Rolled stars blowing blind

[TYRONEEZEKIEL]

Hello. I just started to convert to rolled stars only. I have had a bit of bad trouble with stars igniting lately and I think it either one of 2 problems.

 

Here's what I do with my 3" shells.

 

I roll the colored comp then roll prime, then meal straight from the mill.

 

I have been using an AP lift here is the formula

 

KCLO4 75

Red Gum 12

Charcoal 9

DX 4

 

I roll a few good layers of prime. I dont just dust it on, or roll the stars around. I continue rolling the stars as if the prime is comp, then roll on meal the same way. This was never a problem when I cut stars. I never had problems with blind stars.. Even though I just dusted prime and used a "flash bag" for burst. What a predicament. My current burst is 7:1 Meal to Hulls Coated Rice. I paste with gummed paper tape to leave just a 10% clearance in the mortar.

 

So I think it could be 1 of 2 options.

 

My prime is not adequate for rolling

My burst is too hard

 

Now I dont think it is the latter, because the shell doesnt sound too sharp or off, and the 10% of the stars that do light seem to have a proper trajectory.

 

Please help me fellas, I dont know what to do here.

[Xtreme Pyro]

Sounds to me like you need a hotter prime, meal alone will not light most color compositions. Are your stars "rough" on the surface after priming? Try these primes, roll the first coat of hot igniter prime, than the BP + mgal prime ontop of that.

 

 

http://imageshack.us/a/img829/9950/primes.png

 

Credit: Skylighter.com

[AdmiralDonSnider]

Please post the color formula you are using for the stars. Step priming will do the trick in any case.

[JFeve81]

Just from what I've read or heard as I don't have experience with rolled stars yet is that you might need to change your final BP prime layer a bit. Instead of using meal powder try using a simple screen mixed BP for your final prime layer. As Xtreme Pyro hinted at it gives a rougher surface making it easier to take fire and also might burn slightly slower allowing the prime layer underneath to catch instead of just burning off the outer prime layer.

[TYRONEEZEKIEL]

My colored stars are

 

Lancaster Red #2

KP 70

SrCO3 15

RG 10

C 1

Dx 4

 

Simple White- I dont remember the exact formula off hand, but it was

KNO3

Antimony Trisulfide

Sulfur

DX

 

Also. I use toilet paper inbetween my stars and burst as place for tissue paper. It isnt the fancy thick stuff, but do you think it could be the cause?

[Adamr2889]

I am having the same issue. not sure what comp the OP is using, I've made the red and blue from this:

 

 

Primes:

 

 

A Special dark type prime: 75 KN, 7 KP, 3 Sb2S3, 9 coal, 6 red gum + alcohol(shimizu dark relay modified).

 

B Strong perchlorate first prime composition 75 KP, 12 red gum, 13 coal + alcohol. Both of these primes = thin layer on colored cores(a or b, according to taste). On these prime, must be coated black powder with red gum or dextrin.....

 

 

I really am new to this but I think Sb2S3 would be a type of metal? I used prime a; half my stars blow blind the other half light correctly. That's using a 1.75 shell to test some of the smaller stars in my batch. Burst used was .5g whistle mix and 8g of 4:1 bp coated rice hauls.

 

 

Credit to http://www.amateurpy...ser/453-karlos/ for the chart/primes

Edited June 10, 2013 by Adamr2889

[pyrojig]

What your using is antimony trisulfide . It is a metal salt, and aid 's in the ignition (lowering the ignition temps). I would include a metal in the comp if it is not to be used as a dark delay layer. It appears that an additional bp layer is needed over this comp to aid in ignition. Try rolling a 1-2 mm layer of bp over your stars , it should solve your ignition issues.

[Adamr2889]

What your using is antimony trisulfide . It is a metal salt, and aid 's in the ignition (lowering the ignition temps). I would include a metal in the comp if it is not to be used as a dark delay layer. It appears that an additional bp layer is needed over this comp to aid in ignition. Try rolling a 1-2 mm layer of bp over your stars , it should solve your ignition issues.

 

Sorry noob question what is a dark delay layer?

[Seymour]

Consider it to be a layer that burns black. In reality there will be some dim light output, but the idea is for the star to burn invisibly (so that when it flares up with a visible effect you get a surprise).

 

Often a similar use is between layers of different colours in colour changing stars a thin layer of a "dark relay" prime is added so that the two colours are not both burning at the same time in the sky due to imperfections in stars. This gives the impression of a cleaner colour change.

