5" 5-Timed Spider Construction

[nater]

I am finally able to finish the 5 timed spider I intended on firing at a shoot last fall. This shell will have two breaks. The first will open dark with 4 1.75" inserts with #1 - #4 (1/4" - 1") timing on the spolettes and spider web stars. The second break is a Sfera with 1" Spider Web comets.

 

Starting with the bottom break, the spolette was pressed with 1 1/4" of powder and inserted in an end disc. My former does not have a recess large enough for the flash bag, so I had to fill that after the casing was rolled. That was really awkward, so I will drill out the former before the next one.

 

The casing was rolled with 5 turns of 70 lb Kraft, with the ends pleated over the end disc. The glue is not necessary, but I think it helps hold the first layer of pleats down while you get started. Once all the paper is folded down, use a mallet to set the folds in place. The flash bag was then filled with the end folded and glued shut.

 

 

[Wiley]

Oh neat! I'm hoping to work on some much smaller spiderweb shells soon. Would you mind sharing the composition and amount of comp you used in that second break?

[nater]

I believe the formula I used is public. If not, someone please let me know.

 

Spiderweb Stars - Mike Swisher, I believe he got the formula from Jerry Taylor.

 

Potassium Nitrate: 55

Airfloat Charcoal: 27.5

Sulfur: 10.7

Lampblack: 0.8

Dextrin: 6

 

Each 1" comet weighs 15.6g. 4 rings of 10 comets = 40 comets = 624g

 

Today the bottom break was assembled. I needed a few turns of a chipboard liner to get the comets to fit nice and tight. Sawdust or fine polverone is rammed in the space between the comets and the inside wall of the shell to lock them into place and ensure the shell is nice and firm. I could really feel the shell stiffen up as I worked on this step. Once the comets were all in place, the inside of the shell is filled with polverone. A solid end disc was set into place and the casing folded around it.

 

[marks265]

Agreed, it is said glue is not needed when pleating down the paper. But I like to put down some glue for each layer that I pleat down. I believe it firms up the layers of pleating and makes the shell much firmer. Plus it is an additional help when stacking multi-breaks. I know what you mean about the paper not sticking to the end disc. I've lived that moment too.

[nater]

I applied the vertical spiking with pasted hemp twine. I still have not got the hang of off-center spiking. Right now I am looking at the build up around the spolette and wondering how I am going to get the first break to sit on top.

 

[marks265]

Off center spiking and not so many turns around the spolette would help a lot. That does look like the twine is pretty high off the shell. I would practice stringing a shell a few times before adding paste. Usually when stringing a shell off center I go to the left of center when going across the bottom and then to the right of the spolette when going over the top. It is a pain to unravel and restring a shell but as you can see the end result is much more appreciated.

[nater]

That was the second time I spiked that shell, probably should have gone for a third. Oh well, not a big deal anyway. If the gap is too much to pad with newspaper, I have a few options. With 1 1/4" charge in the spolette, I can finish it as a single break if I have to. I could also punch a larger hole in an end disc to go over all that twine.

[Wiley]

What flavor and how much flash did you use in the break?

[nater]

I was given some ideas to proceed with the second break, so stay tuned.

 

Wiley, the flash bag contains 11g of standard 70/30 flash. This also comes straight from articles linked above. The table in the text recommends 3/8 oz of ordinary flash powder for a 5" shell. That comes to 10.6g and I just rounded up.

[Wiley]

Not seeing the links, nater. Since you're already marking your end disks, off center spiking will be a snap! When you start, just move the string one mark to the right of "straight across" and when you get to the bottom, move the string one mark to the left of "straight across." Keep that pattern up and it should come out real nice

[nater]

I guess it was the thread on the 4" where I mentioned "Traditional Cylinder Shell Construction Parts 1&2 as contained in Pyrotechnica IX and XI. AKA: The Fulcanelli Papers. I have been following those methods as I learn how to build these shells.

