Hey guys I made a video about casting aluminum and when I poured the molten metal into a mold I made, it started to bubble. Why does it do that?

 

 

How was the mold made and what materials were used to make the mold?  

Did you prefect the mold or pour into a cold mold?  

 

The mold is made from versa-bond, a tile mortar.

What does prefect mean?

How long between making the mold from a tile mortar and actually using the mold?

Preheat is to heat the mold to get it up to temperature before pouring molten hot metal into the mold. Did you clean the mold between pours?

Is there a reason you did not remove any of the slag from the top of the metal before you poured into the mold?

Okay, next time I will preheat. Yes I cleaned the mold. I'm super new to this and I want to start this as a hobby.

What ever you pour into MUST BE DRY, as in NO moisture. Steam explosions are very dangerous and can spray molten HOT metal everywhere. 

Personal protection equipment is a must. A plan B is necessary case anything happens. 

I suggest you read everything you can about the subject. There is a bunch of good and bad information out there and you need to figure out the difference. 

ok

 

THEN LEARN HOW TO DO IT RIGHT BEFORE POSTING HOW TO VIDEOS! (Might want to check up on your liability on this too.)    Can you change that title so you don't mislead other people wanting to do likewise?

Besides the off gassing of moisture from your mold material; it also bubbles as hot metals absorb gasses from the atmosphere and exhaust stream.  When you cast the the molten metal the last thing you need to do before pouring is to degass it.

For brass you usually use a flux to cover the metal, for copper and silver you may melt it under a cover of powdered real charcoal and stir with a DRY charcoal stick. Do a web search on Degassing Aluminum (I like the N2 degassing method; but most folks I know use the tablets)

You may want to read the forums at alloyavenue.com which is where the backyardmetalcasting.com moved to.  It's a series of forums dedicated to casting and a wealth of information. A web search on gingery aluminum foundry can turn up a lot of information too as Dave Gingery wrote a series of books on building a foundry and casting Aluminium to build machine tools.

Note that cast iron melts much lower than steel and so is NOT a safe crucible for Aluminium. Aluminium will dissolve steel over time too.  Getting a real crucible is greatly suggested.  Also look at your set up, it looks like you are getting too much oxygen in a localized area.

Finally you do know that not all Al alloys are good for casting?  Al alloys that are cast are generally the best for casting.  Old Al pistons are a good source of good Al. (aluminium cans are terrible!)

So much awesome info I love this site. Thank you so much for that advice.

There you go. Changed the title.

Things will go wrong it, is only a matter of time.  ALWAYS have personal protection equipment and a plan B.

Working HOT molten metals is a whole different level of dangerous.  If you are really interested in the proper way, take classes and learn the proper way to do things. It costs a little more up front, but is much less expensive than an injury, even a minor one. You should learn safety, how to safely go through the process, and how to safely make then the pour. 

 

Changing title ?  why not just remove it, and let real craftsmen make them, this is not funny, "how to" posting when your clueless? will get people hurt.  Look at me I dont know but I want to get noticed for telling you how while wearing  sneekers. ??  I am not going to apologise. any more moisture in that mold could have gotten you an explosion. You making things like this when you don't know anything is beyond reckless and irresponsible.

On Youtube it still is titled "How to Melt Aluminium". I thought you changed the title so as to not mislead anyone?

Head over to http://www.alloyavenue.com/vb/forum.php It's a site dedicated to backyard foundry. Lots of great info and peeps willing to help out. I'm pretty new to casting as well but from what I can tell from your video, looks like whatever you made your mold out of wasn't fully cured. You were getting steam bubbles and, as others have stated, that's pretty dangerous. Your container failing is common with using charcoal. Among other reasons, a blower and charcoal acts like a powerful abrasive and can quickly wear down material. It's why I switched over to propane.

Casting is dangerous but with some basic knowledge AND using common sense, can be done safely and relatively easily. 

Do your research, ask questions at Alloy Ave. Good luck, be safe and have fun!

 

Check out one of my more successful casting videos here - 

 

 

Ah it's not an abrasive, it's an oxidizer.

That's part of "Among other reason" in what I wrote. You'll be surprised how much charcoal dust and forced air will sand blast away material.

Oh my, it scares me watching that aluminum bubble and boil like that.  One "pop" and molten metal is spattered all over. Scary stuff.

I have had the same bubbling and am wondering what is causing it.  I dried my molds in my oven for hours (120 deg C), left them for a week.  Is it remaining moisture in the mold?  Aluminium too hot, wrong mold material?  I used fire mortar, the kind used in pizza ovens and also inside my forge.  Should I cure the mold at higher temps?  Any help would be gratly appreciated