Hit me with a hard Organic chem question, like on a final exam.

Also, Im having a mortar problem. Actually its the lift powder, its too fine. I am pressing it through a screen but it hardens into a solid lump, that I break up, and it winds up like dust. Too little and the mortar doesnt get high enough, too much and it wants to rip apart the tube and splatters the stars inside (setback). Can I use something besides dextrin for a binder... there isnt any pcv to solute so I didnt think I could use methylene chloride. I was thinking of Red Gum, and some 20% alcohol. I tried buying dextrin instead of making it from corn starch, thinking it was my recipe, but its the same $#!T.

Also, I havnt been soaking my rice hulls in BP before loading them to cushion the shells. besides ignition failure, is there any other reason to soak them? my cut stars ignite pretty easy, simple easy BP based mix.

us Dextrin if it is all clumping together im guessing you used to much water... genereally *i* uses a 60 40 mix of iso alchol to water and what i find works good rather then a screen i use a cheese gratter :P the fine side for parm cheese for fine powder and the side for regular cheese for lift :)


PS
enjoy

http://www.cem.msu.edu/~reusch/VirtualText/Questions/problems.htm

I just came out of lurking (for at least a couple years...I registered sometime within that time period...who knows when though) - just to thank you, warweed. As a chem major who's always had an interest in pyrotechnics and is currently in organic chemistry - that question resource is fantastic. I have a chem final next monday and will most definitely be using that to study.

Once again...thank you so very much.

Edit - make that three years ago.

Your using waaaaayyyy too much water/iso... Try thinking of the moisture level of fresh potting soil. Its not wet, though. When you grate it through the screen the pieces shouldn't really stick to each other that much. Personally I use 2-3% dextrin and very little 25% iso in water solution (by vol, its not that critical)...

Use a spray bottle with 25% iso in water... spray a few times, then distribute the moisture all around in the powder by forcing it through a sieve a few times, or some other way... repeat until its moist enough to make good granules when forced through the sieve... do it onto wax paper or something... the granules shouldn't stick to each other much, if they do, your using too much water... spread out all the moistened BP/dextrin in a thin layer and leave it a few minutes to let some of the iso and water evaporate... then try it again... alternatively you could add more dry BP/dextrin and mix it all up.

The mesh of the screen should depend on what size shells your trying to lift.

Red gum can indeed be used, as can NC laquer (without using water of course), CMC gum, guar gum, etc etc etc... I wouldn't recommend PVC...

Soaking rice hulls in BP... what the fuck...?

To coat hulls with BP you use very little water, just moistening them slightly until BP/dextrin will stick to them... then you roll or shake them up with loose BP/dextrin... moisten a small bit after a while... add more BP/dextrin... repeat until a suitable layer has adhered... then set them out somewhere to dry. They really have barely any BP on them at all.

Your using waaaaayyyy too much water/iso... Try thinking of the moisture level of fresh potting soil. Its not wet, though. When you grate it through the screen the pieces shouldn't really stick to each other that much. Personally I use 2-3% dextrin and very little 25% iso in water solution (by vol, its not that critical)...

Use a spray bottle with 25% iso in water... spray a few times, then distribute the moisture all around in the powder by forcing it through a sieve a few times, or some other way... repeat until its moist enough to make good granules when forced through the sieve... do it onto wax paper or something... the granules shouldn't stick to each other much, if they do, your using too much water... spread out all the moistened BP/dextrin in a thin layer and leave it a few minutes to let some of the iso and water evaporate... then try it again... alternatively you could add more dry BP/dextrin and mix it all up.

The mesh of the screen should depend on what size shells your trying to lift.

Red gum can indeed be used, as can NC laquer (without using water of course), CMC gum, guar gum, etc etc etc... I wouldn't recommend PVC...

Soaking rice hulls in BP... what the fuck...?

To coat hulls with BP you use very little water, just moistening them slightly until BP/dextrin will stick to them... then you roll or shake them up with loose BP/dextrin... moisten a small bit after a while... add more BP/dextrin... repeat until a suitable layer has adhered... then set them out somewhere to dry. They really have barely any BP on them at all.

haha like bag potting soil. Ill try pushing it through the sieve more, I See you really mess with it a whole lot. I was just sort of making it and letting it dry.

I have been using window screen. I am lifting 2" canisters and 3" round shells.

I had read in the introductory pyrotechnics book that the rice hulls should be "primed" for fire by wetting with BP then allowing to dry for days. I have not been doing this since my cut stars dont blow blind that easily... maybe when I start using round ones I might have to. I guess your description was better than mine haha.


Also, thank you warweed! I didnt know that page existed. Thats what I wanted!