20 replies to this topic

[Give_me_APCP]

I have some 2.2mm "waterproof" double-laquered and some 1/8" single-coated visco fuse, which work fine when it's dry.

Neither one of these does good in the rain/water however. Well, the 2.2mm sometimes gets lucky, but 30% are failures when submerged.

What is this thick yellow stuff I see people use? It's not nesseccarily what I need, but curious. Or am I hallucinating?

I'm looking for fuse that is able to be handled a bit and bent without its laquer coating breaking so easily and thus rendering it useless in water. Basically the maximum protected fuse available will work. It should be a minimum 1/8" diameter, larger (1/4") would be desireable.

I just don't like the visco stuff, you bend it at sharp angles and you get cracks in the thin laquer coating...

Can anyone give me suggestions/names? Possible online retailers?

Thanks!

[Ritual33]

PIC fuse my friend, you can literally make knots with the stuff and it will still be waterproof. This stuff is the daddy, but as with most decent stuff it comes with a price. Just do a search on the forum, theres plenty of discussion on this. I've no need in the stuff but I've seen on alot of sites it retail for about ?1 per meter, let me know if you find it cheaper.

Regards,
Drew

[ProfHawking]

fraid to say PIC is what you probably want, but its like gold-dust now.
ICI have stopped making it, and i think all the stock has now probably been bought up.

[Creepin_pyro]

Guys - he said he wanted 1/8" minimum, preferably thicker than 1/4"!

PIC fuse is certainly not thick, in fact, it's the thinnest fuse I've ever seen bar blackmatch. Way thinner than 1/8".

Could you describe the thick yellow stuff you've seen in a little more detail?

Seeing as you're looking for something with a relatively large diameter, you might want to consider making your own silicone-bound fuse. This would be completely waterproof, flexible, and short lengths can easily be extruded from a syringe. I've never made it, but it sounds like it may be exactly what you're looking for.

[ProfHawking]

i think he was regarding thickness of fuse to be vital to its waterproofness. in visco, the thicker it is the better the water resistance anyway.

Pic doesnt have to be thick to be waterproof. And, where would you need thick fuse where thin fuse (with wadding perhaps) wouldnt work?

[Give_me_APCP]

i think he was regarding thickness of fuse to be vital to its waterproofness. in visco, the thicker it is the better the water resistance anyway.

Pic doesnt have to be thick to be waterproof. And, where would you need thick fuse where thin fuse (with wadding perhaps) wouldnt work?

Yeah he's right, I really only said those larger diameters as I figured it would contribute to their "waterproofness" factor. If this PIC stuff is what I need, then I will begin my search.

Hopefully I can find some, it sounds like it will be tough. If anyone has a roll they want to sell, pm me please.

Thanks guys.

Edit: And yep, I cannot find this PIC fuse anywhere on the net. I found a thread saying www.kn03.com has it, but I cannot find fuse there.

Could I take some 1/8" visco, and wrap it in thin silicone tape for the same effect? Or would I be better off dipping a length of it in something like the rubber used on tool handles?

Edited by Give_me_APCP, 22 July 2006 - 06:21 PM.

[Creepin_pyro]

Don't bother with kno3.com. The guy is a ripoff merchant!

I think the most important factor which determines water resistance in visco is the quality of the outer coating, not necessarily the diameter. I have some 1/16 visco which is very high quality and has no problem burning underwater, while some of my 1/8 visco is completely useless when it gets slightly damp.

As you mentioned, the easiest solution will probably be to improve the outer coating of the visco by either dipping it or wrapping it. Either way, make sure the modification doesn't turn it into quickmatch before you use it in a device!

I couldn't work out if you're in the UK or US, but if you're in the UK, try these guys for PIC. If you're in the US, you will not be able to find PIC anywhere

http://www.tplpyro.co.uk/

I'd be interested to hear if they're actually still stocking PIC...

Good luck with your quest

[BigG]

The other option - commonly used in the USA, is Delay Fuse - it's a lot of work, but as long as you cover the cross match with a waterproof tape, it works.

[Give_me_APCP]

Alrighty!

I tested the 2.2mm visco I have with a wrapping of silicone pipe thread tape.

Each fuse was wrapped very well, with about a 3mm increase in tape coverage per wrap (rotation). It actually isn't slow and time consuming wrapping them either, you can move right along.

