Priming vs. crossmatching the time fuse

[50AE]

Because I got time fuse on my hands this week, I don't know how to use it correctly. I prepared 5 small pieces of it, but they weren't exactly cross matched, because my black match is very thick and it can't pass through the fuse if I pierce a hole. So I cut the pieces of time fuse on the ends perpendicularly and I stuck the blackmatches in the cut, then I secured it with a string. The 5 time fuses easily ignited, but I'm not sure if I should rely on this method.

I've seen people cutting the time fuse diagonally, then priming it with a black powder slurry. Is it reliable?

 

And what is the best method? Crossmatching or priming?

I will prepare thinner strands of blackmatch if you say so.

Edited March 23, 2010 by 50AE

[Pretty green flame]

Always crossmatch time fuse. Either pierce it or cut it lenght-wise and insert a piece of blackmatch and tie it with string to secure the blackmatch. I personally would only cut time fuse diagonally and prime it, on the inside of the shell to pass fire more efficiently. I doubt priming with black powder slurry is as effective as crossmathing, though i'm no expert on the matter, i've only used time fuse a couple of times.

[qwezxc12]

I always cross-match, either by piercing (for more precise timing - timed reports, etc.) or by slitting, inserting the blackmatch, and either tying the slit with floss or taping with a tiny strip of hi-tack tape.

 

I use only Visco for time fuse. I buy it precut from Cannonfuse.com (link) and burn several pieces to confirm the burn rate. The 3" lengths work for shells up to 6in. 8in shells need a longer delay, so I cut those to length as needed off a roll.

 

I've tried many methods and have settled on wrapping the visco with good ol' duct tape to build it up to ~1/4"OD. It's extremely tacky, waterproof during pasting, totally fireproof, holds timing marks made with a Sharpie for cross-matching, and cuts and pierces well. Here's a few 6in shells from last summer just prior to being fitted with lift cups and leaders:

[NightHawkInLight]

I've had success both ways, never a failure. If it's a large shell I crossmatch simply because it's tried and tested. I use both visco and time fuse for timing depending on the application. I've always simply primed visco, and have never even heard of crossmatching it until now. No failures.

 

When priming time fuse I make sure the BP slurry is melded with the core and call it good.

 

So, based only on my experience, it's perfectly fine to prime the quality time fuse available today.

[dagabu]

That's a lot like asking what is the best way to make black powder, ask 11 of us and you will get 12 different answers.

 

The downfalls of each method (taken from BATFN II)

 

-Cutting the Time Fuse (TF) at a 45° or greater to expose the core to more flame and priming with NC and meal/7 FA etc.

-The problem lies with the lift charge. As the lift burns, it creates a pressure wave that can shatter the prime which takes fire but does not transfer it to the time fuse.

 

-Splitting and tying the time fuse with black match.

-The lift can ignite the string holding the time fuse together causing the black match to fall out before lighting the time fuse.

 

-Punching and cross matching the Time Fuse.

-Punching the Time Fuse can cause tar to cover the powder train.

-Punching needs to be dead center or the powder train will not be pierced.

 

Some prefer to cover the whole thing with a slurry of meal and NC after it is punched or split. The same thing can happen when the lift charge goes off though so top fusing may be a good idea.

 

D

[TheSidewinder]

And, in the category "Everyone has an opinion"......

 

I use genuine Thermalite. There are either 3 or 4 "speeds" available, of which I have two, and I've noticed no difference whatsoever.

 

You *must* strip the plastic wrapping from the piece completely, and remove 3 of the 6(5?) wires under that wrapping. I punch the timefuse with a hole *just* bigger than the Thermalite, insert, crimp lightly with pliers. Bend the "inside" piece towards the inside end of the timefuse so it fits inside the break charge cannule (my preference). On the "outside" end, I loop the QM leader under the fuse, and the QM passfire to the lift over the fuse, then carefully wrap one side of the Thermalite around the leader, and the other around the QM passfire. I've constructed admittedly a relatively few shells, but I have a 100% success rate on my breaks.

[50AE]

Thanks for the useful comments. I'm considering to crossmatch instead of priming, so I'll have to make some thin blackmatch.

[dagabu]

LOL!

 

I guess the next question has to be, "How do you make black/cross match?". Or the better known variant, "Whats the best way to make cross/black match?".

 

All I know is what works for me, 1% CMC, 3% Dextrin, 75:15:10 ball milled for 24 hours in a hobby tumbler 0r 6 hours in a Sponenburgh style jar. Add water until it is a pancake consistency, spool off several feet, soak it in the slurry and pull it out slowly, use an orifice if you want a particular size.

 

I know you know how to make it .50, this is for the curious. BTW- I punch everything, I hate slitting and tying, the old fingers just don't like it any more.

 

D

Edited March 23, 2010 by dagabu

[Bonny]

 

I know you know how to make it .50, this is for the curious. BTW- I punch everything, I hate slitting and tying, the old fingers just don't like it any more.

 

D

 

I guess I'm still young enough to slit and tie ...but I don't tie anyway.

My method is to slit and insert a pc of BM- I usually use the wide ribbon stuff from commercial QM. I then glue it together with BP/NC slurry and a final dip into some granulated BP or mill dust or whatever I have around. I have also simply glued in the BM with NC and dipped in BP. In any case I haven't had any problems.

 

I have punched timefuse for fan cake timing but not shells.

[NightHawkInLight]

I guess the next question has to be, "How do you make black/cross match?". Or the better known variant, "Whats the best way to make cross/black match?".

It just so happens I have an article on my website detailing a black match machine:

 

http://grassrootsdiy.com/black_match.htm

 

I made my machine to make a two strand black match, but it can be made up of any number depending on its purpose. It's not difficult to crank out 100 yards of two strand black match in five minutes. Something I don't mention on the page is that dampening the string with a solution of water and potassium nitrate prior to drawing it through the machine will give a more even coat. It will also allow the string itself to burn rather than just the outside layer of BP.

[dagabu]

Nice tut!

[50AE]

If you want to switch to blackmatch discussion, then I'll add something. From my personal experience, using CMC only as a binder (+5%) CMC makes a very resistant blackmatch. I don't use dextrin anymore.

[dagabu]

.50,

 

I agree that it is resistant/resilient but it blocks pass fire in high quantities while dex does not. Don't take my word for it, make both and see that your timing will change some and it does not propagate fire as fast.

 

D

[50AE]

I haven't noticed, or maybe I don't care much. If I want precision, I'll be using e-matches. I only want that fire passes from point A to point B without error. I agree there is something like acceleration in my quickmatches. The beginning of the quickmatch burns a little slowly, then suddenly accelerates. This problem occured when I was using single stranded QM, but when I started to make double stranded, the speed increased very much.