What is the best (and safest) way to get a good break?

[Stef727]

My shells breaks havent been good laitly...

This is how I want them to look like how my breaks are right now.

http://i.imgur.com/CuF4pYp.png?1

 

My shells are 3" canisters, I use black powder rice hulls for the burst.

 

I'm still scared of of using kno3 flash and I can't get whistle because perclorate isn't allowed in Eu.

 

So what options do I still have?

 

I was thinking of maybe adding a full tablespoon of meal black powder to the center of the shell?

Edited December 1, 2015 by Stef727

[Andres1511]

Maybe pulverone instead of rice hulls, but the difference will be small.
I would go for the flash powder...

 

Or, more spiking & pasting.

Edited December 1, 2015 by Andres1511

[schroedinger]

You will need a stronger burst charge. If you don't have perc or chlorate your only way is to use a stronger bp, straight 2, 4 or 5 FA. Should do the trick.

 

Also the pattern you want to achive will be much easier to achive if you use ball shells.

Edited December 1, 2015 by schroedinger

[Stef727]

Maybe pulverone instead of rice hulls, but the difference will be small.

I would go for the flash powder...

 

Or, more spiking & pasting.

So if I use a stronger rope to spike it and add a few extra layers of pasting the break should be stronger??

[Andres1511]

So if I use a stronger rope to spike it and add a few extra layers of pasting the break should be stronger??

Yes, more confinement will result in a stronger break.

I'm a ball shell maker, so I don't know a lot about spiking. The best way to spike is a question you should ask a cylindrical specialist.

Schroedinger is right, that pattern is easier to get with a ball shell, but it is also possible with a cylindrical shell.

 

BTW: I've read so much of your posts, but just know I see your name probably comes from the schroedinger equation for orbitals in chemistry .

[Stef727]

I see your name probably comes from the schroedinger equation for orbitals in chemistry .

Actually its just my name "Stef" and some random numbers that easy to remember

Edited December 1, 2015 by Stef727

[dynomike1]

What kind of string are you using?

[Stef727]

What kind of string are you using?

It's some kind of cotton string, it's pretty strong but I can still break it with my hands if I try really hard.

Edited December 1, 2015 by Stef727

[schroedinger]

Yes it comes from there.

Stef a stronger twine won't neccesary improve your break, it also can destroy your pattern. Rather use a double strand of twine then a too string twine. What diameter does the steing you use now have. Since you can still break it by hand, it doesn't sound too wrong.

Also pasting won't improve your break much, rather use one or two turns more paper on the inner casing itself. How many turns of what paper type do you use and how is the grqin running?

[Stef727]

How many turns of what paper type do you use and how is the grain running?

I can't really describe what type of paper i'm using, but when I roll it all up the thickness of the wall is about the same as 15 sheets of A4 paper.

 

 

how is the grqin running?

I'm assuming that you meant grain.

 

So there isn't really a clear grain in my paper, the surface is like of a a normal A4 paper.

Edited December 1, 2015 by Stef727

[schroedinger]

Yes i meant grain. Then we got the first point yoj have to work on.

You either need to use jute twine (not the one from the garden store, thinner (1 mm)) and use maltese spiking or use real virgin krafft paper.

The paper you uses sounds more like the recycled paper used for covering floors or objects when painting. It is recycled and doesn't have the right tensile strenght. You will be amazed how much better the breaks get, just by using the right paper. Just using more turns of recycled paper doesn't give the same result.

The recled paper is good to use as dry wrap.

[Mumbles]

Not all paper has a visible grain. There are a couple ways to check though. Paper bends easier if the bend is aligned with the grain and opposed to across it. If you tear it, you get a pretty good idea of which direction the grain runs. If you tear parallel to the grain, it will tear pretty smoothly and go in a roughly straight line. Tearing across the grain gives a jagged edge, and often starts running. The most fool proof way in my experience is to get it damp. Cut a square out of the paper, and mark the direction of the roll, long side of the sheet, etc. Then lay it on a table or something, and lightly spray it with water. It will begin to curl. Paper absorbs water and expands in one direction faster than the other. You'll get a "U" shape or arch type shape. The grain runs down the bend like a tunnel or channel.

 

Maybe you can give us a quick run down of what you typically do. Things like number of turns of paper for the casing, what sort of disks, is your string wet or dry upon spiking, how many verticals and horizontals, number of pasted layers afterwards, etc. It will help to pin point areas for improvement. There have been a lot of good suggestions so far, but it always helps having more background.

[Stef727]

 

You either need to use jute twine

 

Is this the correct tipe of jute twine?? it's from PyroGarage, I have a spool of it but didnt use it yet.

