Re: [CAD_CAM_EDM_DRO] Re: Small Injection molding unit?

What kind of charcoal did you use in the furnace?
I tried melting some aluminum using charcoal briquets and had small aluminum
ingots (poured into cast iron cupcake pans in an earlier pour) piled in a
coffee can. Ran the damn thing for an hour and the aluminum never diod
melt.

I fire up my ceramic wool lined furnace, put the ingots in a silicon carbide
pot or a welded steel pot and get melted aluminum in about ten minutes!
BTW...a ceramic wool lined furnace will get up to operating temperature much
faster than a fireclay lined furnace. It alos cools down faster for storage
when your done using it.

I use my shop shop vac for the blower on all my furnaces. All you need to
do to regulate the air flow is connect a house light dimmer switch between
the vac and the power source.

Thanks for the tips on the injection machine. I'll have to get a set of
plans and see what I can do to improve the design and get it to work well
for wax injection. There's an anti-stick spray you can buy to use on the
inside of the molds before injecting the wax. The foundry in Montana uses
the stuff.

There's a better way of melting aluminum cans...but I wouldn't recommend it
for your area...the smoke would drive the neighbors...and probably the fire
department...crazy! You need a big trunnion mouonted furnace for melting
those cans.

Smoke

>I finally got some time to play so I fired up the injection molder
>and started chunking in pieces of candle wax. Melting the wax was no
>problem at all. I lowered the piston to see what it was like pushing
>it out without a mold in place. I had some leakage from the piston
>until I had pushed the remaining plastic out from the last time I
>used the machine. Once that was clear the leak stopped.
>
>I put my mold in place and tried filling it. The machine has plenty
>of leverage for pushing the wax around. I almost got hit by a stream
>of hot wax shooting out the relief port of the mold. Never had that
>problem with plastic.
>
>I popped the mold into the fridge for a couple minutes to cool the
>wax and then pulled it apart. The wax had filled the mold but I
>wasn't able to pop the pieces out like I normally do with the
>plastic. The wax just crumbled when I tried ejecting it from the
>mold. That's more a problem with the mold design than a short coming
>of the injection molder.
>
>I think the machine will do what you want to do with wax. My machine
>is probably way over powered in terms of heaters. One change I'd
>suggest is adding some moveable shields around the heater nozzle /
>mold area. That hot wax really shoots out under preasure and a
>shield might save you from a burn.
>
>
>I also played with my Gingery charcoal furnace today. When I've used
>it before I've had problems with the blower and the cruciable. I've
>found the perfect setup now. For the blower I'm now using a Wagner
>heat gun for removing paint. Gingery had suggested using a blow dryer
>so this is a close fit and a little beefier design better able to
>handle running a long time during melts.
>
>For the cruciable I found a 4 1/2 inch cast iron melting pot at the
>new Bass Pro shop in town. It fits perfectly and the combination of
>the new cruciable and blower worked so well that I don't have any
>scrap aluminum now. I melted everything I had and turned it into 10
>clean aluminum bisquits (that bisquit tin will never be the same).
>Most of that scrap was swarf I and a friend had saved along with some
>other larger bits and pieces. After I melted down all the good stuff
>I tried a couple of soda cans just to see how they'd worked. Man, you
>got to be pretty hard up for aluminum to go that route.
>
>Dan Eaton (Saint Louis)
>
>
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