Ubehage Posted January 9, 2015 Share Posted January 9, 2015 Hello there, guys and possibly girls I want to share my experience, in case there are other people like me with great desires and limited equipment. I have worked out a way to make simple mortars, using nothing but the paper-tubes available at PyroGarage:I use the 1 inch-tubes for the mortar itself, and then 15mm-tubes for the shot. Depending on which size shots you plan to make, and how much lift you want to give them, anything from 150mm to 254mm-lengths can be used for the mortar. However, the longer the cannon; the more speed the shell will have when it leaves the mortar/cannon. To start with, I ram 39,8 grams of bentonite into the 1"-tube, in increments of 9-10 grams.This will provide a solid base that does not blow out, when you fire the mortar. Anything less than this, and you might end up with launching both the shell and the bottom-plug - which does not give great results Next, you measure how deep the plug is, and drill a hole for the fuse, just 2-3mm above the bentonite.The smaller the fuse, the smaller hole is needed. And smaller hole gives better lift, because the pressure will always find the easiest and fastest way out.I use 2mm-fuse, and 2.5mm drill-holes. And I tighten the fuse with hot glue. Next thing, make your shellshot of the 15mm-tubes, and attach a fuse of the desired length/time.If the fuse is attached on the outside the shell, it's a good idea to cover it with a single layer of gummed tape, to protect it from flames. Just leave the tip exposed, and dip it in NC Lacquer/BP prime, for positive ignition. To make the shot fight tightly into the mortar, wrap it with 8 pieces of toilet-paper (or 4 pieces folded in double).You might need to roll it on a hard surface a few times, to make it as compact as possible.Now, it will fit into the 1"-tube, tight but not "too tight". From my own experiences, I discovered that about 10-15 grams of granulated (not powdered) BP, will provide a good lift. And also a nice BOOM when you shoot it. Link to comment Share on other sites More sharing options...
schroedinger Posted January 9, 2015 Share Posted January 9, 2015 Hello there, guys and possibly girls I want to share my experience, in case there are other people like me with great desires and limited equipment. I have worked out a way to make simple mortars, using nothing but the paper-tubes available at PyroGarage:I use the 1 inch-tubes for the mortar itself, and then 15mm-tubes for the shot. Depending on which size shots you plan to make, and how much lift you want to give them, anything from 150mm to 254mm-lengths can be used for the mortar. However, the longer the cannon; the more speed the shell will have when it leaves the mortar/cannon. To start with, I ram 39,8 grams of bentonite into the 1"-tube, in increments of 9-10 grams.This will provide a solid base that does not blow out, when you fire the mortar. Anything less than this, and you might end up with launching both the shell and the bottom-plug - which does not give great results Next, you measure how deep the plug is, and drill a hole for the fuse, just 2-3mm above the bentonite.The smaller the fuse, the smaller hole is needed. And smaller hole gives better lift, because the pressure will always find the easiest and fastest way out.I use 2mm-fuse, and 2.5mm drill-holes. And I tighten the fuse with hot glue. Next thing, make your shellshot of the 15mm-tubes, and attach a fuse of the desired length/time.If the fuse is attached on the outside the shell, it's a good idea to cover it with a single layer of gummed tape, to protect it from flames. Just leave the tip exposed, and dip it in NC Lacquer/BP prime, for positive ignition. To make the shot fight tightly into the mortar, wrap it with 8 pieces of toilet-paper (or 4 pieces folded in double).You might need to roll it on a hard surface a few times, to make it as compact as possible.Now, it will fit into the 1"-tube, tight but not "too tight". From my own experiences, I discovered that about 10-15 grams of granulated (not powdered) BP, will provide a good lift. And also a nice BOOM when you shoot it.To easen up the method you could also use the 25 mm wood plugs available at hardware stores, these are especially interesting as they also allow for mine construction acording to wouter visser and always have the same height.10-15 g Bp on a 1" shell? That sounds like alittle bit to much a 3" uses about the same amount, normally 2-4 g should be enough for that size shell. 1 Link to comment Share on other sites More sharing options...
Blackthumb Posted January 9, 2015 Share Posted January 9, 2015 Tip...find a local window repair shop and ask them to save you the shipping tubes from their aluminum moldings....you'll be surprised...I use them all the time...get many shots before they unwind inside then I use them for cyl. shells....nothing goes to waste here!! 1 Link to comment Share on other sites More sharing options...
spitfire Posted January 10, 2015 Share Posted January 10, 2015 Allright... this looks like some people need a little education. Or at least a hand to guide them. No offence though, it's a good start! All you need is two tubes, rammers and a fuse. Ubehage, did you ever dismantled a commercial cake? If not, do so in a safe way. Look close at the critical components, and ask yourself how they make that cake function in the fastest and cheapest way. Once you got that you're half way there. Now figure out how to do this yourself. There is a lot to learn on this subject, but it is really easy when you get the commercial picture. I don't want to advertise anything but my blog about ''tailing bombettes'' is a step into this matter. Just one detail but still... I guess a full blog about making bombettes might be something going for. To teach. 1 Link to comment Share on other sites More sharing options...
Col Posted January 10, 2015 Share Posted January 10, 2015 I find 4-5g of lift plenty for 30mm bombettes weighing upto 70g. I use the same amount for starmines fired from the same tubes, using a piston helps to shove the stars out. I have a reloadable 6 x 3-shot fan cake thats still going strong with tubes handrolled a few years ago. 1 Link to comment Share on other sites More sharing options...
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