thechewy Posted July 24, 2012 Posted July 24, 2012 ok,well i want to try to launch a half inch OD shell. Its maybe 1inch long. My mortor tube i just finish making is is like 3/4 ID. And 8inch long. I plan on making small shells with a few small stars to start off making ariel shells:) i know the 10% rule of weight-lift doesnt always apply to small shells. Im using home made lift and not sure the grain size but my shells wont weight more than 5-7grams or less.. What would be a good starting weight of lift? My shells fit my mortor just enough to be able to slide about freely,is it safe or should i have a little more space so my mortor dont go flower pot on me?maybe half a centermeter of space beteen tube and shell
Jason Posted July 24, 2012 Posted July 24, 2012 (edited) I made a small cake with those exact dimensions, and I used only 1.5 grams of lift for each bombette. I would personally start there and dial it in. I found mine flower potted at only 2.2 grams.. I did several tests before the cake was made. My tubes were 9/16" ID and the mortar tube was 3/4" ID for reference. Edit: For reference, I use willow charcoal for my black powder and ball mill it for 3 hours in a Sponenburgh mill. Edited July 24, 2012 by Jason
californiapyro Posted July 24, 2012 Posted July 24, 2012 adding a lift disc can help too, but mainly if your powder is slow. I tend to go with around 20% with these small shells on lift
Arthur Posted July 24, 2012 Posted July 24, 2012 Too many uncertainties, you are taking some serious risks. Making a mortar -have you ever seen a launch tube about that size? What are you making yours from?Making your lift powder, this needs good BP granulated and sorted to about 5, 6 or 7 FA Making the shell- well if you re making the lot -why not, But at that size I'd call it an insert. Do lots of tests but do them from a safe distance, if you are too close and it fails then you get hurt, then the police and hospital may ask what and why.
thechewy Posted July 24, 2012 Author Posted July 24, 2012 lift disc,if that the cardboard disc that sits ontop of the lift powder? Also ty for the afety tips,although i use viso fuse that burns slowly and i hook up my camera igniter to the fuse. I have maybe 100ft of wire connecting my ignite to the fuse so i am pretty far from these tiny shells. I normally hit the igniter,the fuse lights,then i take a few additional feet further back. I done shot myself with rockets and and had a couple mortor shells blow up close to my face to many times lol. Im smarter now and never get close anymore unless im loading my shell into the tube. My shells only have enough room for 2 r 3 tiny stars being im doing very small scaled test still. But i enjoy having everyone tell me their thoughts. Its almost alway very usefull info that helps out alot. Especially being new to the mortor scenee;) btw ill be waiting on a response to the lift disc,very curious and want to try it tonight! i have some chrysanthemums and lift powder thats finally dry and ready to be used
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