Best Method for Punching Fuse Holes in Beraq Tubes

[cmjlab]

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.

[a_bab]

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.

[Arthur]

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

[cmjlab]

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?

[kingkama]

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 January 25 by kingkama

[cmjlab]

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!

[cmjlab]

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.

[cmjlab]

Finally making some progress. Also learning why I don't see YouTube videos of 4" Beraq shells (my hand doesn't fit)... Also encountered issues of how to build traditionally (rolling a shell over a bottom shot leaves a case to long to work with, and not likely to survive lift)....

[Arthur]

Many a traditional Mediterranean shell will stick out of the top of it's mortar when ready to be fired. Shells can be very long especially if there are lots of breaks.

[cmjlab]

My concern isn't necessarily the length of the overall shell, it's more a concern with the length of a single break shell, and the integrity of the sides of such a long casing.

 

14" is a long casing and more chance to compress under the lift setback forces, and split the side of the shell.

 

I ended up trying it two different ways:

 

1. Was to "sand" in a bottom shot and place the inserts on top of the bottom shot, but broke up the rings into 1st Break-2 Rings, 2nd Break-3 Rings and bottom shot.

 

2. Build bottom shot (spiked / pasted in) and enlarge it with chipboard and 2 4" end discs. Then build the 4 rings of reports into a separate shell (spiked / pasted). Then combined.

 

Shells Spiked Together (needs final skirt before full paste layers):

Edited February 19 by cmjlab

[Crazy Swede]

This must be the cleanest possible way of punching holes in cardboard tubes:

 

Tom Rebenklau wrote:

 

"...The punch I use is about .225 in dia. for punching a hole for the 6 mm dia ( .236) fuse that most call 1/4 inch. The stuff that Mark sold was much closer to 1/4 (.250). I concave the end of the punch using a 3/8 or 11/32 ball end mill leaving a slight flat edge on the cutting end. This seems to slightly reduce the force needed to break thru the tube wall. I think this method works "Reasonably somewhat OK" ..."

 

"The punches are 3/8 brass. The tip is turned to the dia of the hole you want. The punch determines the hole size, not the hole in the die. Try about .004 to .005 total clearance. The punch just has to be long enough to cut thru the tube for it to work, however make it long enough to get the slug into the middle of the die. Some times a slug pushes on another slug or two to push it or them out the bottom of the die. I use the quill stop to stop the down movement of the punch.

Die: I drill a smaller dia. hole in the die, then with a boring head I bore it to the size I want all the way thru. With the mill turned off, and with the tip of the boring tool inside the finished hole at the top, and down in the hole about 1/8 or so, not critical, I adjust the tool tip out a few thousands and bore down thru the bottom of the die. This opens up most of the hole so the slugs fall out more easily. Just remember to adjust the tool tip in before you raise up the spindle.

I use thin CA to glue in the time fuse. When you get the fuse to hole fit just right, its a snug, but not too snug, slip fit, watch for a slight wick thru of the CA on the inside. After the CA has hardened I then fillet the outside of the fuse to tube joint. Usually do it twice and watch for the fillet-seal to develop. Pay attention to how the CA works. I have done many side fused inserts not only in headings, but in multi breaks up to 8" and have never had a fuse blow thru or fire leakage at the joint. If you watch and feel what you are doing, you should not have a problem.

The "Its the type of fuse to cross hole fit one would marry if one was inclined to marry a fuse to cross hole fit""

 

To clearify, CA = cyanoacrylate glue

[cmjlab]

TR certainly is a standard to achieve! I'm always amazed at his ability to create precision tools to suit his pyrotechnic needs, someday maybe I'll get there (though not likely).

 

Thanks for sharing.

[FrankRizzo]

This fellow has a setup similar to TR, but uses a pneumatic punch press to drive the assembly and save the arm workout.

 

https://www.facebook.com/Leonar.la.Viccyla/videos/963066048034167

 

Edit: Unfortunately, the video isn't public, so you'll need to be a member of "Fireworks Engineering" to see it.

[cmjlab]

I was able to see it, pretty neat. I wish I had a better understanding of mechanics and machining. I'd love to be able to make tools like that. Thanks for sharing.

[WonderBoy]

Fun looking shells!

 

Catching up A bit here. A sharp drill bit will help make a more clean hole. I use a wood dowel inside the tube to minimize blowouts, rotating the dowel as it gets worn. If the outside of the tube has a ragged edge you can clean it up with a razor blade, but I've not found that to be necessary except for the shortest of timings.

