Mortars

[toboggan]

Im not sure if there are posts in this forum about it or not, and i apologize in advanced if there is. But i want to make a mortar, or 2. How would i go by doing that.

[2ndranger]

I made a german lightweight mortar. It fired great, sorta like a big ol shotgun.

It was used at our June 15th yorkville event.

Franz

[toboggan]

But how did u make it?

[2ndranger]

PVC pipe and wood. I used a pvc splitter and cut that down so it would rest flat on the wood. Then I stuck a metal pipe I had laying around in the holder. The bottom has a screw placed in, so when you drop a moscart it ignites itself. It discharges as a giant shotgun.

Franz

[toboggan]

Well, i really appreciate the posts. But im looking for something that can fire those foam rounds that gunfighter is selling. I've never built one, and i know some people on here have. So i was just wondering, thank you again!

[Garrick Udet]

Look at Biged's mortar thread located here: ww2aa.proboards45.com/index.cgi?board=technical&action=display&thread=2526
I'm currently working on a similar project. Basically what you'll need are 5 basic components:
1. Air supply
2. Regulator (steps down the pressure from your air supply to what's needed to discharge the mortar)
3. Expansion chamber (holds the amount of air needed to discharge one shot)
4. Valve (this is the trigger mechanism, sprinkler valves work great)
5. Barrel(s) (obvious)

While this list is just the 5 main functional components, you'll need to get various pipe fittings to adapt the different pieces to one another.

Also, if your air source is CO2 and not compressed air, you will need to use metal parts rather than PVC, as CO2 can chill and shatter PVC even in warm weather if you're not careful.

This is how to build a barebones air cannon, the basic components are the same whether you're building a mortar, anti-tank cannon, bazooka or mounted vehicle cannon.

Obviously for a mortar you also have to build a base with adjustable elevation. The design of this is heavily dependent on how you build your mortar and how historically accurate you'd like it to be.

[gunfighters]

there are 15 different ways to skin a cat.. it all depends on your skills and wallet.

of note PVC should NEVER be used as an air chamber, if it is handled ruffly while under pressure it can fail...castrioftly

"I want to build a mortar" is like saying i want to build an airsoft gun sure you can cobble together some pipe fitting and a valve and get something that shoots a BB.. but It will not purr like an AEG or have the accuracy of a bolt gun unless you are a skilled builder

so lets narrow things down,
how are you build skills?
how much do you want to spend?
how rapid do you want it to shoot?
do you need a full T&E system?
how "period" does it have to be, and what impresstion.

now if you just want a tube that shoots stuff on the cheap
www.airsoftretreat.com/forums/index.php?topic=45630.0
next step would be to use the above as "shells" and drop down a bigger tube
beyond that its going to get pricey
however there is great performance to be had
ie
www.youtube.com/watch?v=FVaPVzxFj4k
you can see how a 2-3 man crew could lay down some hurt

[toboggan]

Ha, i really like that M1107, would you happen to have a way to build that, like directions or the such. I highly appreciate the posts as well!!

[Garrick Udet]

gunfighters

Nice links to the easy mortar. As you said there are multiple ways to go about this.

I decided to not use a 40mm shell as a propellant as I have numerous HPA tanks laying around from my paintball days. This gives me the ability to tinker with the size of the expansion chamber at different pressures to come up with my optimal setup. This will also allow me longer ranges and not having to mess around with refilling shells.

Each approach has its pros and cons.

Toboggan, I understand your desire for a set of instructions, but in my experience, you'll probably have to take an iterative approach with a good amount of trial and error to get to a finished product.

The good news is that it's winter and there's a lull in events right now.

[toboggan]

Haha, thank you again. And i do have some extra PVC laying around, that i might as well use up!

[gunfighters]

Jan 7, 2009 18:30:41 GMT -5 toboggan said:

Ha, i really like that M1107, would you happen to have a way to build that

yes, i might know a little bit about how it works...
you may have missed the fact it is manufactured by the same company that just started making WWII foam mortar rounds

as Garrick said its about a lot of time and work to tune things just right
I too used to be against "shell type" weapons, but with $25 china clone shells out there it does make sence to help fill the gap $$ for smaller units and level out game play

[2nd Bat]

Indriect fire weapons add a lot to events but do require skill to design and build. As mentioned earlier the pressures generated in an effective weapon are not to be triffled with and you absolutely have to make sure your materials can handle the stress over time. Plastics weaken over time from use and do weird things in severe weather. (Both hot and cold) A failure of materials could create a fatal disaster and I mean that literally.

[gunfighters]

yep..
however the "slip, trip, Boom" factor is the most prelivland..
2004 saw 4 reported cases of pvc guns blowing up on paint ball fields (many more not reported) IE these were injury claimes against the insurance
this lead most of the insurance companys to ban "homemade" launchers in 2005
here is a very lucky young man

to me PVC is the "devil" it lets people build really powerful and dangerous items that are offen beyond there understanding as they read the water pressure numbers and think they are just fine

edit
of note i have no issue with PVC barrels

[2nd Bat]

Excellent way to make my point. Typically weapons made using the mosscart type grenades are fine as the force and power is self contained in the shell itself and the PVS serves simply as the tube. When PVC is used for the expansion chamber you have potential for serious injury and damage. I'm sure there were far more than the four cases reported where home made mortars howitzers or bazookas blew up hurting someone.

[shadycadence]

Suppose the PVC chamber was contained within a steel tube? Would you consider that safe?

[toboggan]

Yeah, they make steel plumbing as well. You could use that as the accelerant tank, and then added weight for realism ; )
But gun fighter, maybe you could get me plans on that M1107?! lol

[gunfighters]

"Suppose the PVC chamber was contained within a steel tube? Would you consider that safe"

nope..
unless you caped the ends and what not...
there are ways to make PVC "better"
but if you are going to that kinda trouble you minds as well make a steel chamber

OSHA band the use of PVC for compressed gass in the 70's, for good reasoning www.osha.gov/dts/hib/hib_data/hib19880520.html
when it goes its goes big..
its fine with water because water doesn't compress so it just transfer engery..
air/co2 etc STORE engery..
crack in a water line it spurts,
same line with air and and boom

here is a gun coming apart do to the force of putting the barrel on
www.youtube.com/watch?v=AQo81nqx-W8
comming apart do to recoil when fired
www.youtube.com/watch?v=sfTHYUSAdPw
www.youtube.com/watch?v=ZZ78gE_4gsU
www.youtube.com/watch?v=01FnLjP5hWA
www.youtube.com/watch?v=XRuD8yFvqJs&feature=related
sice shot of the after efects
www.youtube.com/watch?v=waJDx57n2Jk&feature=related
shot with a .22 to show power of a failur
www.youtube.com/watch?v=Cal71EN5Gt8&feature=related
drop tests on full chambers
www.youtube.com/watch?v=VOPLA9JRNfY&feature=related
www.youtube.com/watch?v=WWVGNTh7sA8&feature=related


point made???

[2nd Bat]

If PVS simply serves as an outer housing for looks and your steel inerts are properly speced and assembled you're fine. Just don't use PVC for the expansion chamber or any component that is going to be asked to directly contain the pressure. It may work fine for numerous detonations and then suddenly fail and when it does...Yikes! Even a single CO2 cartridge is capable of producing 600 Psi.

[CharleyNovember]

use gas pipe for your expansion chamber, it is the only safe way. PVC is just not safe. Also be damned sure before you go off half cocked building one of these things.

[shadycadence]

Point made! My design has been updated.