Edited June 11, 2013 by Seymour

[psyco_1322]

Fence Post Prime....make it, use it, like it....never go back to anything else.

[TYRONEEZEKIEL]

Ok fellas. Heres the deal. I made another shell (which burst great) but still no joy.

 

The 2 colors that dont light are primed then rolled with BP on top. Yes BP is currently already rolled ontop of my prime. It is still not lighting. That is my concern. I am already step priming and no joy.

 

That being said i made the shell this time with no tissue paper. Still no difference. I even hot glued a few stars on bottom of the shell. They did not light from lift gas.

 

They will light under a quick kiss of flame from a blowtorch, but not from the mortar or shell. The stars are kind of smooth on the edges, but not totally. Like very fine sandpaper. I know the problem is not my BP not being able to burn, because I lift and burst with it just fine. Again. This is the same technique from priming as I used to do when I cut stars, but now that they are rolled they simply wont ignite.

 

So. I have resolved that the batches I made are no good. its unfortunate as it was a few pounds of stars, but they just wont work. Here is my question now.

 

Is it possible to put yet another layer on top to make them ignite? I wonder if I put something rougher on the surface and hotter that it will be able to burn through my BP and original prime to light the star. I wonder if my current BP meal outer prime burns too quickly and flashes over the surface of the star.

 

Now, these stars do burn and the colors are great. How can I use these elsewhere?

[Mumbles]

Adding more BP certainly wont make them light less. Perhaps try adding something with that roughens up the surface a bit like diatomaceous earth or wood meal. I would personally be inclined to try something like fence-post prime over the top. It's rough, and tends to be pretty good at lighting things.

 

If nothing else works, I find that stars light better out of starmines. Additionally, a little extra pasting can sometimes help.

 

If you have video, you might want to take a look at it frame by frame. You might be able to tell if it's the BP or the Perchlorate prime underneath. It will hopefully give you an idea if the stars are blowing out or just plain not lighting.

[Bonny]

You could also roll them in a BP slurry and then add a layer of coarse BP, maybe 5FA to 7FA, It makes the stars nice and rough to help ignition.

[Arthur]

How many layers of paper do you actually paste, if the shell breaks too easily then some stars will not light.

 

A hot prime will light many things meal with 5% added silicon (100mesh) will help greatly. The silicon (it's a metal!) burns to silica (sand) which forms as a liquid and the HOT liquid sticks to the star transferring a lot of heat. Metals that burn to smoke lose their heat to the atmosphere.

 

Rough stars light better so let the damp stars pick up some BP granules (7Fa for tiny stars, 2FA for bigger stars).

[Seymour]

I'll second Arthurs recommendation of Silicon metal. While I don't have a lot of personal experience with the stuff (unfortunately), what I've seen in person was exceptionally thin layers of this one prime lighting high MgAl Strontium nitrate reds with absolute ease, even at a respectable velocity.

 

While I personally use and often recommend step priming, this is an example of a fantastic alternative.

[pyrojig]

had a similar experience with perch /shellac stars not igniting. I believe it was due to not enough hot prime and the particle size of the chemicals used for the comp. I had to use them for mines and rocket headings w/o a strong burst. Sometimes it is something you have to chalk up as a learning experience. I always test a 200g batch of any comp before making several #. THis helps eliminate the pain of disposing of a extra large batch of hard work.

[eb11]

what is Fence Post Prime

[TYRONEEZEKIEL]

So I rolled an outer prime on the stars and there has been a minor improvement. The stars now work when glued to the bottom as a rising effect, but still blow blind in a shell. I use an adaptation of the 3 strip method using gummed tape. I have been pasting 6 or so full layers, rotating poles to avoid flat spots. My shell diameter is pasted to 90% of the mortar diameter. I made a separate shell using only C8 and I noticed the burst was ok, but the stars did droop a bit although I believe I did acheive 100% ignition.

 

I have abandoned those 2 batches of stars for now, but I did find something interesting today while reading Best of AFN II

 

There is an article attributed to star ignition failure. The article stated that perc stars are particularly hard to ignite and BP alone will not do the job. They suggested using a step prime of blending comp+BP 50/50 then to straight BP. Luckily I do have a pound of silicone on hand, but no DE to make fence post.

 

Also, I have 2lbs of 3 micron MgAl. I dont know why I bought that instead of 200 mesh, but could the 3 micron have good use for priming?

