3" ball shell construction?

[bob]

I made it just like a 1/4 inch ID nozzle less and core less black powder rocket

I'm making a nother one as soon as I get some info from a guy that says he has some info on spollettes

Thanks

Edited May 19, 2012 by bob

[bob]

I shot of a shell last night, the shell was just like the last one 5 to 1 grass seed

it had 10 layers of pasting and some spiking

I used black poplar milled wetted and put through a screen I made sure that it was bone dry

and the same thing happend the spollette burnt 3/8 of a inch in and stoped

bob

[bob]

Here is a picture of my last shell it light! but broke in a fifth of a circle

bob

[Mumbles]

It sounds like you need to make some test spolettes, and burn them on the ground to figure out what the problem is. I've never heard of this happening before.

[bob]

I've lit 3 spollettes on the ground and all of them burnt fine

but I think I know what the problem was number one my spollette was sticking out to much so it could nail the side of the mortar and cause the black powder to fall out number two my shell was too snug

these things were suggested to me on pyro guide forum and after changing them as you can see it lit

buss thought it might be my stars not lighting but I don't think this was it cause I made a star gun last night and 10 out of 10 stars lit

bob

[bob]

Here are some pictures of how I make my shells and of my black powder burning

1 my spollette is hot glued in and the end of it is in the senter of the shell

2 stars a placed in the heim

3 my paper placed over the stars

4 here you can see my burst it's black power on grass seed in a 1 to 5 ratio (no booster)

5 snaped the two halves together

6 I have taped it using paper tape

7 it is now spiked

8 piece of paper that I have aplide wheat past onto

I will post a picture of the end product soon

9 here is my black powder burning

Thanks

Edited June 2, 2012 by bob

[Mumbles]

One note I should mention. You'll want to fill the empty space of your spolette with black match. This helps to transfer fire from the burning column of BP into the shell. After it is filled with blackmatch, you generally put a paper nosing on it. About 2 wraps of thin kraft paper glued only where it touches the tube,then tie the paper around the blackmatch and trim everything appropriately. Poke a small hole in the paper itself below where the paper is tied, but above where it is glued. This helps to prevent a vacuum being formed and keeps the fire from being "sucked out of the shell).

 

You can see some spolettes loaded with blackmatch here: http://www.amateurpyro.com/forums/gallery/image/440-loaded-spolettesjpg/

 

You can see one (sort of out of focus) that has been nosed. You can't really make out the hole, but it's there. http://www.amateurpyro.com/forums/gallery/image/437-loaded-comets-2jpg/

[bob]

I did fill it with grated black powder and one piece of black match but I did not put a con on it

Thanks

[bob]

I shot of a shell last night

3 inch round 1/4 inch TT stars and ten layers of pasting using wheat past no booster just black powder on grass seed in a 5 to 1 ratio

the picture is not great

but it broke simeller to my last one

I"m going to use more lift on my next one (it was coming done when it broke) I used more lift then my last shell and it did brake a little better it more looks like it has a bad lope side then a fifth of a circle like my last shell

bob

[pyrogeorge]

Usefull Video

http://www.youtube.com/watch?v=Jyb2MD7uMPU&feature=plcp

 

http://www.youtube.com/watch?v=MG4830y5FE8&feature=plcp

[dan999ification]

i would say that the shells are breaking lop sided because of the spiking, the shells are breaking at segments rather than breaking evenly, the solution is no spiking but you can make extra strength by using more layers of thinner paper, or spiking with thinner string so it breaks easier helping with symetry, spiking is not normally used on ball shells mainly because it can ruin round breaks.

 

10 layers of 100 gsm with 1 to 1 bp on grass seed gives nice symetrical breaks for me on 3" balls.

you wont regret getting some proper time fuse either.

 

 

 

dan.

[Potassiumchlorate]

Speaking of spolettes: I have these plastic spolettes from FREAKYDUTCHMEN. If I ram them with meal D, they burn for about 4 seconds. Doesn't seem like they need any fuses in them, though(?) They are 6mm inner diameter 10mm outer diameter and 25mm long.

 

These are probably too big for 3", though the subject is interesting. I haven't tested them in a shell yet.

[bob]

I'm not using string for my spiking I'm using packijing tape

how thin of paper would you use? I'm using grocery bags

why would those spoolletts be to big my'n are 20 mm OD and 6 mm ID and 55mm long

your powder must be a lot slower then my'n cause with 45 mm I get about 3.2 seconds

dan are you using any booster also I've never heard of a one to one that does not seem like much powder at all

Thanks

[dan999ification]

I'm not using string for my spiking I'm using packijing tape

how thin of paper would you use? I'm using grocery bags

why would those spoolletts be to big my'n are 20 mm OD and 6 mm ID and 55mm long

your powder must be a lot slower then my'n cause with 45 mm I get about 3.2 seconds

dan are you using any booster also I've never heard of a one to one that does not seem like much powder at all

Thanks

 

 

rarely ever boost, the one to one thing was discussed on the ukps forum with mixed feelings, my opinion is that the shell opens before the bp is all consumed the only thing to get harder breaks is better confinement ,faster burning powder[not how much] or both unless you boost it.

