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mortor tube length


captainG

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I got some of these cheepo 1 1/4" premade plasic shells from canonfuse I have some schedule 40 I was going to use what length should I start with or is schedule 40 a bad idea thanks
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Those work Perfect on top of a small rocket !!!

You can make a small rocket that size with a shell faster than doing it the traditional way with time fuse lift and leader.

 

If you had some consumer cake left overs they have tubes that size.

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Here is my rule if I would make a shell, which I'm going to make many of them, lol. If I were going to make a three inch shell(2.60-2.80 inches in diameter), I would need a 2.5 inch casing, whether it's a ball shell or a cylinder shell. If you're going to make a shell that has a 1.25 inch diameter casing(either plastic or paper), you're going to need a 1.75 inch inner diameter tube(.25-.40 inches in shell pasting). But, lets say you want to shoot the shell out of a 1.91 inch inner diameter tube, you're going to need to paste the shell .66-.81 inches thick. The reason why I allow .10 inches left is because I want to allow myself to add some fuse to the side, running down to the lift, as well as easily dropping the shell in. When it comes to larger shells, such as 2.5 inches and up, I leave .20 inches of space in the tube, since quickmatch is thick. For launching the shell, I would prefer HDPE mortar tubes, since they are the safest type of tube on the market(as far as I know). Instead of them shattering, they expand/melt. If you're looking for a great place to buy consumer firework tubes, I recommend checking out Pyroboom.com. Other than that, a great place to get display firework tubes is PlatteRiverFireworks.com. Both of these websites have standard lengths and extended lengths. Have fun! :D

Edited by wizard7611
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Anything over 8 inches will work fine for those.

:)

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If by schedule 40, you mean schedule 40 PVC or ABS, just don't. Neither are suitable mortar materials. In the event of a failure they shatter and fragment into sharp pieces. HDPE, fiberglass, and cardboard are going to be the safest for most normal shells.

 

 

 

Here is my rule if I would make a shell, which I'm going to make many of them, lol. If I were going to make a three inch shell(2.60-2.80 inches in diameter), I would need a 2.5 inch casing, whether it's a ball shell or a cylinder shell. If you're going to make a shell that has a 1.25 inch diameter casing(either plastic or paper), you're going to need a 1.75 inch inner diameter tube(.25-.40 inches in shell pasting). But, lets say you want to shoot the shell out of a 1.91 inch inner diameter tube, you're going to need to paste the shell .66-.81 inches thick. The reason why I allow .10 inches left is because I want to allow myself to add some fuse to the side, running down to the lift, as well as easily dropping the shell in. When it comes to larger shells, such as 2.5 inches and up, I leave .20 inches of space in the tube, since quickmatch is thick. For launching the shell, I would prefer HDPE mortar tubes, since they are the safest type of tube on the market(as far as I know). Instead of them shattering, they expand/melt. If you're looking for a great place to buy consumer firework tubes, I recommend checking out Pyroboom.com. Other than that, a great place to get display firework tubes is PlatteRiverFireworks.com. Both of these websites have standard lengths and extended lengths. Have fun! :D

 

I honestly have to ask. What the hell are you talking about?

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Mortar tubes for small ball shells are often about 6x the shell diameter for internal depth, reducing for large shells to perhaps 4D for big shells (16"). Mortars for big salamis (think Maltese ) are often shorter than the shell but probably still 4 - 5D.

 

HOWEVER you must know what material the tube is made of. Thick wall paper is OK as is thick wall HDPE as used for pressure gas or water mains. Any pipe sold for drains will not be suitable. My paper tubes for 3" shells are about 15mm wall thickness! -sourced from industrial cling film.

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:blush:

Edited by calebkessinger
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If by schedule 40, you mean schedule 40 PVC or ABS, just don't. Neither are suitable mortar materials. In the event of a failure they shatter and fragment into sharp pieces. HDPE, fiberglass, and cardboard are going to be the safest for most normal shells.

 

 

 

 

I honestly have to ask. What the hell are you talking about?

He did say he bought plastic ball shell casings, so I was helping him out.

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A common rule forthe min. lenght is 5 times the tube i.d. as lenght over the plug. Only use paper, hdpe or fibreglass mortars.
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By telling him to paste between 17 and 58 layers of paper on it?

Oh man! Mumbles.. :lol: :lol: :lol: I needed this laugh today.

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By telling him to paste between 17 and 58 layers of paper on it?

Not exactly. The paper I use is roughly thick. Thanks for insulting me, I appreciate it(sarcasm).

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Sorry you got your feelings hurt, but you can't expect to give off the wall or questionable advice and not get questioned or called out on it.

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Sorry you got your feelings hurt, but you can't expect to give off the wall or questionable advice and not get questioned or called out on it.

I'm very surprised an admin would say something like that. I'm disappointed.

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In this hobby bad or wrong advice can be extremely dangerous. I see nothing wrong with the way it was called out.

 

DaM

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Sorry you got your feelings hurt, but you can't expect to give off the wall or questionable advice and not get questioned or called out on it.

 

Every time you give a little tough love I learn a little more. Please continue; if I ever say something terribly stupid I know I can depend on someone to set me straight. That gives a small sense of comfort in a potentially very dangerous hobby (obsession).

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I'm very surprised an admin would say something like that. I'm disappointed.

Dissapointed, or dead. I know what i'd go with.

It's called tough love, and is here for a reason. People can actually get hurt doing things wrong around here.

B!

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Dissapointed, or dead. I know what i'd go with.

It's called tough love, and is here for a reason. People can actually get hurt doing things wrong around here.

B!

The true thing is though, I am not and never plan on getting hurt. I've been doing this for the past three years now.

Edited by wizard7611
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The true thing is though, I am not and never plan on getting hurt. I've been doing this for the past three years now.

 

Thinking you're invincible is dangerous.

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No one plans to get hurt. Everyone will suffer some burns or close calls at some point though. The important thing is to minimize exposure and risk.

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There is a guide -five steps to risk assessment- ( http://www.communityactionthroughsport.org/images/HSErisk.pdf) which makes good reading. If you follow every part of it you will have reduced the risk and hazard in any specific situation, in any country. It is specifically applicable to the UK but OHSA would be very happy if you reduced all your hobby risk and hazard to the minimum.

 

OHSA, HSE etc are all work orientated but no-one is stopping you making your hobby as low a risk and hazard as possible.

 

One essential aspect is that the precautions you decide, you adopt ALL the time. I see Youtube vids of people trying fireworks wearing shorts and tee shirt -that's no protection jeans and a jacket is a lot better.

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We have a similar risk assessment approach for start of every shift. Factors such as the crew member's experience, sleep, familiarity with the base / AOR we are working in, the vehicle we are in and the weather a and time of day are factored in. With each mission, the weather is addressed along with duty time or extended shifts.

 

Flight can refuse a call based on FAA and departmental weather minimums while the ground crew is expected to minimize risks as much as possible and consider the risks/benefits for the patient.

 

Granted as an ambulance crew, the acceptable risk taken to save a life is much higher than we would accept in our hobby to entertain. In any occupation or hobby, hazards need to be addressed and minimized. A consistent approach like this works great as long as the potential hazards are realized in the first place. Being ignorant of a hazard can be as bad.

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Thinking you're invincible is dangerous.

I'm not thinking I'm invincible. I take safety very seriously to the expanded measure.

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