 

I did mark out the end discs, but I must get off somewhere while spiking. I have ended up with some pretty interesting patterns. More practice just means more shells to send up.

[Wiley]

Since I only work with one size I realized I didn't even have to mark my disks after making a few dozen. It still helps on the long mulibreaks though, since all that length makes it easy to deviate a bit and goof up the pattern.

[WonderBoy]

Nate, are you turning 90 degrees on the spolette with each vertical, or using another method? Also, did you use a tube or piece of wood to push the twine towards the disk after you were done?

 

WB

Edited May 25, 2015 by WonderBoy

[nater]

Yes, I turned 90 degrees around the spolette with each vertical pass. I did not have a tube or pipe handy that would fit around the spolette. I tried to mash the twine down with a mallet without much luck.

 

I will try some wadding in between the breaks and work more on this tomorrow. I choose a spider shell because everything is easy to make and uses inexpensive chemicals.

[Mumbles]

These are some of my favorite shells. Just a couple of tips for the future. On 5 timed spiders, I like to start with a #2 timing. These things normally have enough airtime to comfortably start there, and allow the breaks to spread a little more. One 9 timed spiders you really do need to get them going. Up until about a month before my accident, I never had a former that allowed for flash bags either. 5" shells are big enough to add the spolette and flash bag after the casing is made, and this works well if the casing is supported on a short piece of tubing to prevent the end disks from sliding around or loosening the pleats. Alternatively, I usually rolled my casings on a 4" HDPE mortar which comfortably supported the flashbag size. They can make a vacuum when trying to remove the casing though.

 

Off center spiking is easy once you get the hang of it. There are a few different ways to achieve essentially the same pattern. Tom R. has a special pattern that I don't particularly understand that works differently than how I do it.

 

If you number the spaces around the end disk 1 through 24 it's easy to follow along, or at least get the idea. 1 and 13 should be exactly 180 degrees apart from each other, and is typically where you'd bring the string up in a traditional pattern. When you do it off center as you cross the bottom of the shell you want the vertical to come up on either 12 or 14. After this it's just every other. If you went 14, then you go 3, then 16, then 5, etc. If you went 12, then you go 22, then 10, then 20, etc. The way you start is just personal preference.

 

[nater]

Thanks for posting that template, Mumbles. I will keep those pointers in mind for the next one too. I am determined to get these shells down.

 

I decided to proceed with the first break. Each insert has 3 rings of 7 1/2" stars stacked as a Sfera shell and filled with 3fg type powder. Each of these stars weighs 2.3 grams. When I attempt a 9 timed Spider, I will need 400 grams of comp for the first break with 8 inserts.

A while back, another respected builder mentioned that he thought the rinfasciature method was especially well suited for insert shells. Keeping that in mind, I figured I would give it a shot.

Each insert was spiked with 8 vertical strands of pasted twine followed by the horizontal strands, wrapped with 2 turns of 30 lb paper and spiked again. I made sure the spolettes were well sealed with hide glue. A final wrap was put in place with the overlapping end wrapped around the spolettes and held in place with 4 verticals of thin twine. The finished inserts are just too large for a consumer mortar. If I had a 2" mortar handy, I bet they would just fit.

 

Now for the part that gives me some concern - joining the two breaks. The spolette on the bottom break was prepared in the normal fashion. I then rolled the casing for the 1st break and assembled it on top of the second. Because of the large build up of string, I filled the gap between the breaks with rolled up newspaper and some wraps of hemp. The insert shells were placed in a ring, the empty spaces around the insert and the cavity in the middle filled with polverone. The prepared spolettes are pointing up with more polverone around them to ensure everything takes fire. Finally, an end disc with the initial spolette charged with 1" of Meal was set into place.

