Double petal shell

[pyrogeorge]

Hi,

I will try to make a 6" double petal shell and i would like to make a review before try,so informations,guides or tutorials will be very usefull.

 

Please post anything you need is usefull.

 

thanks

[allrocketspsl]

Hi,

I will try to make a 6" double petal shell and i would like to make a review before try,so informations,guides or tutorials will be very usefull.

 

Please post anything you need is usefull.

 

thanks

 

how about magenta stars with yellow glitter pistil

[pyrogeorge]

i need info abou the construction my friend

[BJV]

i need info abou the construction my friend

 

 

The say a picture is worth a thousand words.

BJV

 

[fredhappy]

There is not a standard way of constructing a double petal shell, there are multiple choices in regard to construction.

 

First of all, let me advice you to get a paid subsciption to passfire . There are tons of great tutorials which offer a wide variety of building methods. I really enjoy reading those shell autopsys there, those articles alone enabled me to make some big improvements with my own shells.

 

Also, from my own experience, double petals don't work that well with MCRH and 70/30 booster. Kp is preferred as a breakcharge. The best results with double petal shells I always get with KP.

 

May I also advice you to take a close look at the shell section at this forum. There really are tons of examples posted there. A good starting point would be the 5"double petal made by Carlos. He uses a sort of Japanese inside out building. I myself also posted multiple clips of double petals, along with some building snaps. I don''t quite understand your request for information since there is so much stuff posted here about double petals.

 

I am more then willing to advice any serious aspiring pyro, but simply asking to be spoonfed information is not going to get you lots of results here. Part of the fun of building that perfect double petal, is making lots of double petal shells and simply trying out stuff to see what works. They can be made with almost perfect symetry from 4" up. It took me lots of tries to get this specific effect shell right, but now I can build them and get the same results every time.

 

best

 

fred

[Mumbles]

One of the other excellent resources I've found was Jim Widmann's article on building a 12" multi-petal shell. It has some good pictures, and covers a lot of the theory of the art.

 

http://www.pyrobin.com/files/a%20method%20of%20construction%20for%2012%20double%20petalled%20chrysanthemum_1.doc

[pyrogeorge]

BJV thanks for the pictures.

 

fredhappy yes i am member at passfire but i didn't see a quide..i will see again,maybe i didn's see it.

i will try to make a 6" ball shell.\

 

edit.

fredhappy.thanks my friend!

i found the archive at passfire with double petal shell tutorial.

Edited September 1, 2011 by pyrogeorge

[fredhappy]

One of the other excellent resources I've found was Jim Widmann's article on building a 12" multi-petal shell. It has some good pictures, and covers a lot of the theory of the art.

 

http://www.pyrobin.c...santhemum_1.doc

 

 

Indeed,very good article, and also the mentioned silver KCLO4 star in that article is a real keeper for me. I ve always found that forming a depression and using ricepaper gives me the best symetrical results. I ve tried that whole perforated hemi thing a couple of times, but for me it gave a dumped out look to my inner petal. Not saying it couldn't work, but just not for me. Brings me to my previous point: just try out stuff , build, shoot, film, improve .....

[pyrogeorge]

One of the other excellent resources I've found was Jim Widmann's article on building a 12" multi-petal shell. It has some good pictures, and covers a lot of the theory of the art.

 

http://www.pyrobin.com/files/a%20method%20of%20construction%20for%2012%20double%20petalled%20chrysanthemum_1.doc

another usefull document!thanks Mumbles

[Mumbles]

Fredhappy, I'm slowing coming to realize that the full thickness hemi inside isn't as good. I've been holding out hope for the actual hemisphere inside, but that is fading I have gotten better results when I spiked the internal hemi, but it's still not quite there. I've had my share of trouble with the indent too, but that is something that can be worked out. The big problem I've always had with just the intent is that the upper edge never says crisp enough, and the equator of my petals is often a bit out of alignment. How apparent it is depends a lot on the viewing angle.

