johnnypyro Posted September 4 Posted September 4 I am rolling parallel wound paper tubes with thin walls moistened with water glass. They work perfectly for what I have in mind, but I need to cut quite a lot of them. At the moment I just cutting them to length with a sharp craft knife and diminishing patience. So, do any of you have any good ideas to cut thin walled tubes cleanly and squarely without crushing the tube. And do it for 100 or so. Thanks for any tips!
Richtee Posted September 4 Posted September 4 What ya rolling them on? Roll a knife over them on the former. Poof. You MAY knick yer former. Be gentle or buy more dowel stock.
cmjlab Posted September 4 Posted September 4 (edited) *Mitre* Saw (Chop Saw) with the thinnest kerf blade, preferably one with a lot of teeth (typically referred to as a finishing circular saw blade). Using that method you can make a cheap and dirty jig that let's you cut a lot of tube's to the exact same length, very quickly. It works best when you have a dowel inside, butted up as close as possible to where you will make the cut. Edited September 4 by cmjlab Changed "Mistress" to Mitre Saw 1
johnnypyro Posted September 4 Author Posted September 4 Yes, a chop saw is the answer. Another bit of kit to find space for!
Richtee Posted September 5 Posted September 5 18 hours ago, johnnypyro said: Yes, a chop saw is the answer. Another bit of kit to find space for! Or roll a knife blade over it. Why complicate and spend? 1
cmjlab Posted September 5 Posted September 5 8 hours ago, Richtee said: Or roll a knife blade over it. Why complicate and spend? This is blatant and aggregious blasphemy! Why spend.....? My dear man, when it comes to tools and Pyro.... why not?!? Besides, what else is money good for? I can never have enough tools, chems, Pyro tooling, adhesive, paper and strings. Of course time fuse too! 1
cmjlab Posted September 6 Posted September 6 In all seriousness, your idea works great when you roll your own rocket tube's, and I've done it myself for many a tube. But, when you start making timed insert shells the number of tube's that you'd be cutting by hand goes up exponentially. So I prefer to buy tube's for this purpose, and it's cheaper to get long tube's and cut them to any size I want. Even in a 4" shell (smallest timed insert I'd bother trying), I get something like 19 of the 5/16" tube's, 14 of the 3/8" tube's, ~9 or 10 1/2" tube's, and 6 or 7 of the 3/4" tube's. That's per ring of course and I often do at least 2 rings for all but the 3/4" inserts. So it's easier for me to just make a jig for each size on tube cutting day, and knock em out with a mitre saw. Any time I can save adds up quickly, especially since each insert needs 4 end discs, end discs glued in, filled with flash, Time Fuse hole drilled, Time Fuse cut / glued in consistently to the same depth / primed with the exact same thickness of B.P. slurry and granules - all in the name of consistent timings. Then the actual shell building begins..... Good thing I love this hobby! 🙂
Richtee Posted September 7 Posted September 7 Yeah. I’m not as in deep any longer. Wish I was, but things have changed, and all I need is a hand cut tube er three. OK, maybe five er seven. production is not my bag. Used to try to build a show, but honestly, for $150 I can buy one and save money. I’ll never give it up, mind you. Once one has smelt the smoke...
Almostparadise Posted September 8 Posted September 8 (edited) On 9/5/2024 at 10:17 PM, cmjlab said: In all seriousness, your idea works great when you roll your own rocket tube's, and I've done it myself for many a tube. But, when you start making timed insert shells the number of tube's that you'd be cutting by hand goes up exponentially. So I prefer to buy tube's for this purpose, and it's cheaper to get long tube's and cut them to any size I want. Even in a 4" shell (smallest timed insert I'd bother trying), I get something like 19 of the 5/16" tube's, 14 of the 3/8" tube's, ~9 or 10 1/2" tube's, and 6 or 7 of the 3/4" tube's. That's per ring of course and I often do at least 2 rings for all but the 3/4" inserts. So it's easier for me to just make a jig for each size on tube cutting day, and knock em out with a mitre saw. Any time I can save adds up quickly, especially since each insert needs 4 end discs, end discs glued in, filled with flash, Time Fuse hole drilled, Time Fuse cut / glued in consistently to the same depth / primed with the exact same thickness of B.P. slurry and granules - all in the name of consistent timings. Then the actual shell building begins..... Good thing I love this hobby! 🙂 Do you use 4 end disc's for even the smaller sizes you mentioned? How do you hold them in place for drilling the hole for tf? Edited September 8 by Almostparadise
cmjlab Posted September 9 Posted September 9 23 hours ago, Almostparadise said: Do you use 4 end disc's for even the smaller sizes you mentioned? How do you hold them in place for drilling the hole for tf? Yep, 4 discs per insert. If I'm using tubes to make inserts, there is 1 inset end disc flush with end of tube, and an external end disc glued on top. I'd like to take credit, but it's a T Rebenklau idea I plagiarized to ensure no hot gasses leak by and ruin my shells. Keep in mind, I usually only make timed report inserts - i have not made small timed color inserts. I probably would try with a 1 end disc per End, or none are all if I did make color star inserts. There are ways to make report inserts without end discs, Saettines I think, I haven't tried them. I don't usually fuse through the end of small inserts, 1" or smaller. I prefer to side fuse the inserts so they can be stacked in the shell neatly and tightly. If i am fusing through the end, its usually on the main shell itself or larger inserts, so its easier to make the hole - but i usually punch them 5 at a time for a clean hole. Plus the punches i have are tapered so it creates an angled hole that holds a filet of glue nicely to help seal the TF well.
