not the most experienced here. ;)

 

Nonsense, thanks for your input, it's appreciated.

[Algenco]

Stars that are "driven in" will temper/equalize the moisture/solvent when sealed in a ziplock bag for 24 hrs , placing the bag in the sun will speed things up.

But nothing beats patience, I try to let stars set for a month or more before use, with large charcoal based Comets I like 2 months drying/curing time

 

 

[cogbarry]

Hmn,

I would think stars made with acetone and red gum would still function if they were drivin in as I know first hand that some will light and burn through while still wet. I suppose it may change the effects.

[Potassiumchlorate]

Hmn,

I would think stars made with acetone and red gum would still function if they were drivin in as I know first hand that some will light and burn through while still wet. I suppose it may change the effects.

 

If you use acetone as a solvent and metalllic fuels, you might as well make parlon stars. Cut parlon stars are ready to use within few hours.

 

For example:

 

Red parlon star with magnesium as a fuel:

 

Strontium nitrate 36

Potassium perchlorate 30

Magnesium 14

Parlon 14

Red gum 6

 

Green stars are made the same way but with barium nitrate instead of strontium nitrate

 

Blue parlon star with magnesium as a fuel:

 

Potassium perchlorate 58

Copper(II)oxide 14

Parlon 14

Red gum 10

Magnesium 4

[cogbarry]

If you use acetone as a solvent and metalllic fuels, you might as well make parlon stars. Cut parlon stars are ready to use within few hours.

 

For example:

 

Red parlon star with magnesium as a fuel:

 

Strontium nitrate 36

Potassium perchlorate 30

Magnesium 14

Parlon 14

Red gum 6

 

Green stars are made the same way but with barium nitrate instead of strontium nitrate

 

Blue parlon star with magnesium as a fuel:

 

Potassium perchlorate 58

Copper(II)oxide 14

Parlon 14

Red gum 10

Magnesium 4

 

Thanks,

I've actually made these or something close any ways. I think I used copper carbonate for the blue. Had trouble lighting them at first, got them working well with fence post prime, then a layer of meal. I just got some Copper(II)oxide 14 for use in the chlorate stars I was looking into. Maybe I'll try your formula.