superspike23 Posted September 17, 2012 Share Posted September 17, 2012 hi, I just received two 4 inch mortar tubes. I'd like to know how much I should extend the timefuse?. For my 3 inch shells, I use about 3.5 cm. A 4 inch shell rises much higher? we always use the same ratio? 1/10 of the weight lift? Link to comment Share on other sites More sharing options...
Xtreme Pyro Posted September 17, 2012 Share Posted September 17, 2012 (edited) hi, I just received two 4 inch mortar tubes. I'd like to know how much I should extend the timefuse?. For my 3 inch shells, I use about 3.5 cm. A 4 inch shell rises much higher? we always use the same ratio? 1/10 of the weight lift? Hi superspike, For my 4" shells I like to time them to about 3.5 seconds, but some people have used up to 4 seconds. For lift I would start out with 1/10th the weight, if you find the shell is going too high, back it down to 1/12. Edited September 18, 2012 by Xtreme Pyro Link to comment Share on other sites More sharing options...
psyco_1322 Posted September 18, 2012 Share Posted September 18, 2012 4 seconds makes for a little bit of hangtime, I usually time my 4" ball shells for 3 seconds, same with my 3" shells. Link to comment Share on other sites More sharing options...
Mumbles Posted September 18, 2012 Share Posted September 18, 2012 I use 1" of time fuse between crossmatch on 4" shells on my last batch of fuse. This worked out to a little over 3 seconds. XP, 1/8 is more than 1/10. I use around an ounce of 4FA for my 4" ball shells. Link to comment Share on other sites More sharing options...
Xtreme Pyro Posted September 18, 2012 Share Posted September 18, 2012 XP, 1/8 is more than 1/10. I use around an ounce of 4FA for my 4" ball shells. OOPS! Good catch, I was thinking 10% vs 8%. Fixed my error. Link to comment Share on other sites More sharing options...
Arthur Posted September 18, 2012 Share Posted September 18, 2012 Shell lift and timing are just part of the design and artwork that you make. Some people add half a second between shell sizes some like the convenience of 3 seconds for 3s and 4inch shells. Really small shells need lots of lift, moderate shells need something like 8 - 10% lift bigger shells need less lift than that. I saw a 16" shell that weighed 19kilos and only had 750g of lift, which is under 4% Once you put in enough lift to make the shell rise to a safe height, the rest is art -how high do you want your sell to go, and how high you want it to break.. Link to comment Share on other sites More sharing options...
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