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Cakes (the Official Thread)


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#1 portfire

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Posted 11 March 2008 - 05:11 PM

Cakes have always been one of my favorite types of firework devices,more so the Z cake, and so over the last 5 week i've built a 100 shot Z cake.This was not an easy task,lots of testing was needed to get fire transter from one tube to the next, and then the next row,especially when i was using blackmatch.

Anyway,the cake

Pre fire pics

Posted Image Posted Image

Video
http://www.pyrobin.c...0 shot cake.wmv

Effects
1'st 10 shots,hummers w/charcoal tail-All fire at once.
Then 80 shots with 15mm Chrys#6 w/20% 100# MgAl added and D1 stars
Last 10 shots,Ti salutes (KNO3 flash)-All fire at once.

I have enough pics/info one this cake, and as such a tutorial will shortly follow

Dean
"I reject your reality and substitute my own" Adam Savage

#2 karlfoxman

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Posted 11 March 2008 - 06:23 PM

Vey nice cake, you have done very well there. I would love to see some info on the inserts, and some more pics. Please post a tutorial because we dont often see cakes on here. Maybe next make a nice 100 shot multicolour cake.

#3 portfire

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Posted 11 March 2008 - 07:20 PM

Vey nice cake, you have done very well there. I would love to see some info on the inserts, and some more pics. Please post a tutorial because we dont often see cakes on here. Maybe next make a nice 100 shot multicolour cake.


Thanks for your comments Karl,much appreciated.Yes i'll sort some more pics out ASAP, and i'll be starting the tutorial tomorrow.

The cake didn't actually preform how i designed it.While doing tests my stars were breaking up, and bear in mind the stars were made the way i've always made them and i've never had this problem :blink:.In test i would place some light kraft on top of the star to stop it moving, then seal the top with tissue paper (my normal practice).After more tests i found leaving the tube free from anything (big mistake) would give them a fighting chance lol

The sequence should have been..

1'st 10-fire at once,then after 4.5 seconds the cake should have gone into Z mode,then last 10-fire at once,but because i was using Chrys#6 in the hummers, and i didn't cover the tubes,sparks from them must have ignited stars in the next couple of rows, then started a chain reaction. I could have kept quiet and said thats how it was suppose to work,but i'm not like that,an i should have covered the cake in foil,as the stars still broke up :rolleyes:

Anyway i'll sort some more pics out shortly

Dean
"I reject your reality and substitute my own" Adam Savage

#4 portfire

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Posted 11 March 2008 - 10:05 PM

Some more pics

Posted Image

Hummers-10mm ID with around a 1.5mm wall.This is quite uncommon for hummers to have such a thin wall, but when i drill the hole,i also drill a small core which give's them an initial "burst" of thrust.The other reason is that this gives me around 1mm clearance around the 15mm ID shot tubes.This is important,as you can see they are side fused in the same way that beraq inserts are, and that slight clearance allows the flame/hot gas to pass by the prime insuring ignition.

Finished hummers with Chrys#6 pressed in the cavity, and primed with meal

Posted Image

Salute inserts

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'Fire at once' row in a jig ready for gluing together.

Posted Image

Fused left to right shot row.Once the BM is covered the row is complete.

Posted Image

I will go into more detail in the tutorial from start to finish

Dean
"I reject your reality and substitute my own" Adam Savage

#5 Pretty green flames

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Posted 21 March 2008 - 06:17 AM

Fantastic cake!

One question though, if I used visco for shot to shot fusing, should I prime the ends of the visco to ensure ignition or will the 1/16th version take fire easily from the lift charge? I don't want any duds on the first cake I make so just to be on the safe side :)

PGF

#6 marble

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Posted 21 March 2008 - 08:15 AM

Don't you use one long piece of visco / match and run it through?

Then again I did that and I had a cato :(

#7 Arthur Brown

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Posted 21 March 2008 - 08:20 AM

Portfire says he uses blackmatch! He encases the bm to make it into quickmatch for faster effects - the fire at once row.
http://www.movember.com/uk/home/

Keep mannequins and watermelons away from fireworks..they always get hurt..

#8 portfire

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Posted 21 March 2008 - 02:38 PM

Fantastic cake!