[psyco_1322]

what is Fence Post Prime

 

Fence Post Prime

KNO3 - 65

Airfloat - 15

Sulfur - 10

Diatomaceous Earth - 5

Silicon - 5

Dextrin - 4

 

The original formula calls for like 3 parts of the charcoal to be a "slow" and the rest a "fast" charcoal. I have used the same charcoal for all parts, and have used fast and slow charcoal and it still functions just fine. Just prime your stars with it, and that's all you should need. I have yet to have any failed ignitions with this prime, even on mag color stars.

[burningRNX]

If the lit from lift, why shouldn't they from a break?, they are blown out maybey, because of high wind speed during break.

Rolled stars are Always harder to light than cut or pumped stars because there are no rough edges that take's fire very easy.

Did you cut one in half to measure the prime layer? something that looks very well primed can be dissapointing when cut in half.

Something very handy in getting good layer thickness are starscreens, and yes, more work

If you had 100% ignition with TT, roll 1 mm of it on your abandoned batch, and some meal d/green mix/or something other rough outer stuff to finnish it up.

Edited June 17, 2013 by burningRNX

[TYRONEEZEKIEL]

RNX, Today I actually cut some stars in half and I saw that my outer prime layer is about the thickness of a sheet of paper. Im pretty sure that is too thin. I dont have DE for fencepost, so I tried igniter prime using 3 micron mg/al on a new batch of stars. I lit a few on the ground and I noticed that they cover the whole star much quicker than before. Its like the whole prime burns before lighting the star. Before, it would burn quicker radially than it would tangentially, So I do like the new prime I am attempting for now. However. How thick should a prime layer be? I have never thought about it needing a specific depth before.

[burningRNX]

it depends on the size and purpose, but I've rolled a 16 mm perc collor star with 0,5 mm bleser hotprime, 0,5 mm TT, 0,5 mm fast meal and finaly dusted with meal D to get a rough surface.

another option that I use for TT is spider composition, both usefull compositions beside of priming.

reason that I use it is because I've read that carbon rich compositions are hard to extinguis at high speed, and I like logical trains like flamabillity/burnspeed versus speed of star at a given time, something that relays on layer thicness also.

 

as usual I put a thin meal dusting between the TT and bleser, or sometimes I just mix some of the different primings 50/50 to get 'm mixed up a bit, usually this layer is to thin to measure.

its pretty new for me because normally I put a thicker layer of C-streamer on this size, but that will eat a lot of space, and I'm going to the edge of priming for more space, so this is sort a new test project.

 

in general I wouldn't go under 1 mm of priming on smaller stars, and increasing it with the size of the shell.

Edited June 20, 2013 by burningRNX

[FrankRizzo]

Shoot for around 0.5 - 1.0mm of prime. Anything less than that is burned-up during the break. Many star compositions have burning characteristics that won't allow them to burn during the initial acceleration of the shell burst. Having a good layer of prime will keep the prime burning during the most violent stage of the burst, and then light the actual star composition once the star has begun to slow down. If you've look closely at a lot of hard-breaking Chinese consumer shells (Excalibur, Super Magnum, etc.), you'll notice that the prime layer is actually an easy-to-light charcoal streamer comp, usually with a bit of metal. You'll almost never see color or strobe right from the break. Edited June 21, 2013 by FrankRizzo

[FlaMtnBkr]

In your first post you mention AP. Was that a typo? If not that is your problem if using BP prime.

 

Diametetious (sp?) Earth can be bought at most hardware stores (Home Depot or lowes) or a pool store. It will come in 8 lifetime supplies per bag but only about 20 bucks. If you know someone with a pool I'm sure they would give you a gallon zip lock bag full.

 

Also, you don't want to use fast BP out of the mill. You want to just screen it together so it burns slow and transfers the heat. You also can add about 5-8% metal to make it hotter. Atomised aluminum, your MgAl will help but more coarse would be better, or silicon. The DE in the fence post prime will act similar to the silicone metal, creating basically molten glass that sticks to the star and retains heat for a long time.

 

You also want the layer of prime much thicker than a sheet of paper. Like 1 to 2 mm thick. The stars spend a short amount of time in the shell before it bursts and the stars will start burning. Better the prime than the color. A thick layer of prime will make the stars burn a bit longer making the break a bit bigger. So don't worry about putting a good layer on.

[cogbarry]

Fence post solved my ignition issues and you can pretty much just add the silicon and DE to your bp meal.