Priming Visco fuse

[dangerousamateur]

I just shot some little 2" and 1,5" shells today and I had 2 duds in 7 shells.

 

I used simply visco fuse as timefuse and let the fuse protrude about 3mm into the liftcup.

So the fuse was pretty much touching the lift granules... By the way, the lift was H3. (yes, I know, visco contains sulphur...)

 

Well. I don't now how the fuse could not light under these circumstances...

 

I saw many pictures of Shell inserts - lighted with Visco when the shell breaks. so the method can't be wrong.

 

 

Any idea what might be the solution? Priming the Visco? Would have the advantage to prevent sulphur leaking out of the fuse...

What composition would you use? H3 comes to my mind, but it burns very fast, what might be a disadvantage for this task.

 

And no, I don't want to use spolettes for such tiny devices.

[asilentbob]

Do you cut the fuse at an angle to expose more of the core?

 

When I prime visco I cut at an angle, put a bit of dilute NC solution on and then dip in very fine granulated BP. There are a few sulfur-less primes out there that you could use instead. Sealing the ends with the NC solution has the benefit that the composition in the visco is less likely to leak out. If I don't just simply cut at an angle I will use a razor and slice a portion of the fuse in half and then seal and prime as before, for more surface area. In commerical shells I have seen they look like they just dip the whole end of fuse on the completed shell in BP/binder/water or BP/NC slurry.

 

Also, on the insides of the shells I'd leave more than 3mm of fuse protruding, but that's just me.

[MikeB]

Priming both ends is important. Cut your fuse at a slant or split it to form a snakes tongue. I have used a bp slurry and nc mixed with meal successfully. With either method after applying your slurry dip it into something like 7fa or 4fg so it takes fire easily. The additiion of a small amount of fine mgal or ti will really heat up the fire giving end if needed.

 

 

[Peret]

I've fused small shells with visco and it was quite reliable, but I did have a few failures to light. Strangely enough it was all primed fuses that failed. Turns out the acetone in NC lacquer loosened the wrapping threads, and tapping the softened fuse into powder smooshed the end over and blocked the fire.

 

If you could recover your duds (which you ought anyway before some kid finds them first), you could look and see whether the fuse failed to ignite, or if it burned but failed to light the burst.

[dan999ification]

sound advice.

for inserts where i cant use time fuse, ive used straight meal/binder/slurry in the past then dipped in meal again

or dipped in ping pong ball laquer then bp fines

ever thought of attatching a star to the fuse, pasted onto the shell and touching it, you get a large surface to catch fire you could also prime the star and or use it as a rising tail.

only ever launched a few shells with visco and had some fails, time fuse evrything now, for 1.5" i just make bombettes-massive surface to catch fire, simple construction, no drying time, 2mm visco lights evrytime.

 

dan.

[dangerousamateur]

Also, on the insides of the shells I'd leave more than 3mm of fuse protruding, but that's just me.

I meant on the outside, where the liftcup is attached.

 

Do you cut the fuse at an angle to expose more of the core?

Next time

 

If you could recover your duds (which you ought anyway before some kid finds them first), you could look and see whether the fuse failed to ignite, or if it burned but failed to light the burst.

Thats the biggest headache - I found nothing. But it was a very remote area, very likely the farmer will plough them under...

 

If the visco would have lit, it would have ignited the flashbooster for sure. So I think priming on the upper end is not necessary.

 

 

I'll try H3 prime on the visco with exposed core and see what happens...

Edited March 9, 2012 by dangerousamateur

[dagabu]

I just shot some little 2" and 1,5" shells today and I had 2 duds in 7 shells.

 

I used simply visco fuse as timefuse and let the fuse protrude about 3mm into the liftcup.

So the fuse was pretty much touching the lift granules... By the way, the lift was H3. (yes, I know, visco contains sulphur...)

 

Well. I don't now how the fuse could not light under these circumstances...

 

I saw many pictures of Shell inserts - lighted with Visco when the shell breaks. so the method can't be wrong.

 

 

Any idea what might be the solution? Priming the Visco? Would have the advantage to prevent sulphur leaking out of the fuse...

What composition would you use? H3 comes to my mind, but it burns very fast, what might be a disadvantage for this task.

 

And no, I don't want to use spolettes for such tiny devices.

 

 

I take it that you dont fire shield the inside of the shell and that you are relying on the timing of the fuse to be determined by the method of attaching the fuse to the shell or do you use some metal take to fire block and time the fuse?

 

Yes, I have made thousands of inserts using visco cut at 70° (a lot like a syringe needle) after a long length is wrapped up in metal tape, then coat the ends with NCL and a dip into Meal-D. You can protect the chlorate from the sulfur by dipping it in the NCL after it is dry.

 

-dag

 

 

Edited March 9, 2012 by dagabu

[PyroAce]

Use two fuses, you can't go wrong, one of the two has to light, it certainly increases your chance of fuse ignition.

[warthog]

If the visco would have lit, it would have ignited the flashbooster for sure. So I think priming on the upper end is not necessary.

I wouldn't be so sure of this, it is not such a hard thing to prime both ends. Is it? I crossmatch even the best of time fuse for the same reason,

I would want to be as sure as I could that the shell would go off. It can't possibly add much to the cost of the shell either.

