Cast Tin!

 I got an order for some tin cubes. I found that there wasn't an instructable for casting tin, so I recorded my steps and went through it for you all to see. 

Why tin? Tin melts very low in temperature. Basically, the lowest melting point of any useful, non-toxic metal(*). It melts around 500 degrees, is very castable, and looks brilliant. There's only one real good reason not to use it: it's relatively expensive. I got mine from Rotometals in San Leandro for around $10/lb. Its density is similar to lead. 




(*) Tin may cause some illnesses, this is debated. work it as if it does. Do your own research. 

Step 1 Safety!

 Molten metal can f- you up.  Cover yourself compleatly. Liquid metal likes to "jump" when it cools. Think of how fryer oil works, except replace "ouch" burns with "I hope you get to the hospital before you die of shock."

Long story: 

 Tin is cooler than basically any other metal you'll ever work with, that means that if you screw up, you'll probably survive and have to deal with the hospital, burn wards, grievous scars, and potentially being disfigured or crippled for the rest of your life. Always have full face protection, arm and body protection that buttons at the neck, and closed toe shoes. 

Respirator might not be a bad idea either, as who knows what those stray 1 or 2 percent are in the 98-99% pure Tin. I suggest doing things outside. 

Pretty much, dress like you're welding, only with a clear visor. Check out my fashion statement picture for an idea. Do any of this at your own risk, perform your own safety assessments. Only you are responsible for the consequences of your actions. 

Comments

[ASTMB339]

For what its worth -- I buy my tin from www.metalshipper.com. They're cheaper than roto metals and sell tin "shot" which is like little bb's that melt easily and make it easier to add the right amount tin you require.

[ASTMB339]

For what its worth, I bought my tin online from www.metalshipper.com. They seemed to be a little cheaper than Roto Metals and the quality of tin was good (came with a certificate of analysis). I also use a tin "shot" that makes it easier to melt and add to the pots then bars.

[Father Christmas]

Ya know, I have never once had an issue with plaster molds. (other than the one time use problem) 

Well, I change that. I didn't completely melt the wax out of the mold and then kaboom-fizzle-burn  but that is about it. I still use plaster for casting tin.

[atombomb1945]

I am just going to borrow a quote here " With mine, it goes like this. pouring is easy, pouring is uneventful, hey, is it boiling a little in there... Holy splatter, batman!"

That boiling is the release of water that is still in the mold.  Fine if you are using time because of the low melting point.  If you were to have applied this to lead or a lead tin mixture, you would have had a small explosion and would have been nursing burns from 550 degree to 650 degree molten metal. 

I would highly recommend either the use of pre-formed molds from a hobby shop or the use of casting sands for custom molds.  If one were to use plaster for a casting job, it would be a good idea to fire it in a small kiln rather than an oven.  Better yet, get a DIY Silicon mold kit that can take the high temps and be used repeatedly.

Good points on the safety equipment.  Would recommend adding an exhaust fan or opening the garage door for the fumes. 

[HarveyH44]

I use to cast pewter (lead/tin mostly), and this is scary.  Concrete and Plaster of Paris retain moisture, which is released violently when you pour hot metal into it.  Tin by itself is kind of brittle.  I started with a cast iron pot on the kitchen stove, but eventually bought a melting pot.  Not sure how well stainless steel holds up over time, usually kind of thin.

[seraphus]

 Thanks for your input. Really. 

For my molds, I heated the plaster for 3 hours at 400 degrees to reduce the odds of it cracking and spewing everywhere. Dangerous, I know, but I was using what I had. I've edited the mold section to reflect the danger of plaster molds.

 I'm going to change some wording about my pot. Could you look through and see if anything in particular needs changing? If it is horribly wrong all over, just tell me, and I'll take it down, under the condition that you do an instructable over casting.