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Red gum and dextrin


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#1 Vic

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Posted 01 April 2009 - 06:08 PM

When a composition is using red gum and contains dextrin for the purposes of acting as a binder, should you simply use water to activate the dextrin or do you use alcohol as well causing the red gum to also act as a binder?

Also, if alcohol is being used and as such causing the red gum to act as a binder, can dextrin be omitted from the mix as the red gum is serving the purpose in itself?

Finally, does activating the red gum as a binder have any effect on the function of the stars in the form of their burn rate, or anything else?

Sorry for all the questions
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#2 Arthur Brown

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Posted 01 April 2009 - 06:29 PM

Do you have a specified wetting liquid in the formulation? I'd try a 25 to 33% mix of methylated spirit in water.

NO you cannot reliably omit bits from a formula. dextrin is a binder and fuel, take the fuel away and the flame will change.Dextrin, red gum and shellac all have different burning properties so there is a chance that formulae need the components specified.

If you need to make changes then try really TINY tests first.

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#3 Richard H

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Posted 01 April 2009 - 07:08 PM

Red gum is primarily an organic fuel in fireworks. Its use as a binder is much less common. Where a formula includes red gum and dextrin, you should in the vast majority of cases assume that the composition should be dampened with water only. It is common to add a small percentage of alcohol to lower surface tension, but I would avoid activating the red gum as a binder. It is difficult to clean your tooling once they get caked in hardened red gum, so my advice is stick with the water.
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#4 Vic

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Posted 01 April 2009 - 07:34 PM

Thankyou for your replies gentlemen
To go against conscience is neither right nor safe. I cannot, and I will not recant. Here I stand. I can do no other. God help me.
Martin Luther 10 November 1483 – 18 February 1546

Friedrich Wöhle 31 July 1800 – 23 September 1882 Organic Chemist

#5 seymour

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Posted 02 April 2009 - 03:41 AM

Personally, the only time I would use Red Gum for its binding properties, is in compositions where Parlon is the main binder. Parlon also has a tendency to be sticky and annoying, but the addition of a few percent Red Gum really does a great job at reducing this.

It seems that in this case, at least, two negatives do indeed make a positive!
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#6 Vic

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Posted 02 April 2009 - 08:43 PM

Binders
Just to expand a little on binders


NO you cannot reliably omit bits from a formula. dextrin is a binder and fuel, take the fuel away and the flame will change.


The formula is: Shimizu Blue star 70

Potassium Perchlorate 63.8
Parlon 13.8
Copper(II) Oxide, black 12.9
Red Gum 9.5
Dextrin 4
Total: 104

Seeing as the dextrin is added to the 100% I was under the assumption that the dextrin was solely for binding

I have of late switched from dextrin to SGRS as a binder which I have used for most of my formulas. From my limited experience SGRS does alter the burn compared to dextrin: it seems that the flame consumes the star in a different manner compared to dextrin. Has anyone else had experience of this?
To go against conscience is neither right nor safe. I cannot, and I will not recant. Here I stand. I can do no other. God help me.
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Friedrich Wöhle 31 July 1800 – 23 September 1882 Organic Chemist

#7 cooperman435

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Posted 03 April 2009 - 02:00 AM

To add to this discussion Ive just obtained a large sample of cellulose adhesive which is reported from a good source as a better, basic, water soluble binder to be used instead of Dextrin. I use 2% Dextrin currently in my BP and mathematically cellulose is 4 times stronger so .5% should give simalar results.

Ill keep you posted and would love to hear from anyone else who has tried it (or wants to)

#8 digger

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Posted 03 April 2009 - 05:55 AM

To add to this discussion Ive just obtained a large sample of cellulose adhesive which is reported from a good source as a better, basic, water soluble binder to be used instead of Dextrin. I use 2% Dextrin currently in my BP and mathematically cellulose is 4 times stronger so .5% should give simalar results.

Ill keep you posted and would love to hear from anyone else who has tried it (or wants to)


Is that CMC (carboxy methyl cellulose)?

Phew that was close.


#9 Creepin_pyro

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Posted 03 April 2009 - 09:54 AM

If it is CMC, apparently it's used in certain kinds of blackmatch. Certainly seems to give a lot more flexibility in the finished match and doesn't flake easily. Sounds promising.

#10 digger

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Posted 03 April 2009 - 04:12 PM

If it is CMC, apparently it's used in certain kinds of blackmatch. Certainly seems to give a lot more flexibility in the finished match and doesn't flake easily. Sounds promising.


I have some CMC, it is very interesting stuff. It makes your BP soup completely homogeneous so it does not settle out, smashing stuff.

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#11 pyrotechnist

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Posted 03 April 2009 - 04:57 PM

Where do you buy CMC from? Just tried looking on google for a source but found nothing valuable.
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#12 digger

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Posted 03 April 2009 - 06:30 PM

Where do you buy CMC from? Just tried looking on google for a source but found nothing valuable.


There are a few sources. It is used pure as an adhesive for wallpaper in libraries for old books (I can't remember off hand the name of the company I used for mine). The other source (more expensive) is TYLO powder this is used for cake decorating and is again 100% CMC. However you only need less than 1% along with the dextrin so even a 100 gram tub of TYLO goes a very long way.

Hope this helps.

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#13 maxman

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Posted 03 April 2009 - 06:34 PM

Try This :rolleyes: Works well.

#14 digger

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Posted 03 April 2009 - 06:36 PM

Try This :rolleyes: Works well.


Did you find that as good as the CMC?

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#15 digger

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Posted 03 April 2009 - 06:37 PM

Or this Clicky Clicky

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