Casting Alluminium the myths and facts....
I Have often seen on many outboard forums about how bad the Lost Foam casting process is v the other types including
Sand-Casting , Die-Casting and Perma Mold.
Far too many myths going around about Lost Foam being inferior to other molding types.
it realy is just another one of those things about " it was better in the old days" well it actually was not.
Is Lost foam cheaper when doing mass production work ? NO
Is it is cheaper if doing very short run of say 20 to 50 ? possibly YES
As for being a more porous and weaker casting then it is actually the die casting that is the weakest process for casting aluminium.
There will be some die hards who will not be able to take that in as they believe lost foam is the bad boy because they got told it.
They have obviously never realy looked into the complete process of casting and found out what strengths certain types of casting have.
Just because so and so down the road who makes a few parts says his old school way is best, the myth grows and grows.
It is just like " the old cars were far better than the new ones" yeah I suppose those new ones that do 5 times the mileage and dont
rust away inside 5 years are crap. and those new cars are definitely not as strong, except drivers and passengers walk away from
30mph accidents totally unmarked 99% of the time, unlike back when the cars fell to bits and killed everyone in the car..
We like to think old fashioned stuff was better all the time, well that is not true, some things were infact realy bad, but our memory is
often shrouded by silver clouds and rose tinted glasses.
Here is a small passage from the link at the bottom, there are graphs too in the link showing many things about casting.
"Permanent mold has demonstrated the best internal metal soundness. The Lost Foam process has smooth
metal flow characteristics resulting in less gas entrapment during pouring and producing results comparable
to Permanent Mold.
The lack of cores or sand bonding media in the Lost Foam process eliminates gas absorption from the mold during solidification.
By contrast, die castings are noted for air and gas entrapment and can be expected to demonstrate the most porous metal characteristics."
a good bit about the aluminium casting can be found here, it will open a few eyes and cause many to understand a bit more about why
many companies use lost foam and not for it being cheap, far from it...
http://www.lostfoam.com/assets/conte...numcasting.pdf
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