One question though, if I used visco for shot to shot fusing, should I prime the ends of the visco to ensure ignition or will the 1/16th version take fire easily from the lift charge? I don't want any duds on the first cake I make so just to be on the safe side :)

PGF


Yeah,if your using single pieces of visco i would suggest priming.As my design called for a 4.5 second delay, I cut the visco at 450 (standard practice) then primed with BP slurry. I let the BP dry before inserting it into the tubes (I doubt it's needed though, you could insert it while wet ), then held it in place with a dab of hot glue.


Don't you use one long piece of visco / match and run it through?

Then again I did that and I had a cato :(


What was the tube configuration ? If the holes in the tubes are close enough to each other, then the flame/hot gases will ignite the lift in the next tube, and so on. This is something I've exploited in the 'fire at once' rows. (or 'fire all', better phrase i think lol)

You can use a long single piece of visco, but it's a waste if you ask me. Using smaller pieces would be the better option, but make sure you secure them, hot glue or a BP slurry will work.


Portfire says he uses blackmatch! He encases the bm to make it into quickmatch for faster effects - the fire at once row.


Indeed, using blackmatch will give you more control over the rate of fire. The 20 shots before the last 10 was how i wanted the cake to preform, but as I've said i didn't cover the tubes :rolleyes:

I'm hoping to have the tutorial finished sometime next week, so hopfully, It should answer some questions :P

Dean
"I reject your reality and substitute my own" Adam Savage

#9 pyromaniac303

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Posted 21 March 2008 - 06:58 PM

Just to add something, its better practice to use multiple pieces of fuse, as if a tube explodes for any reason and the rest are scattered they dont keep burning and firing in dangerous directions. If multiple fuses are used then the tubes that are scattered don't usually ignite, whereas the single fuse would hold the tubes together and they would most likely keep firing.

This only really becomes a problem though when you use sawdust or clay pressed above the cake insert or star, to give extra pressure buildup and greater height without wasting lift.

Edited by pyromaniac303, 21 March 2008 - 06:59 PM.

You can never have a long enough fuse...

#10 pyrotrev

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Posted 22 March 2008 - 01:59 PM

Wow, that's some piece of work Portfire! I've made a couple of small Z fire cakes for shot interludes in displays and found thaf Wasag fast igniter cord was useful and not too difficult to handle - taped it on the outside with linen tape to prevent cross ignition though.
Trying to do something very beautiful but very dangerous very safely....

#11 portfire

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Posted 10 May 2008 - 01:31 PM

At last! The tutorial is finished, taken longer than the cake itself :rolleyes:

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

Let me know what you think. Any comments good or bad (constructive criticism) would be much appreciated. This is my first tutorial after all.

Dean
"I reject your reality and substitute my own" Adam Savage

#12 David

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Posted 10 May 2008 - 01:59 PM

At the moment I'm working on a large, family sized Battenberg. The problem is that it tends to be very dry, almost chalky. How could I get it to be more moist? I have heard that using buttermilk can help, but my concern is that it will be sickly-sweet.
OK, interest in fireworks to be resumed in the spring. It usually is. ;)

#13 Pretty green flames

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Posted 10 May 2008 - 04:03 PM

Portfire, really great cake tutorial, it explain a lot of things i've never really understood in the past so I thank you for that. It shall be put to good use when I make another cake.

David, your post doesn't really fit this topic :huh:

#14 portfire

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Posted 10 May 2008 - 04:53 PM

Portfire, really great cake tutorial, it explain a lot of things i've never really understood in the past so I thank you for that. It shall be put to good use when I make another cake.

David, your post doesn't really fit this topic :huh:


Thanks PGF. That was the whole idea of the tutorial, it gives people a good idea of how they're put together. We don't see many (if any) cakes on here, partly because the time thats involved, (especially if you roll your own tubes B)) but hopfully we should see more now :)

I still have the art of cake building to perfect. I had 30 shots go off at once the other day, but we learn more from failure. My advice is start with 20 shots right to left, and go from there.

The next cake I build will be 120 shot Z with alternating colors (as Karl suggested). I've got a good idea of why I get the odd failure now, so this one should be quite something...Hopfully

Dean

Edited by portfire, 10 May 2008 - 05:08 PM.

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#15 phildunford

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Posted 10 May 2008 - 08:20 PM

David, your post doesn't really fit this topic


Err joke - cake food, cake firework...
Teaching moft plainly, and withall moft exactly, the composing of all manner of fire-works for tryumph and recreation (John Bate 1635)
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