Plastic Shells for Lampares

[warthog]

I asked Ned last year about making colored lampare, I figured if you can color a Ghost Mine, why not color lampare as well? A while back on Passfire a person posted looking for bottles to make Lampare in the Marketplace. It turned into a discussion on how they are made and I was able to obtain the attached PDF out of it. This came from the person who developed the shell in the first place (at least this was the assertion) though his name now escapes me. It is the hand out from a seminar he gave at one of the PGHI Conventions on how these shells are made.

 

As has been said a number of times about everything pyrotechnic, ask ten pyros how to do something and you'll get a dozen "Best Ways" to accomplish the effect. There seem to be a number of ways to make these and I have never made a single one yet. I have made a few of the film canister "Stealth Lampare" but there is no liquid involved in those at all. They are sort of fun to shoot though.

Lampare-SeminarHandOut.pdf

[Zingy]

Wiley, that is a very interesting photo. It makes me think of the spherical shells, built by the Michigan Pyrotechnics Art Guild, (MPAG), observed at PGI displays, that have a lampare effect in the center. I have only built lampare, cylinder or Italian shells. I suspect, there is little or no cushioning in the spherical shells. There are also more complex stresses on the plastic spherical shells, which can not be adjusted for, like stringing, and subject to fracture or other error. I suspect, the MPAG uses some type of sold fuel, for the spherical shells, with the lampare effect, in the center, like naphthalene, or gilsonite.

 

Lampare shells are the most dangerous or hazardous item, you could make. You should feel very confident in shell building, before making them. Firing them from a good distance, over a body of water, like a lake, or after a hard rain fall, would be advised.

Edited April 29, 2012 by Zingy

[Mumbles]

Ball shells containing "lampare pistils" are actually built like in the picture above. The fuel is on the outside. These were the ones developed by the MPAG. I don't know if they are still made with liquid, but they were originally made that way. You do have to fill them fairly quickly before the shell is fired. Over time the gas will leak out and into the shell contained internally. It blew my mind the first time I heard about it. I couldn't believe it was that simple.

[WonderBoy]

So to make a lampare pistil you would nest a smaller plastic shell containing burst, stars etc, inside of a larger plastic shell and then fill the void between them with the liquid fuel? How would you keep the liquid fuel from softening and melting the plastic hemis?

 

 

WB

Edited April 29, 2012 by WonderBoy

[Mumbles]

Like I said, you have to fire it relatively quickly. Within a few hours at most. I only know two guys personally who have made these. I believe they were using JP-4, which is jet fuel. It's approximately a 50:50 mix of kerosine and gasoline. Perhaps the higher content of heavier hydrocarbons slow down the attack. I saw one in competition once, so I should ask if he had to do anything special for that. The shell would be sitting in the gun for probably 5 hours. You may be able to seal off the internal shell with a polyethylene bag or contain the fuel in something as opposed to just having it loose in the shell.

[Zingy]

I am sure the possibilities are endless, for making an inner pistil lampare. Plastic ball shell, in another plastic ball shell. or paper ball shell in a plastic ball shell, with an petroleum resistant epoxy, (especially if it is going to be shot immediately) like what they use for coating the warped lift, on ghost mines, (even though they use alcohol).The epoxy, I seen, used on ghost mines stays semi soft, so one would not be making a hard plastic shell, out of a paper shell. One could coat the inside of the plastic shell with a petroleum resistant paint, which could bring up other possibilities.. .

 

I am not sure centering the inner ball shell in the outer shell, would be a significant concern, but that would be another big challenge, keeping it centered from the lift force, and one possibly could use some plastic tubing for a pass fire tube.

 

The inner pistil lampare ball shells, I observed of MPAG, had a very large break. The largest plastic ball shells, I have seen available, have been 8". They were impressive, considering they could of only been an 5 or 6" inner shell.

Edited April 30, 2012 by Zingy

[Wiley]

Thanks, that's a great resource Warthog!

[Wiley]

For those of you who have made lampares, what do you do about a sloppy fit between the bottle and the inside of the core? My 20oz bottles have about .25" of gap when inserted into a 3" ID core. I had assumed that the bottle would burst upon lift if it was unsupported, but others have stated the opposite. Does this gap need to be filled with something, or can it be left alone? Also, does a caulk seal around the top of the bottle provide enough retention to keep the bottle from "jumping" and bashing into the time fuse?

[dagabu]

For those of you who have made lampares, what do you do about a sloppy fit between the bottle and the inside of the core? My 20oz bottles have about .25" of gap when inserted into a 3" ID core. I had assumed that the bottle would burst upon lift if it was unsupported, but others have stated the opposite. Does this gap need to be filled with something, or can it be left alone? Also, does a caulk seal around the top of the bottle provide enough retention to keep the bottle from "jumping" and bashing into the time fuse?

 

I have seen many successful shells using expanding foam. There are a few going up this weekend that use caulk for that seal and I do hope they work well. All I can say is to try one and see if it works.

 

-dag

[Wiley]

Thanks dag. I asked Mr. Creagan himself this same question, and he, as usual, gave a very useful response. Here is his answer:

 

"I use sawdust to lock the bottle in. Different bottles will fit differently. I like Gatorade 20 ounce bottles the best but just about any 20 ounce bottle will work. Pour a tablespoon or two of sawdust in the bottom. Put the bottle in. Pour some sawdust around the outside and shake it until it fills/wedges. Seal the bottle in with foam or sealant. It won't move."

 

This method is very simple, and I'll be using it on my next prototype. Perhaps someone besides me will find this informative.

Edited May 3, 2012 by Wiley

[Wiley]

I have another important question about traditional style lampares. Is it safe to shoot them from HDPE guns? I would like to avoid steel if at all possible, though Dutch mentions firing his out of a stainless steel mortar.

[Mumbles]

They're probably light enough to fire from whatever mortar you want. Steel has some advantages with salutes in that any sane person always buries/barricades them. They also hold up to a lot of stress. Lampares can be long shells and relatively heavy.

[psyco_1322]

I've shot 4" Draw Outs in HDPE, those are heavy 3 break shells. I have shot lampares from both HDPE and fiberglass with out any issues. I actually shot a bow tie lampare from the fiberglass with no problems. The bow tie is just a double lampare with two 20oz bottles.

[Wiley]

Thanks psyco, I'll use the HDPE . I'm really interested in that bow tie shell of yours. When I download the video, I get sound, but nothing else. That's not a big deal though, probably something I'm doing wrong. Are you at liberty to reveal in depth how the shell was made? I have a few hunches about it's construction, but I'm sure that I'm not sure.

[psyco_1322]

I basically built two lampares and filled them with about 100g of flash, and put on a single disk on the tops that had large holes cut in them, probably about 2". One had some tissue paper over it so I could flip it without dumping flash every where. One lampare had a hole drill in the side of the tube and that's where the fuse was installed, side fusing the shell. I glued the two shells together, spiked and pasted as normal. Then ran the leader down and over the fuse, that was primed, down to the lift. It worked ok.