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Time fuse


Merlin

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Does everyone use purchased 1/4 time fuse? I had been buying 10 or 20 foot rolls and they burned at a rate of 3.2 seconds per inch. I found a 50 foot Roll of Japanese. I cut a 10" piece from the front and the same from the end. Timed the burn rate which was 2.1 seconds for both ends. I noticed two things it's burn rate was much faster than my previous fuses. Also it burns much more vigorously spitting showers of sparks from the end lit and another shower at the end.

Is this normal?

Before with other fuses you could hardly tell they were burning at all til you got just a little spit of fire from the end when it burned through.

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You might want to try timing a shorter piece. Longer pieces of time fuse burn more quickly - I've been told it's because of the back pressure of the long tube made by the spent portion of the fuse. Still, it sounds like you got some good fuse.

 

Timing itself isn't nearly as important as consistency. Whatever the burn rate of the fuse, so long as each piece performs the same you should be good to go.

 

Kevin

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My timefuse is chinese I think, and it's spits fire like crazy, more sparks and more powerfull then visco for example. You can see the timefuse burning as the shell is going up in the air.
I like it this way, it gives a safe feeling your shell will break, you can see where your shell is going and you know it's ignited when lift-off.

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  • 2 weeks later...

I had been getting 3sec. per inch and the last i bought i think from cannon fuse is 2sec.. As far as the timing i had rather have the 3". I also noticed the 2" did not burn as vigorous as the 3". I guess it depends on when and where you get it.

Edited by dynomike1
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The Japanese fuse Marc sells has very good fire spit and generally runs in the 2.2 second range (his site says 3.2 but the stuff I've received is always in the 2.25 area), which is a little more friendly to work with when short precise timings are needed.

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I like to buy my timefuse in long lengths (50ft or more at a time). Then, burn speed isn't really important. I cut a certain length, time it to determine it's speed, then just make sure that I cut it all consistently.

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I understand the principle of time fuse but don't understand why it would be preferable to spollettes in shells or balls. Is it more accurate in it's timing or just more convenient?

Though I have yet to need one, I've been ramming assorted comps in spollettes to test the timing so I'm very interested in this subject.

Edited by OldMarine
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Time fuse is decidedly more convenient than spolettes, and in my (albeit limited) experience, just as accurate. Ask TR -it's what he uses, and he has the accuracy thing down pat.

 

Also, in order to ram consistent spolettes you need a supply of powder - if you change the powder you are using you potentially change the timing. I've rammed spolettes that burn from 2.1 to 3.3 seconds per inch, depending on the powder I used. So long as you use the same powder and the same technique, they should be quite consistent.

 

With that said, I prefer time fuse. Quick, cheap, and reliable. If I need to make a shell with a short delay (hence a short piece of time fuse), I simply make a 'spolette' out of a piece of time fuse and a section of 1-ounce rocket tubing.

 

Kevin

Edited by Nessalco
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I noticed that Marc has suspended sales of his time fuse, this according to a post he made on another forum. I don't know if this is a temporary suspension or long term, but I also noticed that a few other sites have dropped their listing for time fuse as well. You may very well need to learn consistent spolette manufacture sooner than you think.

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Frederick,

 

From what I've heard, I gather that Marc isn't likely to sell more time fuse, although he MAY be able to continue selling quickmatch.

 

That would be up to him, of course. He might not think it's worth his time to sell only the one, without the other.

 

Lloyd

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Lloyd,

Based solely on what I read I wouldn't be surprised, which is unfortunate. For me.. the time fuse was the important commodity.

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For me.. the time fuse was the important commodity.

 

Indeed. I've been meaning to buy stranded quickmatch, but haven't been able to locate a seller that could accommodate me in EU, for quite some time, but i've made do with home made stuff. Timefuse i simply cant "make" so i'd have to go with spolette's if i couldn't get more. It would be a switch to a somewhat different building process, and we all hate to change things that work...

B!

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I'm very lucky in that respect. I bought one of the old Accrow Fuse spinning machines a few years ago. It's a chore to run it (say "three-hour-long heart attack!), but it will make more fuse in an hour than I can use in a full year.

 

It makes the older-style cotton tape-wrapped style of Bickford fuse (jute and tar inners). It's odd-looking to most pyros, yes; but it works perfectly.

 

Lloyd

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I use chinese time fuse, bought in rolls.

My fuse burns consistently 8mm per second - a tad more than 3 seconds per inch.

I haven't experienced (or noticed) that long fuses will burn faster. On the contrary, I find them to be reliable always.