[fredhappy]

Fredhappy, I'm slowing coming to realize that the full thickness hemi inside isn't as good. I've been holding out hope for the actual hemisphere inside, but that is fading I have gotten better results when I spiked the internal hemi, but it's still not quite there. I've had my share of trouble with the indent too, but that is something that can be worked out. The big problem I've always had with just the intent is that the upper edge never says crisp enough, and the equator of my petals is often a bit out of alignment. How apparent it is depends a lot on the viewing angle.

 

 

Funny you've gotten better results with spiking the inner petal. I ve tried spiking a 2" perforated hemi with flax twine for use as a inner petal in a 4 "er, and it gave me the worst results ever ( I ve posted the clip in the shell section) .

 

To get an almost perfect alignment I use a ruler and simply measure the distance between the outer shell wall and inner petal wall. I then use very thin ricepaper and a normal hemi with a hole in it to form a depression with, exactly as BJV"s pictures point out so nicely. The downside when using this method, is that it is prone to shifting and ruining the shape when closing the shell . You have to be quite gentle when placing the stars in the inner petal. I fill the bottom, and then insert another round piece of ricepaper with my break, so it has some counter force when I fill the inner petal with the remaining stars and break.

 

I always find it very interesting that there are many ways to go about when building stuff, and what works perfect for me, does not work at all for some fellow pyro, or the other way around....

[Mumbles]

Sorry, that didn't come out very clear. I've gotten better results by spiking the petal vs. just leaving them in there to hold the shape which is the way I first learned. The more I learn about it, the more I think I misread or misheard or was just taking a shortcut when it was first presented. Some of my best results came from using a very thin perforated hemisphere in the burst to hold the shape. I've made them from 3-4 layers of gummed tape or pasted newspaper. It's practically invisible to the flame front, and provides just enough strength to make the petal equator hold it's shape a bit more.

 

When I was experimenting with the indent method, I think my downfall was not using enough tissue paper dividers. I believe I was only making an intent and then layering the stars directly onto the burst. In retrospect a layer everytime you are switching between stars and burst is a cheap insurance policy to prevent mixing, and very well could help to contain my stars in a tighter pattern instead of distorting around the equator.

[fredhappy]

Sorry, that didn't come out very clear. I've gotten better results by spiking the petal vs. just leaving them in there to hold the shape which is the way I first learned. The more I learn about it, the more I think I misread or misheard or was just taking a shortcut when it was first presented. Some of my best results came from using a very thin perforated hemisphere in the burst to hold the shape. I've made them from 3-4 layers of gummed tape or pasted newspaper. It's practically invisible to the flame front, and provides just enough strength to make the petal equator hold it's shape a bit more.

 

When I was experimenting with the indent method, I think my downfall was not using enough tissue paper dividers. I believe I was only making an intent and then layering the stars directly onto the burst. In retrospect a layer everytime you are switching between stars and burst is a cheap insurance policy to prevent mixing, and very well could help to contain my stars in a tighter pattern instead of distorting around the equator.

 

No, I understand you Mumbles, no damage done.

 

The problem with ricepaper is that it is so thin, that it's hard not to shift anything during construction. It can be done though. I always use ricepaper dividers between stars and burst. It seems to me, that stars would otherwise migrate easily towards the centre or outwards, ruining the effect.

I struggled with this particular shell to get it right. I've tried every type of construction, but my results with perforated/spiked strawboard hemi's were not good. BJV uses these newspaper hemi's for inner petal, they sure look good and usable.

 

When using a depression and ricepaper, it is important to put some force on the hemi, to make a clear depression. Then you very gently lift out the hemi, and should end up with a perfect half sphere shape. It is more fragile as opposed to a newspaper hemi, I agree to that. But gently putting in the first bottom of stars, and putting in the round piece of ricepaper with some burst, and pressing down on it with a finger, doesn't disturb the pattern for me. It also ommits the need to make newspaper hemi's. You just need a sheet of ricepaper and a strawboard hemi to build double petals, a big plus when building lots of them.

 

I hope this makes sense, I struggle a bit with the level of technical English here sometimes, since it isn't my native tongue. I ve included some building pictures , I hope they show a bit what I mean.

 

best

[pyrogeorge]

Another point that i want some ideas is for the stars.

Wich is the best colour choice for the outer petal and the inside petal stars..

