Use Flux for Al. Keep Oxygen out of the hot metal. It will become
a sponge of tiny holes.

Float Al Flux over the pour and in the pour bucket as well.

Be sure to use the correct flux.

Martin

On 8/31/2017 10:30 PM, Bob La Londe wrote:
"Terry Coombs"Â* wrote in message news
On 8/31/2017 8:37 PM, Ed Huntress wrote:
On Thu, 31 Aug 2017 16:04:36 -0700, "Bob La Londe"
wrote:

I 've been saving all my 6061-T6 scraps for ages.Â* I was planning to
do some
casting with it, but now that I am getting close I find that 6061 -
T6 is
reported to be not very good for casting.Â* I wasn't planning to make
structural parts out of it or anything, but is there anything I can
do with
the stuff other than sell it to the recycler for pennies on the pound?

Seems like it has to be formed at pressure and temperature to be of much
use.
I've never tried it, but it's supposed to be a fairly good casting
material.Â* Why don't you just give it a try?

BTW, the T6 temper has nothing to do with it. Long before you reach
melting temperature, the temper is gone and it's indistinguishable
from annealed 6061.

Â* For a pure 6061 casting to be reasonably machinable it needs to be
chilled as soon as it comes out of the mold and then aged for a while or
it's gummy and smears . Aluminum that was cast originally will machine
easier right out of the mold but also is harder on (HSS) tooling .

**************

Terry,

I was thinking of pouring thick (1-2") bars and rough round stock for
machining for non critical parts.Â* The one video I found that claimed to
be casting stock like that from 6061 (thick bars) for machining was
cooling a steel mold in a kiddy pool filled with water with an anvil in
it for additional heat sinking.Â* Seemed like as soon as it was hard
enough to not run out of the mold it went into the pool and boiled off
water for a while. I wonder if a super quench solution would cool it
down faster, and if it would be a good idea. They had half a dozen
bricks cast that you could see at the end of their video, and they
looked decent.

Another technique I've read about with fair test results in 6061 seems
to be doing something similar.Â* Its called ablation molding where they
use a sand mold (or other easily dissolved away mold, and start jetting
it away with water when its right at the cusp of going from liquid to
solid.

Yeah, Ed.

I was aware the T6 was a designation of its hardening process.