36465Re: lost foam core problems
- Aug 1, 2006Kerry,
It looks like your core failed because the walls of your gypsum
heated, broke through and metal filled the void. I think you have a
of options. (A)Cast the piece solid and machine the void or (B)use a
core piece such as wood, steel, or resin bond sand to fill that
space. Something needs to be there to provide more insulation between
your side walls. Just my opinion, I'm sure others will have theirs.
--- In firstname.lastname@example.org, "lord_kerry" <lord_kerry@...> wrote:
> Ok, did my first casting to a lostfoam pattern saturday.
> Cut out the foam, glued it together with low temp hot glue, pasted
> over with a pancake batter thick slurry of drywall joint compound,
> it dry for a day, cut off the top of the sprue and put the pattern
> a barrel of dry sand using the air from bottom method, jogged the
> to make sure it was well settled, put a head preassure pipe above
> sprue, heated my aluminum, skimmed the dross, poured into head
> preassure pipe, as it smoked and bubled I added more alluminum
> the pipe full. Let it cool and pulled the part from the sand rinsed.
> If you look in the photo file Kerry's Castings you will see that
> outside looks beautiful, my problem is the core, (which is
> the area I was most concerned with for this piece) any thoughts,
> Ideas, opinions?
> Help please
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