Red gum information

[Hypervale]

Many of the star compositions I have read require red gum. Could anyone tell me what this is and where it can be obtained/ how it can be made? Also, are there any things I could substitute for it? Thanks.

[Mumbles]

Red gum is a natural resin from a variety of trees located primarily in Australia and the surrounding region. It's sometimes called Yacca gum or Accroides resin. Most pyro suppliers will carry it. Fireworks cookbook, Phil's General Store, Pyro Chem Source, etc. It's primarily a fuel, and occasionally a binder. I have not really been all that impressed with it's binding ability however.

 

The best substitute is probably phenolic resin. The standard substitution is 0.83 parts phenolic resin per 1 part red gum due to a slightly higher oxygen demand. Shellac, colophony, rosin, etc. might make okay substitutions.

[AustralianPyromaniac]

Red gum is the resin secreted by the Xanthorrhoea genus of plants that grow extensively across Australia. Personally, I Harvest it from the plants directly which are just a short walk away from my house (As is the same with most people in Aus) though this would not be a possibility for you.

 

If you're looking to substitute it then you might look at shellac although I'm not so sure the details on the exact ratio of substitution. Most likely 1:1.

 

Also, Google is an unfathomably valuable resource when used correctly!

 

Regards, AP

Edited November 6, 2017 by AustralianPyromaniac

[JKluth]

Doe anyone have the density of accroides (red gum) resin? I'm trying to set up a spreadsheet of star weights for various formulas to use as a quick check of porosity.

[davidh]

I tend to substitute vinsol for red gum. Always test before making a significant batch.

[Arthur]

Red gum only comes from an Australian plant. It's an OK fuel and a medium poor binder, It's used with alcohol as solvent. It was very popular with chlorate comps. You should be easily able to find it available retail or online in you locality.

 

Other binders exist, is the use of alcohol important in your formula? Consider carefully all the other parts of the formula that you intend to use.

[JKluth]

Thank you for your replies, but I still want to know what is the material density of accroides resin. Perhaps one of the Australians out there could collect some, weigh it, and use the water displacement method to measure the volume?

[SharkWhisperer]

Thank you for your replies, but I still want to know what is the material density of accroides resin. Perhaps one of the Australians out there could collect some, weigh it, and use the water displacement method to measure the volume?

For only $9.99 (plus shipping) I'll happily mail you a sample of the very finest Aussie red gum and you can do the densitometry for your spreadsheet project.

 

It's from a plant. The chemical composition probably changes with the season, the forest locale, specific tree and tree aging, though maybe not enough to hamper a general density evaluation.

 

It's lighter than sulfur and heavier than charcoal. Seems to me it's about as dense as parlon. Or dextrin. Maybe closer to parlon. But it's definitely waaaay less dense than copper oxide!

Edited August 21, 2021 by SharkWhisperer

[JKluth]

Thanks. Is that $AUS or $US?

[SharkWhisperer]

Thanks. Is that $AUS or $US?

I was joking. For just a little more than that, you can buy yourself a full pound of the stuff. Try fireworkscookbook.com or pyrochemsource.com . It's tree sap, so there should be no issue mailing it to you wherever you're located.

 

You might run into obstacles with categorizing some chems such as charcoal that probably varies tremendously in apparent density from batch-to-batch and across different woods. It's fun stuff, and when you get done measuring its density you can use the rest to bind up some rubber stars (Gorski's got some recipes and tutorials out there--his red mix works nicely).

 

And it might be confusing to list a density for parlon for example, because it's final density will probably differ in a star if it's comp is wetted with an organic solvent that dissolves parlon versus if it remains in dispersed powder form if the comp is bound with dextriin/water. Same issue with nitrocellulose and other chems...You can get displacement density values that you'd assume to be true/maximal density, but they might not always exist in that state in end products.

 

Just saying, it might not be as straightforward a task as you envision. Or maybe I'm overthinking it.

 

But if you're firmly committed to carrying on, and you're in the US/Canada, then ping me a snailmail address and you'll have a couple of grams of RG next week.