Issue with sponge TI and burst?

[Richtee]

Made up a nice .75” shell with Mg/chlorate burst and added in a few grams of Ti. 2 grams of BP lift.

 

BAM! there went that mortar tube! Not much fun dodging glowing TI either.

 

Could the roughness of the TI cause this? I DOUBT the shell failed.. it was damn solid.

 

Should one use a bag for touchy bursts when adding the TI, not just dumping it all together?

 

I was bummed..was a really nice mortar I rolled with phenolic impregnated kraft... sigh.

Edited January 18, 2023 by Richtee

[Crazy Swede]

Why would anyone use chlorate burst with magnesium???

That is asking for trouble from the beginning and adding gritty material makes it even worse!

[kingkama]

Made up a nice .75” shell with Mg/chlorate burst and added in a few grams of Ti. 2 grams of BP lift.

 

BAM! there went that mortar tube! Not much fun dodging glowing TI either.

 

Could the roughness of the TI cause this? I DOUBT the shell failed.. it was damn solid.

 

Should one use a bag for touchy bursts when adding the TI, not just dumping it all together?

 

I was bummed..was a really nice mortar I rolled with phenolic impregnated kraft... sigh.

Usually flowerpotting heppens when shell have a structural failure in the case or in the spolette, breaking charge is inside so virtually protected from fire.

I used to make this kind of micro shell to remake the chinese cake insert, but never use magnesium, cause alone is less effective and lead to a less sharp report. How you did te spolette assembly, how made upper and lower side fireproof? Let us know better. IMO the titanium can't change shell behavior.

[Richtee]

Why would anyone use chlorate burst with magnesium???

That is asking for trouble from the beginning and adding gritty material makes it even worse!

I kinda figured this is what happened. Only reason is I had it on hand, and am kinda reducing inventory. Especially the chlorate, which I kinda bought on a whim. Had the idea of making torpedos, but decided I like my fingers as they are.

 

And I’m pretty sure the shell did NOT fail. And I do not use spolettes, I use visco with a wound and glued paper collar, slit the end and primed with NC and fine BP.

[Powderman]

I would try how much does it take to set off a pinch of used composition with hammer. If it goes bang with gentle tap You will have a clue...

[kingkama]

[quote name="Richtee" post="195286" timestamp="16741

 

And Im pretty sure the shell did NOT fail. And I do not use spolettes, I use visco with a wound and glued paper collar, slit the end and primed with NC and fine BP.

 

IMO the problem Is in the paper collar around the visco, that could caused the failure, I solved this probability by creating a recess of a few millimeters in the casing, piercing the already closed mini Shelley and inserting the visco, then filling the recess And creating a collar around the fuse. Some time i experienced that Visco burn all at once when the Powder Is hot and visco a bit deteriorate.

[cmjlab]

I would try how much does it take to set off a pinch of used composition with hammer. If it goes bang with gentle tap You will have a clue...

I'd 2nd this opinion (chlorate and magnesium sensitivity to friction, and setback from lift charge)

 

As for using up the chlorate in a useful for small shells manner, did you consider making H3 burst (surely you have charcoal on hand, and it doesn't have to be your hottest one)? I've used H3 made with mixed hardwood charcoal in small shells / shell of shell inserts that I didn't want to use flash in, but wanted something a bit stronger than B.P. to make up for a few less paste wrap layers.

Edited January 19, 2023 by cmjlab

[cmjlab]

What size stars are you using, and are you just getting a small splatter of coloring (barely enough to make out a color) or more than that?

 

Ive been curious how some of the better shell of shell or snail shell makers get a better star density (is it slightly smaller stars with a bright comp? Or is it that larger shells allow for larger inserts, more stars, better density?)

 

I've also never cared for fumbling around with small shells, especially for inserts. All that work, and less than satisfactory result! (My results anyways, I can't speak for anyone else's)

[Richtee]

Eh.. I’m just gonna assume I smacked a touchy mixture too hard in the gun. Won’t be using that anymore. H3’s an option. I could do whistle as well.

 

Not much ya can do with “stars”. well, I can’t anyway. I’ve used some dragon eggs... they are pretty cool, and do not have to be big to “work”.

 

Sponge Ti is impressive tho.. even in 1-2 gram amounts. Sure, no color but it is pretty.

 

And... I always wrap a “flashing” around the glued in visco/collar, and glue fillet the base/entry point.

[cmjlab]

Not much ya can do with stars. well, I cant anyway. Ive used some dragon eggs... they are pretty cool, and do not have to be big to work.

Okay, thanks anyway. I'm always trying to figure out how to make better looking inserts. I probably ought to work on getting proficient at timing of inserts instead. I had pretty good luck with a couple 4" comet to report shells I posted video of here, not long ago. That timing came out almost perfect, except for the bottom shot going to quickly after.

 

I am finishing up 400 homemade tubes for for making beraq. Since I've cracked the code on simultaneous timing, I'd like to try rings of reports next. I've seen some ugly timing in otherwise nice shells, so I hope to avoid that!

 

I'll share of course once I get my inserts completed.

[Mumbles]

I'd tend to lean toward the sensitivity as a likely root cause for this as well. Chlorate + Mg + Ti are three steps toward higher sensitivities.

 

I've heard stories from very experienced people in pyrotechnics who were around before the widescale adoption of perchlorates. They'd tell me that one "feature" of chlorate flash bottom shots is that in the event that a bottom shot or salute shell didn't have the fuse light or went out, that it'd often go off on it's own upon striking the earth. I suspect there was probably sulfur in the mix often, which might have assisted. Whether this is a good thing or a bad thing probably depends on how close it landed to you. There wasn't a fear of having to find live shells in the field as often at least.

[Richtee]

There wasn't a fear of having to find live shells in the field as often at least.

I guess there is that Mumbles

Edited February 19, 2023 by Richtee