 

"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."

 

Are you using stepped disks? I definitely recommend a few turns of pasted paper or gummed tape around the ends of the inserts. Helps keep the disks from shearing off as well as create a fire barrier.

 

"Also encountered issues of how to build traditionally (rolling a shell over a bottom shot leaves a case to long to work with, and not likely to survive lift)...."

 

Nearly all shells I make start with the final break rolled on the bottom shot. Meaning, the bottom shot is made, ending up at the size of your case former after pasting or the rin wrap (3.5" for a 4), and then the preceding break is rolled over that. There shouldn't be any compression over the bottom shot portion of the casing with the paper rolled tightly against it and closed on the bottom.

 

Are you using Titebond 3? 3 is thinner than I like for most things, you might try Titebond 2.

Edited February 27 by WonderBoy

[cmjlab]

Yeah I encountered the same thing, mainly where the shortest timings are barely longer than the tubes width. It ended up being fine, after I settle the flash, it surely had to be touching the TF.

 

I did end up using a couple turns of paper tape around the seams. I did not used stepped discs and am still somewhat nervous about whether they hold up to the break.

 

The biggest problem with using the bottom shot to roll the case for the inserts, was that I used 3" bottom shots (I've not rolled my own bottom shot casings and didn't want to start with my first report insert shells - if it fails, I want to rule out an issue with a bottom shot manufacturing flaw on my end). That left me trying to pack "sand-in" a 3" bottom shot at the bottom of a 18" long x 4" ID insert case. So I deviated from traditional, which is what I will blame the failure on if they fail!

 

Yes I used Titebond 3 Ultimate glue for the fuses. I'll agree that it's much thinner than I was expecting. I like the Titebond "Thick n Quick" but wasn't sure it'd be strong enough. I'll buy Titebond 2 next shopping trip and give it a try.

 

The shells are built, I'm just waiting for a good day to test them. They came out about 20" long each and about 9 lbs each (mainly because I packed the insert spaces with cat litter instead of just shimming them. Next time I will use shims instead).

 

I'll post the videos good/bad and/or ugly as shit! :-)

Edited February 27 by cmjlab

[cmjlab]

[WonderBoy]

Looking forward to seeing them, hopefully they will work as planned.

 

Inserts made with just disks may work fine in smaller shells, but next time I would recommend either using stepped disks or spiking your inserts. Usually better to have a mechanical bond in addition to the glue.

 

I've never used Thick n Quick, so I can't speak to that, but I do like Titebond 2. I still use at least two glueings on the fuse though. A bead around the fuse before inserting it all the way in, so some gets drawn in as you insert it the rest of the way, and then another after that's dry to create a fillet.

[cmjlab]

The stepped discs are a good point. I did double up the discs to try to strengthen them and protect it from flexing during the burst potentially breaking the glue seal and turning the whole shell into a massive bottom shot.

 

You are correct though and we shall see! I'll fire it tomorrow night hopefully.

[Carbon796]

Using a standard sheetmetal type hand punch. Works great for side fused inserts. As long as the side wall isn't overly thick. Or a small diameter. Though since 1/4" TF isn't really a true 1/4" diameter. For the best fit you'll want to buy a 15/64" die/punch set for it. If your trying to punch small diameter and/or heavy walled tubes. You'll want to make a custom one.

 

If your stuck with drilling. If you drill them slightly undersized. You can burnish them up to size with a tapered awl/punch. That will give you a cleaner and better fit generally.

Edited March 8 by Carbon796

[cmjlab]

Prior to watching TR's video, I had wondered how people were cleanly "punching" holes in a round tube - it makes a little more sense now.

 

I've had a couple conversations with someone here or in fw.com about the idea of a concave cutting punch for something like TF, but it looks like that is what TR was using for Punching holes in his tubes. So it works from a theoretical and practical standpoint.

 

Now if I just had a modicum of TRs machining ability and machines.....

[Arthur]

(I've never used Hide Glue, I wonder if it is thicker than normal ...

 

 

 

The hide glue I've seen was more like cement! Very viscous when wet, and it sets rather than drying so it doesn't shrink and go thin when it sets.

Edited March 8 by Arthur

[cmjlab]

Was it the ready to use glue (Home Depot / Lowes), or melting pot hide glue? Or is both the same. I can order some of the ready to use hide glue, but I don't have a lot more room for a melting pot / bag of hide glue chips.