 

http://www.pyrogarage.pl/img/other/jute_c.jpg

Not all paper has a visible grain. There are a couple ways to check though. Paper bends easier if the bend is aligned with the grain and opposed to across it. If you tear it, you get a pretty good idea of which direction the grain runs. If you tear parallel to the grain, it will tear pretty smoothly and go in a roughly straight line. Tearing across the grain gives a jagged edge, and often starts running. The most fool proof way in my experience is to get it damp. Cut a square out of the paper, and mark the direction of the roll, long side of the sheet, etc. Then lay it on a table or something, and lightly spray it with water. It will begin to curl. Paper absorbs water and expands in one direction faster than the other. You'll get a "U" shape or arch type shape. The grain runs down the bend like a tunnel or channel.

I tested it, and it all works as you explained Sooo the grain should run horizontally or vertically?

 

 

Maybe you can give us a quick run down of what you typically do. Things like number of turns of paper for the casing, what sort of disks, is your string wet or dry upon spiking, how many verticals and horizontals, number of pasted layers afterwards, etc. It will help to pin point areas for improvement. There have been a lot of good suggestions so far, but it always helps having more background.

The number of turns is normally around 8-10 (I didn't always use the same paper, but the thickness of the wall is always pretty much the same, about 15-20 A4 papers)

 

I use 2 disks on each side (on inside and one on top of the folded paper), They are made of solid cardboard about 1.2mm thick. The material is really similar to the one of this hemispheres http://i.imgur.com/fEoa2bR.png?1

 

For the spiking I use dry string, about 16 vectical and 9-10 horizontal, but here is also a photo where you can see the spiking

 

http://i.imgur.com/3cqFMN7.jpg?2

Btw this paper isn't what I use for pasting etc... it's there just on top for the nice finish.

Edited December 2, 2015 by Stef727

[schroedinger]

Yes that string is the right one for maltese spiking.

Can you tell us something about the paper you use, weight, maybe you can also tell us where you got it?

A normal 3" should have only 3 turns of virgin kraft to work. Also one other thing that is good, is using string soaked in wheat paste (best over night). It will strech a little and co tract during drying.

Your disc sound like m0they are made out of a good material and plaxed at the right points.

How do you pleat over the paper? If you just dry pleat it, only pleat 2 layers at one time. If you cut and glue 'em down, more layers can be donenin one turn. But 4 should be a max.

The grain needs to run vertical (from disc to disc).

When you measure the grain, did you tear it and found that the fibres sticking out of the paper, are all same diameter, mostly at least 1mm long and lots, whith ne real spaces between them? Only spraying with water is enough to detect the grain geometry, but you will also find a geometry in recycled paper, due to fabrication process.

 

Btw. your spiking does look good.

Edited December 1, 2015 by schroedinger

[PIL]

Yes that string is the right one for maltese spiking.

Can you tell us something about the paper you use, weight, maybe you can also tell us where you got it?

A normal 3" should have only 3 turns of virgin kraft to work. Also one other thing that is good, is using string soaked in wheat paste (best over night). It will strech a little and co tract during drying.

Your disc sound like m0they are made out of a good material and plaxed at the right points.

How do you pleat over the paper? If you just dry pleat it, only pleat 2 layers at one time. If you cut and glue 'em down, more layers can be donenin one turn. But 4 should be a max.

The grain needs to run vertical (from disc to disc).

When you measure the grain, did you tear it and found that the fibres sticking out of the paper, are all same diameter, mostly at least 1mm long and lots, whith ne real spaces between them? Only spraying with water is enough to detect the grain geometry, but you will also find a geometry in recycled paper, due to fabrication process.

 

Btw. your spiking does look good.

How to do Maltese spiking?And what's the spiking pattern?Covering the shell with jute twine without too much build up around the spollette seems difficult.

[OblivionFall]

I admire the diagrams and pictures you provided for us

 

More pasting. Not goanna tell you to use flash, but you don't seem like the type of guy to get hurt with it.

 

Try more pasting and straight BP in the center of the shell (a bit more powerful than rice hulls.)

 

Yeah perchlorate isn't allowed in the EU. But you can still get it from places online.

[Stef727]

I admire the diagrams and pictures you provided for us

 

More pasting. Not goanna tell you to use flash, but you don't seem like the type of guy to get hurt with it.

 

Try more pasting and straight BP in the center of the shell (a bit more powerful than rice hulls.)

 

Yeah perchlorate isn't allowed in the EU. But you can still get it from places online.

I have already made kno3 flash, but after doing some tests and seeing that it was relatively easy to set off with the hammer, and how powerful it was, I kinda decided to not use it in shells.

 

I'm not really that scared of flash itself (because I would only do 10g max at once) than I am of it as a source of ignition once it's inside the shell, when for example I am spiking the shell, if that were to set off.... in my hands.