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I'm very lucky in that respect. I bought one of the old Accrow Fuse spinning machines a few years ago. It's a chore to run it (say "three-hour-long heart attack!), but it will make more fuse in an hour than I can use in a full year.

 

It makes the older-style cotton tape-wrapped style of Bickford fuse (jute and tar inners). It's odd-looking to most pyros, yes; but it works perfectly.

 

Lloyd

 

Pics... Of the machine, of the fuse, of the machine in a package being shipped of to me, the happy face of everyone when they realize you will now be saved the heartache, and, my happy face when i get to grow old never worrying about time fuse again. Ever.

Well, the first two at least? Pretty please?

B!

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I cannot for the life of me find pictures of the machine right now. It's under cover out of the bay, while I work on another machine for a client. I'll try to get some shots of it, dirty and temporarily abandoned, tomorrow.

 

However, here are two shots of the fuse it makes. It's the old Accrow fuse previously made by Precocious Pyro: powder core with two cotton tracers, 10-strand jute wind, 6-strand jute counterwind, calendaring to size, tar bath, cotton tape wind, cotton tape counterwind, dye bath, drying, spooling.

 

First shot is the disassembled view, second is the cut end.

 

http://www.pyrobin.com/files/DSCN1365.JPG

http://www.pyrobin.com/files/DSCN1366.JPG

 

This is a rejected section, where we got the tar bath too hot, and it permanently stained the outer cotton wrap. Normally, it's a very clean blue, green, or pink, depending upon the batching code.

 

The fuse is lying on the cavity plate for a 54-cavity, 22mm crossette pressing mold <G>.

 

Lloyd

Edited by lloyd
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Heh! Yep. It's an old "standard" style.

 

Also, when the machine's not set up and making fuse, I still occasionally fire up the tar pot on it to make blocks of tar for r'infasciature shell assembly: (The "A.M.D." is my company, Automation Machine Design, LLC)

 

http://www.pyrobin.com/files/Rinfasciature_tar.gif

 

<G>

L

Edited by lloyd
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Looks nothing like the old blasting-fuse i used, so i guess that to differs depending on taste, availability, and so on.

 

Thanks for the pics. Will be looking forward for the rest of em.

B!

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Couple of shots of the fuse machine. I took off the tarps, because it's stored in an open bay right now. It's dirty, but only takes about an hour to clean up.

 

The first is a long view showing the top 10-cord winder and the bottom 6-cord winder.

The second is centered on the tar pot.

 

Not shown is the powder hopper, which mounts up above the first winder (and has a stirring motor to keep the powder flowing), and the two tracer spool holders, which mount above the powder pot.

 

http://www.pyrobin.com/files/DSCN1424.JPG

http://www.pyrobin.com/files/DSCN1425.JPG

 

Lloyd

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Yeah... they rust a little when the machine sits in the humidity; but it is just minor surface rust. I lubricate them before storage, and a healthy squirt of penetrating oil and about two minutes of 10+HP of hydraulic power to the thing (oh... did I mention it's hydraulically run? <G>), and they clean right up. It's been through this cycle about ten times. 'Recovers just fine each time.

 

I don't hate the machine, I just have little but 'personal' use for it. So it sits until I need fuse. Then I make 500', and put it away again.

 

It isn't small... but you see only 1/10th of it while operating. There are those taken-off parts I mentioned, then there's also the 150' drying run out and back, before the fuse is spooled. (I did 'fold' the drying run to make it only about 30' long, though.)

 

Lloyd

Edited by lloyd
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ALL 'spun' fuse is made by basically the same process: Contain and surround BP with fabric or yarn in multiple layers, counter-wound. Seal the outside with some sort of binder to prevent unraveling.

 

Yeah... more steps for waterproof 'sump' fuses, but basically the same process.

 

LLoyd

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Oh, BTW, Mr. B.,

 

You had gotten me worrying whether or not I forgot to lube the chains before this last migration out of the fuse-making bay.

 

All that "rust" is only superficial, and much of what looks like rust is actually just dust blown in under the tarp. (it gets very windy here during Summer thunderstorms, and the outdoor bays are dirt-floored). And most of the dust is vegetative matter blown in from the surrounding pastures... basically just 'lint'. A very light brushing with a hair brush revealed almost-perfect, lubricated steel underneath, with only the very lightest dusting of actual rust.

 

I manually checked all of them, and they're as free-moving as new.

 

They're fine! <G> (whew!)

 

LLoyd

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