ST1DinOH Posted October 3, 2007 Posted October 3, 2007 first off i'm new at shell building so if my lingo, methodology, or technique seems a bit off it's because i'm a noob at all things not 1.4. on to the problem... so i built 2 shells. both comprised of the innards of some spare black cat gold series AS-1 shells i had collecting dust. so i harvest 6 random shells worth of various comps/fishes and stars and mixed them on a paper plate (i loathe un-labeled shells) and then seperated the lift on the shells into 2 equal piles. i reused the lift cups of two of the AS-1's and just added 2 more lifts worth... fast forward a bit... the problem is the timing so i'll just skip the rest of the details and go to that. i cut a 1 inch length of time fuse i procured from cannonfuse.com (japanese i think) and pushed it through the fuse hole from inside out. i then used an exacto blade to make a bisecting cut through the core of the time fuse (both ends of the time fuse were cut flush BTW). then i opened up that slice i made a bit to cross-match the powder core with what i thought was black match...later i learned it was a stick of thick paper fuse. that paper fuse was about 4 inches in length, i had to kinda curl the tips clockwise to get the time fuse to fit in the lift cup. once the paper fuse was bi-secting the core of the time fuse i applied a few coats of NC laq to aide in the passfire and to secure the paper fuse. the shells were plastic, i sealed them with PVC glue, and both ends of the time fuse were coated in NC now the results... 2 shells 1st shell: fired fine, got pleanty of lift, about 3.5 - 4 seconds from lift to apex. then it topped out, fell back to earth, splashed down in the river and entertained the spectators with an underwater ball of fire. 2nd shell: smae results from the lift, appeared to stay lit/glowing though not as bright/noticable as the first shell. no break. hit the water and did nothing but splash. now as noob as i am with shell building i belive i have the awnser to what happened but i came to the experts to try to make some sense of this. best i can figure the paper fuse i had procured from the inside of a #400 forward gold willow preloaded tube (1.4) somehow increased the burn time of my time fuse. i had learned this technique from a tutorial i saw on united nuclear's page where they had used real black match to bisect the time fuse. i was in a pinch for black match so i used this paper fuse thinking the lift would passfire to the entire length of the paper fuse, thus aiding in the passfire to the time fuse. as i mentioned i had also primed the end of the time fuse with that NC laqure. just wanted to grab some opinions to see if thats probably what happened or if i have somehow screwed up my math on the time fuse. i'm under the impression that the time fuse i purchased from cannon fuse has a burn rate of 3 seconds per inch. if thats the case then thoes shells should have been breaking close to the apex. i also didn't do anything special to the inside of the shells time fuse other than tht same NC prime. the shells i made more reciently i've been using that "straw technique" but these first two just had the time fuse terminating into the shell with a mix of break/stars/fish/coated rice hulls. so am i right? is that paper fuse the culprit or was it the comp inside that screwed me? IMO the shells should have done something if that time fuse started burning. and like i said, that first shell did break but it was a good 6 or 7 seconds after the lift. is it possible for a shell to "detonate" on impact? any help will be greatly appreciated, and thanks a million in advance. EDIT: also it be nice if ya'll could be gentile...i'm a shell building virgin. so light some candles, put on some barry white, and talk me through it nice and slow
LGM Posted October 4, 2007 Posted October 4, 2007 I'm pretty sure that the NC laquer will prevent flame from reaching the fuse, not act as a primer, It's what makes it hard to light visco from the outside if I remember right. It may have been the reason for the long delay and subsequent missfire by not allowing flame into the shell. Perhaps the paper fuse burned from the ends, just use the blackmatch like on UN. If there was flash or whistle in the shell it might have been able to go off on impact, but seeing as these landed in water that can be ruled out. How big were they?
fredjr Posted October 4, 2007 Posted October 4, 2007 Plain nc laquer can slow things down or block fire but if you mix in some milled BP it works great for priming.
qwezxc12 Posted October 4, 2007 Posted October 4, 2007 Using the paper fuse (firecracker-type fuse, maybe?) is probably your most likely culprit. I know from experience that the slower burning firecracker fuse doesn't necessarily take fire simultaneously along it's length from a lift charge - it may have only lit at the ends...especially in a smaller shell...less heat/pressure in the mortar. If you used a 4" length for cross-match and it lit at the ends, you'd be adding another ~4 seconds (2.2 sec / in burn rate) of additional burn time to your time fuse. If you don't make your own black match and need a quick substitution, I would suggest buying some of Skylighter's "super fast paper fuse", Item No. GN1205:http://www.skylighter.com/images/web_pictures/gn1205.jpg If you unwrap the paper, you can harvest three strands of really nice flexible black match. This stuff takes fire from a dirty look and doesn't flake at all even when making severe bends - they must mix paper pulp into the BP or something. I use it for cross-matching all the time. Here a link to a post with it pictured on a 6in shell:Cross-matched Visco Also, I wouldn't use NC lacquer to affix the cross-match. You do not want any potential fireblock or delay agent between the first fire of the cross-match and the initiation of your timefuse. Dental floss is the traditional way...I use tiny strips of high-tack masking tape. Good luck - the feeling of launching a nice aerial shell is worth the work. Your Youtube vid was pretty nice arrangement of shells and cakes.
