22 replies to this topic

[StevenRS]

I need to make some salute cannons (signal mortars, whatever, just a cannon that shoots a Bp blank with a lot of noise and smoke) for a civil war reenactment , and I need some help. Aesthetics are not important. I was wondering what the best size charge size would be, barrel thickness, length, and some good ignition methods.
I already have a rack of 6 1" galvanized steel tubes with caps for a volley gun, but the thing scares me, I don't know how much pressure they can take, and I really don't want flying metal everwhere. Any help would be appreciated, Thx.

[Caramanos2000]

I think they will hold several thousand psi at best. Probably operates aroung 600 to 800 psi. I believe they should hold, if not you could talk to the guy at pyrocreations since he makes something like that.

[StevenRS]

I was able to get a hydraulic cylinder for a larger cannon, 1 3/4" bore, 1.5 cm walls, I'm guessing 10,000 psi would be about right, possibly more? (the thing is huge )

[Caramanos2000]

Tale a look over at powerlabs as they also used on of those with great results.

[paul]

I was able to get a hydraulic cylinder for a larger cannon, 1 3/4" bore, 1.5 cm walls, I'm guessing 10,000 psi would be about right, possibly more? (the thing is huge )

Haha, 1.5cm walls?! Thats pretty damn thick. I got a paper mortar which got 2cm thick walls (3" ID). I used a 50g black powder lift charge once. DAMN what a bang. With 1,5cm wals you don´t have to fear anything, using blackpowder.

[StevenRS]

Ok, cool. i got the cannons. How how bout ignition? I was thinking something along the lines of quickmatch, but electrical sounds promising, I just have VERY limited electrical supplies. Any ideas using just copper wire and steel wool?

The large cannons will be ignited one by one, and the smaller ones in volleys from 3 to 12.

[Caramanos2000]

Use nichrome wire with Bp and a few 9v and a switch from radioshack, total should be less than $20.

[StevenRS]

Use nichrome wire with Bp and a few 9v and a switch from radioshack, total should be less than $20.

Problem-- no nichrome wire. Would hobby shops sell it, or must it be ordered?

Could you use fine steel wool in place of nichrome wire? If you touch it to a 9V battery, it ignites.
I will be testing this later this weekend.

Edited by StevenRS, 07 April 2007 - 09:38 PM.

[pudi.dk]

I've used a lot of steel wool. I use a electrical ignition the disposeable flash camera method so it fire one quick snap rather than a slow one. Slow is better for nicrome and thick gauges, whereas my camera likes thin gauges better. I use thick steel wool strings, works good for me (a litte brittle), but havent tried with 9v.

[Caramanos2000]

Thats exactly what I was thinking of but along the lines of a model rocket ignitor. Dont know about the nichrome, I got a few hundred feet on ebay for $7.99 and free shipping. I tried doing it with steel wool but it wood ignite at the contact points not propagating enough to light visco or bp.

Edited by Caramanos2000, 08 April 2007 - 12:33 AM.

[StevenRS]

Ok, so it works. I will insure the points of contact are inside the Bp charge, along with the steel wool.
I will also try the model rocket ignitors for larger cannons, as i bet they will be more consistent.
When I fire them off, I will try to get a video, and post it here.

[Caramanos2000]

Amen to the video my friend!

[Caramanos2000]

I was thinking and why not just use hdpe? Cheap as hell and you know its safe.

[hst45]

Problem-- no nichrome wire. Would hobby shops sell it, or must it be ordered?

Could you use fine steel wool in place of nichrome wire? If you touch it to a 9V battery, it ignites.
I will be testing this later this weekend.

StevenRS, try bridge less igniters. I don't have the link handy, but Brainfever has a great tutorial on his site. These little gems are cheap, easy and 100% reliable with a 14.4V battery. They are basically twin-lead stranded copper (I use the smallest gauge speakerwire that Radio Shack sells), stripped approximately 1/4", dipped in NC lacquer, them dusted with graphite. In my experience thin NC lacquer works best, and the finer the graphite powder the more reliable. Do the dip-and-dust thing twice.

They have the advantage of being very thin so they can easily be inserted into a thin hole in the base of your mortar or cannon. Once they have been fired, cut off the last half inch and re-strip the end and you can recoat them and use them again.

[StevenRS]

Ok, thanks guys, those all are great ideas. I will defiantly use the bridgeless ignitors, those sound promising.

Where would one go to get the HDPE?

But one last question that refers to ignitors.
---for my smallest cannons, I need a electrical igniter that will fit in 1mm hole.---

Any ideas? The hole size cannot change.
I was thinking a very small bridgeless igniter, or a externally ingnited fuse.

Edited by StevenRS, 08 April 2007 - 09:05 PM.