Cannon cast by casting is fun

[castingisfun]

"welcome here castingisfun
please tell us what you are shooting
preferably with some photos
all here are very curious     at least I am   "

I'm in Virginia, USA.  I don't have the deep pocketbooks you all have, so I don't own a cannon except an 8.5" long aluminum reproduction of a 24 pounder on the constitution.  I cast it myself.  I also cast a few oddball tiny cannons out of aluminum.

[Zulu]

Was this barrel cast horizontally?  I can't figure it out.  It can't have been cast vertically can it?
Zulu

[castingisfun]

It was cast vertically, but my forms are made for horizontal use so I added a cheek to the cope that allowed me to turn it upright.  The right side of the previous picture is UP.  The following picture is in the orientation that it was cast.

[Soot]

I always wanted to do my own casting. I spent some time looking into it and it's not expensive at all.
Can you post some pics of your setup?

[cannonmn]

Cool.  If you can cast aluminum, I presume you could cast bronze also if you chose to do so?

[KABAR2]

What type of sand are you using in your flask?  is it commercial or home brew?

[BoomLover]

Nice work, try bronze....BoomLover

[GGaskill]

Bronze needs much higher temperatures to melt than does aluminum.

[castingisfun]

My furnace is simply a 20# propane cylinder that was cut open.  I lined it with portland cement/perlite in a 1:4 ratio by volume.  I dried it, then lined the cement with furnace cement (Rutland black furnace cement good to 2000 degrees Fahrenheit).  It has a vent on top, a torch hole tangentially, and a spill vent on the bottom.  I used wood and aluminum sheet to hold the form during construction.







It runs off of propane via a homemade burner.

The flasks are simple wooden creations.

As stated by Gaskill, aluminum melts around 1200 degrees F and bronze is about 1800 F.  I'm afraid my furnace cement/perlite might slump at that temp.

I'm using homemade greensand made from sand, bentonite clay, and water.  I use a homemade muller to season it.

[GGaskill]

In the Art Dep't bronze casting class, we used to take the crucible out of the furnace at about 2100° F.

[castingisfun]

2100F is WAY out of my league!

[dan610324]

if you start with a 55 gallon drum cut to the height of your wish and put in 2" rockwool + 2" kaewool + a thin plastic sheet of any kind
then you cast a 2" thick layer of a good refractory quality
then you got a furnace that can handle bronze without any problems
the upper part from the drum you can use as the lid , there you only need the rockwool and kaewool insulation
cut the drum 4" higher then you need , and cut 1" wide strips from the top and 4" down
when the 2 different insulations is in place you just fold down the strips to hold the insulation in place before the casting of the refractory
then use a large plastic bag or something similar first on the inside to separate the insulation from the refractory during the casting
same with the top of the drum , make it 4" higher then needed and cut it in strips , place the insulation there and fold the strips to hold the insulation in place
a 5" exhaust hole would probably be enough , but it depends a little on your burner
after a few runs you will probably need to replace the outer layer of kaewool in the lid , but its done in 5 min and the lid is easier to handle without any refractory in it
use a half inch sheet of kaewool as a gasket between the lid and the main furnace
if you make a basket of steel net you can place it over the exhaust and preheat  the metal if you need to fill up the crucible when the first have melted

[GGaskill]

How do you handle the bottom of the furnace?

Dan, how do YOU handle the bottom of the furnace?

[castingisfun]

The bottom was made first with the same portland/perlite mix.  I had the drain hole form made from wood bolted in place.  I then rammed excess material in the base around the drain and the whole floor of the furnace.  I made a template to sweep around the drain plug that left the proper contour in the cement.  The template can be seen in the photo with the sheet metal form.  It is the white little piece resting in the middle.  The 90 degree rabbit rests on the wooden drain plug edge as you sweep it around the plug to remove excess cement.  After the bottom of the furnace is complete, I cut two small troughs in it to feed spilled metal to the center drain. One is just barely visible on the final picture on the left of the "soup can" crucible I was using at first.  I now use the cast iron pot pictured.  I coated the pot with "kiln wash" that I bought for nothing at a clay shop.  Just after the base of the furnace firmed up a little, I set the sheet metal forms in, filled them with loose sand for backing, then rammed the outside with cement/perlite.

[dan610324]

same as the walls
first rockwool then kaewool
some plastic bags or similar at the inside before you pour the refractory in it
today with the experiance from it I would add some stainless steel fibers to the refractory
they will help to reduce the cracking of the refractory from being hot cold hot cold and so on

first you put in the 2 different insulations and plastic
then you put in a center piece the same shape as your wished cavity
pour the refractory and use a good vibrator to get all the air out and get a homogeneous refractory casting
the wooden center piece should be slightly conical and oiled to make it easier to pull it out after the refractory is hard enough
so here you cast the complete inner refractory in one piece

sorry
forgot to say that you of course need the hole for the burner also
thats a wood dowel shaped to fit against the center piece