Metal Casting Zone

Well I have been looking to cast metals for many years now and I figured I had better start before I get too old. Anyways I built a DIY CNC router and I would like to build parts out of blue foam with the CNC machine and then invest the design into some sand and of course pour molten metal in/on it.
I have ordered an A10 silicon-carbide crucible as this states it will hold up to 7 lbs of aluminum. So based on the size of the crucible I made a quick design of my proposed furnace. It is to be 15" high and 15" diameter, the lining will be 2.5" thick. The refractory mix I plan on attempting to make will be as follows:
Fire Clay 40%
Silica Sand 40%
Alumina 13%
Borax 7%
I hope this sounds like it should work.
The burner will be a typical propane pipe type burner and of course I will need to make some lifting tongs, pouring handle, dross spoon and charging tongs. I have alot to do and I am sure I will be asking many questions, so thanks ahead of time.
DT (Tom)

PS how do you attach more than 1 photo at a time? Well this is pic 1 of 3

pic 2 of 3

pic 3 of 3

Looks good so far Tom, just make sure you have some kind of lig lifter on it to keep you fingers cool and make life easy on you.

Welcome, looks like you have a good start, sizing the furnace to the crucible is a good idea. And remember, it's not the size of your furnace, it's how hot you get the metal...

Thanks for the comments, I have not put any details on the furnace yet and yes I will make some type of lid lifter as I do value the use of my fingers.
DT

Welcome to the forum!

I use Photobucket. I upload the pictures in forum size so they aren't too big, and just copy and paste the link.
Do you have photos of your CNC and are you on any of the CNC forums? I still working on mine. It's been over a year but I'm making slow progress.

Jammer,
Sorry for the delay I had a very busy weekend.
Yes I am on the CNCZone.com forum under the woodworking DIY-CNC table router JGRO area.
JGRO is the user name of the guy who designed the machine and offered the plans free online.
I modified the base and a few other little odds and ends, but for the most part it is the JGRO design. The picture below is a little older and some things have changed like I added some hold down clamps and attached my dust collector to the router. I have other mods lurking in the depths of the old mind to increase my speed.
DT (Tom)

Oops, the pic is too big, let me adjust then I will repost.
Let's try this.

Yes, I did a quick search last week and found you on there. Nice looking machine, I keep pluggin away at mine.

A few questions regarding my furnace design;
Should I put a drain hole in the bottom? and,
should I use some plinth blocks to set the crucible upon?
Any thoughts are appreciated, thank you.
DT