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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.

#4 Vic

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Posted 01 April 2009 - 07:34 PM

Thankyou for your replies gentlemen
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#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?
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#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)?
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#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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