I'm very new to these forums, and the concept of casting in general.

I want to melt and cast an everyday brass house/apartment key.

Short story behind this is that my EX girlfriend and I broke up a some time ago, and the key I have is the copy I made her give back. Her birthday is coming up, and I would like to give the key back, but she wont know its the key due to it being melted down into an entirely new form.

Obviously giving the copy of the key back so she can let herself in my apartment again is not my goal, as I intend on staying broken up... but sentimentality is the keyword. It will be a whole other new charm, and the idea is for it to be a simple peace offering.

Also, I am reading up on the forums for what I need, as I am sure that will be suggested.

My findings are that brass is pretty dangerous when melted due to zinc. Also, I would most likely need a "small" crucible. Could I make my own crucible easily? Or would it be best to buy one? Where could I buy such a thing locally? Should I be overly concerned about the fumes given the size of what is being melted down?

Due to the key's small size, I'm assuming making a simple cast out of ceramic or plasture would work... but I would certainly like an expert opinion on the quickest and safest way to go about all of this.

Get yourself a soft fire brick and dig out a shallow depression in it. Put the key in the depression and heat it with a torch until it melts into a puddle. Now you can forge it into whatever you like. You will need to heat and quench in water every so often to soften the brass during forging or it will crack.

My advice is to move on and keep the key as a spare.

So, carve the depression into a brick (preferably a fire brick?), and melt key over depression? Should I also enclose the key with additional firebricks to make a mini furnace?

As for moving, that will happen soon. I'm not doing this project to prevent anything or be spiteful. Simply put, her and I both are pretty artistic, and when she sees the charm's shape, and realizes what it is made of... she will be pretty moved. She will be quite impressed rather than annoyed. ;)

I'm no expert in foundry work but you have such a small amount of brass in a key that I think you will need to use centrifugal casting the way they make jewelry if you want to cast a charm. That's a pretty big enterprise for one charm.

On the other hand, if you want to make a small brass billet and and forge something out of it or perhaps cut out a charm with a jewelers saw then that is doable on a small scale.

Soft fire brick can be worked with ordinary woodworking tools like drills and gouges. You just scrape a depression in the brick and lay the key in it and melt it with a torch.

Here is a video showing simple centrifugal castin.

Here is another method.
http://www.youtube.com/watch?feature=endscreen&NR=1&v=v8Td2c3-0tI

Thank you for the information. Just a few more questions.

All I need for the small amount of brass is a fire brick with the indention in it that forms my design? Centrifugal is optional? I'm not aiming for the brass design to turn out magnificant, just identifiable. Also, should I worry about zinc fumes at all if I am outside? I imagine that such a small amount of brass wouldnt emit mass amounts of harmful fumes.

You should always do this type of work in a well ventilated area but I don't think you have much to worry about melting a key. If you use the brick as a mold the casting will be rough. You can use plaster for a mold if you first make a positive but you need to dry out the mold in an oven to be sure that all the moisture is driven out before you pour in molten metal. You should also use safety equipment such as a face shield and aprion and gloves.

Roger that. I think I will be ready to attempt this project tomorrow. As you say, fire brick as a mold would possibly look rough because it has pores im assuming. Any suggestions on what kind of plaster to use? Everyday water based plasture would suffice once completely dried out?

Carved in soapstone (Marking out chalk used by fabricators, welders, and blacksmiths) would also work, any moisture is a definite NO NO

You don't need to worry much about zinc oxide fumes if you don't overheat the melt. You'll know it's overheated by the blue flame and feathery blue/white smoke. Leave in a cross wind direction and you're fine, provided you are NOT alergic to the stuff.

What I'd do is hit the local store and buy a key blank. same basic pattern and use my needle files to file out something for the X.

That's just me though.

Frosty The Lucky

FWIW, something as small as a key you may have a lot of loss due to dross, oxidation, etc. You also have to factor in the extra metal for the sprue and gating. I'm going to kind of go with Frosty, you are going to need some extra, find a couple of old keys that you aren't using anymore, or buy a couple of extra blanks at the hardware store for some extra. Your original key will still be in the mix so it can still be said that you made it from "that" key. Go to www.alloyavenue.com and search "Steam Casting". It's a pretty simple technique and for small pieces like that it's pretty easy to do. Also a nice thing about that technique is that you need a minimum of equipment.