[schroedinger]

Stef once the flash is inside the shell, there is no real risk. Nothing should be able to put any impact onto it inside. A shell with flash got no problems surviving the hit from the lift charge in a mortar.

 

The maltese spiking is very easy, first you wrap your shell in jute twine, horizontally around the shell. String touching string (if you imagine your shell standing on an enddisc) after tjat the same is done vertically.

[Mumbles]

Yes that string is the right one for maltese spiking.

....

 

 

Since when did the maltese switch over to using thick garden twine which has been dyed? The correct stuff is less that 1mm thick, and has a break strength of about 10lbs. Maybe the dyed stuff reduces the strength so much during the bleaching process that it accidentally works.

[OblivionFall]

I have already made kno3 flash, but after doing some tests and seeing that it was relatively easy to set off with the hammer, and how powerful it was, I kinda decided to not use it in shells.

 

I'm not really that scared of flash itself (because I would only do 10g max at once) than I am of it as a source of ignition once it's inside the shell, when for example I am spiking the shell, if that were to set off.... in my hands.

You're right about it being easy to set off with a hammer. It only really takes a good whack. My reasoning is that if it ignites in the open I get burned but it won't make a huge BOOM. (Unless it's in a 50g batch or more.)

 

But yes you have a very valid point. When I get into shells again I'm not sure I will use flash in them. I just can't help but think about all that pressure and the hard BP granules working up against the flash. Maybe I'll make a semi weak container for the flash in the center of the shell so it doesn't get smooshed. Hard decision.

[zan89]

My shells breaks havent been good laitly...

This is how I want them to look like how my breaks are right now.

http://i.imgur.com/CuF4pYp.png?1

 

 

 

I'm still scared of of using kno3 flash and I can't get whistle because perclorate isn't allowed in Eu.

 

 

Če rabiš kakšno pomoč le povej.

[FlaMtnBkr]

I'm not a big cylinder shell maker either but there are a few things you can try.

 

Have you tried pasting your string before spiking and using a spiking horse to get it tight? The paste will help it slide when pulling on it and usually makes the string shrink a little when it dries which also helps to tighten it up. Paste will give paper a little strength but also is supposed to help the paper break in smaller pieces instead of tearing in one place if you ever want to try pasting the paper (I think I read you're not). You can still do a dry wrap on the outside to keep things clean and help fire proof it.

 

But the big thing you can try is a trick to increase burst strength. Since you don't want to use flash, but have made it, I assume you have some dark aluminum on hand. You can take your BP burst and give it a light dusting of aluminum. Put the BP in a bag with around 3-4% aluminum and shake it up to coat the granules. The type of aluminum will change the amount that will stick but you just want a light coat and don't want to add so much that it doesn't stick and there is extra in the bottom that isn't sticking. It won't hurt to do so but is wasteful and you don't need that much.

 

Since there is no oxidizer mixed in the aluminum it is not sensitive like flash. But when the BP burns the aluminum also burns which really increases the burning temperature which increases pressure and greatly speeds up the burn rate of the BP which increases the burst strength.

 

It can actually make a shell sound like it's loaded with flash and almost sound like a salute if you use good BP, a dark small micron aluminum, and good confinement. So be aware that you might be making more noise as well. It will also increase the light output of the break which some people don't like but if you only use a small amount it shouldn't be as much light as a healthy boost of flash. At least it doesn't look as bright to me but I haven't tried them side by side. If you try it let us know what you think.

[Ubehage]

My shells breaks havent been good laitly...

This is how I want them to look like how my breaks are right now.

http://i.imgur.com/CuF4pYp.png?1

 

My shells are 3" canisters, I use black powder rice hulls for the burst.

 

I'm still scared of of using kno3 flash and I can't get whistle because perclorate isn't allowed in Eu.

 

So what options do I still have?

 

I was thinking of maybe adding a full tablespoon of meal black powder to the center of the shell?

I have been watching Ned Gorski make a 3" shell, where he talked about "..for a shell this size, I want as much black powder in there as possible. No rice hulls."

However, I don't think that BP makes a good break in this size, unless you spike it VERY good.

 

Maybe try some BP/whistle mix, like the one they call Spanish Booster. I'm trying this for my next shell.

[Stef727]

Thank you very much to all of you guys for all the help and tips

 

I did everything as you guys said and there is definitely improvement

 

 

Btw I put a bit to much lift into it (48g lift shell was 245g, will use 40g next time) Got new charcoal and it appears to be better than my own.

 

ps Set video to 720p/1080p or you won't be able to see much.

 

http://i.imgur.com/tZUITUT.jpg?1

The shell in the video

Edited December 3, 2015 by Stef727

[schroedinger]

Thats a nice shell. Can you make some pictures how you constructed that shell?

Also for lift, you should be able to cut it back to 24 g. If not, then you have to work on your bp.