Almostparadise Posted September 9 Posted September 9 "If I'm using tubes to make inserts, there is 1 inset end disc flush with end of tube, and an external end disc glued on top" As in one disc is pushed in as an end plug with the other external glued on top?
cmjlab Posted September 9 Posted September 9 16 hours ago, Almostparadise said: "If I'm using tubes to make inserts, there is 1 inset end disc flush with end of tube, and an external end disc glued on top" As in one disc is pushed in as an end plug with the other external glued on top? Exactly. I think TR called it a "stepped end disc" and it's just to make sure no gasses get in and set off the insert inside the shell, setting off all the other reports, and creating one giant "bottom shot" or salute (due to the pre-made tubes being weaker spiral wound and not convolute tubes).
cmjlab Posted September 9 Posted September 9 Another way I've seen a few experienced people seal the ends of the report inserts is to have a single end disc, but inset approximately 1/8" to 1/4" from the end of the tube. Then that space is filled with epoxy, a good wood glue, or something similarly strong. If it's a good adhesive that soaks into the paper, it creates a plug that is equal to, or stronger than the tube itself. One could use got glue to make that plug too, but I'd make it more towards the 1/4" size to make sure it doesn't melt through; but I don't like using hot glue in fireworks (personal preference to avoid the risk of sparks and heat all together). It's too expensive for my taste (cost of epoxy and good adhesives these days). Compared to free chipboard (kids book covers, or even better the toddler books that all the pages are made from a hard chipboard material so they don't get ruined from kids slobber!).
Richtee Posted September 10 Posted September 10 (edited) 2 hours ago, cmjlab said: Compared to free chipboard (kids book covers, or even better the toddler books that all the pages are made from a hard chipboard material so they don't get ruined from kids slobber!). You are a true Renascence man. Personally I use paper towel moistened with water/wood glue. Tap in with former, spin and backset maybe a 16th. a wood glue topper on that contains decent BP Fairly well. For the fuse end, again the moistened paper towel, Wound just under just under tube ID, and fold the top over after splitting it a bit to re-enforce. With glue of course. Edited September 10 by Richtee 1
johnnypyro Posted September 10 Author Posted September 10 I'm making custom "inserts" (really bombettes) from thin walled tubes of 11mm internal diameter. The tube walls are no more than 1mm. Cutting them by rolling them on the form is fine for a few, but I was hoping to do 100 or so and get nice clean cuts that are straight and consistent. My bombettes are 3cm long and have a 1g payload. The tube ends are a double layer of Kraft paper pushed through so it's flush with the tube end with a green visco fuse cut for 1s delay. The end/fuse is then sealed with sodium silicate. Stars and MgAl flash are loaded and then another double layer of Kraft paper pushed in the enclose the whole thing. I use cyanoacrylate glue.This end is deliberately designed to give way as the I don't want the bombette tube to explode to reduce noise (I live in the UK). Example with Buell orange stars primed with mill dust. Buell Orange.mp4 1
Almostparadise Posted September 10 Posted September 10 Wow, really nice. And for such a small tube! What size do the stars come out after priming? Those would look great in a multi shot cake of some sort.
