Ignition-issues

[enanthate]

Hey guys,
Seeking advice as I'm becoming more frustrated.
Had a break from the hobby the last half a year or so, my last shell was a very successful 6". Fired a couple of 3" and one 4" today, only worried about the wind and size of my break. These were the least of my problems, as the stars didn't even ignite. I'm quite certain I've done everything pretty much by the book, so will throw out some details here, hoping that someone can point out my misstakes. Here goes, sorry for all the text;

I mill my BP, both for lift and break. Lift is decent, good enough. They also break nice and hard.
My bp:rh ratio is not the best, putting 100g milled bp on ~30g dry hulls (wetted in the process, of course). This to save millingtime and costs. Would this cause big problems? My successful 6" had 100g bp on 50g hulls, so I assumed the ratio is not critical. Will post the video in an hour or so.

Stars were parlonbound, with 30%mgal. Primed with pinball, then bp +5% si (with a 50-50 mix of both in between). A 100g batch is primed with about 10-15g of each powder. Not enough prime?

Stars are filled around the walls, covered with a very thin tissuepaper before filling the shells with hulls.
The 4" had 3g FP.
3" had 90% BPRH, 10%KPRH.
All shells pasted with 5-7 layers (x2, 3-strip-method).

The 4" had a few ralph's glitter #1, these ignited but was blown to dust. Guess my dextrin is bad. These were pumped, with a relatively large amount of water/alc 75/25, about 15% by weight. It felt very dry and didnt feel right, but I guess that's how it is when pumping your first batch of stars. I left it for 20minutes to activate the dextrin before pumping.


Gotta mention that there were quite alot of different star-sizes and colors, from 3mm to 16mm. An average of around 100 stars in each shell, with an average of 3-5% ignition?

I really don't know what the problem is, but I suspect that it's a combination of prime and not enough heat when the shell breaks. Might slower BP on hulls be helpful, or make it worse? I've seen large shells with non-milled breakcharge, but that might not work on 3" and 4".

These are the details I can think of as I'm sitting here, please ask if anything is left out.
Really appreciate some further advice, thanks in advance.

Stay safe!
enan

Edited October 10, 2014 by enanthate

[enanthate]

Video of my last 6". Barely made the video, sorry for poor quality and filming. You get the idea from it though.

http://youtu.be/in1pkFtgCzk?list=UUXBV6kjy7RhE_vtPvNgSucw

[dynomike1]

Sorry

Edited October 11, 2014 by dynomike1

[enanthate]

For what it's worth, after checking the videos from yesterday carefully it seems that the prime does ignite, but it doesn't ignite the star. So, either the pinballprime is not good enough, or I'm doing it wrong. Got some pine charcoal of extremely variable meshsize, leaving alot of #10-50 powder in the bowl after priming. This might have ruined my pinballprime.

Remaking some now, milling the charcoal to 100% airfloat, and trying to prime with pure bp + 10% si and 5% german dark. New dextrin is also made, hopefully this will make the next stars "hard as rocks", cause mine certainly are not.

[dagabu]

You may want to try step priming then. That helped me with an AP red I did some years back. Lots of metals made it hard to light at shell break speeds, the step prime gave it more time away from the shell to light.

[FlaMtnBkr]

I would suspect something to do with the prime. Maybe try something else. Pinball can light stuff that is hard to light but needs a prime itself because out can be hard to light.

 

The monocopa prime from the Spanish article that was published by a member seems to be working well for a lot of people.

[pyroMIKE]

your BP coated rice hulls are a 2:1 ratio (too low in my opinion)..Good, I mean good BPCRH is 7:1..That would be much hotter than 2:1. Here's a pic of my 7:1 BP hulls.

http://i288.photobucket.com/albums/ll194/mkillian_2008/photobucket-22040-1412539831633_zpsc2359afa.jpg

[enanthate]

Thanks Mike, I also suspected it would have something to do with that. Will try a thicker mix on my next shells.

Flamtnbkr, you are probably right, like i said i could see the prime ignite in the video. Probably just the BP igniting, while pinball didnt.

Tried a thick layer of bp / 10%Si prime on the same kind of stars, will see if that can help. i recall i had some luck with that half a year ago, although thats much easier-to-ignite compositions.

 

FYI, my new dextrin is kickass compared to my last one. I made the last one light yellow, while this one is light brown. Big difference! Noticed already when i cleaned the pan after cooking it.

[Seymour]

I'd say 7/1 is one extreme and 2/1 is another, but both are valid and have a place.

 

If the stars which are not lighting are not hard as rocks, I'd say that is likely your problem. I'm not sure if your dextrin was the problem, or if they are just not dry. Seal some stars in a plastic bag and put it in the sun. If it fogs up you have not fully dried them. How long had they been dried?

 

With your prime, is the black powder fast and clean burning, or a bit slow and drossy? For prime you want the latter. Lift quality BP burns too quickly and cleanly to be as effective.

[enanthate]

Most were parlon-bound, hard as rocks obviously, but the glitter and charcoal ones weren't. Dried for a week, constant weight last 24 hours. They were dry.

As i said my dextrin wasnt too good, so it should be solved now.

 

Good point, my last bp-prime was milled stuff, same as my liftpowder. This time its only screened.

Will build a couple of 4" today and test in a couple of days. Hoping for ignition.

[enanthate]

The issue seems to be fixed, only using the slowburning BP +10% silicon and removing flash (using no booster at all). Im sure its not a 100% ignition, but to me its good enough. Videos below. Not the greatest shells, but we're slowly getting there.

 

http://youtu.be/ZZsBNUKxQNk

 

http://youtu.be/-fHkRrZJb3c

 

3" starmine, will make this stuff again. Very cool!

http://youtu.be/dLDitksPfKM

[enanthate]

By the way, the stars i used contained 30% mgal. This makes them hard to ignite, no? Maybe this is why it felt so different. My previous stars have normally been at 5-15% mgal.

[Bobosan]

They all looked real good, enanthate.

[enanthate]

Thanks Bobosan, makes me happy to hear that