to spike or not to spike

[pyrochris732]

Guys, do you think i'll see a difference in the break if i spike my small canister shells with cotton string? Any methods you recommend?

 

The can shells are made of plastic, do you think spiking plus wrapping them in some gummed kraft paper will give me a nicer break?

 

Chris

[dagabu]

With plastic canisters, I like strapping tape, one layer in both directions for a good break.

 

D

[gordohigh]

I agree with the strapping tape, and also glue the lid on properly. If you make some canister shells out of paper, spike them with a hemp or jute type string, the brown color stuff you find at home depot or lowes because cotton isn't very strong. Small shells are hard to get a symetrical break unless well taped/spiked and usually require a bit of whistle mix or a nitrate based flash. You could use a regular flash but the nitrate and whistle are a slight bit safer but still require much respect.

[dagabu]

Sorry Grodo, gotta disagree with the cotton statement. The Uline cotton string (8 & 12 strand) is very strong and pasts well. it is also pretty inexpensive.

[Bonny]

I also use cotton string on my shells...not sure how many strands though, but it soaks up the glue/paste well and dries hard. IF you are going to use jute, be sure it's not the crappy green garden stuff as it's very weak.

[Mumbles]

I used cotton for a very long time as well. I've switched to hemp mostly now. It doesn't stretch as much, and I get seemingly harder breaks. Cotton absorbs paste much better, so when it dries it really bites into the paper well. The cotton is soaked ahead of time of course.

 

I currently only use cotton when spiking together several breaks from a multibreak shell. It's partly from expense, but I also like it's stretching properties here. When I do the horizontal spikings over the joints, it just seems to lay down much better. I know I'll always have solid fire-proof seals.

[gordohigh]

Yes, I guess the cotton will soak up the pasting material better, I was just taught the use of hemp/jute from an old timer so I guess it's personal preference when it comes to your individual string type.

 

The spiking of paper canister shells however is still a good thing to do though regardless of which of the string types you use. I'm always happy to have other opinions on these types of things because I learn something new everytime

[dagabu]

That being said, I still use 20# and 40# Hemp for spiking but it is made very unevenly and can cause some problems. I will go to all cotton once I run out of the Hemp.

[Ventsi]

Dave I use 20# hemp now and I must say its very nice, its thin, bites into the paper well and doesn't stretch. But as you said the off the shelf brands aren't super high quality which can get annoying, I had the string snap on me when I was spiking some 3" cans. I'm pretty sure I was maintaining a consistent tension too...

[dagabu]

Speaking of spiking, I was shown a video of an Italian fireworks canister shell being spiked where a chair was used to provide the tension on the string, no horse needed, no posts, just a chair and a place to direct the string back. I use a piece of cardboard to protect my butt and an eyelet in a vice to return the string.

 

This is my new preferred method and I will not go back to pins or a horse.

 

http://pyrotechnics.no-ip.org/files/spiking%20chair.wmv

[dagabu]

Chris,

 

Are you using flash to break them? I conferred with a guy that has been making all small shells for 40 plus years and he told me that you probably were not breaking them properly by using the wrong stuff to break them. His suggestion was to use 2 grams of flash in a small cannula (flash bag) that is tied off on both ends one with the time fuse the other just closed off and centered in the shell with pulverone or coated hulls around it.

 

I am told that small shells need a hard break (not too hard) to shatter the plastic shell. Spiking is not needed according to my source.