ST1DinOH Posted October 4, 2007 Author Posted October 4, 2007 I'm pretty sure that the NC laquer will prevent flame from reaching the fuse, not act as a primer, It's what makes it hard to light visco from the outside if I remember right. It may have been the reason for the long delay and subsequent missfire by not allowing flame into the shell. Perhaps the paper fuse burned from the ends, just use the blackmatch like on UN. If there was flash or whistle in the shell it might have been able to go off on impact, but seeing as these landed in water that can be ruled out. How big were they? *facepalm wow...not sure how i didn't put two and two together on that one. we've been using that NC for a second dip on e-matches for some extra heat and protective coating soi guess somewhere along the line i forgot it's also used as a coating on the outside of visco. well my first day here and i'm already learning oh and these were 3 inch plastic hemi's i got from cannonfuse. Plain nc laquer can slow things down or block fire but if you mix in some milled BP it works great for priming. we did sprinkle a bit of the burst on the nc whiel it was drying, but we didn't mix it at all. man i can't believe i missed something that obvious. this last time around i angle cut my lift cup side of the time fuse (to expose more of the core) and dipped them in a coat of greendot and acetone (our primary ematch dip) so hopefully i'll get better results when i send this next batch up. Using the paper fuse (firecracker-type fuse, maybe?) is probably your most likely culprit. I know from experience that the slower burning firecracker fuse doesn't necessarily take fire simultaneously along it's length from a lift charge - it may have only lit at the ends...especially in a smaller shell...less heat/pressure in the mortar. here's a pic of the fuse... http://www.pyrouniverse.com/gallery2/data/614/medium/IMG_0070.jpg you can see about 10 sticks of the stuff in a pile off to the right. they came out of the bottom of a preloaded single shot tube. the paper fuse is real stiff and was kinda reluctant to bend. in a 3 inch shell i'm guessing what you say is the case. not enough heat to pass fire to anything but the ends, thereby efectivly doubleing my time fuse delay. If you used a 4" length for cross-match and it lit at the ends, you'd be adding another ~4 seconds (2.2 sec / in burn rate) of additional burn time to your time fuse. and that is exactly the added delay i had, that must have been it. so not only did i use the wrong type of cross-match but i cemented my mistake further by flameproofing the connection with a double coat of NC i guess i was lucky to even have the thing go off in the water. luckily i only wasted two sets of shell hemi's on that method. If you don't make your own black match and need a quick substitution, I would suggest buying some of Skylighter's "super fast paper fuse", Item No. GN1205:http://www.skylighter.com/images/web_pictures/gn1205.jpg If you unwrap the paper, you can harvest three strands of really nice flexible black match. This stuff takes fire from a dirty look and doesn't flake at all even when making severe bends - they must mix paper pulp into the BP or something. I use it for cross-matching all the time. Here a link to a post with it pictured on a 6in shell:Cross-matched Visco nice! i was debating on making some of my own but if i can order it up without turning my spare bedroom into a spiderweb of drying blackmatch i might go that route. the other option i had was harvesting some from a few feet of QM. that should give me enough to build pleanty of shells. Also, I wouldn't use NC lacquer to affix the cross-match. You do not want any potential fireblock or delay agent between the first fire of the cross-match and the initiation of your timefuse. Dental floss is the traditional way...I use tiny strips of high-tack masking tape. Good luck - the feeling of launching a nice aerial shell is worth the work. Your Youtube vid was pretty nice arrangement of shells and cakes. yeah now that i've been shown the light on the NC dipped fuse i'll be sure to stray away from "waterproofing" things i'm trying to pass fire to and hey man, thanks for the props on the 4th show. actually i was a little dissapointed in that show, this year i wound up doing my own thing, the year before 2 other pyro buddies and i put up a group show...it was much better. also i figured out that i'm the last person who should be allowed to press buttons on firing systems. i somehow turned a 25-30 minute show into an 8 minute finale. but hey it was fun so that's all that counts right? any time you get to press buttons and sun-burn tonsils is a good night right?
Mumbles Posted October 4, 2007 Posted October 4, 2007 I think the main culprit here was the paper fuse. The length may have has something to do with it. There are two possible failure points, taking fire, and giving fire. Either could have been a problem. Given the long delay, I'd say at least one came in taking fire. Likely the fuse took fire from the ends before giving fire to the time fuse. It's fully possible that the paper fuse didn't light at all on one, or it lit and the paper fuse was still burning when it hit the water, and was quickly extinguished.
ST1DinOH Posted October 4, 2007 Author Posted October 4, 2007 I think the main culprit here was the paper fuse. The length may have has something to do with it. There are two possible failure points, taking fire, and giving fire. Either could have been a problem. Given the long delay, I'd say at least one came in taking fire. Likely the fuse took fire from the ends before giving fire to the time fuse. It's fully possible that the paper fuse didn't light at all on one, or it lit and the paper fuse was still burning when it hit the water, and was quickly extinguished. this would explain why one did manage to go, and the other didn't. come to think of it the "submarine" shell (the one that did break) had more fire on the way down, that had to be the paper fuse finaly reaching the core of the time fuse, and throwing a bit of a tail as it came tumbeling back to earth. the shell that didn't break didn't have that tail, so the paper fuse must not have passed fire to the time fuse at all. then again with that paper fuse bisecting the core of the time fuse you'd think it would have passed fire once the paper fuse made it to the core... so either the paper fuse didn't catch fire at all from either end, or as you said it was extinguished just before it reached the time fuse via the mighty, muddy, maumee river.
psyco_1322 Posted October 10, 2007 Posted October 10, 2007 I prime my visco fuse for shell by dippnig the end in nc lacquer then into the same bp that I used for lift. Works every time. I used2-3fg for lift by the way. Just curious, how good are those black cat gold series shells, seen some one and they seemed expensive for shells. They worth it?
ST1DinOH Posted October 10, 2007 Author Posted October 10, 2007 I prime my visco fuse for shell by dippnig the end in nc lacquer then into the same bp that I used for lift. Works every time. I used2-3fg for lift by the way. Just curious, how good are those black cat gold series shells, seen some one and they seemed expensive for shells. They worth it? the AS-1's are nice shells, but they are kinda expensive and not labeled for effect. i won't buy them again but i will enjoy the ones i have left.
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