Jump to content


Photo
- - - - -

Roman Candle Construction and Delay


  • Please log in to reply
21 replies to this topic

#1 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 16 July 2020 - 01:59 PM

Does anyone have any links to a good roman candle construction guide and/or a good delay composition? I'm only finding the skylighter page.



#2 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 16 July 2020 - 05:38 PM

I tried the skylighter delay composition and couldn't get it to light. Had to add more KNO3. 



#3 kingkama

kingkama

    Pyromaniac

  • Full Member
  • PipPipPip
  • 183 posts

Posted 16 July 2020 - 07:48 PM

Well delay composition can be a 60 30 10 but made up from ingredients worked in a blender, then sifted together, bigger particles slower powder,

#4 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 17 July 2020 - 07:29 AM

Yeah that sounds real close what I ended up using but a little less sulfur. 



#5 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,784 posts
  • Gender:Male
  • Location:Above You

Posted 17 July 2020 - 08:52 AM

Many delay comps will have something like coarse charcoal or metal in them so there's something interesting happening between shots.

 

Some of the better roman candle guides are in books.  Degn's Westech Fireworks Manual has a good procedure if I recall.  Something like Weingart's Pyrotechnics or Lancaster's Fireworks Principles and Practice also probably have good coverage.

 

I'll see if I can dig it up, but there is an interesting different method some people have used to create roman candles more recently. Effectively each shot is created in a stand alone tube, which are then joined together, and pasted, taped or placed into a larger tube together for the final device. 


Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#6 Arthur

Arthur

    Firebreather

  • HE Qualified
  • PipPipPipPipPip
  • 3,602 posts

Posted 17 July 2020 - 02:22 PM

Big candles in the UK tend to be delayed by the use of a felt plug with a length of time fuse through the middle, then only fast powder is needed



#7 davidh

davidh

    Pyrotechnician

  • HE Qualified
  • PipPipPipPip
  • 221 posts
  • Gender:Male

Posted 17 July 2020 - 07:32 PM

This is a decent project page. http://www.brianredm...n/romancan.html



#8 kingkama

kingkama

    Pyromaniac

  • Full Member
  • PipPipPip
  • 183 posts

Posted 18 July 2020 - 02:34 PM

A simple roman candle is made up in a hand rolled 1.5 cm paper tube, 4mm wall thickness pressed comet of 1.2 cm the tube can be long as you can manage easily (ie 60 cm). Ram some clay at bottom (3-5 cm) then add 2 gram of fast bp then the comet, on top 5/7 grams of delay comp not granulated ram gently untill compacted, more compacted more delay, but attention to not use too much force or stars can ignite, then star again bp, comet, delay, bp, comet, delay and so on. This is a errors and correctiin process, cause anyone has different ingredients e charcoal so difderent results.

Edited by kingkama, 18 July 2020 - 02:37 PM.


#9 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 18 July 2020 - 03:21 PM

A simple roman candle is made up in a hand rolled 1.5 cm paper tube, 4mm wall thickness pressed comet of 1.2 cm the tube can be long as you can manage easily (ie 60 cm). Ram some clay at bottom (3-5 cm) then add 2 gram of fast bp then the comet, on top 5/7 grams of delay comp not granulated ram gently untill compacted, more compacted more delay, but attention to not use too much force or stars can ignite, then star again bp, comet, delay, bp, comet, delay and so on. This is a errors and correctiin process, cause anyone has different ingredients e charcoal so difderent results.

Yeah I wung it and essentially did this yesterday. I plan to light it tonight and see how it works. If it comes out well I'll post instructions. 


  • kingkama likes this

#10 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 19 July 2020 - 04:29 PM

Did a quick test last night. I tried my hand at hand rolling some tubes. I started with some butcher paper, a 3/8" dowel, some wood glue diluted with water, and a paint brush. I cut 2 feet of butcher paper and then split it in half lengthwise.

 

A0likH4m.jpg

I placed the paper down, brushed on some diluted wood glue, and started rolling.

99oKhIZm.jpg

First tube I rolled was awful and promptly put into the garbage. The second was passable after I did some trimming.

DdELDDUm.jpg

 

Ended up making 4 tubes total. They came out each a little different length due to rolling accuracy. 

zPjLITkm.jpg

 

I 3D designed and printed some spike stands. The tolerances were pretty loose so I used two drops of super glue to secure the tube in the base. The tips were a bit melted because the hot end of the printer is working in a small area with very little filament being extruded. Not that big of a deal. Stuck in the ground perfectly. Rough estimate on cost is about $0.15 a spike. As long as you don't put too much super glue in there, I think you should be able to pull the spent tube out and reuse the spike since the tube and clay insulate the spike from any heat. 