Almostparadise Posted September 10 Posted September 10 On 9/5/2024 at 10:17 PM, cmjlab said: In all seriousness, your idea works great when you roll your own rocket tube's, and I've done it myself for many a tube. But, when you start making timed insert shells the number of tube's that you'd be cutting by hand goes up exponentially. So I prefer to buy tube's for this purpose, and it's cheaper to get long tube's and cut them to any size I want. Even in a 4" shell (smallest timed insert I'd bother trying), I get something like 19 of the 5/16" tube's, 14 of the 3/8" tube's, ~9 or 10 1/2" tube's, and 6 or 7 of the 3/4" tube's. That's per ring of course and I often do at least 2 rings for all but the 3/4" inserts. So it's easier for me to just make a jig for each size on tube cutting day, and knock em out with a mitre saw. Any time I can save adds up quickly, especially since each insert needs 4 end discs, end discs glued in, filled with flash, Time Fuse hole drilled, Time Fuse cut / glued in consistently to the same depth / primed with the exact same thickness of B.P. slurry and granules - all in the name of consistent timings. Then the actual shell building begins..... Good thing I love this hobby! 🙂 For the smaller ID inserts that are side fused, are you just pushing the tf in until it hits the back wall of the tube when you glue it, to maintain the same depth?
johnnypyro Posted September 11 Author Posted September 11 11 hours ago, Almostparadise said: Wow, really nice. And for such a small tube! What size do the stars come out after priming? Those would look great in a multi shot cake of some sort. Multi-effect cakes are the goal for this year now I've got the bombettes working reliably. I started with screen cut micro-stars just to get things going, find out which compositions I liked, and which primes worked. Because these are close-up fireworks (5-8m watching distance) you really see everything that happens in the burst. I used monocapa prime at first and it will ignite just about any composition, but it's noticeably smokey and I couldn't get rid of this even with ball-milling, so I moved to simple BP as a prime which is burns off quick without the smoke. Star sizes obviously depend on the composition burn rate and density as well as getting two different stars to burn well together in a multi-effect bombette. That's where I am now, rolling stars on mustard seed cores, selecting the biggest ones, priming, firing, not big enough?, roll some more, and repeat. It's taking time, but good fun. I guess the stars will be 3 -6mm diameter. 1
cmjlab Posted September 11 Posted September 11 15 hours ago, Almostparadise said: For the smaller ID inserts that are side fused, are you just pushing the tf in until it hits the back wall of the tube when you glue it, to maintain the same depth? Most of the inserts are timed with fuse that's 3/10", 4/10", 6/10" long and are pretty small (thats for 3 rings of inserts) so I use a thick washer placed flat on my bench, then use the opening in the washer to make sure the TF is all set to the same depth. I can usually only fit 3 timings worth of inserts into a single break because all but the shortest timing have a 2-insert tall stack of inserts (that probably doesn't make sense). Basically each break would be 5 inserts tall (1 ring of insert for the shortest timing, 2 rings of inserts for the 2nd timing, 2 rings of inserts for the longest timing). If I want more rings of inserts, then I add another break. Where you get into longer time fuse (like with consecutively timed inserts such as a bebbux shell or snail shell) then I would use a jig to make sure the time fuse was pushed in as far as possible, but NOT touching the opposing wall of the tube. I would be concerned of it blocking fire if it touched the opposing side. You bring up an excellent point though - if you want exact timing, then consistency is crucial. All the inserts need to be processed to identical specs to achieve that precise effect. For me this includes TF depth, priming slurry, down to how I press the TF into B.P. granules and ensuring consistent thickness / amount granules on the TF as well. I want to point out, I learned the timed insert process mostly by reading Wiley's article / process, because he make some seriously nice "Maltese like" multi-break beraq shells. When I copy his process, I get really precise results. **So, credit where credit is due** (I don't know if he still visits here, I hope he does) 1
Richtee Posted September 11 Posted September 11 (edited) God that 4/10, 6/10 bothers me. I have never used time fuse proper. But it’s properly measured in tenths of an inch? Surprised they don’t use MM. Edited September 11 by Richtee
cmjlab Posted September 11 Posted September 11 (edited) No. It's not "proper" per se, but the article I discussed following did use 1/10 increments which probably relates to the incremental turns of a bolt thread pattern used as the fuse stop on purchased fuse cutters, if I had to guess. I'm not a machinist, but when making incrementally timed shells, people often achieve timing by 1/2 turn, 3/4 turn or 1 turn per time fuse increment. I don't know on a 1-24 TPI what that equates to in inches or if they used a metric thread...... So I built my cutter with an engineer ruler which uses 1/10 increments. I'm sure they could be converted to the normal imperial scale of 8/16/32, etc. I wanted to get the timing right before I changed it to my purpose, but stuck with it since it worked well. Edited September 11 by cmjlab
cmjlab Posted September 11 Posted September 11 (edited) You have me second guessing myself. If you were told to cut something at the following lengths, how would you express them in imperial inches? 0.3" 0.4" 0.65" Correction to my previous post is that the common bolt size used in Caleb's Time Fuse cutter is 1/4"-20, which is my guess as to where the 1/10 measurements came from so that the person who wrote the article could express a common to everyone increment between insert timings. Edited September 11 by cmjlab
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