 

 

You will notice more space in between the breaks that needs to be filled. I thought it might compress as the first break was closed, so it was not completely solid. I was happy that it feels solid and nothing appeared to settle any further when I tapped the first break with a mallet. I will have to finish filling in that space and ensure the breaks remain straight while spiking the shell as the next step.

Edited June 6, 2015 by nater

[WonderBoy]

Nice man! Always love seeing cylinders being build.

 

The spiking on the rin on your inserts seems a bit light for my taste. For an insert of that size I usually spike it, wrap it, do 8 longitudinals, then wind the twine around the spolette/timefuse covering most of it. I usually use 1mm hemp or similar so I can use pretty good pressure while wrapping around the spolette without snapping the twine.

 

I'd probably try and compress that sucker as much as possible before spiking, sit on it even, or atleast press on it real hard. How did you "prime" your spolette, and how far does it go into the preceding break?

 

 

WB

 

edit: Wait, did I missread how you rin'd your inserts? I read it again, and it sounds like maybe you spiked it both longitudinally and circumferentially twice with an intermediate wrap, then did an additional wrap of paper and 4 more longitudinals? If so, then my response is the opposite, I think your spiking si a bit heavy. I usually only do a second spiking of longitudinals, still wrapping quite a bit of twine around the paper that is around the spolette. I've got some photos around here somewhere.

Edited June 6, 2015 by WonderBoy

[nater]

Each wrap on my inserts has 8 verticals plus the horizontal wraps. The 4 strands visible is a third wrap of light Kraft folded and held on with the thin string. I was not sure if that step was necessary on inserts or not. Ned pictured something similar on a few 4" shells he built, so I just followed his pictures.

 

The spolette are all prepared to take fire by scratching the surface, a dab of BP / NC slurry on half the exposed core and strands of black match folded like rabbit ears and tied into place. The initial spolette protrudes into the cavity of the 1st break about 3/4 inch plus the nosing. With all the polverone, there should be enough fire to get everything going. This method has worked for me on smaller shells without failure.

 

I could stick the shell in my press. I think I have bar clamps long enough for it too. I do want to make sure it is solid enough that it will not compress with the lift. It would be disappointing to fall apart on the way up or flowerpot.

[nater]

Both breaks were spiked together and the circumferential spiking applied. After double checking the fit in the mortar, it will be close but will fit after the paste wrap is applied. I will use thinner twine in the future.

The space between the breaks was filled solid with rolled up newspaper, wraps of twine and he in place with a band of pasted paper. I did use the press to make sure everything was solid before the spiking was applied. I think I will work on building a jig to he the breaks together like what was posted on Passfire.

Here is the first few turns of the final paste wrap drying. One those are dried, more layers will be applied for a total of 5 turns of 60lb Kraft. The shell will be lifted and leadered in the normal way and is to be fired on Saturday.

 

The final paste wrap layers were applied and are now fully dry. The completed shell weighs in at 5 lbs 1.5 oz. The only thing left is to apply the lift wrap, lift charge and leaders.

Edited June 12, 2015 by nater

[nater]

Here is the finished shell, ready for a match and to be dropped.

 

 

https://www.youtube.com/watch?v=3otMquy_bFk

[Wiley]

Well done! The size of a well-built spiderweb break never fails to amaze me.

[braddsn]

Hell yes man!! What a cool shell! You nailed it

[Sparx88]

Nice build and very helpful pics. I'm just getting around to making can shells this year so I be needing all the info. Thanks for taking the time to post this.

[nater]

Thanks guys. If anyone is inspired to make a multibreak, learn from some of my headaches on this build. Use thin twine and take care to avoid too much build up on the breaks so they join together nicely.

 

I will be starting on a 5" 9-timed spider next as well as a 4" 2 break with bottom shot. I think I will use 3/8" stars in the insert shells instead of 1/2" for fuller breaks with less droop. Still on deck is a 4" 3 break - RWB with bottom shot for PGI 2016.

Edited June 14, 2015 by nater

[coogan1997]

PGI 2016?