Found Dreaming

I gave the Cannon Contest a Nudge.
(I have posted this on the AA forum. I wanted to put it here too so that anyone can see it)

I started by gluing and doweling some Kauri together with paper in between it (This helps for easy parting later). It was bulked down to a rough size with my little wood lathe.

The cannon is 500mm (Approx 19.5”) over all by 80mm dia. (Approx 3”) at the widest point.
I added some “Safety Straps” to the blank because it was starting to Part Company, long before I wanted it to.

Starting to get the basic shape.

The details where marked using a profile pattern. As you can see I maxed out the lathe.

Close up of one of the details.

After all of the detailing and sanding, I crossed drilled the hole for the trunnions and the core print. The trunnion and core print where made in the same manner as the barrel (two bits glued together).The trunnions are 20mm (0.78”) and the core print is 16mm (Approx 5/8”).

The pattern was then split and the paper cleaned off to get it ready for painting.

The finished pattern ready for painting.

After a quick coat of paint.

It’s off to the sand box for a proof of concept pour in Aluminium.
Rammed up. I plan on pouring this one vertical. I have marked out where the runner will be.

I poured the Aluminium concept cannon with boards on the side of the flask to keep the sand in place once it had the pressure of the metal on it.
After the pour, with the boards removed.

The core for this cannon is a baked sand core, I used an Aluminium tube as a form and re enforced the core with a thin tube with holes drilled along its length. (I forgot to take a Pic. of the core)
The shake out.

I got a bit of flash but it was quite thin and easy to break off.

That was a success!

Now it is time to try it in Bronze

Hey nudge thats cool. Are the Nzed authorities like the Aussie authorities when you start making things such as a cannon , I myself hope to make a cannon one day and use my son-inlaws property as a firing range

Mike

Yup
It is not a cannon at all...... it just looks like one
I wont be cleaning up the bore for that reason

Nudge wrote:Yup
It is not a cannon at all...... it just looks like one
I wont be cleaning up the bore for that reason

Oh bugger

Nudge, one thing I just noticed you poured that proof of concept in Aluminum, You didn't have any boards on the sides to keep the sand frrom blowing out from the weight of the metal.
I would get me a couple planks, and if nothing else some heavy wire and put them on the sides when you stand it up the next time you pour to keep it from maybe getting all over your toes. It also may help with the flash.

DAllen

dallen wrote:Nudge, one thing I just noticed you poured that proof of concept in Aluminum, You didn't have any boards on the sides to keep the sand frrom blowing out from the weight of the metal.
I would get me a couple planks, and if nothing else some heavy wire and put them on the sides when you stand it up the next time you pour to keep it from maybe getting all over your toes. It also may help with the flash.

DAllen

UMMMM yes he did
Mike

Nudge wrote:

I poured the Aluminium concept cannon with boards on the side of the flask to keep the sand in place once it had the pressure of the metal on it.
he core for this cannon is a baked sanAfter the pour, with the boards removed.



)

Had a go at casting the cannon in bronze.
It didn't look too bad... until I started to clean it up.

Have a look for yourself.
I don't think I need to say too much more
The bob should have been at the top of the casting... not at the bottom, that way the casting wont feed the bob
When I first did the shake out I thought it was a winner, I guess not
I guess I will have to have another go

too get the bob into the top of your flask your going to have to make a new one that will be taller, what I have read says the bob will be needing to be 1.4 of the volume of the barrel for it to be effective. the problem lies in the core support, how are you going to be able to take care of that.

as you are not be able to fire the cannon from what I saw written in an earlier post, could you not use chaplets made of brass or even and iron support, which from the book that I read is surely accurate to the process to support the core at the breach to hold it in position lengthwise in the barrel then all you would need at the top would be sideways stability.

DA

1.4 is a good number, but it is not the volume of the entire barrel, but rather the volume of the shrinkage. I would move an open riser to the top of the casting, the barrel end, after the mold is full, add molten metal directly into the riser top, promoting directional solidification. if you are pushing near to the metal melting capability of your furnace, the sprue could probably be smaller

HT1

That is going to look great Nudge, impressive size to it too.