First, I started with a wrapped visco against a standard visco, each 7" length, in open air. They were lit and each finished burning almost at exactly the same time.

Submerged, I observed an approximate 20-25% increase in burn rate, but of coarse I do not contribute this to the wrapping (since they burnt the same rate unsubmerged), simply the added water confinement.

I even took one fuse after it was wrapped in silicone, and twisted and bent it all over as badly as I could. I burnt this underwater and it burnt flawlessly.

Silicone tape is the answer!

[Kevin J]

kind of unhelpful, but, up in Canada where I live, you cant get any sort of fuse, it's black match all the way, or whatever else you can make.

[Creepin_pyro]

I've seen theatrical suppliers who carry fuse in Canada. I don't think there are many places on earth where you cannot aquire visco if you try hard enough!

Here are a couple of photos of the ultimate waterproof fuse!
PIC - view of core
Side view

A couple examples of visco that is waterproof:
waterproof 1
waterproof 2
and
not waterproof 1
not waterproof 2

You can see the difference in quality straight away. The waterproof stuff has more string wrapping, and a thicker layer of NC laq.

[Anders Greenman]

Silicon laquer should make a non waterproof visco fuse pretty good. The only problem is the price and availability of ethyl acetate. The best source may be nail polish.
Frogfot describes where to find and how to make silicon laq.

www.frogfot.com (see synthesis and pyrotechnics)

Edited by Anders Greenman, 29 July 2006 - 03:17 PM.

[lew]

Alrighty!

I tested the 2.2mm visco I have with a wrapping of silicone pipe thread tape.

Each fuse was wrapped very well, with about a 3mm increase in tape coverage per wrap (rotation). It actually isn't slow and time consuming wrapping them either, you can move right along.

First, I started with a wrapped visco against a standard visco, each 7" length, in open air. They were lit and each finished burning almost at exactly the same time.

Submerged, I observed an approximate 20-25% increase in burn rate, but of coarse I do not contribute this to the wrapping (since they burnt the same rate unsubmerged), simply the added water confinement.

I even took one fuse after it was wrapped in silicone, and twisted and bent it all over as badly as I could. I burnt this underwater and it burnt flawlessly.

Silicone tape is the answer!

Is this tape you mention the same as commonly available PTFE thread tape?

I ask because PTFE is extremely non-flamable, and I wondered if it would retard the burning of the fuse.

[Suusi M-B]

I have some 2.2mm "waterproof" double-laquered and some 1/8" single-coated visco fuse, which work fine when it's dry.

Neither one of these does good in the rain/water however. Well, the 2.2mm sometimes gets lucky, but 30% are failures when submerged.

What is this thick yellow stuff I see people use? It's not nesseccarily what I need, but curious. Or am I hallucinating?

I'm looking for fuse that is able to be handled a bit and bent without its laquer coating breaking so easily and thus rendering it useless in water. Basically the maximum protected fuse available will work. It should be a minimum 1/8" diameter, larger (1/4") would be desireable.

I just don't like the visco stuff, you bend it at sharp angles and you get cracks in the thin laquer coating...

Can anyone give me suggestions/names? Possible online retailers?

when I was at school I improvised a fuse for a depth charge useing a plastic straw and the fuse was sodium chlorate weed killer and sugar 4:1 impregnated into toilet paper then dried and stuffed into the straw.

The burn rate is fairly slow and it doesn't burn hot enough to melt the straw, so when lit burns underwater the gas pressure keeps the thing dry

[Give_me_APCP]

Is this tape you mention the same as commonly available PTFE thread tape?

I ask because PTFE is extremely non-flamable, and I wondered if it would retard the burning of the fuse.

Yes that's what is is. I said silicone because I believe they are merely the same.

PTFE will not slow the burn rate, because it is not the PTFE which is burning as a fuel. The fuse doesn't "know" it's there, it simply gets burned through.

That PIC fuse looks to the eye like it would create quickmatch, as the plastic separates from the propellant easily (although I'm sure it burns perfectly).

But honestly, now that I've tried this, I'd much rather buy visco and wrap it with tape as opposed to buying PIC, the stuff works wonders. The added structural strength you can choose to add yourself by how many wraps you do is a plus too.

You can increase the burnrate up to about 60% by very thick tape wrapping, I tried this with the 2.2mm stuff. Bigger diameters would burn even faster if wrapped well. As I said a light wrapping has no influence on burnrate.