Jump to content


Photo
- - - - -

Best Method for Punching Fuse Holes in Beraq Tubes


6 replies to this topic

#1 cmjlab

cmjlab

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 206 posts

Posted 24 January 2023 - 09:55 AM

I was hoping someone here had a bunch of experience making and prepping Beraq Tubes. I made approximately 500 (total tubes, two sizes) but have found it difficult to get a clean fuse hole. I've used a drill press with different bits, and different speeds, with wood dowel on inside, metal pipe on inside, and the holes always turn out fuzzy.

Does anyone have tips, or experience of a better method?

Thanks.

#2 a_bab

a_bab

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 282 posts
  • Gender:Male

Posted 24 January 2023 - 12:45 PM

In Malta they poke the holes instead of drilling. This way the material gets pushed in giving more support for the BP paste.

Apart from that, I'm preferring TF as it gives precise and reliable timings for me. Even in Malta some bread inserts use TF.

#3 Arthur

Arthur

    Firebreather

  • HE Qualified
  • PipPipPipPipPip
  • 3,780 posts

Posted 24 January 2023 - 01:35 PM

My understanding is that the filled inserts were pierced with a spike or awl, comparable to a sewing needle. 



#4 cmjlab

cmjlab

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 206 posts

Posted 25 January 2023 - 07:36 AM

I should have clarified - I'm not making "traditional" beraq. I don't have the experience to get consistent timing with a paste yet (though with as many inserts as they appear to use in a single break and per row, I don't think the timing would have to be ultra-precise).

I'm making them with TF, as that is one way I can get consistent timing by controlling all factors to ensure everything is done the exact same, and by keeping fuses in order of how they were cut so that variations would be less perceptible.

My main issue is with the shortest timing, where the TF is 0.3" and is barely thicker than the tubes being used (~1/10" sticks out on inside, and 1/10" on outside). Any fuzz or material that obstructs the hole, could block fire partially. That's why I wanted to get the cleanest holes possible, without investing in an expensive laser cutter.

Any tips?

#5 kingkama

kingkama

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 221 posts

Posted 25 January 2023 - 02:25 PM

I should have clarified - I'm not making "traditional" beraq. I don't have the experience to get consistent timing with a paste yet (though with as many inserts as they appear to use in a single break and per row, I don't think the timing would have to be ultra-precise).

I'm making them with TF, as that is one way I can get consistent timing by controlling all factors to ensure everything is done the exact same, and by keeping fuses in order of how they were cut so that variations would be less perceptible.

My main issue is with the shortest timing, where the TF is 0.3" and is barely thicker than the tubes being used (~1/10" sticks out on inside, and 1/10" on outside). Any fuzz or material that obstructs the hole, could block fire partially. That's why I wanted to get the cleanest holes possible, without investing in an expensive laser cutter.

Any tips?

Maltese make the holes piercing the Wall of the shot, the thickness of the walls determines the timing. A green mix added with dextrin and or redgum may already be good for obtaining the beraq effect. If time match is to be used at this point, isn't it better to integrate it directly into the shot structure? Also because the time match is very inaccurate and does not give the beraq effect but plus one "ripresa" That is, something similar but not the same.
The solution used for short timefuse cut Is to use a paper tube of the same diameter(this are sold for the purpose,but i don't know of there someone Who sell it's in US)where the cut Is inserted then glued or crimped with a twine. In the back side a cut of black match Is inserted To ensure ignition. These tubes can be also hand made with craft papers and a strong glue, the tubes are not much that two mm.

Edited by kingkama, 25 January 2023 - 02:37 PM.


#6 cmjlab

cmjlab

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 206 posts

Posted 26 January 2023 - 07:26 AM

I appreciate the info, I have used time fuse and achieved near perfect timing (I posted a video of a 4" comet to report somewhere here recently). So I know the timing can be achieved this way.

As for the tubes with black match for the small TF, I appreciate how you've seen that done - but man, I can't imagine doing it that way, nor do I understand why. I've been using Thunder #3 to ensure ignition, even by the small amount of fire spit out by the TF, so I would think that tubes and black match in a small insert like that would be overkill! (And extremely time consuming. I guess if you have a factory with workers, then it is feasible.

I also don't claim the idea for my method of construction, a gentleman on FW.com makes "Beraq" style shells this way, and they sound exactly the same as ones I've seen in Maltese videos. So I do know it's feasible this way.

*Update* I've fused all the inserts for a couple multi break shells, so I'm making progress towards a completed shell to test. Next up - loading the inserts!

#7 cmjlab

cmjlab

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 206 posts

Posted Today, 08:39 AM

Another lesson learned is that when doing hundreds of inserts with time fuse:
1. A roll of TF does not last long.
2. Wood glue is okay, but takes several coats to "build" up around the TF. As non-traditional as it is, I ended up using hot glue for the 3rd coat just to make sure the TF had something supporting it, and preventing any movement / surviving the break. (I've never used Hide Glue, I wonder if it is thicker than normal PVA/Elmer's/Wood Glue OR if there is a thicker glue that would work)

Anyways, still working on filling inserts and capping them off. Also debating if it's worth throwing a wrap of paper tape around the ends to make sure no gas leaking in around the end disks.



Reply to this topic



  


1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users