[fredhappy]

Another point that i want some ideas is for the stars.

Wich is the best colour choice for the outer petal and the inside petal stars..

 

 

George....get some colour pencils out, and make a couple of sketches of double petal shells. Choose a colour combination you like, and research KCLO4 based formulaes ( no KCLO3 or ammonium perc based ones). Why ask other people what they think is a good colour combination? The great thing about building shells yourself is that YOU can choose what colours you want to make/use.

 

Just pick a composition, screen the compo, fire up your starroller and roll some stars. Build a double petal shell and see how it works out.. If it's not perfectly symetrical , build another one using a different technique. Photograph every step you take during building, and make a file of these pictures for your own research. Do take notes during building in regard to weight, starsize , pasting, break and so forth. By making mistakes, and simply trying out stuff yourself you learn the most....I'm not trying to be negative or something, I am just trying to stimulate you to research and try stuff out yourself. It's great fun!

 

best

 

fred

[pyrogeorge]

You are right fredhappy,i will teach from my mistakes,so i will take good notes

i have ready rolled stars c8 on green cores..maybe i will use this stars for outer petal..

 

but maybe will need more C8 composition..they are 12mm.

20mm is good for 6" shell?less or more??

 

thanks

[FREAKYDUTCHMEN]

15mm, so roll them to 13mm, then prime to 15mm.

[fredhappy]

You are right fredhappy,i will teach from my mistakes,so i will take good notes

i have ready rolled stars c8 on green cores..maybe i will use this stars for outer petal..

 

but maybe will need more C8 composition..they are 12mm.

20mm is good for 6" shell?less or more??

 

thanks

 

C8 burns way too fast for my taste for use as rolled stars .Making your stars larger is one way of prolonging the burn time I guess. It all depends on your way of mixing it, the used chemicals and especially what kind of C you use. It is however a good base compo for matrix comets.

 

Just prime your stars , put them in a shell, and see what happens. Or roll up to 15mm, and add some Ti when going from 12 mm to 15 . When you look at my 4" double petal salvo in the shell section, I use 10 mm C8 to 6 mm B70 for a double petal. The C8 burns off so fast, it almost gives a dark relay like effect, it's barely visible. An unintended yet cool effect as I like to call it....

Edited September 2, 2011 by fredhappy

[pyrogeorge]

Ti sponge rolling easily or not?

[fredhappy]

Ti sponge rolling easily or not?

 

Depends on mesh size, when rolling with Ti in C based stuff, keep the water content close to 100% when you use dex as a binder . Don't add alcohol to the water as you normally would do. Adding alcohol results in less TI being picked up,and Ti depositing on the bottom of the starroller, at least with me it does.

 

Shame on you son, you coerced me into spoonfeeding you anyway ....... Now shhhhhh shhhhhh, go build and shoot stuff!!

[pyrogeorge]

Finally i make my double petal shell!

thanks all for your help.

 

6" shell with c8 on emerald green cores-white strobe for inner petal and some emerald green microstars.

 

http://img192.imageshack.us/img192/6904/dsc00762zo.jpg

http://img560.imageshack.us/img560/534/dsc00765u.jpg

http://img845.imageshack.us/img845/6829/dsc00766y.jpg

http://img829.imageshack.us/img829/9793/dsc00779r.jpg

http://img197.imageshack.us/img197/5573/dsc00780zb.jpg

http://img841.imageshack.us/img841/6834/dsc00770jt.jpg

http://img717.imageshack.us/img717/4879/dsc00772l.jpg

http://img69.imageshack.us/img69/4905/dsc00773id.jpg

http://img689.imageshack.us/img689/7557/dsc00774u.jpg

http://img26.imageshack.us/img26/3759/dsc00781mn.jpg

http://img828.imageshack.us/img828/6084/dsc00785tf.jpg

[leosedf]

Dude!

Nice Raspberry stars :lol:

[pyrogeorge]

[guntoteninfadel]

Do the raspberries light easier? Just askin.....

[dan999ification]

Do the raspberries light easier? Just askin.....

 

i think so , well easier than hard pressed charcoal comets, but then i have never primed charcoal stars because they light easy if not broken too hard.

 

dan.