 

 

dan.

[Potassiumchlorate]

I used my old BP, which is made with BBQ charcoal. It also burns slower the harder it is rammed. I ram with all my might, since any loose powder might cause a flowerpot.

 

About the 1:1 ratio: Dr. Shimizu himself recommended a 52:48 powder/carrier ratio from and including 4". For 3" he reccomended 80:20, thus 4:1, although many people here use 5:1 or more, even if they mostly use BP and not H3 or KP.

[Mumbles]

The roughly 1:1 ratio given by Shimizu is for cotton seed, not rice hulls. Even then it's only for larger shells. For shells 6" and less, he still is recommending 1.3-1.4 to 1.

[bob]

it stoped raining last night so I got to shoot my shell

only diffrens was the timing and it was quite abite better athough it was coming doen when it went of so the next one should be better.

bob

[Potassiumchlorate]

The roughly 1:1 ratio given by Shimizu is for cotton seed, not rice hulls. Even then it's only for larger shells. For shells 6" and less, he still is recommending 1.3-1.4 to 1.

 

1.4 to 1 seems pretty sufficient if using H3, though. By the way, I have used H3 on cotton seed 52:48 in 6" with good results, except for in my two 6" with 20mm barium chlorate stars, but that was probably due to the stars being too heavy and also too slowly burning, since it was the 9:1 barium chlorate shellac composition without any potassium chlorate to speed the burning up.

[dan999ification]

yes cotton seeds are much smaller than rice hulls so less bp in a shell on hulls, grass seed is similar in size to cotton seed and works fine for me, without rolling it on you cant get much more than equal weight of bp on grass seed as they dont have a hollow hull.

 

you probably need much more on hulls to achieve a similar g per cc ratio.

 

 

 

dan.

 

edit: nice shell, ditch the tape save yourself the learning curve

Edited June 12, 2012 by dan999ification

[dagabu]

yes cotton seeds are much smaller than rice hulls so less bp in a shell on hulls, grass seed is similar in size to cotton seed and works fine for me, without rolling it on you cant get much more than equal weight of bp on grass seed as they dont have a hollow hull.

 

you probably need much more on hulls to achieve a similar g per cc ratio.

 

 

 

dan.

 

edit: nice shell, ditch the tape save yourself the learning curve

 

Huh? Not mine, my cotton seed is a good 3/16" and with BP, it is about 1/4", twice as large as my coated rice hulls.

 

-dag

[bob]

I'm making one more shell with tape and then the next one will be with out tape so do you think I should try it with say 12 layers and no tape just to make up for the tape?

I"m hopping that the timing will make my next one better I should be able to shoot it tomory night if it does not rain

oh and I'm using my star roller to coat my grass seed I want to make a bigger one though cause I can only make about 1.3 lbs at a time in the one I have now

Thanks

[dagabu]

I'm making one more shell with tape and then the next one will be with out tape so do you think I should try it with say 12 layers and no tape just to make up for the tape?

I"m hopping that the timing will make my next one better I should be able to shoot it tomory night if it does not rain

oh and I'm using my star roller to coat my grass seed I want to make a bigger one though cause I can only make about 1.3 lbs at a time in the one I have now

Thanks

 

Er, what tape are we talking about?

 

-dag

[bob]

I"m talking about packaging tape some other people told me to use it to spike round shells instead of string

any way I shot of that shell last night and it flower potted were is a picture of it

I don't know what I didn't do right cause it was a loose fit and I have not had a flower pot since I've used hot glue

bob

[dagabu]

I"m talking about packaging tape some other people told me to use it to spike round shells instead of string

any way I shot of that shell last night and it flower potted were is a picture of it

I don't know what I didn't do right cause it was a loose fit and I have not had a flower pot since I've used hot glue

bob

 

I'm sorry Bob. I don't think I have ever seen a ball shell spiked with string and only a few nice looking ball shells spiked with packaging tape. I use kraft water activated tape with no reinforcing even on plastic shells for good breaks.

 

Whats the hot glue used for, the time fuse?

 

-dag

[Potassiumchlorate]

Huh? Not mine, my cotton seed is a good 3/16" and with BP, it is about 1/4", twice as large as my coated rice hulls.

 

-dag

 

Mine too. He must be confusing it with something else.