 

There are ways the bare fuse may not pass fire to even the hottest receptor, like maybe being blocked by something tin the shell that shifted during handling and firing. By adding the priming, you get a much larger bit of fire at the end of the burn making it far more likely to pass fire to the burst than even angle cut visco would give you. Also, angle cutting will also allow the very tip of the fuse's powder to drop out unless you seal it in there, which the priming will do for you.

 

Of course, it is your call.

[PyroAce]

Here's two baby shells that I use Visco wrapped in masking tape, double fusing almost never fails.

 

You also need to take into account the force of the lift going off can shred the visco, this would be more likely to happen on larger shells which should be using proper time fuse of spolettes anyway.

 

[allrocketspsl]

mate make up some benzolift youll like the height youll get and its a hotter flame than bp or h3.Dip visco after you have cut at an angle into nc slurry then into bp with 10 silicon and youll get 100 percent.

[dangerousamateur]

OK your right. I'll give em a big blob of fuel on the upper end , it can't hurt. Doublefusing will be adapted too.

 

Well I've got no experence with benzolift yet, but I really like to use H3.

I like chlorate, because when times get harder I can make it myself and be independent from pyro supplies.

 

Is there something I can put into my H3 without raising the ignition temperature to much, for use as prime?

Most metal fuels seem to hinder ignition, especially when the comp is bound with something. Like in some silver stars.

 

I'm looking for something like "Thermalite", but of course without sulphur/sulphides...

Edited March 13, 2012 by dangerousamateur

[allrocketspsl]

OK your right. I'll give em a big blob of fuel on the upper end , it can't hurt. Doublefusing will be adapted too.

 

Well I've got no experence with benzolift yet, but I really like to use H3.

I like chlorate, because when times get harder I can make it myself and be independent from pyro supplies.

 

Is there something I can put into my H3 without raising the ignition temperature to much, for use as prime?

Most metal fuels seem to hinder ignition, especially when the comp is bound with something. Like in some silver stars.

 

I'm looking for something like "Thermalite", but of course without sulphur/sulphides...

 

dan something show how ro make it

[Mumbles]

Dan Williams. Though, I don't know how much use it will be. I wouldn't always consider the formula given a prime of sorts. Priming even time fuse with thermalite has lead to failures in the past. Even if pyro is shut down completely, you'll still probably be able to get agricultural grade potassium nitrate.

 

http://fogoforum.us/thermalite.php

[dangerousamateur]

Priming even time fuse with thermalite has lead to failures in the past

Can you imagine what was the problem?

Since these fuses contain pretty much flashpowder, the might just explode and blow the prime away...?

[Mumbles]

Many silver streamers are basically flash mixes, but several will take some heat to get them going.

 

I think the issue that happened before is on the giving, not the receiving end of the time fuse. Some time fuse has difficulty lighting the internal crossmatch, and thus can cause shells to have a round trip. This happened to a number of shells a few years ago at PGI. Even still, it does not light as easily as black powder. Flash is potent not because it is extremely easy to light (it's not), but because after it gets going it releases so much energy and the products are much more stable. On a basic level flash is just a modified thermite, and most people know how hard they can be to get going. However, once they get started, they sure do go.

[oldguy]

Yes, I have made thousands of inserts using visco cut at 70° (a lot like a syringe needle) after a long length is wrapped up in metal tape, then coat the ends with NCL and a dip into Meal-D. You can protect the chlorate from the sulfur by dipping it in the NCL after it is dry.

 

-dag

 

When you say METAL TAPE.

Do you mean like high temp aluminum foil tape used on furnace vent ducts?

[dagabu]

When you say METAL TAPE.

Do you mean like high temp aluminum foil tape used on furnace vent ducts?

 

Yes, the real "duct tape". I can find it locally for a few bucks a roll at the local surplus center. Even the really violently burning Chinese green visco doesn't burn through the tape and hot glue sticks to it very well.

 

-dag

[oldguy]

Thanks & good to know.

I have a few rolls, but (if I remeber correctly) paid over $20 a roll.

[dagabu]

Thanks & good to know.

I have a few rolls, but (if I remeber correctly) paid over $20 a roll.

 

That's the stuff. That a vacuum bead?

 

-dag

 

 

 

[dangerousamateur]

Is that really necesary?

I'm using such stuff:

http://www.builders-buddy.co.uk/products/9660/386/masking-tape.aspx

Winding about 80mm of this stuff around the visco never failed me.

[dagabu]

Is that really necesary?

I'm using such stuff:

http://www.builders-...sking-tape.aspx

Winding about 80mm of this stuff around the visco never failed me.

 

Here is the deal with masking tape. It's flammable, it drys out over time, it burns for a long time floating on the air and it can "pipe" a flame front if not done well.

 

I am all for working with whatever you want to use but it doesn't mean it is the BEST thing to use or the only thing to use. It is better for us to discuss ALL of the varieties of fire-blocking then to just settle on one unless the rest are dangerous. After all, gummed kraft tape works pretty darn well too if you let it fully dry before lighting it.

 

-dag

[pyrogeorge]

I use wet BP for prime the visco fuse and then i add it to granulated BP.

[dangerousamateur]

Nice large surface.

 

Is there any reason not to use NC for this task?

 

Water based stuff seems to roll off the fuse, doesn´t adhere very well...

Edited March 27, 2012 by dangerousamateur

[dagabu]

3mm chines 100 foot rolls of fuse for sale 80.00 free shiping

 

Ignore the spammer...