Up3OlIFm.jpg

I then poured in a small amount of powdered clay cat litter and rammed it solid with a second 3/8 inch dowel that I sanded down to reduce the diameter a bit. I 3D designed a small scoop to load the roman candles and printed out a couple. One for the delay and one for the lift. 

lx3D3gQm.jpg

 

I alternated 1 scoop of black powder, one star, and two scoops of delay. Ended up with 6 or 7 shots I think but I lost count. This is the end result:

 

The first shot was an electric violet star, which I really like. It burned up fully, even though it was not shot very high. The green was a bit delayed and may need a thicker coat of prime. The third star was Independence red and it didn't ignite (definitely need to prime those stars more). The force of the black powder going off extinguished the layer of delay. The delay composition from skylighter was trash. It was essentially half and half KNO3 and charcoal with a tiny amount of sulfur and dextrin. I couldn't even light the original ratios and ended up tripling the KNO3. Even that did not keep it from being extinguished by the black powder lift charge for the red star. 

 

I plan to re-do the test. I will add more sulfur to the delay (because if my memory serves me right, that helps with flammability)? Hopefully that stays lit. I'll also use two scoops of lift, two scoops of delay. Hopefully the extra lift will throw the initial stars a bit higher. Since the scale of my devices are so small, it's hard to use gram measurements for lift charged. The stars don't even show up on my scale that has a 0.1 gram sensitivity. We'll see what happens. Thanks for all the help and comments! 



#11 SeaMonkey

SeaMonkey

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 214 posts
  • Gender:Male
  • Location:Very Southern California
  • Interests:Electricity, Electronics, Electro-Chemistry, Vintage Computers, Fixing and Restoring Old Stuff, Amateur Pyrotechnics

Posted 20 July 2020 - 12:23 AM

Steigede,

 

Your test result is encouraging in spite of the flameout!

 

Here's a Delay Comp formula which may work well.



#12 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 20 July 2020 - 06:57 AM

Steigede,

 

Your test result is encouraging in spite of the flameout!

 

Here's a Delay Comp formula which may work well.

Thank you! That's about what I ended up with after messing around with the original formula! I'll write that one down in my notebook for the future!



#13 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 20 July 2020 - 04:29 PM

More progress. Think I have it down. First one had a few un-primed stars. Second one I used some electric violet stars that I knew were easy to light. They look a bit red on the camera but they're a really cool neon purple in person. I was actually able to just repack the spent tube for the second fire.  



#14 kingkama

kingkama

    Pyromaniac

  • Full Member
  • PipPipPip
  • 183 posts

Posted 20 July 2020 - 09:00 PM

Cool result, but BP is slow or granulated too big,seeing scoop you used you have had heard a sharp shot, not pouf.

#15 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,784 posts
  • Gender:Male
  • Location:Above You

Posted 20 July 2020 - 09:53 PM

One hint I was given when I was looking into these is to use proportionally more lift on the first few shots.  The smaller amount of tube leads to the first few shots being underlifted, or the last few being shot to the moon.


Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#16 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 21 July 2020 - 06:12 AM

Cool result, but BP is slow or granulated too big,seeing scoop you used you have had heard a sharp shot, not pouf.

The scoop's volume is is about the size of a star. The tube is also bigger than the star and there's quite a bit of room around it. Does it matter if I don't get a sharp shot? I'd rather have a pouf than a sharp shot. My neighbors and their dogs would probably agree  :)

 

One hint I was given when I was looking into these is to use proportionally more lift on the first few shots.  The smaller amount of tube leads to the first few shots being underlifted, or the last few being shot to the moon.

That's a good point! I do notice that. I'll give that a go on my next one.



#17 kingkama

kingkama

    Pyromaniac

  • Full Member
  • PipPipPip
  • 183 posts

Posted 21 July 2020 - 11:50 AM

Sharp shot indicates that stars fly in air and not fall like gerbs sparks.

#18 Richtee

Richtee

    Firebreather

  • Donator - HE
  • PipPipPipPipPip
  • 1,947 posts
  • Gender:Male
  • Location:U S of Eh! (Close to Canuckia!)
  • Interests:Electronics and security professional. A fair cook/pitmaster, and bourbon drinker :{)

Posted 14 January 2022 - 01:58 PM

Steigede,

 

Your test result is encouraging in spite of the flameout!

 

Here's a Delay Comp formula which may work well.

Hey... all I get is a blank page on this.. can ya post the formula here? I’m gonna do some small rockets... thanks!


I like smoke! On food or in the air equally well.

#19 Steigede

Steigede

    Playing with fire

  • Full Member
  • PipPip
  • 47 posts

Posted 14 January 2022 - 02:03 PM

Hey... all I get is a blank page on this.. can ya post the formula here? I’m gonna do some small rockets... thanks!

Yeah it looks like the page is down for me as well. I'm not sure what the formula was unfortunately.



#20 dynomike1

dynomike1

    Firebreather

  • Donator - HE
  • PipPipPipPipPip
  • 1,243 posts
  • Gender:Male
  • Location:W. Tn.
  • Interests:Blowing Beaver dams, Shooting Cannons, Hunting, making fireworks.Buying guns.

Posted 17 January 2022 - 05:40 PM

I use Tiger tail in rockets for a delay between bp and whistle or report


Edited by dynomike1, 17 January 2022 - 06:05 PM.

  • Richtee likes this
There are very few problems that cant be solved with explosives.
                             Explosives are a bang up job.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users