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I started with aluminum molds, never used a rest, and all was fine. Then I got a brass 4 cav and suddenly it felt heavy. Still used it fine. Made myself a rest, but I'm left wondering why makers don't lighten the molds with holes to make them easier to use?
Would change how they hold heat. Not saying it wouldn't work. Just that it would change how they cast. Not using a rest is something I never understood. It falls under work smarter, not harder.
well, I felt like the rest was making it harder. Do you keep the mold level to the table when using the rest? I feel like tilting the mold slightly down away from me is better for controlling the sprue.Quote:
Originally Posted by dragon813gt
But regardless of the rest, you still gotta lift the mold and shake it every time it gets full so it's in your hand most of the time anyway.
http://i198.photobucket.com/albums/a...0FD78ECA49.jpg
I don't use the cheap ones that come w/ the pot. This is an old pic. I have a piece of plywood that's the entire width between the posts. The plywood is level.
W/ a brass mold I cast at a relaxed pace. It's sitting down more than it's in my hands. Having everything at the correct height is the most important part of using a rest properly.
I wouldn't lighten it with holes.
metal expands and contracts when it heats and cools.
imagine 5 more holes in the mold all expanding and contracting as the temperature varies.
I use a little sheet metal covered box under my pot, instead of a mold guide.
I drag and fill [consistent grip on the handles] then let go and count.
then pick the mold up and break the sprue while moving the mold down to the bench. [both hands on the mold]
return the sprue to the pot and knock open the mold.
close the mold [with both hands] while moving it back to the box again.
Holes or fins would affect expansion and also heat retention. the extra surface area from the holes or fins will bleed heat off faster. If the mould is heavy a balancer set up to offset weight may be a better option. A simple pulley mounted to the ceiling or a frame with a light cable or heavy string one end snap attached to the mould handles hinge pin. ( a small eye let could be drilled and tapped into it) and a counter weight on the other end, I have used a empty powder can with lead shot or old bullets in it to just slightly more than the mould. This counter acts the weight of the mould and handles, all your handling is the offset weight now.
What country gent said... make it lighter and it will lose heat faster. One of the main benefits of brass for mould material is the heat capacity so it remains a pretty constant temperature while casting.
If that isn't a concern, I am sure you could get someone to mill narrow slots in it to reduce weight. After all the slot for the mould handles is pretty substantial and doesn't affect mould performance by warping at that slot.
Alternately you could likely mill an even thickness off both sides, bottom and ends to reduce weight some without increasing surface area so you'd lose mass but not see a lot of heat dissipation like holes or fins would give.
Me, I'd just live with the weight. I hate to muck around (bubba) nice stuff.
The counterweight idea of country gent's is also viable without modifying the mould and in industry similar things are used to improve ergonomics:
https://www.ergonomicpartners.com/gorbel-g-force.aspx
Bigger than you need but gives you the idea.
Longbow
im cheap and lazy, i only use aluminum molds anymore.