rogeryermaw Posted August 28, 2014 Posted August 28, 2014 i may have searched insufficiently but came up empty handed. mods feel free to delete this post if it has been done to death. given my recent experience with incompatible stars and priming, i came to wonder how such combinations can be safely used. if you fire things as you make them, chances of issue are somewhat reduced but this is not always possible or desirable. there are more instances when you will want or need to store several finished items until they can be used. my question is: can you safely seal...say...ap stars in a shell with bp burst if you coat the stars in nitrocellulose lacquer? would this provide a reliable, yet, ignitable layer of protection through which ion exchange would not occur? sorry if this has been posted before. if so, could someone please point me in that direction?
Carbon796 Posted August 28, 2014 Posted August 28, 2014 Yes you can, for that example. Generally, I will use about a 5-7% N/C solution to apply one of my primes with, on AP stars.
Arthur Posted August 28, 2014 Posted August 28, 2014 I have also seen makers using tissue paper to bag the burst charge to isolate components. Really the way you separate the components is a big part of your shell design. Some components may be too risky to mix, others may sit safely together, some may be better used with physical separation. Sulphurless BP, NC Lacquer, polythene bags and tissue paper all come directly to mind as separators for some purposes. Your design includes choice of separator. Remember that the rules of commercial fireworks include "is it cheap"!
rogeryermaw Posted August 28, 2014 Author Posted August 28, 2014 thank you very much, fellas! i'm hard at work on a blue formula and this info will come in very handy
Mumbles Posted August 28, 2014 Posted August 28, 2014 Usually a "barrier prime" is used. Something like pinball prime comes to mind as a popular example. Usually it's something based on potassium perchlorate and red gum. This can be applied with alcohol, or preferably something like NC lacquer. Once this is on, a traditional BP or nitrate based prime can be added over the top, usually with water. The idea being you put down a barrier with one solvent, and apply the top layer with another solvent that wont dissolve or leech into the first. Once this is done they can be broken with normal BP if you wish. Otherwise things like KP type mixtures can be used for burst as well so you don't need to worry about barrier primes. Sufficient priming will still need to be done though of course.
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