Author Topic: How to blow up a cannon (Read 9461 times)

armorer77 · « **Reply #90 on:** October 17, 2009, 01:56:58 AM »

While reviewing Knight's Mechanical Dictionary of 1876 . I found a chart for Gun Metal alloys
Common formula is Copper 9 Tin 1 Sterling's [English] Copper 50 Zinc 25 Iron 1-8 Navy [Austrian ] Copper 60 Zinc 38.12 Iron 1.8
So using Zinc was acceptable in the past . Armorer77

GGaskill · « **Reply #91 on:** October 17, 2009, 09:04:32 AM »

I don't know the exact alloy the Art Department bought so I can't speak to that beyond saying it is silicon bronze. I always poured the mountain howitzers breech down in a vertical mould so the breech end has quite a bit of metal above it and has not seemed to have a lot of porosity. The horizontal moulds I've done were always worse in this matter.

Check out the thread One of my half scale mountain howitzers for more info on its casting.

dan610324 · « **Reply #92 on:** October 17, 2009, 10:29:35 AM »

anything before now is considered as in the past for some people,
1876 , well for me thats modern or at least semi modern stuff

yes there is a reason to why all original pieces was cast standing , and thats the quality of the casting
if its cast standing muzzle up without a core you probably got most of the impurities, slag and porosities in the shrinking head (feeder)

with todays chemicals as flux , degasing and desoxidation you can have an almost perfect casting .
if you add an ceramic foam filter and have an perfectly controlled temperature for your alloy you cant get it much better without having some very complex equipment

next step would be to flush the mold with argon gas just before and during the pour
but the question is where to draw the line between good quality and insanity

or vaccum casting
centrifugal casting
the posibilities is endless if you want to spend a million dollars or so

but are we talking cannons or some very critical parts for nasa ??

silicone bronze is an extremely nice alloy to cast , but Im not sure how suitable it is as an gun alloy
Im sure someone here could check it up for us

GGaskill · « **Reply #93 on:** October 17, 2009, 12:58:36 PM »

I would have liked to have known about the ceramic filters when I was casting these guns.

dan610324 · « **Reply #94 on:** October 17, 2009, 02:39:44 PM »

google : foseco ceramic foam filters
or check this http://www.foseco.com.tr/tr/downloads/FoundryPractice/238-01_First_for_Filtration_the_Foseco_story.pdf

there you got some info on them for your next project

they also got the following products:

flux cuprex standard, for all copper based alloys

logas 50 to get rid of the hydrogen in the metal

deox ds , its used for the desoxidation process to help slag and other impurities to float up to the surface easier, but thats not neccessary if you use the filters as they catch all small impurities

but even if you use them all you should be very careful to skim all visible slag before you pour

GGaskill · « **Reply #95 on:** October 17, 2009, 02:59:00 PM »

We always skimmed but I was not convinced that was all that could have been done. The filters would have been a good addition.

dan610324 · « **Reply #96 on:** October 17, 2009, 03:17:27 PM »

yes the filters are very good
if you prepare the molten metal as careful as you can with the 3 chemicals first,
then such an small filter as 2" X 2" x 1/2" CAN FILTER 90 LBS OF LIQUID BRONZE
it will probably filter much more , but thats what I was told from an foseco sales man

armorer77 · « **Reply #97 on:** October 17, 2009, 11:45:23 PM »

Back to the subject of accuracy , I shot a dozen shots yesterday , it is deer season and my renters & hunters came over so I quit with a 3 shot group at 100 yds . that was 18" for 3 shots . Windage was dead on but I was stringing them up & down . Armorer77

Victor3 · « **Reply #98 on:** October 18, 2009, 02:30:18 AM »

That's outstanding accuracy for a stubby smoothbore with a 1# ball. What was the charge?

I can't hardly do as well with my stock 1911 at that distance.

armorer77 · « **Reply #99 on:** October 18, 2009, 04:20:07 AM »

My charge is 475 grs. of 1Fg Armorer77

armorer77 · « **Reply #100 on:** January 12, 2010, 05:21:40 AM »

I am bringing this post back up for 2 reasons . 1. I want the new guys to see it and 2. I had a virus that required the total wipe of my computer . The movies didn't come up but can still be viewed on youtube by searching Armorer77 . Those I am currently dealing with , when your money arrives , I will ship . Thank you . Armorer77

Cannoneer · « **Reply #101 on:** January 12, 2010, 06:38:53 AM »

Armorer77,

I'm sorry to read about the virus, this is a very interesting thread; at least the vids still exist on Y-tube.
If you've ever got some time on your hands, and you felt the inclination to do so, you could match up the vids that still exist on YouTube with the posts they were originally attached to, and imbed them on those posts.

Smokey Diesel · « **Reply #102 on:** September 10, 2011, 01:43:51 PM »

*nevermind

*

Smokey Diesel · « **Reply #103 on:** September 10, 2011, 01:47:28 PM »

*nevermind

*

Double D · « **Reply #104 on:** September 10, 2011, 04:05:45 PM »

Quote from: Smokey Diesel on September 10, 2011, 01:43:51 PM

http://www.youtube.com/watch?v=SJDCAWuAcr0
MODERATOR NOTE: do not watch this video if you are language sensitive.

Read description for mortar specs.

http://www.youtube.com/watch?v=zSR35L8BMEg

Same mortar but GOEX instead of Pyrodex.

Some very serious and dangerous over loads.

dittles · « **Reply #105 on:** September 10, 2011, 05:20:12 PM »

Don't worry Double D, that pickup bed will block any shrapnel! I found myself ducking and I was behind my monitor

.

Double D · « **Reply #106 on:** September 10, 2011, 05:23:00 PM »

Here is my thought on that. If you feel you must hide from your cannon why are you shooting it.

Smokey Diesel · « **Reply #107 on:** September 11, 2011, 12:48:06 AM »

Double D · « **Reply #108 on:** September 11, 2011, 04:30:17 AM »

We promote safe cannon firing here. We also understand proofing. We also understand the increased strength of 4140.

There in lies the problem. we understand, but not every one does. That is why we point out safety issues when we see them. We defend our hobby as unsafe acts like this make us all look bad.

What you don't seem to understand about this thread, is that is about a destructive test, an attempt to stress the cannon to the make it fail if possible. Ed controlled the test. He planned for the failure of the gun at every shot. He took safety precautions. It's a testament the strength of guns he builds.

It is not a bunch of good old boys out to make a bunch of noise.

You have a pretty neat looking gun and you can have a lot of fun with it, but do it safely. Look at our safe loads post and learn how to determine what is the correct maximum safe load is for your gun. For example the maximum safe load for your 1 1/4 bore is about 300 grains of Fg. Patching is never recommend it raises pressures.

With such massive loads I have to ask if you know where the golf balls are landing, have you seen them land, have you even found one yet.

Big bangs are fun, but its even more fun to watch the ball fly and see it land, or even better hit a target you aim at. Order up some steel or Zinc golf balls from one of the Group buys set up in the cannon classifieds. Shoot them with out a patch and elevate you fun level.

armorer77 · « **Reply #109 on:** May 23, 2012, 09:32:20 AM »

I have been looking for a reason to bring this back to the top and here it is . These videos show the strength of welded trunnions .
Double D , thanks for getting rid of that guy with the mortar . Ed

Double D · « **Reply #110 on:** May 23, 2012, 01:49:54 PM »

That's back in my old meek and mild Moderator days when I expressed concern about safety...