Pumping comets with phenolic (success)

[braddsn]

It might not be enough Chuck, I am not sure. All of the color comps that I use have at least 10% redgum. I use the Jopetes (spanish) formulas for all of my stars.

[chuckufarley]

Thanks. I might do a test of one of the greens on there.

[Mumbles]

Dextrin does have some fuel value, even though most tend to ignore it. The values for red gum, dextrin, and phenolic resin are all known. It would be the most reasonable point of departure to try to minimize changes to burn rate and color balance. It can be a hassle though. I include the values and conversion factors below if you're interested though. They're in units of grams of fuel consumed per gram of oxygen produced. The lower the number, the higher the oxygen demand and fuel value.

 

Dextrin - 0.82g per gram of oxygen

Red gum - 0.48g per gram of oxygen

Phenolic - 0.42g per gram of oxygen

 

To sub phenolic in for red gum it'd be 0.875 parts per 1 of red gum. Jim Widmann's website says 0.89 parts per 1 of red gum, so the approximation is pretty close.

 

To sub phenolic in for dextrin it'd be .51 parts per 1 of dextrin.

 

Unfortunately, not every formula lends itself to phenolic binding, and this is one of them. Emerald green doesn't really lend itself to a straight forward phenolic substitution. The binders are dextrin or parlon, and there really isn't a good organic fuel to substitute out. Even accounting for the dextrin, you're still at around 4.3% of total. I think your best bet swapping out the dex, red gum, sulfur, and charcoal, and just accepting that the formula may be drastically different, though much simpler.

 

Sulfur is .42 parts phenolic for 1 part sulfur.

Charcoal is 1.1 parts phenolics for 1 part charcoal.

 

The final formula would be:

Barium Nitrate - 50

Parlon - 18

MgAl - 12

Potassium Perchlorate - 10

Phenolic Resin - 11.9

 

 

Let us know what you end up deciding and trying.

[dynomike1]

Do you guys talk about the resin with- or without hexamine content?

I am using without Hex.

[chuckufarley]

Mum,

 

The test batch I made (100 grams) was using the original formula exactly.

 

Barium Nitrate 47.6%

 

Parlon 17.1%

 

Magnalium, granular, -325 mesh 11.4%

 

Potassium Perchlorate 7.6%

 

Sulfur 4.8%

 

Charcoal, airfloat 4.8%

 

Dextrin 4.8%

 

Red Gum 1.9%

 

I bound these using dex as the binder with straight water as the solvent. I pumped them in a single 3/8" pump, and they have dried very solid. I really like the color too, very deep rich green. After hearing the various comments about binding this formula with phenolic I think I might just stick with what's working. There are other formulas that I think would be better suited to phenolic binding. Either way, it seems like a nice green if your looking for one